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NOT I CE

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National Aeronautics and Space Administration Scientific and Technical Information Facility P.0. Box 33 College Park, Md. 20740

NASA C R - 7 2 6 9 7 A P S - 5 2 8 4 - R 2 4

FINAL REPORT

CONTROL S Y S T E N FOR T H E 2- TO 15-KWe

BRAYTON POWER SYSTEM

by

E n g i n e e r i n g S taf f

A I r n S E A R C H MANUFACTURING COMPANY O F ARIZONA (A D i v i s i o n of T h e G a r r e t t C o r p o r a t i o n )

4 0 2 S. 3 6 t h Street P h o e n i x , A r i z o n a 8 5 0 3 4

prepared f o r

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

A u g u s t 3 0 , 1 9 7 0

CONTRACT NAS 3 - 1 0 9 4 3

NASA L e w i s R e s e a r c h C e n t e r C l e v e l a n d , O h i o

R o n a l d L , T h o m a s , P r o j e c t M a n a g e r Space P o w e r S y s t e m s D i v i s i o n

TABLE CONTENTS Page

1-1 . . . . . . . . . . . . . . . . . . . . GENERAL DESCRIPTION

. . . . . . . . . . . . . . Control System Definition . . . . . . . . . . . Brayton Power System Description

. . . . . . . . Gas-Filled Power Conversion Loop . . . . . . . . . . . . . . Heat Rejection System . . . . . . . . . . . . . . Gas Management System . . . . . . . . . . . . . . Electrical Subsystem

. . . . . . . The Electrical Control Package . . . . . . . . . . . . . . DC Power Supply . . . . . . . . . . . . . . . Pump Inverters . . . . . . . . . . . . . . . . Heat Source

. . . . . . . . . . . . Control System Specifications

. . . . . . . . . . . . . . . Signal Conditioner . . . . . . . . . . . . Data Transmission System . . . . . . . . . . . . . . . . . . Control Panel . . . . . . . . . . . . . . . . Monitoring Panel

. . . . . . . . . . . . . . . . . . . . . DESIGN PROCEDURES

. . . . . . . . . . . . . . Reliability Considerations

. . . . . . . . . . Failure Mode Effects Analysis Redundancy . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . Design Criteria

. . . . . . . . . . . . . . . . . SIGNAL CONDITIONERDESIGN

. . . . . . . . . . . . . . . . . General Description . . . . . . . . . . . . . . . . Design Considerations

. . . . . . . . . . . . . . . . Conditioner Power . . . . . . . . . . . . . . IntegratedCircuitry . . . . . . Pressure and Temperature Environment . . . . . . . . . . . . Radiation Considerations

. . . . . . . . . . . . Effects of Radiation . . . . . . . . . . . . . . Gamma Radiation

. . . . . . . . . . . . . . . Five-Year Operation

Page i

TABLE OF COIITEMTS (CONTD)

Page

(Contd)

Analog Circuit Designs . . . . . . . . . . . . . . . . Low-Level Amplifier for Thermocouples . . . . . . Low-Level Amplifier for Shunts . . . . . . . . . AC to DC Conditioner . . . . . . . . . . . . . .

Test Results . . . . . . . . . . . . . . . . Conclusions . . . . . . . . . . . . . . . .

Three-Phase Power Measurement . . . . . . . . . . Frequency-to-DC Conversion . . . . . . . . . . . High-Level Buffer . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . Control Circuit Designs

Continuous Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Latching Driver

. . . . . . . . . . . Pulse Driver Ground Control Pulse Driver . Positive Control . . . . . . . . .

. . . . . . . . . . . . . Battery Charger Control . . . . . . . . . . . . . . . . . . . VRE Control

. . . . . . . . . . . . . Speed Control Override . . . . Engine-Mounted Emergency Shutdown System

. . . . . . . . . . . . POWER AND SIGNAL TRANSMISSION CABLE

. . . . . . . . . . . . . . . . . . Cable Descriptions

Connectors . . . . . . . . . . . . . . . . . . . Wire . . . . . . . . . . . . . . . . . . . . . .

Operational Environment . . . . . . . . . . . . . . . Temperature . . . . . . . . . . . . . . . . . . . Humidity . . . . . . . . . . . . . . . . . . . . SandandDust . . . . . . . . . . . Nuclear Radiation . . . . . . . . . . . . . . . . Electromagnetic Interference Shielding . . . . .

CONTROL CONSOLE . . . . . . . . . . . . . . . . . . . . . Human Engineering Considerations . ; . . . . . . . . .

Proposal Mock-up . . . . . . . . . . . . . . . TaskIMock-Up . . . . . . . . . . . . . . . . .

Page ii

TABLE OF CONTENTS (CONTD) Paae

. . . . . . . . . . . . Workplace Dimensions . . . . . Location of Controls and Displays Selection of Controls and Displays . . . . .

. . . . . . . . . Control Panel Mechanical Design

. . . . . . . . . . . . . . . . . . . . Design Criteria

. . . . . . . . . . . . . . . . General Derating . . . . . . . . . . General Design Considerations . . . . . . . Component Procurement Requirements . . . . . . . . . . . . . . . . . . . . . Testing

. . . . . . . . . . . . . . . . . Module Descriptions

StartModule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . StopModule . . . . . . . . . . . . . . . Liquid Loop Module . . . . . . . . . . . . . . Gas Inventory Module . . . . . . . . . . . Critical Parameters Module . . . . . . . . . . . . Emergency Shutdown Module . . . . . . . . . . . . . . . Gas Bearing Module . . . . . . . . . . . . . . . Heat Source Module . . . . . . . . . . . . . . Valve Control Module . . . . . . . . . . . . . . Electrical Control AC . . . . . . . . . . . . . . Electrical Control DC

. . . . . . . . . . . . . . . . . . . Monitoring Panel

. . . . . . . . . . . . . Functional Description . . . . . . . . . . . . . . . . . Metering System Alarmsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Supply

. . . . . . . . . . . . . . . . . . Calibration Tester . . . . . . . . . . . . . . . . . . . Special Circuits . . . . . . . . . . . . . . . . . . . . Power Supplies

. . . . . . . . . . . . . . . . . . . . . 6 . ACCEPTANCETESTS

. . . . . . . . . . . . . . . . . . . . . Requirements . . . . . . . . . . . . . . . . . . . . Load Simulator

. . . . . . . . . . . . . . . . . . . . Procedure . . . . . . . . . . . . . . . System No 1 Results

Page iii

TABLE OF CONTENTS (CONTD) Page

6 . (Con td )

. . . . . . . . . . . . . . . . Ambient T e s t 6-8 . . . . . . . . . . . . . . . M a x i m u m S t r e s s 6-9 . . . . . . . . . . . . . . . M i n i m u m s t r e s s 6-9

. . . . . . . . . . . . . . . S y s t e m No 2 R e s u l t s 6-9

DISCUSSION OF RESULTS . . G e n e r a l . . . . . . . . . . . . . . . . . . . . 7 - 1 T e s t i n g . . . . . . . . . . . . . . . . . . . . . . 7-1 S i g n a l c o n d i t i o n e r . . . . . . . . . . . . . . . . . . 7-2 T r a n s m i s s i o n S y s t e m . . . . . . . . . . . . . . . . . 7-3 . . . . . . . . . . . . . . . . . . . C o n t r o l C o n s o l e 7-3

. . . . . . . . . . . . . . . . . . . . 8 . CONCLUDINGREMARKS 8 - 1

9 . REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . 9-1

APPENDIX A: C o n t r o l Sys tem C o n t r a c t S p e c i f i c a t i o n s

L I S T OF TABLES

. . . . . . . . 2.1 . P r e f e r r e d F a i l u r e Mode and C r i t i c a l i t y D a t a 2-2

. . . . . . . . . . . . 3.1 . S i g n a l C o n d i t i o n e r Thermal A n a l y s e s 3-5

. . . . . . . . . . . . . . . . . . . 5.1 . P r e - S t a r t Check L i s t 5-20

. . . . . . . . . . . . . . . . . . . . 5.II.Pre.Stop Check L i s t 5-21

L I S T OF DRAWINGS F o l l o w i n g

Number Page

. . . . . . . . . . 306623 Marker . I d e n t i f i c a t i o n . Ca rd F i l e 1-1

306882 P lumbing a n d I n s t r u m e n t a t i o n Diagram . . . . . . . . . 5-40

Page i v

L I ST OF I LLUSTRAT IONS Page

. . . . . . . . . . . . . . . . Brayton Control System 1-2

. . . . . . . . . . . Brayton Power System Components 1-3

. . . . . . Brayton Power System Development Assembly 1-4

. . . . . . . . . . . . . . . . . . Signal Conditioner 3-2

. . . . . . . . . . . . . . . . . AC-to-DC conditioner' 3-11

Gain Vibration Versus Harmonic Content for . . . . . . . . . . . . . AC-to-DC Signal Conditioner 3-12

. . . . . . . . . . . . . . . . Basic Control Circuit 3-15

. . . . . . . . . . . . . . Redundant Control Circuit 3-16

. . . . . . . . . . . . . . . . . . . . Override Logic

. . . . . . . . . . . . . . . . Basic Receiver/Driver

. . . . . . . . . . Series Receiver/Driver (Fail Off)

Parallel Redundant Receiver/Driver (Fail On) . . . . . . . . . . . . . . . Triple-Redundant Receiver/Driver

. . . . . Power and Signal Transmission Cable Lengths

BCS Control and Monitoring Panel . . . . . . . . . . . . . . . . . . (Proposed Mock-Up)

. . . . . . . . . . . . . . Task I BCS Console Mock-Up

. . . . . . . . Artist Conception of Final BCS Design

. . . . . . . Completed Brayton Control System Console

. . . . . . . . . . . . . Typical BCS Module Mounting

. . . . . . . . . . Printed Circuit Card File Location

. . . . . . . . . . . Printed Circuit Boards. Typical

. . . . . . . . . Brayton Control System Panel Layout

. . . . . . . . . . . . . . . . . STTM and STPM Panel

Page v

LIST OF ILLUSTRATIONS (CONTD) Page

L L M a n d G I M P a n e l . . . . . . . . . . . . . . . . . 5-22

CPM. HSM. GBM. and ESM P a n e l . . . . . . . . . . . . . . 5-25

V a l v e M o d u l e P a n e l . . . . . . . . . . . . . . . . . . 5-28

E l e c t r i c C o n t r o l - AC P a n e l . . . . . . . . . . . . . 5-30

E l e c t r i c C o n t r o l - D C P a n e l . . . . . . . . . . . . . 5-35

M o n i t o r P a n e l . . . . . . . . . . . . . . . . . . . . 5-38

. . . . . . . . . . . . . . . . . . . . L o a d S i m u l a t o r 6-4

ECS Checkou t P r o c e d u r e Da t a S h e e t s ( 3 ) . . . . . . . . 6-5

Page v i

ABBREV I AT IONS

BCS

BHXU

BPS

BRU

CPM

DDAS

E CP

EM

E m s

ESM

FIWA

GBM

GIM

He -Xe

HSM

LLM

LS

MP

P&I

SC

STPM

STTM

TC

VM

VRE

Brayton Control System

Brayton Heat Exchange Unit

Brayton Power System

Brayton Rotating Unit

Critical Parameters Module

Digital Data Acquisition System

Electrical Control Package

Electrical Module

Engine-Mounted Emergency Shutdown

Emergency Shutdown Module

Failure !?ode Effects Analysis

Gas Bearing Module

Gas Inventory Module

Helium- Xenon

Heat Source Module

Liquid Loop Module

Load Simulator

Monitoring Panel

Piping and Instrumentation

Signal Conditioner

Stop Module

Start Module

Thermocouple

Valve Module

Voltage Regulator Excitation

Page vii

ABSTRACT

The Brayton Engine Control System was designed to provide control and protection for a Brayton power system. The basic objectives were to develop control techniques and circuitry that would provide flexibility during initial power system testing, yet meet the basic requirement of reliability and fail- safe operation associated with a 5-yr space mission.

The control system consists of an engine-mounted signal conditioner connected to an operator control panel through a hard-wired cable system. A detailed discussion of the control system, including design and salient features, is presented.

Page ix

F I M A L REPORT

CONTROL SYSTEM FOR T H E 2- 15-KWe BRAYTON POWER SYSTEM

SUMMARY

This r e p o r t p rov ides a d e t a i l e d t e c h n i c a l d e s c r i p t i o n of t h e Brayton engine c o n t r o l systems suppl ied under c o n t r a c t NAS 3-10943 t o t h e NASA Lewis Research Center . Two c o n t r o l systems and one load s i m - u l a t o r were designed, f a b r i c a t e d , t e s t e d , and shipped. The two primary o b j e c t i v e s were:

( a ) Develop c o n t r o l t echniques and c i r c u i t s us ing s t a t e -o f - the - a r t i n t e g r a t e d components t h a t would provide t h e f l e x i b i l i t y needed f o r ground development t e s t i n g of t h e complete power system

(b ) Achieve t h e r e l i a b l e c o n t r o l system performance r equ i r ed t o ope ra t e t h e 2- t o 15-kwe Brayton power system dur ing a 5-yr space miss ion

The Brayton engine c o n t r o l system c o n s i s t s of an engine-mounted s i g n a l cond i t i one r connected t o t h e c o n t r o l console by a hard-wired cab le system. The c o n t r o l system provides t h e c o n t r o l s and d i s p l a y s r equ i r ed f o r power system s t a r t - u p , shutdown, s t eady- s t a t e o p e r a t i o n , and power system malfunct ion p r o t e c t i o n . Extensive human f a c t o r engineer ing was used dur ing a l l phases of t h e c o n t r o l panel des ign . The c o n t r o l system was designed t o a s su re t h a t no s i n g l e f a i l u r e w i l l degrade t h e power system ou tpu t .

One of t h e two systems d e l i v e r e d t o NASA has s u c c e s s f u l l y con- t r o l l e d a Brayton power system f o r 1 2 o p e r a t i n g cyc l e s t o t a l i n g 2561 h r . D e t a i l s of t h e system c o n t r o l conso le , s i g n a l c o n d i t i o n e r , and d a t a a c q u i s i t i o n p rov i s ions a r e desc r ibed i n t h i s r e p o r t . A d i s - cuss ion of t e s t r e s u l t s , problems, and c o r r e c t i v e a c t i o n i s a l s o included.

Page x i

The NASA Lewis Research Cen te r i s c u r r e n t l y engaged i n a program t o deve lop a Brayton power sys tem c a p a b l e of g e n e r a t i n g e l e c t r i c power i n space . The c u r r e n t v e r s i o n of t h i s system i s des igned t o d e l i v e r from 2- t o 15-kw of e l e c t r i c power u s i n g a r a d i o i s o t o p e h e a t s o u r c e .

Brayton space power sys tems a r e c u r r e n t l y pr imary c o n t e n d e r s f o r s u p p l y i n g t h e e l e c t r i c a l power requ i rements of f u t u r e e a r t h - o r b i t i n g s p a c e s t a t i o n s . Such m i s s i o n s a r e t e n t a t i v e l y p lanned t o have a l i f e o f 5 t o 10 y r . To m e e t t h i s r equ i rement , a l l e l ements of t h e power sys tem must have t h e same l i f e , which d i c t a t e s s t r i c t r e l i a b i l i t y and f a i l - s a f e o p e r a t i o n .

The c o n t r o l sys tem f o r a Brayton space power sys tem h a s been d e s i g n e d , f a b r i c a t e d , and t e s t e d by t h e AiResearch Manufactur ing Company under C o n t r a c t NAS 3-10943 f o r t h e NASA Lewis Research C e n t e r . Two of t h e s e c o n t r o l sys tems have been d e l i v e r e d . One i s p r e s e n t l y b e i n g used t o c o n t r o l a Brayton power sys tem undergoing e x t e n s i v e t e s t i n g a t t h e Space Power F a c i l i t y o f t h e NASA Plumbrook S t a t i o n . A second i s be ing e v a l u a t e d i n a complete Brayton power sys tem e l e c - t r i c a l subsystem tes t a t t h e Lewis Research Cen te r .

The Brayton c o n t r o l sys tem c o n s i s t s of an engine-mounted s i g n a l c o n d i t i o n e r connected t o an o p e r a t o r ' s c o n t r o l p a n e l by means o f a hard-wired c a b l e system. The s i g n a l c o n d i t i o n e r i s d e s i g n e d t o oper- a t e on a c o l d - p l a t e i n a vacuum environment and p r o v i d e a l l t h e i n t e r - f a c e c o n d i t i o n i n g between t h e c o n t r o l p a n e l and t h e eng ine c o n t r o l hardware and t r a n s d u c e r s . The c o n t r o l p a n e l s u p p l i e s a u t o m a t i c con- t r o l and p r o t e c t i o n f o r t h e power sys tem, w i t h t h e o p t i o n of manual o v e r r i d e s , and p r o v i d e s t h e o p e r a t o r wi th t h e power sys tem s t a t u s through meters, a l a rms , and i n d i c a t i n g f l a g s .

T h i s r e p o r t d i s c u s s e s t h e requ i rements and d e s i g n o b j e c t i v e s i n t h e development of t h e Brayton c o n t r o l system. D e t a i l e d d e s c r i p t i o n s o f t h e s i g n a l c o n d i t i o n e r c i r c u i t s , c o n t r o l p a n e l modules, redundancy t e c h n i q u e s , and mechanica l d e s i g n a r e i n c l u d e d . Also p r e s e n t e d a r e t h e r e s u l t s of t h e accep tance t e s t i n g and a d i s c u s s i o n of problems and c o r r e c t i v e a c t i o n s .

Page x i i

The basic Brayton Control System (BCS) consists of an engine- mounted signal conditioner connected to an operator control console by a hard-wire cable system (Figure 1-1).

The BCS, with the exception of the monitoring panel, is an inte- gral part of the self-contained Brayton Power Conversion System. Sys- tem operation is independent of all ground support power and relies only on Brayton Power System (BPS) batteries or rectified engine power. Communication between the control console and engine-mounted signal conditioner is accomplished through a 400-ft transmission cable. Both the cable and signal conditioner are designed to meet engine vacuum and radiation requirements. Figure 1-2 shows the basic BCS elements and their relative locations. The actual BPS is shown in the lower right-hand corner. The signal conditioner is engine-mounted and is a "blow-up" in the center of the figure. The control console (controls, control logic, and monitoring devices) is in the upper left-hand corner. The load simulator, furnished as part of the contract, is in the lower left-hand corner. The simulator was used in place of an actual BPS during development and acceptance testing of the BCS. The heart of the BPS, the Brayton Rotating Unit, appears in the upper right-hand corner.

In order to gain some perspective of the requirements for this control system, a brief description of the BPS follows.

Drawing 306882 is a piping and instrumentation diagram of the Brayton system, which consists of a gas-filled power conversion loop, a liquid-filled heat rejection loop, and gas-management and electrical subsystems. Figure 1-3 shows the BPS installed in the NASA-Lewis Space Power Facility. Brief descriptions of the subsystems are in the following paragraphs.

Gas-Filled Power Conversion Loop

The working fluid of the gas-filled power conversion loop is a mixture of helium and xenon gases. This closed gas loop consists of the Brayton Rotating Unit (BRU), heat source heat-exchanger, recupera- tor, waste heat-exchanger, and the required gas ducting. The BRU has a turbine, a solid rotor, Rice-type alternator, and a compressor mounted on a common shaft that rotates at 36,000 rpm and is supported on gas-lubricated bearings.

Page 1-1

S P A C E ENVIRONMENT

E N G I N E MOUNTED T I G N A L C O N D I T I O N E R

BRAYTON- POWER CONVERSION SYSTEM

400 FT T R A N S M I S S I O N CABLE

CONTROL PANEL

FIGURE 1-1. BRAYTON CONTROL SYSTEM (BCS)

BRAYTON ROTATING UNIT ' 2-15 KW, 0 1280 H z @ 1201208 VOLTS

CONTROL 8 MONITORING PANEL o AUTOMATIC CONTROL o SELF CHECKING @FAIL SAFE

SIGNAL CONDITIONER @ 82 ANALOG PARAMETERS o 26 CONTROL AMPLlFlERS o OVERSPEED SHUTDOWN

LOAD SIMULATOR @ 82 PARAMETERS e 26 CONTROLS @ 23 POSITION FEEDBACK

ACTUAL BRAYTON POWER SYSTEM AT NASA SPACE POWER FACILITY

DEVELOPMENT ASSEMBLY

AT

NASA LEW S SPACE POWER

LEGEND

@ - c-r 5TLTU5

@ - C W RATE

@---vars (r-n)

@--AMPS

0 -CYCLE STATE POIM MARKER

a - n o w METER

I;/------- ORIFICE

CV - CMCK VAL* 2 TG- Pl ID l DPERATCD PNUWATIC VALVE

@ -- PRESS-

@ - SPEED

@ - D6FFiQENTIU PRESSURE

PRESSURE SWITCH (n DEMTES NUMBER &VAlLhBLE)

COMMAND AND FEEDBUU -AI OPEH(MI) AZ CLO~ED (OFF)-SKJUC TO e -

E S M - EMERSENtY SHUTDOWN MODLILE

GEM - GAS BEARING MOOULE

GIM - GAS INVENTORY MODULE

FM- FLOW WTER

* S M - H U T SOURCE hODW

LLM- LIQUD LOOP M O D U S

STPM - STOP MOaJCL

STTM - START M O W

V M - VALVE WDW:

EM-ELECTRIC U(XYM

FC-FLOW COI~~RDC

M - M A W

X - SCRAM FUFS- ENMNE MCUMTED ENFRGENCY +UUTDOWN 1

The gas loop is monitored by the SCS via 14 temperature measurements from thermocouples, nine pressure indications from variable reluctance transducers, and output from two pressure switches.

Heat Reiection Svstem

A silicone liquid, Dow Corning 200, is circulated through three parallel paths to remove waste heat from the Brayton Heat Exchanger Unit (BHXU), cool the alternator in the BRU, and cool the system electrical packages mounted on cold-plates. This waste heat is rejected to space through a radiator. For added reliability, two identical cooling loops are available, each with an individual pump. During normal operation, one loop is active while the other is inactive.

Interfacing with the heat rejection system is accomplished by the BCS through 15 temperature measurements (13 thermocouples and two thermistors), six flow-rate indications from turbine flowmeters, and two pressure indications from variable reluctance transducers. f he BCS includes the controls and displays to operate the two liquid loops.

Gas Management System

The gas management system (GMS) furnishes injection start-ups, hydrostatic support of the BRU gas bearings, and system pressure aajustments. It has a gas storage bottle, gas bottle heater, pressure regulator, nine solenoid valves, filters, and connecting lines to the gas loop. The nine solenoid valves include the main injection, make- up, main vent, small bleed, check valve, and four valves controlling flow to the gas bearings.

The BCS mbnitors and controls GMS operation through one thermocouple signal, one pressure signal from a variable reluctance transducer, the outputs from three pressure switches, and position indications from each valve. The BCS includes the controls for all the solenoid valves and the gas bottle heater power.

Electrical Subsystem

The electrical subsystem contains all the electrical hardware necessary to operate the Brayton power system. This subsystem can be divided into the following parts:

(a) Controls for the heat source

(b) The electrical control package (ECP), parasitic load resistors, and user load bus

(c) The dc power supply

Page 1-5

( d ) Two i n v e r t e r s f o r t h e l i q u i d loop pump motors

( e ) The Brayton e n g i n e c o n t r o l sys tem

The ~ 1 e c t r i c a l ' ~ o n t r o l Package: The ECP c o n t a i n s t h e BRU speed c o n t r o l , t h e a l t e r n a t o r v o l t a g e r e g u l a t o r , f o u r o f t h e sys tem r e l a y s , i n s t r u m e n t a t i o n f o r m o n i t o r i n g t h e e l e c t r i c a l p a r a m e t e r s , and i s t h e d i s t r i b u t i o n c e n t e r f o r t h e a l t e r n a t o r o u t p u t power.

The BRU speed c o n t r o l m a i n t a i n s t h e a l t e r n a t o r f r equency a t 1200 Hz +' p e r c e n t f o r v e h i c l e l o a d changes o f no-load t o f u l l l o a d .

-0 The speed c o n t r o l i s accomplished by s e n s i n g a l t e r n a t o r f r equency and p r o p o r t i o n a l l y changing t h e power d i s s i p a t e d i n t h e p a r a s i t i c l o a d r e s i s t o r t o m a i n t a i n a f i x e d l o a d on t h e a l t e r n a t o r independent o f t h e v e h i c l e l o a d .

The v o l t a g e r e g u l a t o r m a i n t a i n s a l t e r n a t o r v o l t a g e a t 120 l i n e - t o - n e u t r a l 2 1 p e r c e n t when t h e speed i s + 1 0 p e r c e n t of d e s i g n . Th i s i s accomplished by s e n s i n g a l t e r n a t o r l i n e v o l t a g e and p r o p o r t i o n a l l y c o n t r o l l i n g t h e amount of c u r r e n t t o t h e a l t e r n a t o r s h u n t f i e l d .

The f o u r r e l a y s i n t h e ECP a r e :

( a ) K501 - The f i e l d c o n t r o l r e l a y used t o s w i t c h t h e s h u n t f i e l d t o a c o n s t a n t d c supp ly i f abnormal o p e r a t i o n i s expe- r i e n c e d from t h e v o l t a g e r e g u l a t o r e x c i t e r

(b) K502 - The f i e l d f l a s h i n g r e l a y used t o f l a s h t h e a l t e r n a t o r f i e l d p r i o r t o s t a r t - u p

( c ) K503 - The v e h i c l e l o a d b r e a k e r used t o connec t o r d i scon- n e c t t h e u s e r l o a d t o t h e power sys tem

( d ) K505 - The g a s b o t t l e h e a t e r r e l a y used t o e n e r g i z e t h e b o t - t l e h e a t e r from t h e +28-v b u s , p r i o r t o s t a r t - u p

The i n t e r f a c e s between t h e ECP and t h e BCS a r e :

( a ) C o n t r o l each o f t h e f o u r r e l a y s and p r o v i d e p o s i t i o n r e a d o u t from a u x i l i a r y c o n t a c t s on each r e l a y

( b ) Over r ide i n p u t s t o each of t h e t h r e e channe l s of p a r a s i t i c l o a d speed c o n t r o l f o r t u r n i n g e i t h e r bank f u l l - o n o r f u l l - o f f

( c ) O v e r r i d e i n p u t f o r e l e c t r o n i c a l l y keep ing t h e s h u n t f i e l d c u r r e n t t o z e r o

( d ) C u r r e n t t r a n s f o r m e r o u t p u t s f o r measuring t h r e e a l t e r n a t o r phase and t h r e e v e h i c l e l o a d c u r r e n t s (and power)

Page 1-6

(e) Instrumentation for monitoring series- and shunt-field currents

(f) Voltage taps for the three alternator phases for monitoring alternator frequency (engine speed) and alternator voltage

(g) Thermocouple output for monitoring the ECP cold-plate temperature

DC Power Supply: DC power is needed to operate engine controls during normal operation, prior to start-up and after shutdown. Prior to Brayton engine start-up, the power (a nominal +28 v) is supplied by batteries to a dc bus. During normal systems operation, this bus is supplied by a transformer rectifier connected to the three phases of the alternator. The dc supply contains logic to automatically switch the batteries to the dc bus through a relay if the alternator voltage drops below a safe value. Also contained in the dc power supply is circuitry for automatically recharging the batteries, as needed.

The interfaces between the BCS and the dc power supply are:

(a) BCS receives all its power from the dc bus.

(b) Override inputs to the battery disconnect relay K504 are provided by the BCS. Also, auxiliary contacts on the relay indicate the relay position.

(c) Override inputs to the battery charger to turn charger full- on or full-off are provided by the BCS.

(d) Battery voltage, current, charge status, and temperature signals are sent to the BCS. Also dc power supply base- plate temperature is monitored.

(e) Bus voltage and current signals are sent to the BCS.

Pump Inverters: Two 400-Hz pump inverters operating off the 528-vdc bus are used to drive the two coolant loop pumps. START-STOP signals are provided by the BCS for turning either of these inverters on and off. Inverter base-plate temperature is also monitored by the BCS .

Heat Source: For-the power system development tests, a facility electric heat source is used to supply energy to the power system. BCS interfaces, with this electrical heat source, include commands for operating relay K12 that controls voltage to the heater, auxiliary contacts for monitoring K12 position, and three heat source hot-spot thermocouples.

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Contract NAS 3-10943 outlined in detail the specifications that the BCS was to meet. The specifications are included as Appendix A. A brief summary of these are in the following paragraphs.

Control specifications require careful checking to successfully fulfill the following characteristics:

(a) Start-up and shutdown logic

(b) Power level control

(c) System parameter monitoring and out-of-tolerance protection

(d) Overload protection

(e) Overspeed protection

(f) Over and under ac voltage protection

Design specifications are precise and must adhere to the following requirements:

(a) System operates from BPS dc supply.

(b) No single failure or correction of failures will result in loss of power to the load (fail-safe design).

(c) No component with a known wear-out life under 5 yr will be used.

(d) Normal engine operation will continue with all control signals de-energized to prevent engine shutdown due to power failure.

(e) Maximum reliability will be obtained through design with integrated circuits connected in f3il-safe configurations.

(f) Fabrication will be with MIL-STD components or equivalent.

(g) All control modules must be subjected to power-aging at maximum stress within specification.

(h) All components will be derated to ensure reliability.

(i) Maximum use of dual- or triple-redundant control circuits will be required.

Page 1-8

(j) There w i l l be no redundant c i r c u i t r y c o n t a i n e d i n a s i n g l e package , t h u s p r e v e n t i n g c a t a s t r o p h i c f a i l u r e .

(k) Each c o n t r o l c i r c u i t , analyzed f o r f a i l u r e e f f e c t s , w i l l be des igned t o e n s u r e normal e n g i n e performance i n t h e e v e n t of c i r c u i t f a i l u r e .

(1) T e s t p o i n t s w i l l be f u r n i s h e d t o s i m p l i f y sys tem t e s t i n g and conf i rm redundancy o f engine-mounted c i r c u i t r y .

( m ) Bu i ld ing-b lock c i r c u i t r y t e c h n i q u e w i l l f a c i l i t a t e ma in ta in - a b i l i t y .

The BCS, w i t h t h e e x c e p t i o n of t h e moni to r ing p a n e l , i s an i n t e - g r a l p a r t of t h e s e l f - c o n t a i n e d Brayton Power Conversion System. Sys- t e m o p e r a t i o n i s independen t o f a l l ground s u p p o r t power and r e l i e s o n l y on BPS b a t t e r i e s o r r e c t i f i e d e n g i n e power. Communications between t h e BCS and e n g i n e a r e accomplished through a 400-f t t r a n s m i s - s i o n c a b l e and an engine-mounted s i g n a l c o n d i t i o n e r . Both a r e des igned t o meet e n g i n e vacuum and r a d i a t i o n requ i rements . F i g u r e 1-1 shows t h e b a s i c BCS e lements and t h e r e l a t i v e l o c a t i o n s .

A l l components of t h e BCS have , a s a d e s i g n o b j e c t i v e , a 5-yr l i f e r equ i rement . I n t e g r a t e d c i r c u i t technology i s used th roughou t c o n t r o l p a n e l and s i g n a l c o n d i t i o n e r d e s i g n . High q u a l i t y commercial and MIL-STD components ( e q u i v a l e n t i n s i z e and e l e c t r i c a l c h a r a c t e r i s - t i c s t o f l i g h t - r a t e d components) w e r e s e l e c t e d f o r d e s i g n p u r p o s e s .

A l l s i g n a l s between t h e BCS and s i g n a l c o n d i t i o n e r a r e normal ized t o v o l t a g e l e v e l s o f 0 t o 5 , t h u s a l l o w i n g a c h o i c e of t r a n s m i s s i o n between ha rd -wi r ing , m u l t i p l e x i n g , and t e l e m e t e r i n g . The e n g i n e s t a t e - p o i n t pa ramete r s and c o n t r o l s i g n a l s a r e c o n t r o l l e d by t h e engine-mounted s i g n a l c o n d i t i o n e r . Logic f u n c t i o n s , e x c e p t overspeed shutdown, a r e i n i t i a t e d a t t h e c o n t r o l conso le a u t o m a t i c a l l y o r manually.

Tr ip le - redundan t a n a l o g c i r c u i t s have been i n c o r p o r a t e d f o r e i g h t c r i t i c a l s i g n a l s t o e n s u r e t h e s p e c i f i e d r e l i a b i l i t y . Analog s e l e c t o r c i r c u i t s moni tor t h e s e s i g n a l s , and agreement of a t l e a s t two o u t of t h r e e i s r e q u i r e d t o i n i t i a t e a command t h a t w i l l a f f e c t e n g i n e opera- t i o n . An a u d i b l e warning a la rm i s a c t i v a t e d when any one of t h e t r i p l e - r e d u n d a n t s i g n a l s d i s a g r e e s w i t h t h e o t h e r two. Th i s warning a l lows t h e t e c h n i c i a n t o r e p a i r t h e t r o u b l e w h i l e t h e sys tem i s s t i l l f u n c t i o n i n g normal ly . Manual c o n t r o l s t h a t always o v e r r i d e l o g i c - g e n e r a t e d commands a r e p rov ided on t h e c o n t r o l p a n e l t o m a i n t a i n com- p l e t e c o n t r o l of t h e BPS under maintenance c o n d i t i o n s and t o p r o v i d e development t e s t i n g f l e x i b i l i t y .

Page 1-9

S i g n a l C o n d i t i o n e r

The s i g n a l c o n d i t i o n e r i s t h e i n t e r f a c e between t h e BPS and t h e c o n t r o l and moni to r ing p a n e l s . S p e c i f i c a l l y , t h e s i g n a l c o n d i t i o n e r w i l l :

( a ) E x c i t e , c o n d i t i o n , and t r a n s m i t 9 3 s i g n a l s t o t h e c o n t r o l and moni to r ing p a n e l s from d a t a - p o i n t t r a n s d u c e r s on t h e BPS

( b ) Amplify and c o n d i t i o n d i s c r e t e and ana log s i g n a l s from t h e c o n t r o l p a n e l and d i s t r i b u t e them t o 2 6 BPS c o n t r o l p o i n t s

( c ) Shu t down t h e BPS under runaway c o n d i t i o n s w i t h t h e u l t i m a t e a u t h o r i t y s a f e t y c i r c u i t ( t h e engine-mounted emergency s h u t - down)

( d ) Operate under t h e BPS env i ronmenta l ext remes

Data Transmiss ion System

The d a t a t r a n s m i s s i o n sys tem p r o v i d e s a communication and power l i n k between t h e s i g n a l c o n d i t i o n e r and t h e Brayton c o n t r o l c o n s o l e . The d a t a l i n k c o n s i s t s of f o u r groups of 11 c a b l e s o f v a r i o u s l e n g t h s . The sys tem p r o v i d e s hard-wire t r a n s m i s s i o n f o r 1 7 1 s i g n a l s , 4 3 r e t u r n s , 30 power l e a d s ( + 2 8 v d c ) , 4 5 s h i e l d s , and 80 s p a r e c o n d u c t o r s .

C o n t r o l Pane l

The c o n t r o l p a n e l p r o v i d e s a u t o m a t i c c o n t r o l d u r i n g i n j e c t i o n s t a r t - u p , s t e a d y - s t a t e o p e r a t i o n , t r a n s i e n t s , o f f - d e s i g n p o i n t opera- t i o n , and shutdown. I n a d d i t i o n , t h e c o n t r o l p a n e l p r o v i d e s manual c o n t r o l f o r v a r y i n g t h e sys tem o u t p u t power s e t p o i n t .

P e r t i n e n t eng ine pa ramete r s a r e d i s p l a y e d on t h e c o n t r o l p a n e l t o p r o v i d e t h e o p e r a t o r w i t h s u f f i c i e n t i n f o r m a t i o n t o c o n t r o l t h e sys tem manually w i t h c o n t r o l l e r o v e r r i d e s w i t c h e s . Alarms n o t i f y t h e opera- t o r of sys tem a b n o r m a l t i e s .

System s t a t u s i s determined from e n g i n e pa ramete r s i g n a l s r e c e i v e d a s ana log v o l t a g e s from t h e s i g n a l c o n d i t i o n e r . D i s c r e t e c o n t a c t s i g n a l s deno te t h e s t a t u s o f s w i t c h e s , v a l v e s , and c o n t a c t o r s .

Pa ramete r s and a b b r e v i a t i o n s on t h e conso le a r e d e f i n e d on t h e sys tem g r a p h i c d i s p l a y l o c a t e d on t h e w r i t i n g s u r f a c e .

Monitorincf P a n e l

The moni to r ing p a n e l d i s p l a y i n c l u d e s mete r s f o r moni to r ing s t a t e - p o i n t pa ramete r s n o t d i s p l a y e d on t h e c o n t r o l p a n e l and n o t e s s e n t i a l f o r o p e r a t i o n . V i s u a l and a u d i b l e a larms n o t i f y t h e

Page 1-10

o p e r a t o r when one of t h e moni tor p a n e l pa ramete r s i s above o r below t h e d e s i r e d o p e r a t i n g range . A r e c o r d e r i s p rov ided t o moni tor s e l e c t e d c r i t i c a l pa ramete r s .

A l l s i g n a l s t r a n s f e r r e d t o t h e moni to r ing p a n e l a r e b u f f e r e d o u t - p u t s (by use of i s o l a t i o n a m p l i f i e r s ) from t h e c o n t r o l p a n e l . These a r e made a v a i l a b l e on a j u n c t i o n p a n e l f o r e x t e r n a l moni to r ing and r e c o r d i n g . S h o r t i n g , grounding, or a p p l i c a t i o n o f e x t e r n a l v o l t a g e t o t h e s e s i g n a l s w i l l n o t a f f e c t sys tem c o n t r o l .

Page 1-11

2, DESIGN PROCEDURES

The 5-yr sys tem l i f e r e q u i r e d by t h e c o n t r a c t r e s u l t e d i n e s t a b l i s h i n g d e s i g n g u i d e l i n e s t o a s s u r e p r o p e r a n n u n c i a t i o n of f a i l - u r e s , p r o p e r u t i l i z a t i o n o f r edundan t c i r c u i t s , c o n s e r v a t i v e d e r a t i n g of a l l e l e c t r i c a l components, and u t i l i z a t i o n o f h i g h - r e l i a b i l i t y components o r e q u i v a l e n t . These g u i d e l i n e s a r e d e s c r i b e d i n t h e f o l - lowing pa ragraphs .

For t h i s c o n t r a c t , r e l i a b i l i t y was d e f i n e d t o e n s u r e t h a t no i n d i v i d u a l BCS c i r c u i t f a i l u r e would r e s u l t i n l o s s of e l e c t r i c a l power t o t h e v e h i c l e l o a d c o n t a c t o r . This r equ i rement was implemented by v a r i o u s t e c h n i q u e s and g u i d e l i n e s .

F a i l u r e Mode E f f e c t s A n a l v s i s

A f a i l u r e mode e f f e c t a n a l y s i s (FMEA) f o r t h e complete BPS was performed t o d e f i n e c r i t i c a l f a i l u r e and p r e f e r r e d f a i l u r e modes. T h i s covered a l l BPS hardware such a s v a l v e s , r e l a y s , t h e a l t e r n a t o r , e t c . , a s r e l a t e d t o t h e BCS. R e s u l t s of t h i s a n a l y s i s a r e summarized on Table 2-1. The t a b l e l i s t s t h e component, t h e e f f e c t of a f a i l u r e of t h e component i n v a r i o u s modes (on-off o r o p e n - c l o s e d ) , and t h e p r e f e r r e d f a i l u r e mode. Depending upon t h e c r i t i c a l i t y of t h e f a i l - u r e , t h e n e c e s s a r y redundancy r e q u i r e d i n t h e BCS f o r t h e a s s o c i a t e d c o n t r o l c i r c u i t was e s t a b l i s h e d . The r e s u l t i n g d e f i n i t i o n i s i n c l u d e d i n t h e redundancy column o f t h e t a b l e .

Table 2-1 was used t o e s t a b l i s h t h e l e v e l o f redundancy f o r each of t h e BCS c o n t r o l c i r c u i t s . Those w i t h p r e f e r r e d f a i l u r e i n t h e ON- c o n d i t i o n a r e p rov ided w i t h p a r a l l e l redundancy, t h o s e i n t h e OFF- c o n d i t i o n w i t h s e r i e s redundancy. F a i l u r e s i n e i t h e r p o s i t i o n r e s u l t - i n g i n l o s s o f o u t p u t power a r e p rov ided w i t h s e r i e s - p a r a l l e l ( t r i p l e - r edundan t ) redundancy.

C i r c u i t s implementing t h e s e redundancy requ i rements were d e v e l - oped. The FMEA f o r each c i r c u i t was performed p r i o r t o f i n a l d e s i g n t o e n s u r e t h a t no s i n g l e f a i l u r e i n a c i r c u i t would r e s u l t i n l o s s of o u t p u t power.

Redundancy

The redundancy r e q u i r e d t o meet t h e p r e f e r r e d f a i l u r e mode was implemented th roughou t t h e BCS c i r c u i t s . T r ip le - redundan t c i r c u i t s f o r a l l c r i t i c a l a n a l o g s i g n a l s , t h e s i g n a l c o n d i t i o n e r power sup- p l i e s , and c r i t i c a l v a l v e d r i v e r s a r e p rov ided . Dual-redundancy i s

Page 2-1

APS-5284-R24 Page 1 of 3

Component

I n j e c t i o n Valve ( N . C . ) SV-1

Primary Jacking- Gas Valves ( N . C . ) SV-5 and SV-6

Secondary Jacking-Gas Valves ( N . C . ) SV-8 and SV-9

Dump Valve (V2) P i l o t SV-11 ( N . C . )

Bleed Valve ( N . C . ) SV- 3

Check Valve P i l o t SV-4 ( N . C . )

Make-Up Valve (N.C.) SV-7

TABLE 2-1. PREFERRED FAILURE

P F M ~

Closed

None

Closed

None

Closed

S i g n a l Cond.

S e r i e s Dr ive r

" T r i p l e Redundant

S e r i e s D r i v e r s

T r i p l e Redundant




Redundancy

Cont. Panel

None

P a r a l l e l w i t h SV-8 and SV-9

P a r a l l e l w i t h SV-3 and SV-5

Dual Switch P a r a l l e l Pa th

None

MODE AND CRITICALITY

F a i l u r e Mode

F a i l Open

F a i l Closed

F a i l Open

F a i l Closed

F a i l Open

F a i l Closed

F a i l Open

F a i l Closed

F a i l Open

F a i l Closed

F a i l Open

F a i l Closed

F a i l Open

F a i l Closed

DATA

F a i l u r e E f f e c t

Loss of a l l b u t one i n v e n t o r y of gas .

Required on ly f o r s t a r t - u p .

Leaves j acking-gas on con t inuous ly . Would e v e n t u a l l y r e s u l t i n l o s s of a l l b u t one i n v e n t o r y of g a s .

Requires use of au tomat ic back-up supp ly .

Leaves jacking-gas on con t inuous ly - no o v e r r i d e - would r e s u l t i n l o s s of emergency g a s .

Loss of back-up jacking-gas .

Would r e s u l t i n immediate degrada t ion t o approximately 800 w a t t s .

E l i m i n a t e s main emergency shutdown p r o v i s i o n . Loss of primary o v e r p r e s s u r e r e l i e f system.

System s h u t down when primary and emergency g a s s u p p l i e s exhaus ted .

Requires manual g a s inven tory c o n t r o l w i t h V-2 v i a SV-10 o r au tomat ic o v e r p r e s s u r e c o n t r o l r e q u i r e d .

I n s e r t s 3- t o 4-psi p r e s s u r e drop i n t o loop.

Gas i n j e c t i o n s t a r t - u p impossible .

Loss of a l l b u t one inven tory of gas.

Requires manual i n j e c t i o n v i a SV-1, -4 and -5 , -6 and -8, o r -9


TABLE 2-1 (Contd)

Component I Redundancy

Signal Cond. Cont. Panel I Load Contactor

K503 (Latching)

Gas Heater Contactor (Latching) K505 I

VRE Auxiliary Contactor (Latching) K502

Battery Connect Contactor (Latching) K504

Battery Charger Control Signal (Latching)

Heat Source Control

Field Control K501

Parallel

Series

-----

None

-----

Parallel

Series

~ 9 0 % Sp Only

None

Parallel

Parallel

Parallel Contacts

Series Contacts

None

None

Parallel

Parallel

Closed

Off

Auto

Armed

VRE

Failure Mode

Closed

Closed

Open

Off

On

Closed

Open

On

Off

Off

Armed

VRE

Batt.

Failure Effect

Loss of main alternator overload protection - backed by individual subload breakers.

Loss of output power - no manual alternatives.

Loss of heater control - heater tied directly to battery (critical if system shut down) .

~ e - X e will separate - consequences unknown - emergency facility back-up supply available.

Loss of disconnect capability - no apparent degradation.

Battery life reduced with continuous on- line operation

No start-up power. No back-up for dc power supply.

Results in battery charger staying on - battery will overheat and fail.

No charger to allow for heater power used - could cycle K504 manually.

Requires manual override at heat sonrce panel.

Requires manual override at heat source panel.

would affect plans for motor start and shutdown.

Fixed field on alternator. I


TABLE 2-1 (Contd)

Component

Primary Liquid Loop Pump Inverter

Secondary Liquid Loop Pump Inverter

VRE Inhibit

Speed Control Over- ride "Full-Off" (Three Identical Controls)

Speed Control Over- ride "Full-On" ('Three Identical controls)

Engine-Mounted Emergency Shut- down (EMES)

I Redundancy

S.C. 0 n

C. P. Off

S.C. On

C.P. Off

Off

Failure Mode

Off

On

Off

On

Off

On

Off

On

Off

On

Off

On

Failure Effect

Back-up available

Normal

Loss of back-up.

Could perturbate the system - NASA has indicated this would be undesirable.

Required for motor start.

Automatic switch-over to fixed-field excitation.

No effect unless primary speed control sensing section fails ON (6 kw on).

Loss of 6 kw of available parasitic load - no effect on system (barring second failure) .

No effect unless equivalent of two primary speed control sections fail OFF.

Applies 6-kw parasitic load, very critical.

Loss of overspeed protection.

System shuts down.

*Provided for flight system with no back-up valves. iPFM: Preferred Failure Mode.

provided f o r c o n t r o l c i r c u i t s t o meet p r e f e r r e d f a i l u r e mode c r i t e r i a . Analog s e l e c t o r c i r c u i t s i n t h e console compare t r i p l i c a t e d s i g n a l s con t inuous ly , s e l e c t a s i g n a l f o r use by l o g i c , and annunciate any s i g n a l d isagreement . Redundant ana log s e l e c t o r c i r c u i t s provide s i g - n a l s t o redundant l o g i c .

Dual complementary l o g i c c i r c u i t s i g n a l s a r e t r a n s m i t t e d over t w i s t e d s h i e l d e d p a i r s t o d i f f e r e n t i a l r e c e i v e r / d r i v e r s i n t h e s i g n a l c o n d i t i o n e r . Redundant r e c e i v e r / d r i v e r s a r e used a s r equ i r ed . Logic s i g n a l s must agree o r t h e fo l lowing occurs :

( a ) Continuous d r i v e r s - Valves SV-1, SV-3, SV-4, SV-7, and 'SV-10 r e t u r n t o t h e normally c lo sed

s t a t e

( b ) Latching d r i v e r s - Valves SV-5, SV-6, SV-8, and SV-9 remain i n t h e l a s t commanded p o s i t i o n

( c ) Pu l se d r i v e r s - Contac tors remain i n t h e l a s t commanded p o s i t i o n

To des ign r e l i a b l e l o n g - l i f e e l e c t r o n i c c i r c u i t s f o r t h e BCS, s e v e r a l procedures were followed. These inc luded a d e t a i l e d FMEA on each c i r c u i t , i n d i v i d u a l component s tudy t o a s s u r e no o v e r s t r e s s , and d e t a i l e d thermal ana lyses t o a s c e r t a i n a l l components opera ted s a f e l y w i t h i n temperature l i m i t s .

A l l p a r t s i n t h e des ign of t h e BCS a r e t h e same type a s t h o s e on approved p a r t s l i s t s f o r m i l i t a r y and space a p p l i c a t i o n s . The l a t e s t a v a i l a b l e i n t e g r a t e d c i r c u i t s g i v i n g t h e promise of h igh r e l i a b i l i t y performance were used whenever p o s s i b l e .

The thermal a n a l y s e s , d e r a t i n g f a c t o r s , and procurement s p e c i f i c a - t i o n s a r e d i scus sed l a t e r i n t h e r e p o r t under t h e S i g n a l Condi t ioner and Cont ro l Panel Sec t ions . The d e r a t i n g f a c t o r s f o r t h e s i g n a l con- d i t i o n e r and t h e c o n t r o l pane l a r e d i f f e r e n t because t h e former i s designed f o r 5-yr unat tended vacuum o p e r a t i o n , whi le t h e l a t t e r i s designed t o o p e r a t e i n a c o n t r o l room environment and can be main- t a i n e d .

Page 2-5

3, SIGNAL CONDITIONER DESIGN

GENERAL DESCRIPTION

The s i g n a l cond i t i one r shown i n Figure 3-1 provides an i n t e r f a c e between t h e c o n t r o l s and t h e engine. A l l s i g n a l s between t h e condi- t i o n e r and t h e c o n t r o l s a r e 0- t o 5-v analog l e v e l s o r d i s c r e t e l o g i c l e v e l s of 0 o r 5 v . This a l lows hard-wiring, mu l t i p l ex ing , o r t e l e - metering f o r i n t e r connec t ing t h e two u n i t s .

The cond i t i one r p rov ides seventy-nine 0- t o 5-v analog s i g n a l s of engine s t a t e - p o i n t parameters and t h r e e 0- and 5-v d i g i t a l frequency s i g n a l s . Twenty-six 0- o r 5-v d i s c r e t e s i g n a l s from t h e c o n t r o l panel a r e condi t ioned t o provide pu lsed , cont inuous, o r l a t c h i n g d r i v e r s i g - n a l s , a s r equ i r ed f o r engine r e l a y , va lve , and l o g i c c o n t r o l . Twenty- t h r e e va lve and c o n t a c t o r p o s i t i o n - i n d i c a t i o n s i g n a l s and t h e console power t e rmina t ions a r e a l s o suppl ied .

The s i g n a l cond i t i one r inc ludes t h e overspeed shutdown c i r c u i t r y . I n t h e event t h a t a l t e r n a t o r frequency exceeds 1380 Hz (115-percent r a t e d ) , l o g i c au toma t i ca l ly p o s i t i o n s t h e valves and r e l a y s i n t h e shutdown cond i t i on , ove r r id ing s i g n a l s from t h e c o n t r o l s . A s i g n a l i n d i c a t i n g t h e shutdown condi t ion is s e n t t o t h e c o n t r o l panel .

The s i g n a l cond i t i one r c i r c u i t s a r e l oca t ed on n ine teen 4-3/4 x 10 - in . , 56-pin, p r i n t e d c i r c u i t boards i n a 26.56 x 14.56 x 8.06-in. aluminum c h a s s i s . The c o n d i t i o n e r , wi thout power supply boards ,* weighs 78 l b . Space f o r two a d d i t i o n a l boards i s a v a i l a b l e . Each c i r c u i t c a rd assembly inc ludes a s t r u c t u r a l heat-s ink frame t h a t b o l t s t o t h e c h a s s i s . Power supply induc to r s , d iodes , and thermocouple re fe rence- junc t ion ovens a r e a t t ached t o a v e r t i c a l heat-s ink b racke t along one s i d e of t h e c h a s s i s , perpendicu la r t o t h e c i r c u i t board assemblies . The power d i s t r i b u t i o n t e rmina l board and d r i v e r c i r c u i t f u s e s a r e on t h e oppos i t e s i d e of t h e c h a s s i s . A p l a t e a f f o r d s access t o t h e fu ses . The t o p of t h e s i g n a l cond i t i one r provides a j unc t ion f o r t h e i n t e r connec t ion of power and d i s c r e t e con tac t s between t h e engine and c o n t r o l s . An aluminum p l a t e between t h e t o p and bottom s h i e l d s t h e cond i t i one r c i r c u i t s i n t h e bottom from i n t e r f e r e n c e by switching t r a n s i e n t s i n t h e t o p s e c t i o n . (The c o n t r o l console power s u p p l i e s u t i l i z e switching- type r e g u l a t o r s . ) A ground s t r a p between t h e t o p and bottom has a connector s p l i c e t o a l low complete s e p a r a t i o n of t h e two s e c t i o n s . The c h a s s i s i s i s o l a t e d from t h e c i r c u i t ground.

*The t h r e e power-supply boards wi th t h e cond i t i one r were no t developed s a t i s f a c t o r i l y a s shipped. Exte rna l power s u p p l i e s fu rn i shed by NASA were used f o r checkout and a r e r equ i r ed f o r opera t ion .

Page 3-1

Cables , wi th numbers PlOl through P l l l from t h e c o n t r o l conso le , a r e a t t a c h e d t o t h e end of t h e s i g n a l cond i t i one r by connectors iden- t i f i e d a s J l O l through J l P l , r e s p e c t i v e l y . Cables 1P1 through 1P16 from t h e engine a r e a t t a c h e d t o t h e o t h e r end wi th connectors marked 1J1 through 1J16, r e s p e c t i v e l y . Plugs a r e keyed s o t h a t they cannot be i n s e r t e d i n t o t h e wrong r e c e p t a c l e s wi th t h e except ion of J l O l and J 1 0 2 , which, l i k e 1J1 and 1 J 2 , a r e s i m i l a r and func t ion interchange- ab ly . Tes t connectors 1517 and 1J18 a r e l oca t ed on t h e console end.

The cond i t i one r c i r c u i t s were designed t o meet t h e fol lowing requirements :

( a ) U t i l i z e t h e BPS u n i n t e r r u p t i b l e t28 dc bus vo l t age

(b) U t i l i z e s t a t e of t h e a r t i n t e g r a t e d c i r c u i t s

( c ) Operate i n a p r e s s u r e environment from hard-vacuum t o 15 p s i a

(d ) D i s s i p a t e h e a t t o a co ld p l a t e wi th a c o o l a n t d i scharge temperature ranging from -65O t o +150°F

(e) Operate f o r 5 y r i n a r a d i a t i o n environment wi th a t o t a l l y i n t e g r a t e d dosage of 5 x 1 0 1 0 n v t ( f a s t ) and 5 x 105 r a d ( y ) c l

(f) Operate cont inuous ly , wi thout maintenance, f o r 5 y r

Design cons ide ra t ions t o meet each of t h e s e requirements a r e desc r ibed i n t h e fo l lowing paragraphs .

Condi t ioner Power

Power f o r t h e c o n d i t i o n e r i s der ived from t h e u n i n t e r r u p t i b l e BPS d c bus. Three independent s e t s of + lo- , - l o - , +5- and reference-5-vdc r e g u l a t o r s a r e used t o a s s u r e independence of redundant c i r c u i t s .

It was e s t a b l i s h e d du r ing t e s t i n g t h a t t h e power s u p p l i e s ( o t h e r than t h e 5-v r e f e r e n c e ) , designed a s an i n t e g r a l p a r t of t h e condi- t i o n e r package, r e q u i r e d f u r t h e r development t o reduce vo l t age s p i k e s and conducted and r a d i a t e d i n t e r f e r e n c e . C i r c u i t changes a r e a l s o needed t o prevent power supply f a i l u r e s t h a t w i l l r e s u l t i n a high v o l t a g e ou tpu t c o n d i t i o n , The power s u p p l i e s i n t h e c o n d i t i o n e r s a r e p r e s e n t l y d i s a b l e d , and ope ra t ion i s dependent upon e x t e r n a l r egu la - t o r s .

Page 3-3

Intearated Circuitrv

Conditioner circuitry consists of both integrated circuits and discrete electronics; however, the circuitry is basically compatible with thick- or thin-film requirements. Initially, the conditioner was to be fully integrated, utilizing thick-film techniques. Development of precision thick-film resistors ('0.1 to tl.O percent) with low- temperature coefficients (good high-resistance ratio tracking and low drift) did not progress satisfactorily enough for further integration.

Pressure and Temperature Environment

All components are rated Eor operation in pressures ranging from hard-vacuum to 15 psia. The thermal analysis and subsequent design assumed operation in a vacuum. All heat (230 w) is radiated or dis- sipated via aluminum structural members to the cold plate.

A digital heat transfer study was performed on the signal conditioner. The whole conditioner was divided into approximately 88 nodes.

Basic assumptions were:

(a) Internally no convection heat transfer considered, only radiation heat transfer

(b) Base-plate to cold-plate interface thermal conductance assumed to be 100 ~tu/hr-ft2, OF

(c) Thermal conductance through cold-plate to secondary fluid equal to 300 ~tu/hr-ft2, OF

(d) Surrounding environment equal to 160°F

(d) Coolant temperatures of 115' and 150°F

Thermal analyses were performed for the six cases listed in Table 3-1. Based upon these data, potting should be utilized for a flight package with coolant temperatures above 115OF. It is, therefore, recommended that the coolant discharge temperature be maintained at llS°F or less. Because these temperatures will not exceed 115OF during development tests, it was decided not to pot the signal conditioner boards for these tests.

Radiation Considerations

The specified radiation to which the signal conditioner must be designed to survive, and through which it must remain operable, are 5-year exposures for a total of:

Page 3-4

TABLE 3 - 1 . SIGNAL CONDITIONER T H E W L ANALYSES

6 boards* 1 2 boards*"

6 boards* 1 2 boards**

* P o t t i n g C o m p o u n d w i t h K = 0 . 0 8 4 7 B t u / h r - f t , O F

* * P o t t i n g C o m p o u n d w i t h K = 1 . 2 B t u / h r - f t , OF

P a g e 3-5

(b) 5 x lo5 rad ().)C1

The effects of the two types of radiation are well known and documented in the literature for pulse-type irradiation. The neces- sity for most tests stems from the hazards of atomic explosion and a military environment.

Little literature exists on the effects of long-time exposure, since this type of test ties up experimental equipment interminably. When the requirements are coupled with a space environment, practi- cally no pertinent experimental data are available. Therefore, it is necessary to examine materials separately for the effects of vacuum environment and neutron and gamma irradiation. Effects of space environment are elsewhere of concern. This discussion will deal with irradiation hazards only.

Effects of Radiation: Reference 1 delineates the effects of radiation damage for various materials to levels of irradiation. In the summary (Table A) of the reference document, materials are listed that are available and satisfactory in each of the following four classifications, to better than two orders of magnitude (or 5 x 1012), for fast neutrons:

(a) Structural metal damage for the intended materials is accomplished only in an environment many orders of magnitude more severe than will be encountered in the Brayton cycle engine control system.

(b) Ceramics of interest are principally alumina and beryllia. The alumina property, showing deterioration at the lowest level, is the dissipation factor at levels of 1016 and above. Beryllia experiences dimensional changes at levels of 1020 or above. Ceramics under consideration are, therefore, not considered a problem at the specified levels.

( c ) Electronic components consist primarily of resistors and capacitors. Resistors of the film-type may show significant changes at about 1013 and above. Other resistors show insignificant damage until levels of 1015 are reached. Capacitors show moderate change, starting at 1012 and above, and primarily dependent upon the characteristics of the dielectric material. Dielectrics at the low end of the range of sensitivity will be minimized.

Page 3-6

( d ) Semiconductors a r e p r e d i c t e d a s t h e components most l i k e l y a f f e c t e d by i r r a d i a t i o n . The d e t a i l s of manufacture o f each i n d i v i d u a l t y p e o f component (which va ry from manufac tu re r t o m a n u f a c t u r e r ) a f f e c t t h e s u s c e p t i b i l i t y of t h e i n d i v i d u a l components t o r a d i a t i o n damage.

E l e c t r o n i c s i n t h e s i g n a l c o n d i t i o n e r w i l l be des igned around i n t e g r a t e d m i c r o c i r c u i t s i n c o r p o r a t e d i n t o t h i c k - f i l m modules. Micro- c i r c u i t s i n t e n d e d f o r t h e s i g n a l c o n d i t i o n e r a r e s i m i l a r t o t h o s e d i s c u s s e d i n Reference 2 (Page 391), which show minor e f f e c t s u n t i l i r r a d i a t e d t o a t l e a s t 5 x 1012 ( o r two o r d e r s of magnitude more t h a n r e q u i r e d ) . MOSFETs, which have known s u s c e p t i b i l i t y t o lower l e v e l s , w i l l be avo ided .

Gamma R a d i a t i o n : Damage from gamma r a d i a t i o n , a s i n t h e fo l low- i n g examples , o c c u r s (Reference 1, F i g u r e A) w e l l above t h e e x p e c t e d l e v e l ( 5 x 107 e r g s g-l) i n t h e Brayton c y c l e e n g i n e sys tem, e x c e p t i n semiconduc to r s :

( a ) The e f f e c t on e l a s t o m e r s i n c o n n e c t o r s and e l sewhere i s com- p l i c a t e d by t h e vacuum environment . The f i r s t e f f e c t s of i r r a d i a t i o n o c c u r i n t h e p h y s i c a l r a t h e r t h a n e l e c t r i c a l c h a r a c t e r i s t i c s of t h e m a t e r i a l . This means t h a t c o n n e c t o r s , s u b j e c t t o environment f o r a number o f y e a r s , might n o t re- s e a l i f s e p a r a t e d and j o i n e d a g a i n . S ince s e a l i n g i s n o t i m p o r t a n t t o t h e s i g n a l c o n d i t i o n e r , e l a s t o m e r s w i l l n o t be i n h i b i t e d by d e t e r i o r a t i o n of i r r e l e v a n t c h a r a c t e r i s t i c s . I n o r g a n i c s , which t y p i c a l l y show less damage t h a n o r g a n i c s , w i l l be u t i l i z e d p r e f e r e n t i a l l y .

( b ) R e s i s t o r s and c a p a c i t o r s show d e t e r i o r a t i o n a t l e v e l s asso- c i a t e d w i t h t h e d i e l e c t r i c s . Ceramic, mica, and g l a s s c a p a c i t o r s t y p i c a l l y t o l e r a t e a t l e a s t l o 9 e r g s g-l w i t h o u t s i g n i f i c a n t damage and a r e p r e f e r r e d f o r t h e Brayton c y c l e c o n t r o l sys tem. Magnetic components a r e a t l e a s t e q u a l l y r e s i s t a n t .

(c) Semiconductor d e v i c e s such a s d i o d e s and t r a n s i s t o r s s t a r t t o be a f f e c t e d a t t h e gamma r a d i a t i o n l e v e l s s p e c i f i e d . I n f o r m a t i o n on r a d i a t i o n e f f e c t s d u r i n g long p e r i o d s i s s p a r s e . There a r e two e f f e c t s produced by gamma i r r a d i a - t i o n . The f i r s t i s l o c a l h e a t i n g . This can be n e g l e c t e d i f t h e r a t e i s low ( r a t h e r t h a n v i o l e n t r e a c t i o n p u l s e s ) . The second i s s t r u c t u r a l d i sa r rangement of t h e c r y s t a l l i n e m a t e r i a l of t h e semiconductor . Th i s s t r u c t u r a l damage may s t a r t t o o c c u r a t from 1 x 102 t o 1 x l o 6 r a d . S p e c i f i c a - t i o n l e v e l i s 5 x 105 r a d (Refe rences 1 and 2 ) .

Page 3-7

Hence, s e l e c t i o n of semiconductor t y p e s i s n e c e s s a r y t o a s s u r e s u r v i v a l , w i t h a p p r o p r i a t e d e r a t i n g a s r e q u i r e d by t h e i n d i v i d u a l t y p e . D e t e r i o r a t i o n of t h e c r y s t a l l i n e s t r u c t u r e r educes g a i n and f requency r e s p o n s e and i n c r e a s e s l e a k a g e s . Design w i l l be o r i e n t e d , t h e r e f o r e , toward minimizing t h e e f f e c t s of t h e s e changes.

I n summary, t h e l e v e l of f a s t n e u t r o n r a d i a t i o n poses no d i f f i - c u l t i e s . Gamma r a d i a t i o n problems can be m e t by a p p r o p r i a t e d e r a t i n g .

Five-Year Opera t ion

The b a s i c premise was t h a t t h e s i g n a l c o n d i t i o n e r would be l o c a t e d i n a non-man-rated envi ronment . To a s s u r e t h a t a c i r c u i t f a i l u r e would n o t r e s u l t i n l o s s of sys tem o u t p u t power, a thorough f a i l u r e mode e f f e c t a n a l y s i s was completed, a s d i s c u s s e d e a r l i e r . The f o l l o w i n g d e r a t i n g c r i t e r i a were used i n t h e d e s i g n o f t h e s i g n a l c o n d i t i o n e r c i r c u i t s f o r wors t -case c o n d i t i o n s :

R e s i s t o r s

C a p a c i t o r s

Diodes

a c t u a l power < n . 2 0 r a t e d power -

a c t u a l v o l t a g e r a t e d v o l t a g e 5 0.50

a c t u a l PIV , 0 . 5 0 r a t e d PIV

a c t u a l V,, LLi

T r a n s i s t o r s 5 0.50 r a t e d VCE

a c t u a l power i 0 . 2 0 r a t e d power

A l l t r a n s i s t o r s were checked i n t h e c i r c u i t d e s i g n t o make c e r t a i n t h e y c o u l d d e l i v e r t h e c u r r e n t under a l l condi- t i o n s .

Example of t r a n s i s t o r d e r a t - i n g : The v a l v e - d r i v e r t r a n - s i s t o r s a r e r a t e d f o r 50 w a t 100°C. These d i s s i p a t e on ly 2 . 3 w d u r i n g normal o p e r a t i o n a t 85OC.

Page 3-8

I n t e g r a t e d c i r c u i t s A l l I C ' s powered from 110 v ( r a t e d t o 118, normal ly used a t t 1 5 v ) .

Logic g a t e s Rated a t 8 v , used a t 5. Dr ive on ly h a l f o r less t h a n h a l f t h e number of g a t e s recommended by vendor.

C o n d i t i o n e r c i r c u i t s a r e d i v i d e d i n t o t h e two b a s i c c a t e g o r i e s of a n a l o g s i g n a l s and c o n t r o l c i r c u i t s . The f o l l o w i n g f i v e b a s i c a n a l o g s i g n a 1 , c o n d i t i o n e r c i r c u i t s w e r e developed f o r t h i s system and a r e d i s c u s s e d i n t h e succeed ing pa ragraphs :

( a ) Low l e v e l ( thermocouple and s h u n t s i g n a l s )

( b ) A l t e r n a t i n g c u r r e n t ( v o l t s and amps)

( c ) Power ( t h r e e - p h a s e )

( d ) Frequency ( a l t e r n a t o r f requency and c o o l a n t f low)

( e ) B u f f e r s ( h i g h l e v e l d c o u t p u t t r a n s d u c e r s )

Low-Level A m p l i f i e r f o r Thermocouples

S i g n a l c o n d i t i o n e r c i r c u i t s f o r 31 thermocouples a r e p rov ided . C i r c u i t r y i n c l u d e s a 212°F r e f e r e n c e j u n c t i o n , v a r i a b l e g a i n , and v a r i a b l e o f f s e t . S p e c i f i c a l l y , c i r c u i t r y i s i n c l u d e d f o r 0- t o 5-v o u t p u t w i t h i r o n - c o n s t a n t a n s i g n a l s from -100° t o +400°F, chromel- a lumel s i g n a l s from -100" t o +900°F, and chromel-alumel s i g n a l s from -100" t o 1900°F. P e r t i n e n t s p e c i f i c a t i o n s a r e a s f o l l o w s :

( a ) Gain (maximum) 500

(b) I n p u t s i g n a l r ange -10 t o 60 m v

(c) Common mode 15 v P/P

( d ) Common mode r e j e c t i o n 60 db f o r 10 t o 2.6 kHz

(e) D r i f t (-65O t o 250°F) <50 mv

( f ) Accuracy 12%

( g ) D i f f e r e n t i a l i n p u t 6K ohm impedance

Page 3-9

The c i r c u i t i s des igned t o o p e r a t e w i t h grounded o r ungrounded thermocouples .

Low-Level A m ~ l i f i e r f o r Shunts

The c o n d i t i o n e r i n c l u d e s two c i r c u i t s f o r s i g n a l s from t h e a l t e r n a t o r s h u n t and s e r i e s f i e l d c u r r e n t s h u n t s . These a r e s i m i l a r t o t h e thermocouple c i r c u i t s e x c e p t t h e common mode v o l t a g e may be a s h i g h a s 80-v peak and t h e d i f f e r e n t i a l s i g n a l may be a s h igh a s 5 v .

AC t o DC C o n d i t i o n e r

The c o n d i t i o n e r i n c l u d e s t h r e e c i r c u i t s f o r p r o v i d i n g 0- t o 5-v a n a l o g s of a l t e r n a t o r l i n e t o n e u t r a l v o l t a g e of 0 t o 2 0 0 v r m s , t h r e e c i r c u i t s f o r a l t e r n a t o r - p h a s e c u r r e n t s , and t h r e e f o r a c load-phase c u r r e n t s . The 0- t o 80-amp c u r r e n t s i g n a l s a r e o b t a i n e d from 2-ohm s h u n t r e s i s t o r s a c r o s s 8 0 : l c u r r e n t t r a n s f o r m e r s .

The c i r c u i t c o n s i s t s of a p r e a m p l i f i e r , demodula tor , and a c t i v e f i l t e r . The p r e a m p l i f i e r p r o v i d e s g a i n c o n t r o l and low-impedance i n p u t t o t h e demodulator . Demodulation i s performed synchronously by f e e d i n g an a c r e f e r e n c e s i g n a l t o t h e base of a t r a n s i s t o r t h a t s w i t c h e s on and o f f a s t h e r e f e r e n c e swings p o s i t i v e and n e g a t i v e . T h i s , i n t u r n , changes t h e g a i n of t h e demodulator a m p l i f i e r from +l t o -1, which demodulates t h e a c i n p u t , w i t h no v o l t a g e d r o p , t o a f u l l - wave r e c t i f i e d v o l t a g e . The a c t i v e f i l t e r c o n v e r t s t h e demodulator o u t p u t t o a r i p p l e - f r e e d c v o l t a g e e q u a l t o t h e average v a l u e o f t h e i n p u t s i g n a l . A b lock diagram a p p e a r s i n F igure 3-2.

T e s t R e s u l t s : Labora to ry t e s t s on a breadboard c o n s t r u c t i o n of t h e c i r c u i t v e r i f i e d t h e g a i n f a c t o r of 0 . 9 f o r a s i n u s o i d a l i n p u t v o l t a g e and d i s p l a y e d e r r o r s of l e s s t h a n 0 . 1 p e r c e n t o v e r t h e tempera- t u r e r a n g e from -55' t o +lOO°C. An i n p u t s i g n a l c o n t a i n i n g second harmonic was f e d i n t o t h e c i r c u i t and r e s u l t e d i n t h e g a i n f u n c t i o n shown i n t h e graph of F i g u r e 3-3. A 20-percent second harmonic con- t e n t a f f e c t s t h e g a i n by o n l y 2 p e r c e n t ( o r +1 p e r c e n t of a normal ized g a i n v a l u e ) .

Conc lus ions : An ac/dc c o n d i t i o n e r of t h e t y p e d e s c r i b e d above i s c o n s i d e r e d s a t i s f a c t o r y f o r t h i s a p p l i c a t i o n . Commercially produced a c m e t e r s o f t h e r e c t i f i e r t y p e have a d e f l e c t i o n p r o p o r t i o n a l t o t h e average v a l u e of t h e a p p l i e d s i g n a l . However, t h e y a r e u s u a l l y c a l i - b r a t e d i n r m s v a l u e s f o r a s i n u s o i d a l i n p u t and would, t h e r e f o r e , s u f f e r from t h e same e r r o r d e t a i l e d i n t h e g a i n a n a l y s i s f o r a s i g n a l w i t h harmonic c o n t e n t .

Page 3-10

I DEMODULATOR ACTIVE FILTER

FIGURE 3-2. AC-TO-DC CONDITIONER

0 5 10 15 20 2 5 30 35

HARMONIC, %

FIGURE 3-3. GAIN VARIATION VERSUS HARMONIC CONTENT FOR AC TO DC SIGNAL CONDITIONER

Page 3-12

Three-Phase Power Measurement

The t o t a l power measurement i n v o l v e s n o n s i n u s o i d a l v o l t a g e s and c u r r e n t s . For t h i s r e a s o n , a s t r a i g h t f o r w a r d synchronous demodulator and m u l t i p l i e r c i r c u i t , where t h e m u l t i p l i e r i n p u t s a r e d c a n a l o g s , cannot be used. I n s t e a d , t h e chosen method i s a m u l t i p l i c a t i o n of t h e i n s t a n t a n e o u s v a l u e s of v o l t a g e and c u r r e n t , and t h e r e s u l t i n g i n s t a n - taneous power is summed f o r t h e t h r e e phases and t h e n f i l t e r e d t o g i v e t h e average power a s a d c ana log v o l t a g e o u t p u t .

The sys tem u s e s a q u a r t e r s q u a r e - m u l t i p l i e r based on t h e a l g e b r a i c e x p r e s s i o n :

The s q u a r i n g i s done by a d i o d e f u n c t i o n g e n e r a t o r , which gener- a t e s a p a r a b o l a by s t r a i g h t - l i n e approximat ions . The f u n c t i o n gener- a t o r a c c e p t s a n e g a t i v e i n p u t o n l y . For t h i s r e a s o n , a demodulator i s i n c l u d e d i n t h e sum and d i f f e r e n c e i n p u t s t a g e s . The ( V + I I 2 and (V - I ) ~ f u n c t i o n g e n e r a t o r s use a common o u t p u t s t a g e , and t h e r e s u l t - i n g V I a c a n a l o g i s summed w i t h t h e o t h e r two phase ana logs and f i l - t e r e d i n t h e f i n a l two-pole a c t i v e f i l t e r s t a g e .

The c o n d i t i o n e r w i l l p robab ly be a c c u r a t e w i t h i n 2 1 / 2 p e r c e n t over t h e working t e m p e r a t u r e s of 20' t o 65.5OC, r i s i n g t o 9 1 / 2 per - c e n t over t h e f u l l range of -55' t o +125OC due t o d iode t e m p e r a t u r e d r i f t . Matched d i o d e s would reduce t h e s e e r r o r s . The d i o d e d r i f t could be reduced by t h e a d d i t i o n of an o p e r a t i o n a l a m p l i f i e r a round each d i o d e , b u t t h i s would r e q u i r e an a d d i t i o n a l 2 4 a m p l i f i e r s i n t h e t o t a l power c o n d i t i o n e r . The accuracy i n t h i s c a s e would p robab ly b e w i t h i n 2 p e r c e n t .

The c i r c u i t s a r e s c a l e d t o p rov ide a 0- t o 5-v a n a l o g f o r 0- t o 15-kw l o a d s . T o t a l a l t e r n a t o r l o a d and t h e v e h i c l e load a r e moni tored .

Freauencv-to-DC Conversion

The f requency- to-dc c o n v e r t e r g e n e r a t e s a d c v o l t a g e p r o p o r t i o n a l t o t h e i n p u t f requency. The c o n d i t i o n e r i n c l u d e s c o n v e r t e r s t o pro- v i d e 0- t o 5-v a n a l o g s f o r f requency ranges of 0- t o 1200-, 0- t o 1440-, and 0- t o 2000-Hz. The i n p u t s i g n a l may va ry from 1 2 mv t o 200 v. The c i r c u i t s a r e a c c u r a t e t o w i t h i n t 0 . 5 p e r c e n t o v e r t h e -65' t o 150°F c o l d - p l a t e t empera tu re range . A l i m i t a t i o n of t h e c i r c u i t i s t h a t t h e o u t p u t d e c r e a s e s t o a b o u t 3 v i f t h e i n p u t f requency exceeds t h e f u l l - s c a l e r ange .

The c o n v e r t e r c o n s i s t s of s i x d i f f e r e n t f u n c t i o n a l b l o c k s : (1) i n p u t s t a g e , ( 2 ) one s h o t , ( 3 ) decade c o u n t e r i ( 4 ) s w i t c h , ( 5 ) f i l t e r and o u t p u t , and ( 6 ) a d i g i t a l o u t p u t . The c i r c u i t a l s o r e q u i r e s o t h e r i n p u t such a s r e f e r e n c e v o l t a g e , c l o c k s i g n a l , and power s u p p l i e s .

Page 3-13

T h i s c i r c u i t is i n t e n d e d t o a c c e p t a d i f f e r e n t i a l i n p u t and p ro - d u c e a l:l o u t p u t r e f e r e n c e d t o s i g n a l g round . The o u t p u t c i r c u i t h a s a 510-ohm r e s i s t o r i n s e r t e d i n series w i t h t h e l o a d s o t h a t e x t e r n a l m a l f u n c t i o n i n g , e i t h e r i n t h e Load c i r c u i t o r t h e c a b l e s ( e . g . , a s h o r t t o g r o u n d ) , w i l l n o t damage t h e s i g n a l c o n d i t i o n e r . The c i r - c u i t r y h a s a n a c c u r a c y o f +1 p e r c e n t .

Seven b a s i c c o n t r o l c i r c u i t s were d e s i g n e d f o r t h i s sy s t em:

( a ) Con t inuous d r i v e r ( v a l v e c o n t r o l )

( b ) L a t c h i n g d r i v e r ( j a c k i n g - g a s v a l v e c o n t r o l )

( c ) P u l s e d r i v e r - ground c o n t r o l ( l a t c h i n g r e l a y c o n t r o l )

( d ) P u l s e d r i v e r ( l i q u i d l o o p pump c o n t r o l )

( e ) B a t t e r y c h a r g e r c o n t r o l

( f ) Speed c o n t r o l o v e r r i d e

( g ) Emergency shutdown (EMES)

S e v e r a l b a s i c t e c h n i q u e s were u sed i n t h e BCS t o meet t h e " n o s i n g l e f a i l u r e s h a l l r e s u l t i n l o s s of power" r e q u i r e m e n t . The b a s i c c o n t r o l c o n c e p t i s shown i n F i g u r e 3-4. T r i p l e - r e d u n d a n t ( t r i d u n d a n t ) a n a l o g s i g n a l s a r e t r a n s m i t t e d t o t h e c o n s o l e . An a n a l o g s e l e c t c i r - c u i t compares t h e s i g n a l s , s e l e c t s one t h a t a g r e e s w i t h a t l e a s t o n e of t h e o t h e r s i g n a l s , and t r a n s m i t s it t o t h e c o n t r o l l o g i c . Comple- men ta ry c o n t r o l s i g n a l s a r e t r a n s m i t t e d t o a r e c e i v e r i n t h e s i g n a l c o n d i t i o n e r t h a t c o n t r o l s t h e d r i v e r c i r c u i t . F i g u r e 3-5 shows a r e d u n d a n t c o n t r o l l o g i c c i r c u i t . O v e r r i d e l o g i c i s p r o v i d e d i n t h e s i g n a l c o n d i t i o n e r t o a l l o w engine-mounted emergency shutdown c i r - c u i t r y t o o v e r r i d e c o n t r o l s t o t h e d e s i r e d s t a t e ( F i g u r e 3 - 6 ) . S e v e r a l v a r i a t i o n s o f t h e d r i v e c i r c u i t a l l o w imp lemen t ing p r e f e r r e d f a i l u r e mode r e q u i r e m e n t s . A l l c o n t r o l c i r c u i t s u t i l i z e a two-wire d i f f e r e n t i a l i n p u t f rom t h e c o n t r o l c o n s o l e t o r e q u i r e ag reemen t f o r a c t u a t i o n o f t h e c o n t r o l c i r c u i t .

To t u r n t h e d r i v e r o n , i t is n e c e s s a r y t o have a h i g h s i g n a l on t h e p l u s i n p u t and a low s i g n a l on t h e minus i n p u t ; two h i g h s o r two lows w i l l n o t o p e r a t e t h e d r i v e r , T h i s t y p e of d i f f e r e n t i a l / r e c e i v e r f o r t h e d r i v e r s p r e v e n t s s i n g l e f a i l u r e s f rom o p e r a t i n g t h e v a l v e s o r

Page 3-14

I 128 VDC

I I 1 I TRANSMISSION I I I I

TRI- DUNDANT ,,, T F a N S - DUCERS

Q (D

W I I--' w

I I I I

RECEIVER

F I G U R E 3-4 . B A S I C CONTROL C I R C U I T

TRIDUNDANT TRANSDUCERS

R E C E I V E R

FIGURE 3-5, REDUNDANT CONTROL L O G I C

uvLnu

I N H I B I T I I

LOCAL I

OVERRIDE -.__._.. - I OVERRIDE L O G I C

TO CONTROL ELEMENT

C O I L

FIGURE 3 - 6 , OVERRIDE LoeIe

Page 3-16

the relays (Figure 3 - 7 ) . All circuits were analyzed for failure mode effects. The following types of redundancies were incorporated as necessary to meet system requirements:

(a) Series

(b) Parallel

(c) Triple-redundant

For controls where the preferred failure mode is OFF, series redundant drivers are used (Figure 3-8). If either of the drivers fail ON, the circuit will operate the control element normally. How- ever, if either driver fails OFF, the circuit will cause the control element to remain in its preferred failure mode.

For controls where the preferred failure mode is ON, parallel redundant drivers are used (Figure 3-9). If either driver fails OFF, the control element can still be controlled normally. However, if either fails ON, the circuit will cause the control element to go to its preferred failure mode.

For critical circuits where it is necessary to retain control of an element even if a driver fails, triple-redundant circuits are used (Figure 3-10). If any one of the drivers fails ON or OFF, the circuit can still provide normal operation of the control element.

Continuous Driver

The driver to control valves consists of a discrete receiver, logic control, and power amplifier. The receiver accepts either a positive or negative differential input voltage, and the driver output is a switched-ground capable of passing a 2-amp load current from a +2 8-v source.

The receiver consists of a PA 709 operational amplifier, with differential input to eliminate common-mode effects. An 11:l voltage division on each input allows voltage variation of +1 to +55 vdc for the ON condition and 0 to -55 vdc for the OFF condition.

A small positive bias is added to the positive input of the PA 709 to shift the operating threshold to approximately +0.9 v, as shown below.

Page 3-17

t 2 8 VDC

CONTROL

OPERATIONAL A M P L I F I E R ELEMENT

C O I L

COMMAND S I G N A L S

R E C E I V E R DRIVERfr

~ 2 8 VDC


CONTROL ELEMENT

co I L


FIGURE 3 - 8 , SERIES RECEIVFR/DRIVER (FAIL OFF)

Page 3-18

+ 2 8 VDC


CONTROL ELEMENT

C O I L


FIGURE 3-9. PARALLEL REDUNDANT RECEIVER/DRIVER ( F A I L ON)

~ 2 8 VDC


ENGINE CONTROL ELEMENT

P a g e 3-19

T h i s i s t o e n s u r e t h a t , i n t h e e v e n t o f a t r a n s m i s s i o n l i n e f a i l u r e when t h e i n p u t d i f f e r e n t i a l would b e z e r o , t h e d r i v e r w i l l r e t u r n t o t h e OFF c o n d i t i o n .

L a t c h i n g D r i v e r

The l a t c h i n g d r i v e r u s e d t o c o n t r o l t h e j a c k i n g - g a s v a l v e s , d i f - f e r s f rom t h e c o n t i n u o u s d r i v e r i n o n l y two r e s p e c t s : namely, t h e l a t c h i n g d r i v e r h a s no i n h i b i t i n p u t , and i t s r e c e i v e r h a s h y s t e r e s i s i n s t e a d o f p o s i t i v e b i a s . The h y s t e r e s i s i s a c h i e v e d by a d d i t i o n o f a s m a l l amount o f p o s i t i v e f eedback and g i v e s a n o u t p u t a s shown be low.

Page 3-20

This i s t o ensure t h a t i n t h e e v e n t of a t r a n s m i s s i o n l i n e f a i l u r e , when t h e i n p u t d i f f e r e n t i a l w i l l be z e r o , t h e d r i v e r w i l l remain i n i t s l a s t commanded p o s i t i o n .

P u l s e D r i v e r - Ground C o n t r o l

The p u l s e d r i v e r f o r c o n t r o l l i n g l a t c h i n g r e l a y s c o n s i s t s o f a d i s c r e t e r e v e i v e r , l o g i c c o n t r o l , and two one-sho t and power -ampl i f i e r s t a g e s . The r e c e i v e r a c c e p t s e i t h e r a p o s i t i v e o r n e g a t i v e d i f f e r e n - t i a l i n p u t v o l t a g e , and t h e d r i v e r o u t p u t i s a pulsed-ground t o t h e " l a t c h " l o a d o r t h e " d e l a t c h " load . The o u t p u t s t a g e i s c a p a b l e of p a s s i n g a 0 .5 - sec , 2-amp l o a d c u r r e n t from a +28-v s o u r c e .

The r e c e i v e r i s i d e n t i c a l w i t h t h e l a t c h i n g d r i v e r r e c e i v e r . I t a c c e p t s a d i f f e r e n t i a l i n p u t v o l t a g e v i a a v o l t a g e d i v i d e r , and t h e yA 7 0 9 , h a s p o s i t i v e feedback t o add h y s t e r e s i s .

The l o g i c c o n t r o l i s i d e n t i c a l w i t h t h a t o f t h e con t inuous d r i - v e r , w i t h o v e r r i d e and i n h i b i t i n p u t .

P u l s e D r i v e r - P o s i t i v e C o n t r o l

Purpose of t h e 5-v p u l s e r u n i t i s t o d r i v e l o g i c l e v e l p u l s e s , one each a s commanded from t h e c o n t r o l p a n e l , t o c o n t r o l t h e two coo l - a n t pumps.

The u n i t i s des igned t o : p u l s e "on" t h e c o o l a n t pump; p u l s e " o f f t h e c o o l a n t pump.

I f a d i f f e r e n t i a l e x i s t s s o t h a t i n p u t l e a d - N o . 1 i s p o s i t i v e w i t h r e s p e c t t o i n p u t l e a d No. 2 , t h e r e c e i v e r w i l l r e c o g n i z e a command and supp ly a 3-v, 0.5-sec p u l s e t o " t u r n on" t h e pump. I f No. 2 i s p o s i t i v e w i t h r e s p e c t t o No. 1, an "o f f " p u l s e w i l l be g e n e r a t e d . Only one p u l s e w i l l be f u r n i s h e d , no m a t t e r how long t h e s i g n a l i s r e c e i v e d .

B a t t e r y Charger C o n t r o l

The b a t t e r y c h a r g e r s normal ly o p e r a t e a u t o m a t i c a l l y a s r e q u i r e d ; however, o v e r r i d e l o g i c i s i n c l u d e d . A 28-v, 30-ma s i g n a l on one l e a d w i l l t u r n t h e c h a r g e r on and a 28-v, 30-ma s i g n a l on t h e o t h e r l e a d w i l l t u r n t h e c h a r g e r o f f . No s i g n a l r e s u l t s i n au tomat ic o p e r a t i o n . A series o f two d r i v e r c i r c u i t s a s s u r e s t h a t a f a i l u r e w i l l r e s u l t i n a u t o m a t i c o p e r a t i o n .

VRE C o n t r o l

The a l t e r n a t o r v o l t a g e r e g u l a t o r may be i n h i b i t e d w i t h a 28-v s i g n a l . T h i s i s accomplished w i t h two s i n g l e - b a t t e r y c h a r g e r d r i v e r c i r c u i t s i n p a r a l l e l . Th i s r e s u l t s i n an " i n h i b i t on" as t h e pre- f e r r e d f a i l u r e mode t o a s s u r e removal of e x c i t a t i o n d u r i n g s t a r t - u p and shutdown.

Page 3-21

Speed C o n t r o l o v e r r i d e

The speed c o n t r o l c o n s i s t s of t h r e e independent u n i t s a s shown below. Each u n i t v a r i e s p a r a s i t i c l o a d i n g a s a f u n c t i o n of d e v i a t i o n of a l t e r n a t o r f requency from t h e s e t - p o i n t f requency ( 1 2 0 0 H z n o m i n a l ) . Each speed c o n t r o l may be o v e r r i d d e n o r i n h i b i t e d v i a two c o n t r o l p o i n t s .

$A D E V I A T I O N PARASITIC (FREQ)

DETECTOR

OVERRIDE (OFF)

OVERRIDE ( O N ) 1

TYPICAL SPEED CONTROL

The o v e r r i d e c i r c u i t r y a l l o w s f o u r o p e r a t i n g modes:

( a ) Automatic p a r a s i t i c c o n t r o l wi th a u t o m a t i c o v e r r i d e from c o n t r o l p a n e l l o g i c

( b ) Automatic p a r a s i t i c c o n t r o l w i t h o v e r r i d e o f f

( c ) Over r ide t o t u r n p a r a s i t i c l o a d f u l l ON

( d ) O v e r r i d e t o t u r n p a r a s i t i c load f u l l OFF

An independent o v e r r i d e c i r c u i t i s provided f o r each of t h e t h r e e speed c o n t r o l s . C i r c u i t l o g i c p r e v e n t s a s i n g l e f a i l u r e from t u r n i n g t h e c o n t r o l on o r o f f . The p r e f e r r e d method of c o n t r o l i n t h e e v e n t of f a i l u r e i s t o t u r n t h e load f u l l OFF, a s t h e two remaining c o n t r o l s can app ly s u f f i c i e n t l o a d i n g t o m a i n t a i n eng ine speed c o n t r o l .

Page 3 - 2 2

Ensine-Mounted Emeraencv Shutdown Svstem

The purpose of t h e engine-mounted emergency shutdown sys tem (EMES) i s t o s e n s e t h a t normal e n g i n e speed c o n t r o l has n o t o p e r a t e d c o r r e c t l y and t h a t t h e e n g i n e i s i n danger o f runaway overspeed , and hav ing s e n s e d t h e overspeed , t o s h u t down t h e e n g i n e -

The eng ine speed i s normal ly c o n t r o l l e d by t h e p a r a s i t i c l o a d t o w i t h i n 2 1 p e r c e n t o r b e t t e r . A backup c o n t r o l through t h e c o n t r o l p a n e l s h o u l d h o l d speed t o w i t h i n +5 p e r c e n t of normal i f t h e normal c o n t r o l f a i l s . I f b o t h t h e normal and backup sys tems f a i l , t h e EMES sys tem must s h u t down t h e e n g i n e . E n t r y from t h e c o n t r o l p a n e l t o t h e EMES sys tem i s p rov ided s o t h a t t h e engine-mounted-emergency shutdown mechanisms may b e u t i l i z e d from t h e c o n t r o l p a n e l i f r e q u i r e d .

The p a r a s i t i c l o a d normal ly c o n t r o l s eng ine speed . A t t h e t i m e t h a t t h e EMES sys tem i s a c t u a t e d , it must be assumed t h a t t h e pa ra - s i t i c l o a d i s p robab ly i n e f f e c t u a l . Prime r e l i a n c e i s p l a c e d , t h e n , on t h e o p e r a t i o n of t h e dump v a l v e f o r shutdown r e l i a b i l i t y . Major e f f o r t i s a l s o e x e r t e d t o open jacking-gas v a l v e s t o p r o t e c t t h e e n g i n e b e a r i n g s .

Normal channe l s f o r c o n t r o l of t h e dump v a l v e and pr imary jacking-gas v a l v e s a r e t r i p l e - r e d u n d a n t s o t h a t no s i n g l e f a i l u r e may e i t h e r o p e r a t e o r i n h i b i t t h e i r f u n c t i o n . This a l s o a f f o r d s conven- i e n t e n t r y f o r t h e t r i p l e - r e d u n d a n t EMES s i g n a l s .

Opera t ion i s a s f o l l o w s :

( a ) Three s e p a r a t e speed s i g n a l s ( 0 t o 5 v ) d e r i v e d from t h e a l t e r n a t o r a r e f e d t o s e p a r a t e compara tors . I f any o f t h e v o l t a g e s ( 0 t o 5 v ) i n d i c a t e speed i n e x c e s s of 15-percen t overspeed (115-percent of n o r m a l ) , t h a t comparator produces a n o u t p u t t h a t c o n n e c t s i n p a r a l l e l w i t h t h e manual c o n t r o l s i g n a l t o a l a t c h i n g shutdown/rese t r e c e i v e r , The o u t p u t of t h e r e c e i v e r i s f e d , w i t h t h o s e of t h e o t h e r two r e c e i v e r s , t o a l o g i c c i r c u i t , a l s o t r i p l e - r e d u n d a n t .

( b ) Output of t h e t h r e e l o g i c c i r c u i t s a r e connected t o c o r r e s - ponding d r i v i n g s e c t i o n s ( o v e r r i d i n g normal s i g n a l s ) o f t h e dump v a l v e and pr imary jacking-gas v a l v e s . Note t h a t no one - l o g i c c i r c u i t can o p e r a t e any v a l v e ; agreement o f two i s r e q u i r e d t o accomplish shutdown.

Page 3-23

( c ) The l o g i c o u t p u t a l s o o v e r r i d e s c o n t r o l of o t h e r b r e a k e r s , v a l v e s , e t c . , t o t h e d e s i r e d p o s i t i o n s ( o v e r r i d e o r i n h i b i t ) f o r t h e shutdown o p e r a t i o n . Two channe l s a r e p rov ided , s i n c e most a f f e c t e d f u n c t i o n s a r e dual - redundant , t o f o r c e f a i l u r e s i n t o a c c e p t a b l e modes. A c t u a t i o n through d u a l channe l s p r e s e r v e s such fa i lure-mode p r e f e r e n c e s .

( d ) "Rese t " i s accomplished when t h e "shutdown/rese t r e c e i v e r s " r e c e i v e a r e s e t p u l s e from t h e c o n s o l e .

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4, PONER AIdB S% GUAL TRAI4SIlISS I ON CABLE

The power and s i g n a l t r a n s m i s s i o n c a b l e i s des igned and f a b r i - c a t e d t o o p e r a t e w i t h o u t system mal func t ion o r performance d e g r a d a t i o n f o r a p e r i o d of 5 y r when s u b j e c t e d t o t h e s p e c i f i e d envi ronment . The c o n d i t i o n s i n c l u d e " o p e r a t i o n a l envi ronments" and " t r a n s p o r t a t i o n envi ronments ." These c o n d i t i o n s a r e a p p l i c a b l e t o t h e sys tem through a l l phases of t h e 5-yr l i f e c y c l e , such a s manufactur ing and f a b r i c a - t i o n , t r a n s p o r t a t i o n , s t o r a g e , h a n d l i n g , i n s t a l l a t i o n , and o p e r a t i o n . During a p o r t i o n of t h e o p e r a t i o n a l envi ronment , t h e 1 0 0 - f t segment of t h e t r a n s m i s s i o n c a b l e connected t o t h e s i g n a l c o n d i t i o n e r may be s u b j e c t e d t o n u c l e a r r a d i a t i o n .

The d a t a t r a n s m i s s i o n sys tem had t o be l o c a t e d a t t h r e e s e p a r a t e f a c i l i t i e s . Th i s n e c e s s i t a t e d two s e p a r a t e c a b l e sys tems, a s f o l l o w s :

( a ) Three segments f o r t h e space power f a c i l i t y , amounting t o 400 f t

( b ) Two segments f o r use a t AiResearch d u r i n g accep tance t e s t s and l a t e r a t Lewis Research C e n t e r , amounting t o 65 f t

The c a b l e segments a r e shown i n F i g u r e 4 - 1 w i t h r e f e r e n c e s t o t h e i r r e s p e c t i v e l e n g t h s .

CABLE DESCR I PTIONS ,

The sys tem c o n s i s t s of 11 c a b l e s i n f o u r groups:

( a ) Power - Two c a b l e s w i t h 20 No. 16 AWG conduc to r s and one s h i e l d i n each c a b l e

( b ) Analog S i g n a l - Three c a b l e s w i t h 36 No. 20 AWG c o n d u c t o r s , two No. 16 AWG conduc to r s , and one s h i e l d i n each c a b l e

( c ) D i s c r e t e Con tac t s - Two c a b l e s w i t h 4 0 No. 20 AWG conduc to r s and one s h i e l d i n each c a b l e

7 -

( d ) D i s c r e t e Commands - Four c a b l e s w i t h 1 0 No. 2 0 AWG t w i s t e d s h i e l d e d p a i r s and one o v e r a l l s h i e l d i n each c a b l e

The t o t a l we igh t of t h e c a b l e s i s approximate ly 4.8 l b / f t .

The c a b l e sys tem i s des igned i n such a manner t h a t mismat ing o r t r a n s p o s i n g i s i m p o s s i b l e . The d e s i g n i s such t h a t any g i v e n segment may be removed and t h e remaining segments can be mated t o t h e open r e c e p t a c l e s w i t h o u t m o d i f i c a t i o n t o t h e sys tem,

Page 4 - 1

SEGMENT

SIGNAL CONTROL

CONDITIONER CONSOLE

S P A C E P O W E R F A C I L I T Y

SEiMENT

SIGNAL :' 50 CONTROL

CONDlTIONCR CONSOLE

L E W I S R E S E A R C H C E N T E R

FIGURE 4-1. POWER AND TRANSMISSION CABLE LENGTHS

Each c o n n e c t o r and c a b l e assembly i s i n d e p e n d e n t l y i d e n t i f i e d , and a l l ma t ing c o n n e c t o r s have c o l o r i n d i c a t o r s f o r p r o p e r k e y i n g and p o s i t i o n i n g .

Connectors

The c o n n e c t o r s , p l u g s , r e c e p t a c l e s and through-bulkhead f i t t i n g s (TBF) a r e of t h e NAS-1599 type and c o n f i g u r a t i o n b u t a r e n o t NAS-1599 s p e c i f i c a t i o n - t e s t e d components. A l l c o n n e c t o r s ( e x c l u d i n g t h e TBF1s) have been manufactured and f a b r i c a t e d t o t h e f o l l o w i n g d e t a i l s :

( a ) Connec to r s , w i t h p l u g s and r e c e p t a c l e s , a r e of t h e C l a s s "G" e n v i r o n m e n t - r e s i s t a n t type .

( b ) Connector s h e l l s a r e manufactured of aluminum a l l o y and c o a t e d w i t h a c o n d u c t i v e - n i c k e l .

( c ) C o n t a c t s of t h e No. 16 and 20 AWG, e x c e p t t h e thermocoup1.e c o n t a c t s on t h e eng ine s i d e of t h e s i g n a l c o n d i t i o n e r , a r e of c o p p e r - a l l o y and a r e g o l d - p l a t e d ( e l e c t r o - d e p o s i t e d ) i n accordance w i t h IG-G-45204 S p e c i f i c a t i o n .

( d ) The s e a l i n g grommet i s a s i l i c o n e - b a s e e l a s t o m e r and of t h e " d o u b l e - r i p p l e " d e s i g n .

(e) The i n s u l a t o r s a r e of t h e r m o s e t t i n g p l a s t i c .

W i r e

The w i r e used i n t h e manufac tu r ing and f a b r i c a t i o n of t h e d a t a t r a n s m i s s i o n l i n k sys tem c o n s i s t s of two s i z e s , No. 16 and 20. These a r e AWG s i n g l e - c o n d u c t o r s w i t h No. 20 t w i s t e d - s h i e l d e d p a i r s .

The c o n n e c t o r s f o r f a b r i c a t i n g t h e segments of c a b l e which a r e n o t s u b j e c t e d t o t h e n u c l e a r environment do n o t u s e b a c k s h e l l s , b u t a l l p l u g s a r e p r e p o t t e d w i t h epoxy 2850FT o r e q u i v a l e n t and hot-molded w i t h Hunt ington Rubber M i l l s N262U Neoprene. T h i s was n e c e s s a r y t o m e e t c u r i n g t e m p e r a t u r e l i m i t a t i o n s f o r t h e v i n y l i n s u l a t e d w i r e . Four d i f f e r e n t t y p e s of c a b l e co r respond ing t o each of t h e l a y o u t s were r e q u i r e d . I n s u l a t i o n i s Type BN p e r MIL-W-16878/1 and t h e j a c k e t i s p e r MIL-R-6855, Grade 60, Type 11. A l l c a b l e s i n c l u d e o v e r a l l s h i e l d s t h a t a r e t e r m i n a t e d t o a c o n t a c t a t b o t h ends i n each o f t h e c o n n e c t o r s .

Cable f o r t h e Type 18-32 connec to r s c o n s i s t s of 10 No. 20 t w i s t e d p a i r s , s h i e l d e d and j a c k e t e d w i t h o v e r a l l s h i e l d . Each of t h e s h i e l d s i s t e r m i n a t e d t o c o n t a c t s i n t h e c o n n e c t o r s .

Page 4-3

APS -5284-R24

The segment that will be subjected to the nuciear environment is polyethylene insulated wire and cable jacket. All cables correspond to the connector% layout except the Type 18-32 connector, which consists of 10 No. 20 twisted pairs. All have overall shields terminated to one pin in each connector.

The polyethylene insulated wire is per MIL-W-16878, Type J, and the jacket is polyethylene per MIL-LP-590.

The cable is designed to withstand temperature and humidity vari- ations, sand and dust specifications, nuclear radiation, and electromagnetic interference.

Temwerature

The cable, inside and outside the hard-vacuum (1~-* torr) environment, can withstand thermal variation from -65' to +160°F.

Humiditv

The cable, inside and outside the hard-vacuum environment, can withstand humidity variation over a 24-hr period as follows:

(a) Six hours of 9g°F with 50-percent relative humidity and vapor concentration of 26.9 gm/m3

(b) Six hours of 76OF with 100-percent relative humidity

(c) Eight hours of 70°F with 3.9 gm of ~ ~ 0 / m ~ of air with the humidity remaining at 100 percent

(d) Four hours of 9g°F with 41-percent relative humidity

The above temperatures and relative humidity are considered worst-case conditions and are three-sigma values.

Sand and Dust

The cable system outside the hard-vacuum can withstand the environment specified by MIL-STD-810B Method 510.

Nuclear Radiation

The cable assembly that will be placed in the hard-vacuum environment can withstand a nuclear radiation integrated dosage of 5 x 1010 nvt and 5 x 105 rad 6.

Page 4-4

Electromaanetic Interference Shieldins

All cabling in and out of the vacuum chamber is shielded from either radiated or conducted interference. This shielding is in accordance with Vol. IV Aerospace Systems Design "Electromagnetic Compatibility" and MIL-STD-826A.

Page 4-5

The c o n t r o l and moni to r ing p a n e l s a r e t h e i n t e r f a c e between t h e o p e r a t o r and t h e power system. The c o n t r o l p a n e l p r o v i d e s t h e s t a r t - up and shutdown l o g i c , c o n t r o l and p r o t e c t i o n c i r c u i t s , c o n t r o l hardware s t a t u s , and power sys tem s t a t u s f o r t h e o p e r a t o r . The c o n t r o l p a n e l a l s o p e r m i t s t h e o p e r a t o r t o manually o v e r r i d e any a u t o m a t i c c o n t r o l f u n c t i o n s . The moni to r ing p a n e l i s a supplement t o t h e con- t r o l p a n e l and s u p p l i e s a d d i t i o n a l s t a t u s i n f o r m a t i o n d u r i n g development t e s t i n g ,

The f o l l o w i n g s e c t i o n s d i s c u s s t h e c o n t r o l and moni to r ing p a n e l d e s i g n s . S p e c i a l a t t e n t i o n i s g i v e n t o human-factor c o n s i d e r a t i o n s i n p a n e l l a y o u t , c o n t r o l , and p r o t e c t i o n c i r c u i t d e s c r i p t i o n s and s p e c i a l c i r c u i t s .

The c o n t r o l p a n e l c o n s i s t s of 11 i n d i v i d u a l c o n t r o l and p r o t e c - t i o n module f r o n t p a n e l s , a s d e f i n e d i n t h e c o n t r a c t . The ar rangement of t h e c o n t r o l s and d i s p l a y s was de termined by a thorough e v a l u a t i o n of t h e human-factors r e q u i r e m e n t s . The d e s i g n has been o p t i m i z e d f o r o p e r a t i o n by a s i n g l e o p e r a t o r . The human e n g i n e e r i n g d e s i g n p r o c e s s , implemented through t h e a p p l i c a t i o n of documented human e n g i n e e r i n g p r i n c i p l e s and t o o l s (such a s f u l l - s c a l e mock-ups), was a p p l i e d d u r i n g BCS c o n s o l e d e s i g n . Confidence i n h igh sys tem r e l i a b i l i t y was g a i n e d through c o n s i d e r a t i o n of t h e man-machine i n t e r f a c e e a r l y i n t h e d e s i g n p r o c e s s .

I n a sys tem development program (such a s t h e BCS program) where man i s a n i n t e g r a l p a r t , c a r e f u l c o n s i d e r a t i o n must be g iven t o man- machine i n t e r a c t i o n . I f t h e man-machine sys tem i s t o perform a t i t s b e s t , t h e d e s i g n must beg in and r e v o l v e around t h e human components and t h e i r c a p a b i l i t i e s .

Although t h e BCS o f f e r s f u l l y a u t o m a t i c c o n t r o l of t h e BPS, t h e c o n t r o l p a n e l was des igned t o f a c i l i t a t e manual c o n t r o l d u r i n g o f f - normal development t e s t i n g . C o n s i d e r a t i o n was g i v e n e a r l y i n t h e BCS d e s i g n phase t o human f a c t o r s r e l a t i n g t o s e a t i n g , component s e l e c t i o n , d a t a d i s p l a y , p a n e l l a y o u t , and v i s u a l and p h y s i c a l a c c e s s .

I n conduc t ing t h e BCS human e n g i n e e r i n g s t u d y , t h e NASA S t a n d a r d f o r Human E n g i n e e r i n g Design C r i t e r i a (MSFC-STD-267A) and The Human Engineer ing Guide t o Equipment Design, Morgan, e t a l , were used a s t h e major d e s i g n r e f e r e n c e s . In fo rmat ion based upon space f l i g h t e x p e r i e n c e was o b t a i n e d from t h e NASA MSC human f a c t o r e n g i n e e r i n g s t a f f . Major s u g g e s t i o n s were:

Page 5-1

(a) Divide the subsystems into functional groupings and use subgraphics

(b) Use lights only where required to gain immediate attention (not for status) to perform a task. (Do not annunciate unless a corrective measure is needed and possible.)

Proposal Mock-Up

A mock-up of the BCS control and monitoring panel, described in the proposal, was constructed and its design evaluated from a human engineering standpoint. A photograph of the mock-up for the proposed BCS is shown in Figure 5-1. Based on the proposal mock-up evaluation, the following recommendations were made; these served as guides to construction of the Task I mock-up:

(a) A semicircular configuration would greatly facilitate panel operation, the modules of least importance being at the ends of the semicircle. The more important modules would be cen- tralized, and no module would be below the level of the workshelf or above eye level of a seated operator. (For example: The valve module should be more centrally located than in the proposed configuration.)

(b) Each module should be reduced in size and complexity of dis- play, if possible. Specifically, an effort should be made to eliminate the superabundance of lights on some modules.

(c) A panel of critical system parameter indicators and alarms should be located centrally on the control console. These indicators would serve as instant trouble spotters, monitoring such things as loop temperatures, pressures, and rotating speeds.

(d) Incorporation of the graphic panel, in reduced size, in the panel workshelf (perhaps internally illuminated) should be considered, also semi-graphic displays on certain control panels to improve comprehension.

Task I Mock-up

As a result of recommendations for the proposal mock-up evaluation, changes in BCS design requirements, and other refinements in the problem definition, a complete redesign of the control console was effected.

Page 5-2

The human engineering study leading to the Task I design was conducted primarily in the following areas:

(a) Workplace dimensions

(b) Location of controls and displays

(c) Selection of controls and displays

(d) Control panel mechanical design

Other areas of change also existed. In general, all proposal mock-up recommendations previously listed were incorporated into the Task I design.

Workplace Dimensions: Determination of workplace dimensions was based upon the proposal mock-up evaluation, data in the aforementioned references, and certain constraints, such as number and size of the various modules and the number of console operators (one or two). Refinement and simplification of the various modules reduced the number of control and monitoring consoles to four, grouped in a configuration that would afford one or two operators maximum ease and sim- plicity of operation.

Location of Controls and Displays: The control panel cabinetry was designed with control accessibility and visual clarity as prime considerations. All components were grouped on the control panels by sequence of operation or according to function. Hardware, color- coding, physical layout, lettering and abbreviations, and panel-to- panel repetitive grouping were used consistently throughout the BCS to (1) benefit operator training, (2) improve maintenance, and (3) maximize overall operating efficiency.

Below are the major design features (and philosophies) of the console :

(a) The most critical and frequently used modules are given preferential positioning in the operator's primary field of vision.

(b) The panels are sloped at an angle of 15 deg, permitting the operator to observe the components as directly as possible with a minimum of parallax (the operator's line-of-sight to the center of the panel is perpendicular).

(c) The control panel is designed with shadow-box trim to reduce reflective glare from facility sources.

Page 5-4

jd) The b a s i c c a b i n e t i s designed t o prevent ope ra to r f a t i g u e du r ing long t e s t ope ra t ion . For convenience, maximum l e g room and optimum w r i t i n g su r f ace he igh t i s combined wi th minimum console and maximum ( sea t ed ) v i s i b i l i t y , pe rmi t t i ng t h e ope ra to r v i s u a l c o n t a c t wi th o t h e r s i n t h e c o n t r o l com- p l ex .

( e ) Bonded t o t h e conso le w r i t i n g su r f ace is a g raph ic system l ayou t f o r r e f e rence and ready awareness of t h e f u n c t i o n a l r e l a t i o n s h i p of c o n t r o l s and t h e Brayton system,

( f ) Subgraphics a r e u sed ,on t h e i n d i v i d u a l modules, where prac- t i c a l , t o s i m p l i f y o p e r a t o r t r a i n i n g and c o n t r i b u t e t o i nc reased awareness of t h e c o n t r o l func t ion involved.

Cont ro l s and d i s p l a y s ( three-dimensional) were s imula ted i n t h e Task I 'BCS console mock-up shown i n Figure 5-2 . This mock-up al lowed f u r t h e r eva lua t ion of con t ro l -d i sp l ay p o s i t i o n i n g , o p e r a t i o n , and op t imiza t ion . The f i n a l d i s p l a y was o r i g i n a l l y an a r t i s t ' s concept (F igure 5-3) and was u t i l i z e d f o r f i n a l console design. The conso le , a s d e l i v e r e d , i s shown i n F igure 5-4.

S e l e c t i o n of Cont ro l s and Displays: Components f o r t h e c o n t r o l pane l were s e l e c t e d f o r r e l i a b i l i t y , accuracy, l e g i b i l i t y , and com- pac tnes s . J u s t i f i c a t i o n f o r t h e s e l e c t i o n s i s a s fo l lows:

( a ) Tr ip-Flags - T r i p f l a g s a r e used i n p l ace of i n d i c a t o r l i g h t s t o g i v e s t a t u s i n d i c a t i o n s . They have a l i f e of 1 0 6

c y c l e s (minimum), w i l l w i ths tand shocks of 175 g a t 11 msec, and ope ra t e over a temperature range of -50' t o +71°C. These f l a g s show t h e o p e r a t o r immediate component s t a t u s .

The f l a g i s a t h r e e - p o s i t i o n i n d i c a t o r and a l e r t s t h e opera- t o r when a va lve o r c o n t a c t o r i s open o r c lo sed o r t h e f l a g c o i l has been de-energized.

The use of i n d i c a t o r l i g h t s has been r e s t r i c t e d t o alarms and warnings when s i g n i f i c a n t a c t i o n should be taken--e.g. , START AND RESET J K G GAS. Another advantage of t h e t r i p - f l a g versus t h e incandescent lamp i s t h e reduced power consump- t i o n . A lamp r e q u i r e s 4 0 ma a t 28 vdc, compared t o t h e 26 ma t o a c t u a t e a t r i p - f l a g .

Page 5-5

c-

NASA BRAYTON ENGINE CONTROL SYSTEM

CONTROL AND MONITORING CONSOLE

FIGURE 5-3. ARTIST CONCEPTION OF F INAL BCS DESIGN

(bj Alarm Indicators (Illuminated Switches) - All alarm indicators in the Brayton control system contain four 28-vdc lamps; however, only two lamps (in parallel) are wired into the circuitry, the other two are spares.

During the normal mode of operation, 12 to 15 vdc are supplied to the lamps. These provide low illumination which results in a pastel lens color. When an out-of-tolerance parameter condition or system failure occurs, the indicator flashes bright red and an alarm sounds. In order to silence the alarm, the operator must acknowledge the out-of- tolerance condition by depressing the flashing red indicator switch. Upon acknowledgment, the indicator will change from flashing red to continuous red. This philosophy has two advantages:

(1) By having the lamps illuminated at a low intensity, the operator will know that there is a faulty lamp in the system (this eliminates the need for a "press-to-test" operation). Loss of one bulb results in an increased brilliance. A faulty lamp may then be replaced at the operator's convenience.

(2) The low "keep alive" current preheats the lamp fila- ments, preventing high in-rush current and increasing lamp-life. For all illuminated components in the Brayton control system, the lamps are hand-replaceable from the front of the control panel. In addition, all components utilize the same lamp (28-vdc T 1-3/4 midget flanged-base).

(c) Switches - Those switches or controls which, if accidentally actuated, could cause damage to the BRU have been guarded by one of the following methods:

(1) Push-to-turn mechanism

(2) Spring- loaded guard (cover)

(d) Meters - Dual edge-wise panel meters have been used throughout the system. By using two separate movements in one instrument case, it is possible to compare two input signals with one instrument, thus reducing control panel space. All panel meters in the BCS are the same basic meter movement (0- to 500-pa range 22 percent) to minimize spares. Only the scales are different.

Page 5-9

APS -5284-R24

(e) N m e r i c a l Readout - W r e a r - p r o j e c t i o n - t y p e r e a d o u t was d i g i t a l speed d i s p l a y based on l e g i b i l i t y ,

ease of r ep lacement , and l a c k of lamp t e s t requ i rement . I n t h e c a s e o f a lamp f a i l u r e , t h e r e w i l l be a d a r k a r e a on t h e v iewing s c r e e n where normal ly t h e r e would be a number. To r e p l a c e a f a i l e d lamp, t h e o p e r a t o r s imply s l i d e s t h e b e z e l approx imate ly l / 4 i n . e i t h e r r i g h t o r l e f t . Th i s r e l e a s e s t h e b e z e l from t h e p a n e l . The u n i t c o n t a i n i n g t h e f a u l t y lamp can t h e n be d e p r e s s e d , t h e lamp p u l l e d o u t , and t h e r e - a f t e r r e p l a c e d .

C o n t r o l P a n e l Mechanical D e s i ~ n

A l l p a n e l s , l o g i c c i r c u i t s , e t c . , must be e a s i l y a c c e s s i b l e . To accompl ish t h i s , t h e f o l l o w i n g t e c h n i q u e s were used:

( a ) A l l module f r o n t p a n e l s were mounted t o t h e c o n s o l e by means o f b a l l - b e a r i n g r o l l e r drawer s l i d e s t h a t p i v o t 9 0 deg up o r down, a s shown i n F i g u r e 5-5. The s l i d e s a r e t h e quick- d i s c o n n e c t t y p e . Handles were n o t mounted on t h e c o n t r o l p a n e l s , t o m a i n t a i n t h e compactness and t o p r e v e n t v i s i b i l i t y i n t e r f e r e n c e . Should a c c e s s t o a p a n e l be n e c e s s a r y , o n l y f o u r p o s i t i v e lock f a s t e n e r s must be u n l a t c h e d . The p a n e l must be r o l l e d o u t t o a d i s t a n c e of 18 .5 i n . , where i t w i l l l o c k i n t h e open p o s i t i o n . To r e t u r n t h e p a n e l t o t h e oper- a t i n g p o s i t i o n , d e p r e s s t h e s t o p assembly, push t h e p a n e l i n t o p o s i t i o n , and l o c k t h e f o u r f a s t e n e r s .

The p r i n t e d w i r i n g boards a r e mounted i n a c a r d f i l e assembly i n t h e r e a r of one c a b i n e t , a s shown i n F i g u r e 5-6. S i x c a r d f i l e s were r e q u i r e d (each f i l e c o n t a i n i n g up t o t h e 21 p r i n t e d w i r i n g boards shown i n F i g u r e 5 - 7 ) . The c a r d f i l e s w e r e mounted i n t h e r e a r of t h e c o n s o l e i n o r d e r t o have a l l s i x f i l e s h inged t o g e t h e r by one con t inuous h i n g e . T h i s a l l o w s i n t e r c o n n e c t i o n of t h e p r i n t e d w i r i n g boards w i t h a s s h o r t a c a b l e a s p o s s i b l e , t o minimize EM1 problems.

(c) T o avo id wasted s p a c e , t h e p ie-shaped f i l l e r s e c t i o n s a r e used t o house t h e c a b l e d i s t r i b u t i o n p a n e l s .

The seven i n d i v i d u a l c o n t r o l p a n e l drawer assembl ies a r e f a b r i - c a t e d from heavy gauge s h e e t m e t a l w i t h 0 .030- in . - th ick v i n y l bonded t o t h e m e t a l s u r f a c e . A l l s u b g r a p h i c s and nomenclature a r e s i l k - sc reened on t h e back s i d e o f t h e v i n y l . Advantages of t h e v i n y l c o a t - i n g a r e :

Page 5-10

FIGURE 5-5, TYPICAL BCS ~IODULE MOUNTING

-

( a ) T h e r e a r e no e n g r a v i n g c a v i t i e s t o g a t h e r s o i l .

( b ) T h e r e i s no p o s s i b i l i t y o f t h e nomenc la tu re s u r f a c e w e a r i n g and becoming i l l e g i b l e .

( c ) T h e r e i s no p a i n t on t h e p a n e l s u r f a c e t o become s c r a t c h e d .

( d ) I f t h e p a n e l becomes s o i l e d , t h e s u r f a c e may be wiped c l e a n w i t h a damp c l o t h .

( e ) The v i n y l s u r f a c e i s n o n r e f l e c t i v e .

( f ) U n l i k e a c o n v e n t i o n a l eng raved m e t a l p a n e l , an a r e a c a n be c u t o u t o f t h e v i n y l and a new p i e c e set i n i t s p l a c e , s h o u l d a f u t u r e change b e r e q u i r e d .

The s y s t e m g r a p h i c l a y o u t on t h e c o n s o l e w r i t i n g s u r f a c e i s a l s o f a b r i c a t e d o f 0 . 0 3 0 - i n . - t h i c k v i n y l bonded t o t h e w r i t i n g s u r f a c e b a s e m a t e r i a l .

The c o n t r o l p a n e l i s d e s i g n e d t o o p e r a t e i n a c o n t r o l room e n v i - r o n m e n t , n o t on t h e e n g i n e c o l d - p l a t e . A l l components c o u l d be r e p l a c e d w i t h h i g h r e l i a b i l i t y p a r t s and t h e c a r d f i l e r e d e s i g n e d f o r mount ing o n a c o l d - p l a t e i n a f u t u r e a p p l i c a t i o n .

G e n e r a l D e r a t i n a

The f o l l o w i n g d e r a t i n g f a c t o r s were used f o r a l l e l e c t r o n i c s com- p o n e n t s :

R e s i s t o r s a t 70°C

C a p a c i t o r s a t 85OC

Diode a t 100°C - U s i n s 100 t o 400 PIV

maximum power r a t e d power

i 0.80

maximum v o l t a g e < 8 0 r a t e d power -

maximum power r a t e d power I 0.80

d i o d e s , v o l t a g e s h o u l d n e v e r exceed 70 v

Page 5-14

Transistors at 100°C

I

maximum power 5 0.80 rated power

maximum VCE 5 0.80 rated VCE

Check all transistors for current rating; use limiting resistors where needed.

Integrated circuits The WA operational amplifier used at t15 v, rated at t18. Rated temperature, 100 "C.

Logic gates used at 5 v, rated to 8. Never used maximum loading.

General Design Considerations

All circuit designs were breadboarded and operated over a temperature range from -65' to 150°F. All circuit designs were checked part- by-part for stress.

All electronics are located on printed circuit boards, which are mounted in a standard-type card file. Cooling is by natural convection. Louvers are provided in the doors and on the top to aid in airflow.

Component Procurement Requirements

The same requirements and specifications were used on the control logic as on the signal conditioner without the screening. In most cases, the electronics were delivered with "certificates of compliance'' and were not electrically screened. However, all breadboard circuits used the components from the same batch as those in final assembly.

Testing

Each circuit was breadboarded and test.ed to overtemperature. In addition, each module was tested with the proper input and output cards. Following individual tests, drawings were released to build each printed circuit card. These cards were then checked to ascer- tain that wiring and parts were correct.

Page 5-15

The c o n t r o l p a n e l c o n s i s t s of 11 d i s t i n c t modules f o r c o n t r o l l i n g and p r o t e c t i n g t h e BPS. These modules a r e d e f i n e d by t h e i r s p e c i f i c c o n t r o l and p r o t e c t i v e f u n c t i o n s a s f o l l o w s :

( a ) S t a r t - u p c o n t r o l ( S t a r t Module - STTM)

( b ) Shutdown c o n t r o l (S top Module - STPM)

( c ) L i q u i d loop c o n t r o l (L iqu id Loop Module - LLM)

( d ) Power l e v e l r e g u l a t i o n and o v e r p r e s s u r e p r o t e c t i o n (Gas I n v e n t o r y Module - G I M )

( e ) S t a t u s r e a d o u t s ( C r i t i c a l Pa ramete r s Module - CPM)

( f ) Emergency shutdown (Emergency Shutdown Module - ESM)

( g ) Gas b e a r i n g p r e s s u r e c o n t r o l (Gas Bearing Module - GBM)

( h ) Heat -source c o n t r o l (Heat Source Module - HSM)

(i) Manual o v e r r i d e (Valve Module - VM)

(j) E l e c t r i c a l c o n t r o l - a c ( E l e c t r i c Module - EM-AC)

( k ) E l e c t r i c a l c o n t r o l - d c ( E l e c t r i c Module - EM-DC)

F i g u r e 5-8 shows t h e a c t u a l p h y s i c a l l o c a t i o n of t h e module f r o n t p a n e l s . Fol lowing a r e d e s c r i p t i o n s of t h e modules and t h e i r f u n c t i o n s .

S t a r t Module

S e v e r a l a s p e c t s of t h e s t a r t - u p and shutdown of a Brayton Power System, u t i l i z i n g g a s b e a r i n g s , a r e unique and c r i t i c a l . Gas b e a r i n g s a r e e s s e n t i a l l y f r i c t i o n l e s s a t hydrodynamic s p e e d s , s i n c e t h e s h a f t i s s e p a r a t e d from t h e housing by a t h i n f i l m of t h e system-working g a s . The b e a r i n g l o a d s a r e t r a n s m i t t e d through t h i s f i l m . The b e a r i n g load- c a r r y i n g c a p a c i t y i s dependent upon speed and g a s p r e s s u r e . R o t a t i o n of t h e r o t o r a t l e s s t h a n hydrodynamic speed f o r t h e e x i s t i n g sys tem p r e s s u r e would r e s u l t i n b e a r i n g s u r f a c e c o n t a c t .

To a l low r o t a t i o n a t below t h e hydrodynamic speed, jacking-gas i s i n j e c t e d from t h e g a s b e a r i n g pads . Th i s g a s " j a c k s " , o r l i f t s , t h e r o t o r o f f t h e pads , I n j e c t i o n of jacking-gas a l s o i n t r o d u c e s a t o r q u e i n t h e r e v e r s e d i r e c t i o n and, i f unopposed, r e s u l t s i n a r e v e r s e r o t o r speed of abou t 3000 rpm. Consequent ly , once jacking-gas has been

Page 5-16

MOUNTING CONTROL PANEL = -4--- PANEL -

END VIEW

F I G U R E 5 -9 . BRAYTON CONTROI, S Y S T E M PAhZI, LAYOTIT

a p p l i e d , it should n o t be removed u n t i l r o t o r speed has been reduced t o a "sa fe -s topping speed" o r u n t i l hydrodynamic speed has been a t - t a i n e d . U n t i l e m p i r i c a l l y e s t a b l i s h e d o the rwi se , sa fe -s topping speed has been s e t conse rva t ive ly a t " l e s s than 5 rpm".

Movement of t h e r o t o r whi le i n c o n t a c t wi th t h e pads can r e s u l t i n damage t o t h e bea r ing s u r f a c e . I t i s , t h e r e f o r e , impera t ive t h a t jacking-gas be a p p l i e d p r i o r t o any p e r t u r b a t i o n of t h e system p re s - s u r e , which could cause s h a f t r o t a t i o n . Merely opening t h e dump va lve wi th a d i f f e r e n t i a l p r e s s u r e p r e s e n t can be of s u f f i c i e n t r o t a t i o n t o cause damage.

The s t a r t - u p and shutdown sequences shown on t h e s t a r t and s t o p pane l s (F igure 5-9) p rov ide procedures f o r engine s a f e t y . These procedures , when fol lowed s e q u e n t i a l l y , provide feedback t o a s s u r e t h e o p e r a t o r t h a t a l l c o n t r o l s a r e i n t h e proper p o s i t i o n and t h a t c o n t r o l a c t i o n ' h a s r e s u l t e d i n t h e d e s i r e d system s t a t u s . Table 5-1 shows t h e P r e - S t a r t Check l i s t t h a t must be performed p r i o r t o an a c t u a l s t a r t sequence.

The f l a g s a r e t h ree -pos i t i oned ; one unpowered (gray) and two powered (yellow and g r e e n ) . During normal o p e r a t i o n , t h e pane l s a r e OFF and a l l f l a g s a r e i n t h e unpowered s t a t e . Any gray f l a g s p r e s e n t dur ing t h e pe r iod when a pane l i s ON denote a f l a g o r c i r c u i t f a i l u r e .

Stop Module

The Stop Sequence i s a sys t ema t i c procedure shown i n diagram form on t h e upper r i g h t f r o n t pane l of Bay 1 console f o r s h u t t i n g down t h e Brayton Power System (F igure 5 - 9 ) . By f o l l o w i n g . t h i s procedure , t h e ope ra to r - o b t a i n s feedback d a t a , a s s u r i n g t h a t an a c t i o n has achieved t h e d e s i r e d r e s u l t . This i s shown by t r i p - f l a g s c o n t r o l l e d by a u x i l - i a r y c o n t a c t s on va lves and r e l a y s , and parameter s t a t u s comparators, where a p p l i c a b l e . The Stop Sequence inc ludes t h r e e d i s t i n c t phases:

( a ) P re - s top p r e p a r a t i o n (Table 5-11)

(b ) System spindown

( c ) Pos t - s top , s e c u r i n g t h e system

Liquid Loop Module

The Liquid Loop Module (LLM) i nco rpo ra t e s t h e p rov i s ions f o r man- u a l c o n t r o l of t h e c o o l a n t pumps, moni tor ing coo lan t flow r a t e s and r e l a t e d tempera tures , and annunc ia t ing pa rame t r i c d e v i a t i o n s from t h e p r e s e t r e f e r e n c e va lues of temperature and flow (Figure 5 - 1 0 ) .

Page 5-18

FIGURE 5-9, STTM AND STPM PANEL

TABLE 5-6. PRE-START CHECK L I S T

S w i t c h

STTM STPM P R I PUMP S E C PUMP GIM ( S E T P 2 S E T - P O I N T )

RESOLUTION GBM L O G I C HEAT SOURCE SV- 6 SV- 8 sv-5 sv-9 sv- 4 sv- 1 sv-7 s v - 1 0 sv- 3 ( S E T P 8 / 1 0 S E T - P O I N T )

VRE I N H I B I T V E H I C L E LOAD F I E L D CONTROL VRE AUX POWER LOAD 1 LOAD 2 LOAD 3 CHARGER CONTROL BATTERY CONTROL (ACKNOWLEDGE ALARMS) STTM VRF: AUX POWER SV- 6 SV- 8 sv-5 sv-9

C o n t a c t o r

P o s i t i o n

O F F O F F O F F O F F O F F

RPM/ 1 0 O F F AUTO

CLOSED CLOSED CLOSED CLOSED

AUTO AUTO AUTO AUTO AUTO

O F F O F F AUTO

ON AUTO AUTO AUTO O F F

ON

ON AUTO AUTO AUTO AUTO AUTO

vm OPEN OPEN

CLOSED

Page 5 - 2 0

TABLE 5-11. PM-STOP CHECK L I S T

S w i t c h P o s i t i o n

STTM

G I M

RESOLUTION

GBM L O G I C

HEAT SOURCE

SV-6

SV- 8

sv- 5

sv- 9

sv- 4

sv- 1

sv- 7

s v - 1 0

sv-3 VRE I N H I B I T

V E H I C L E LOAD

F I E L D CONTROL

VRE AUX POWER

LOAD 1

LOAD 2

LOAD 3

CHARGER CONTROL

HEATER CONTROL

BATTERY CONTROL

STPM

C o n t a c t o r

P a g e 5-21

O F F

O F F

RPM/ 1 0

AUTO

O F F

AUTO

AUTO

AUTO

AUTO

AUTO

AUTO

AUTO

AUTO

AUTO

O F F

O F F

AUTO

AUTO

AUTO

AUTO

AUTO

O F F

O F F

ON

ON

OPEN

FIGURE 5-10, LLM AND GI11 PANEL

Primary and secondary pump switches provide manual coolant pump control. Assuming no faults, either the primary pump or secondary pump flow is sufficient to satisfy the required input to the logic for normal operation.

A three-position flow selector switch provides the capability to monitor both primary and secondary flows to the COLD PLATE, ALTERNATOR, and BHXU. The readout for the flows are indicated on the double scale flowmeter labeled PRIMARY PUMP FLOW and SECONDARY PUMP FLOW.

The HOT SPOT SELECT switches serve the dual purpose of switching the individual temperatures to the HOT SPOT TEMPERATURE meter for monitoring and providing the alarm indication when any one of the hot- spot temperatures is greater than the corresponding preset temperature reference. Battery temperature switches T30 and T31 serve as visual alarm lamps and acknowledge switches only. The readouts for these parameters are located on the dc module.

Gas Inventory Module

The Gas Inventory Module (Figure 5-10) is designed to control the engine compressor discharge pressure, P2, to within a predetermined deadband around the reference pressure. The system pressure control set-point is established manually at the GIM. This module also provides protection for relieving system pressure, should an extreme overpressure condition exist.

If the system pressure exceeds the reference pressure, a signal from the GIM is sent to automatically open the small bleed valve, SV-3. If, on the other hand, the system pressure drops below the reference pressure, the GIM will automatically signal the make-up valve, SV-7, to open. The GIM logic is such that the valve actuated by the over- or under-pressure condition remains latched in the open position until system pressure adjusts to within the narrower (hysteresis) control band, at which time the valve is allowed to close. This mode of operation will maintain system pressure to within an adjustable deadband of 0.5 to 5 psi over a system range of 0 to 80 psia. The reference set-point pressure may be adjusted in 0.1-psi increments by a dial indicator potentiometer located on the GIM.

When the deadband limit has been exceeded, a timer is started. If the pressure has not been restored to within the adjustable time- span (0.5 to 5 min), the continuous operation alarm is actuated. If the pressure is restored within the deadband before the time runs out, there is automatic-reset.

Hysteresis, adjustable on the upper and lower pressure limits, precludes the need for timers in the actuation circuitry.

Page 5-23

C r i t i c a l Parameters Module

The CPM p r o v i d e s c e n t r a l l y l o c a t e d moni to r ing equipment f o r e a s e i n d e t e r m i n i n g t h e s t a t u s of t h e most c r i t i c a l BPS paramete r s and a la rms ( F i g u r e 5-11) . The f o l l o w i n g mete r s and a larms a r e i n c l u d e d on t h e CPM:

( a ) RPM Meter (0 t o 54,000 rpm) - I n p u t i s o b t a i n e d from t h e a l t e r n a t o r f r equency . The a l t e r n a t o r phases moni tored may b e s e l e c t e d by t h e SPEED SIGNAL s w i t c h .

( b ) P2 COMP DISCH PRESS. Meter (0 t o 80 p s i a ) - I n d i c a t e s t h e o u t p u t o f t h e t r i p l e - r e d u n d a n t P2 t r a n s d u c e r sys tem.

( c ) P14 BEARING CAVITY PRESS. Meter ( 0 t o 80 p s i a ) - I n d i c a t e s t h e o u t p u t o f t h e t r i p l e - r e d u n d a n t P14 p r e s s u r e t r a n s d u c e r system.

( d ) TI COMP INLET TEMP Meter (-100° t o 400°F) - I n d i c a t e s t h e o u t p u t of t h e t r i p l e - r e d u n d a n t T I t empera tu re t r a n s d u c e r system.

(e ) T6 TURBINE INLET TEMP Meter ( - l o o 0 t o 1900°F) - I n d i c a t e s t h e o u t p u t o f t h e t r i p l e - r e d u n d a n t T6 t empera tu re t r a n s d u c e r system.

( f ) T 4 0 ALTERNATOR TEMP Meter (-100° t o 900°F) - I n d i c a t e s t h e o u t p u t of t h e t r i p l e - r e d u n d a n t T 4 0 t e m p e r a t u r e t r a n s d u c e r system.

( 4 ) T 1 2 HEAT SOURCE HOT SPOT TEMP Met,er (-100° t o 1900°F) - I n d i c a t e s t h e o u t p u t of t h e t r i p l e - r e d u n d a n t T12 t e m p e r a t u r e t r a n s d u c e r sys tem.

( h ) TI H I Alarm - T1 g r e a t e r t h a n t h e p r e s e t r e f e r e n c e

( i) T6 H I Alarm - T6 g r e a t e r than t h e p r e s e t r e f e r e n c e

( j ) T12 H I Alarm - T12 g r e a t e r t h a n t h e p r e s e t r e f e r e n c e

(k) 90-Percent SPEED Alarm - Sp40 l e s s t h a n t h e p r e s e t r e f e r e n c e

(1) 95-Percent SPEED Alarm - Sp40 less t h a n t h e p r e s e t r e f e r e n c e

( m ) 105-Percent SPEED Alarm - Sp40 g r e a t e r t h a n t h e p r e s e t r e f e r e n c e

( n ) LOGIC POWER Alarm - The 5-vdc r e f e r e n c e i s n o t w i t h i n t h e a c c e p t a b l e d e v i a t i o n l i m i t s , o r t h e +5 , +15-vdc maximum o r minimum s u p p l i e s a r e above t h e p r e s e t l i m i t s .

Page 5-24

F I G U R E 5-11, CPM, HSM, GBM, A N D ESM PANEL

The Emergency Shutdown Module (ESM), shown i n F i g u r e 5-11, i s des igned t o e f f e c t a s a f e BPS shutdown i f an overspeed c o n d i t i o n e x i s t s o r i f t h e manual emergency shutdown swi tch i s t u r n e d on.

I f t h e BRU speed shou ld i n c r e a s e t o over 115 p e r c e n t o f r a t e d - speed , t h e a la rm on t h e p a n e l w i l l be sounded and t h e SHUTDOWN i n d i - c a t o r w i l l beg in f l a s h i n g . The f l a g s on t h e module p a n e l w i l l i n d i - c a t e t h a t t h e p r o p e r o p e r a t i o n of t h e r e q u i r e d e v e n t s has o c c u r r e d .

I f i t becomes n e c e s s a r y t o manually s h u t down t h e BRU due t o an emergency, t h e o p e r a t o r must r a i s e a guard and d e p r e s s t h e EMERGENCY SHUTDOWN s w i t c h t o i n i t i a t e a sys tem shutdown. The same sequence o f e v e n t s shown on t h e e v e n t c h a r t w i l l a u t o m a t i c a l l y o c c u r .

~ e ~ r e s s i n ~ t h e jacking-gas r e s e t - s w i t c h resets t h e s i g n a l condi- t i o n e r c i r c u i t r y and o v e r r i d e s t h e au tomat ic shutdown a s long a s t h e s w i t c h is a c t i v a t e d .

Gas Bear ing Module

The pr imary f u n c t i o n of t h e Gas Bear ing Module ( F i g u r e 5-11) i s t o p r o t e c t t h e BRU g a s b e a r i n g s d u r i n g system o p e r a t i o n . Th i s i s accomplished by moni to r ing b e a r i n g c a v i t y p r e s s u r e (P14) and s h a f t speed (Sp40) and by a p p l y i n g h y d r o s t a t i c gas t o t h e b e a r i n g s i n t h e e v e n t o f low p r e s s u r e o r low s p e e d , s i n c e e i t h e r c o u l d cause a l o s s of b e a r i n g hydrodynamic l o a d - c a r r y i n g c a p a b i l i t y . The GGM opens t h e jacking-gas v a l v e s a u t o m a t i c a l l y when r e q u i r e d ; however, t h e o p e r a t o r can manually c o n t r o l t h e jacking-gas supply from t h e v a l v e module ( V M ) . C o n t r o l a c t i o n , au tomat ic o r manual, w i l l supp ly t h e b e a r i n g pads w i t h j ack ing-gas . C l o s u r e of t h e v a l v e s can on ly be accomplished manual ly . T h i s r e q u i r e s d e p r e s s i n g t h e "Rese t Jacking-Gas" on t h e GBM, which r e s u l t s i n a p u l s e s i g n a l t o c l o s e t h e v a l v e , o r t u r n i n g t h e s w i t c h e s on t h e VM t o OFF.

The module c o n t a i n s l o g i c i n which t h e b e a r i n g c a v i t y ambient-gas- p r e s s u r e s i g n a l i s compared t o a s e t - p o i n t p r e s s u r e . I f t h e p r e s s u r e d rops t o t h e p rede te rmined minimum v a l u e , an a larm i s a c t i v a t e d . I f t h e v a l v e c o n t r o l s a r e s e t t o t h e AUTO p o s i t i o n , t h e p r o t e c t i o n sys tem sends a s i g n a l t o t h e v a l v e module which opens jacking-gas v a l v e s SV-5 and SV-6. (These a r e pr imary c o n t r o l s , and SV-8 and SV-9 p rov ide t h e back-up f u n c t i o n . )

The g a s b e a r i n g module a l s o c o n t a i n s l o g i c t h a t compares t h e BRU speed s i g n a l t o t h e minimum speed s e t - p o i n t (below which hydrodynamic o p e r a t i o n i s u n s a f e ) , I f t h e speed d rops below t h i s minimum v a l u e , an a la rm i s a c t i v a t e d , and t h e l o g i c sends a s i g n a l t o t h e v a l v e module a u t o m a t i c a l l y opening jacking-gas v a l v e s SV-5 and SV-6.

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The alarm indicators inform the operator when an underspeed or underpressure condition exists.

Because of the extremely critical nature of the GBM function, speed and pressure inputs are triple-redundant, and an analog select system is used to confirm input validity.

Two fully independent comparator and valve actuation circuits are employed (the back-up system is independent of the primary system) to preclude the possibility of bearing failure caused by a single comparator malfunction or circuit failure.

Should the analog-select circuit detect a missing input signal, the module malfunction alarm is actuated. A latching relay is used to preclude limit-cycling of the jacking-gas valves when a low pressure is detected.

Heat Source Module

Temperatures T1, Tg, and T12 are processed by the Heat Source Module (HSM) shown in Figure 5-11. All three temperature locations have triple-redundant signals and separate analog-select circuits. The channel selected from each analog selector is supplied to the associated meter on the CPM and also to a comparator with an alarm for annunciating an overtemperature condition on the CPM. T12 is supplied to three separate comparators to establish "Heat Source Warm" and "Heat Source Ready" logic signals for the STTM and a "Heat Source Cool" logic signal for the STPM. The HSM alarm is energized by a failure of one or more of the triple-redundant inputs for any one of the three temperatures (T1, compressor inlet; Tg turbine inlet; T12, heat source) .

In the event of an emergency shutdown or a compressor inlet overtemperature, the HSM is used to turn off the heat source input power by opening relay K12. The K12 relay has a set of auxiliary contacts that provide position feedback to the BCS.

Valve Control Module

The Valve Module, shown in Figure 5-12, provides the operator with manual system valve control, valve and pressure switch status flags, helium-xenon (He-Xe) supply system control, and monitoring requirements displayed graphically.

The valve controls are three-position switches, ON and OFF for manual valve control and AUTO for the valve response to command signals from BCS logic. The VM acts as a coordination interface between valves and the other control modules. This will occur only if the override switches are in the AUTOMATIC mode. The VM override switches

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a r e push- to- turn a c t i v a t e d t o emphasize t o t h e o p e r a t o r t h a t automat ic c o n t r o l f o r t h a t v a l v e i s provided on ly when t h e swi tch i s i n t h e AUTO mode.

The T LOW a larm i s provided t o a l e r t t h e o p e r a t o r t h a t T8 has decreased !o a va lue l e s s t han t h e p r e s e t r e f e r e n c e t empera tu re . The T8 tempera tu re may be monitored on t h e T8 GAS BOTTLE TEMP m e t e r .

The P8 SET POINT ADJUST p rov ides t h e o p e r a t o r w i th a convenient means f o r a d j u s t i n g t h e P8 LOW Alarm s e t - p o i n t . The P8 GAS BOTTLE PRESSURE meter p rov ides t h e c a p a b i l i t y t o monitor t h e P8 p r e s s u r e con- t i n u o u s l y .

E l e c t r i c a l Cont ro l - AC (F igu re 5-13)

The a c c o n t r o l l o g i c p rov ides t h e fo l lowing p r o t e c t i v e f e a t u r e s :

( a ) Overvoltage - Switches t o f i x e d a l t e r n a t o r s h u n t - f i e l d s UPP IY

(b ) Undervoltaye and low s h u n t - f i e l d c u r r e n t - Switches t o f ixed- a l t e r n a t o r s h u n t - f i e l d supply

( c ) Overcur ren t , 150 p e r c e n t - Opens load c o n t a c t o r

Underspeed, 95 p e r c e n t - Removes p a r a s i t i c load

(e) Underspeed, 90 p e r c e n t - Removes v e h i c l e l oad

( f ) Overspeed, 105 p e r c e n t - Appl ies f u l l p a r a s i t i c l oad

(g ) Overspeed, 115 p e r c e n t - Shuts system down ( l o g i c mounted i n s i g n a l c o n d i t i o n e r )

System o p e r a t i o n i s d i s cus sed i n t h e fo l lowing paragraphs i n t e r m s of t h e pane l l a y o u t , F igure 5-13. The a c c o n t r o l c i r c u i t r y pro- v i d e s t h e o p e r a t o r w i th pane l r eadou t s , a la rms , and o v e r r i d e s . The fo l lowing i s a d e s c r i p t i o n of t h e a c c o n t r o l pane l r eadou t s :

( a ) Frequency - 0 t o 1440 H z (120 p e r c e n t ) - This readout u t i l - i z e s t h e o u t p u t of t h e ana log - se l ec t c i r c u i t used fox t h e speed a larms on t h e CPM and t h e GBM underspeed l o g i c .

( b ) AC Vol tage , Three-Phase - 0 t o 200 v ( 1 2 0 nominal) - The a c v o l t a g e meter p rov ides t h e o p e r a t o r wi th con t inuous d i s p l a y of a l t e r n a t o r t e r m i n a l , l i n e - t o - n e u t r a l v o l t a g e s .

( c ) AC Load Ki lowa t t s , Three-Phase - 0 t o 15 kw - This meter p rov ides cont inuous d i s p l a y of t h e connected a l t e r n a t o r load and t h e v e h i c l e l oad . The d i f f e r e n c e i s t h e p a r a s i t i c load .

Page 5-29

( d ) = Thz s i g n a l c o n d i t i o n e r u t l l i z e s s i x v o l t a g e s developed a c r o s s 2-ohm r e s i s t o r s shun t i ng t h e o u t p u t of 8 0 : l c u r r e n t t r a n s - formers l o c a t e d a t t h e a l t e r n a t o r o u t p u t and v e h i c l e l oad i n p u t . The d i f f e r e n c e s between t h e a l t e r n a t o r o u t p u t cur- r e n t s and t h e a s s o c i a t e d l oad c u r r e n t s a r e t h e r e s p e c t i v e p a r a s i t i c l oad c u r r e n t s .

The fo l lowing i s a d e s c r i p t i o n of t h e a la rms i n t h e e l e c t r i c a l a c module:

( a ) EM Alarm - The e l e c t r i c a l module a c t u a t e s an a larm i n t h e even t o f l o s s of one of t h e t r i p l e - r e d u n d a n t speed, v o l t a g e , o r a l t e r n a t o r t empera tu re s i g n a l s (from ana log s e l e c t o r s ) o r d isagreement between pr imary and back-up commands t o K501, K502, K503, o r MC42.

( b ) 150-Percent Cur ren t - The alarm i s a c t u a t e d i f any o f t h e t h r e e a l t e r n a t o r phase c u r r e n t s exceeds 150 p e r c e n t . The v e h i c l e load-breaker i s opened s imul taneous ly .

(c) 105-Percent Cu r r en t , $A, $B, o r $C - An alarm i s a c t u a t e d i f t h e a s s o c i a t e d a l t e r n a t o r c u r r e n t exceeds 105 p e r c e n t of t h e nominal c u r r e n t . No o t h e r l o g i c f u n c t i o n s a t t h i s s e t - p o i n t .

( d ) Undervoltage and Cur ren t - An alarm i s a c t u a t e d i f two of t h e t h r e e a l t e r n a t o r t e r m i n a l v o l t a g e s a r e low s imul taneous ly w i t h low a l t e r n a t o r s h u n t - f i e l d e x c i t a t i o n . T r a n s f e r from VRE t o a f i x e d - a l t e r n a t o r f i e l d e x c i t a t i o n from t h e d c sup- p l y would occur a f t e r a p r e s e t 0.2- t o - 2 - s e c d e l a y .

(e ) Overvol tage - I f two of t h e t h r e e t e r m i n a l v o l t a g e s a r e h i g h , a n a larm i s a c t u a t e d . T r a n s f e r from t h e VRE t o a f i x e d - a l t e r n a t o r f i e l d e x c i t a t i o n from t h e dc supply would occu r a f t e r a p r e s e t 0.2- t o 2-sec d e l a y .

( f ) S e r i e s F i e l d - Should t h e series f i e l d c u r r e n t d rop below t h e nominal e x c i t a t i o n f o r r a t e d l oad v a l u e , an a larm would be a c t u a t e d .

The fo l l owing o v e r r i d e sw i t ches a r e p rov ided on t h e a c c o n t r o l pane l :

( a ) F i e l d Con t ro l (K501)

(1) B a t t e r y P o s i t i o n - This connec t s t h e a l t e r n a t o r shunt- f i e l d t o a f i x e d - e x c i t a t i o n from t h e dc supp ly .

Page 5-31

(2) AUTO Position - In this position, the unit allows the under- and over-voltage logic to automatically switch the shunt-field excitation from the VRE to the fixed- field excitation supply.

(3) VRE Position - The VRE position allows the operator to manually connect the shunt field to the VRE, thus over- riding the under- and over-voltage logic.

(b) VRE Auxiliary Power (K502)

(1) OFF Position - OFF position removes battery power from VRE .

(2) AUTO Position - The switch in this position allows over- and under-voltage protection logic to function automatically to remove the VRE auxiliary power. Closure of K502 is inhibited during start-up until the speed is above the VRE excitation speed. Below this speed, the field magnetization due to full shunt-field current could collapse the bearings.

(3) ON Position - This provides VRE control power for flashing and control, prior to establishinq alternator output voltage. ~ i o d e isolation eliminates dc supply drain after the alternator voltage is established, as control power is derived from a separate transformer- rectifier in the VRE.

VRE Inhibit

(1) ON Position - This position inhibits VRE output and is included to allow flexibility for establishing a motor start procedure.

(2) AUTO Position - The AUTO position inhibits VRE output until the critical speed at which shunt-field current is allowable.

(3) OFF Position - Normal voltage control logic functions with the VRE switch in the OFF position.

(d) Parasitic Load-Speed Control Override Switches - The parasitic load-speed control consists of three sections with a maximum load capability of 6 kw each (2 kw per phase per section) or 18 kw total. The override switches permit automatic turning of all the sections to FULL ON or FULL OFF or to manual operation.

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(1) Load-OFF P o s i t i o n - This p o s i t i o n t u r n s t h e a s s o c i a t e d s e c t i o n FULL OFF.

( 2 ) Override-OFF P o s i t i o n - The pr imary engine-mounted pa ra - s i t i c load-speed c o n t r o l i n t h e override-OFF p o s i t i o n f u n c t i o n s w i t h o u t manual o r au tomat ic o v e r r i d e a c t i o n .

( 3 ) AUTO P o s i t i o n - Should two of t h e th ree - speed s i g n a l s t o t h e overspeed l o g i c i n d i c a t e a 105-percent overspeed c o n d i t i o n , t h e a s s o c i a t e d s p e e d - c o n t r o l s e c t i o n w i l l be t u r n e d FULL ON. The sys tem w i l l t h e n o s c i l l a t e abou t 105 p e r c e n t . NASA i s t o i n v e s t i g a t e t h e e f f e c t of an 18-kw "band-bang" c o n t r o l on sys tem s t a b i l i t y . Should a component f a i l u r e r e s u l t i n t u r n i n g a s e c t i o n FULL ON, t h e underspeed s i g n a l w i l l c o u n t e r a c t t h i s a s t h e speed d rops t o 95 p e r c e n t and t h e n o s c i l l a t e s .

The most p r o b a b l e cause of an overspeed c o n d i t i o n would be t h e l o s s of one a l t e r n a t o r phase . This would r e s u l t i n t h e r e d u c t i o n of t h e maximum pr imary speed-con t ro l l o a d from 1 8 t o 8 kw (two remaining phase l o a d s on t h e two remaining c o n t r o l s e c t i o n s ) . Assuming l e s s t h a n a 2.5-kw two-phase v e h i c l e l o a d , t h e system speed would i n c r e a s e t o 105 p e r c e n t , a t which t ime t h e o v e r r i d e c i r c u i t r y would app ly t h e a d d i t i o n a l 4 kw ( 2 kw p e r remaining two p h a s e s ) a v a i l a b l e i n t h e unused c o n t r o l s e c t i o n . This i s because t h e o v e r r i d e c o n t r o l s e n s e s a l l t h r e e phases and uses a m a j o r i t y v o t e r c i r c u i t t o de te rmine speed. The pr imary c o n t r o l s e c t i o n s s e n s e i n d i v i d u a l phases and, t h e r e f o r e , t h e s e c t i o n s e n s i n g t h e l o s t phase would sense an underspeed and t u r n FULL OFF.

( 4 ) Load-ON - This p o s i t i o n t u r n s t h e a s s o c i a t e d p a r a s i t i c l o a d s e c t i o n FULL-ON.

(el Veh ic le Load - The b a s i c o p e r a t i o n a l c r i t e r i o n i s t h a t no s i n g l e f a i l u r e i n t h e s i g n a l c o n d i t i o n e r s h a l l r e s u l t i n l o s s of power t o t h e v e h i c l e l o a d . However, t h e p r o t e c t i v e l o g i c i n t h e c o n t r o l p a n e l shou ld open t h e v e h i c l e l o a d c o n t a c t o r (K503) under o v e r c u r r e n t o r underspeed c o n d i t i o n s . A comple te ly f a i l - s a f e scheme would r e q u i r e a t r i p l e - r edundan t c o n t r o l c i r c u i t w i t h s e r i e s p a r a l l e l b r e a k e r s t o a s s u r e p r o p e r c o n t a c t o r s t a t u s . Space i s a v a i l a b l e i n t h e c o n s o l e and s i g n a l c o n d i t i o n e r , and w i r e s and p i n s a r e a v a i l - a b l e i n t h e t r a n s m i s s i o n c a b l e f o r implementing t h e t r i p l e - redundant approach f o r a space system i f t h e development t e s t s i n d i c a t e t h e need. The c o n t r o l l o g i c b e i n g implemented

Page 5--33

f o r t h e s i n g l e con tac to r a v a i l a b l e f o r t h e development system i s a s fol lows: The s i g n a l cond i t i one r implements p r e f e r r e d f a i l u r e mode c losed l o g i c . The console implements fa i l -open l o g i c . E i t h e r 150-percent phase c u r r e n t o r l e s s than 90-percent speed r e s u l t s i n a s i g n a l t o t h e s i g n a l cond i t i one r t o open t h e load con tac to r .

Contactor K503 i s a l a t c h i n g dev ice . S igna l s a r e r equ i r ed t o change t o e i t h e r open o r c losed .

(1) - OFF - The OFF p o s i t i o n opens t h e load con tac to r K503. Para l - lei po le s a r e a v a i l a b l e t o provide redundant pa ths t o pa ra l - l e l d r i v e r s i n t h e s i g n a l cond i t i one r . This a c t i o n i s r equ i r ed a s p a r t of t h e p re s top c h e c k l i s t t o avoid applying low-frequency power unneces sa r i l y , a s t h e breaker does n o t open au tomat ica l ly u n t i l BRU speed i s 90 percen t .

( 2 ) AUTO - - This p o s i t i o n al lows l o g i c t o l a t c h open t h e contac- t o r i n t h e event of an underspeed (90 pe rcen t ) o r 150- pe rcen t load c u r r e n t (any phase) cond i t i on . The switch must be turned t o t h e "OFF-RESET" p o s i t i o n t o r e c l o s e K503.

( 3 ) - ON - The ON p o s i t i o n c l o s e s t h e load con tac to r K503.

E l e c t r i c a l Control - DC

The dc c o n t r o l l o g i c i s included i n t h e engine-mounted d c power supply fu rn i shed by NASA. Operator c o n t r o l func t ions a r e desc r ibed i n t e r m s of t h e pane l l ayou t (Figure 5-14) . The dc c o n t r o l pane l pro- v ides t h e o p e r a t o r wi th panel readouts , a larms, and ove r r ides . Fol- lowing a r e t h e readouts on t h e dc c o n t r o l panel :

( a ) Ba t t e ry Charge Rate - -40 t o 10 amp - This meter i n d i c a t e s t h e r a t e of b a t t e r y d i scharge o r charge f o r both t h e pos i - t i v e and nega t ive buses.

(b ) Ba t t e ry Voltage - 0 t o 50 v (28 v nominal) - The b a t t e r y i s n o t normallv connected t o t h e dc bus a s t h e b a t t e r i e s a r e n o t d e s i g n e i t o " f l o a t " on t h e l i n e . This readout p rov ides t h e o p e r a t o r wi th a continuous d i s p l a y of t h e b a t t e r y vo l t age f o r both p o s i t i v e and nega t ive b a t t e r i e s .

( c ) Ba t t e ry Charge S t a t u s - 0 t o 1 2 0 Percen t (95% nominal) - The b a t t e r y i s normally maintained au tomat ica l ly by l o g i c i n t h e engine-mounted dc supply between 90- and 95-percent f u l l charge.

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- This from

e i t h e r t h e b a t t e r y o r t h e dc supply t r ans fo rmer r e c t i f i e r u n i t and does n o t i nc lude t h e c u r r e n t of t h e H e - X e s t o r a g e b o t t l e h e a t e r t h a t i s supp l i ed d i r e c t l y from t h e b a t t e r y .

(e ) DC Bus Voltage - 0 t o 50 v (28 v nominal) - Disp lays t h e v o l t a g e on t h e p o s i t i v e and nega t i ve dc busses .

( f ) B a t t e r y Temperature - -10' t o 200°F (80°F nominal) - D i s - p l a y s t h e p l u s and minus b a t t e r y t empera tu res .

S i x dc supply v o l t a g e alarms a r e a v a i l a b l e t o n o t i f y t h e o p e r a t o r of abnormal s t a t u s :

( a ) P o s i t i v e bus low

(b) Negative bus low

( c ) P o s i t i v e b a t t e r y low

(d ) Negative b a t t e r y low

( e ) P o s i t i v e b a t t e r y h igh

( f ) Negative b a t t e r y h igh

The p o s i t i v e and n e g a t i v e b a t t e r y temperature alarms a r e i nc luded on t h e l i qu id - loop module.

Three o v e r r i d e swi tches a r e l o c a t e d on t h e dc pane l :

( a ) Charger Cont ro l

(1) OFF - I n h i b i t s charger ou tpu t t o bo th t h e p o s i t i v e and - n e g a t i v e b a t t e r i e s .

('2) AUTO - The dc supply l o g i c main ta ins t h e p o s i t i v e and n e g a t i v e b a t t e r i e s a t between 90 and 95 p e r c e n t o f f u l l charge .

( 3 ) - ON - P e r i o d i c topp ing ( f u l l o r s l i g h t overcharge) i s r e q u i r e d t o ex tend t h e l i f e of t h e b a t t e r i e s . Th is c o n t r o l pe rmi t s t u r n i n g t h e cha rge r on t o exceed t h e 95-percent l e v e l mainta ined au toma t i ca l l y .

( b ) B a t t e r y Con t ro l

(1) - OFF - Opens K 5 0 4 t o d i sconnec t t h e b a t t e r y from t h e dc bus , This i s r e q u i r e d a f t e r a shutdown t o p r even t

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t h e dc supp ly u n d e r v o l t a g e ( less t h a n 2 5 v) l o g i c from c o n n e c t i n g t h e b a t t e r y t o t h e bus a u t o m a t i c a l l y . Power f o r t h i s c o n t r o l i s s u p p l i e d d i r e c t l y from t h e b a t t e r y .

( 2 ) AUTO - Allows t h e d c supp ly l o g i c t o d i s c o n n e c t t h e b a t t e r y from t h e bus when t h e d c supp ly v o l t a g e i s above 2 5 . A d i o d e - i s o l a t e d s e n s e l e a d i s used t o p r e v e n t c y c l i n g .

( 3 ) ON - C l o s e s K 5 0 4 . Th i s a c t i o n i s r e q u i r e d d u r i n g s t a r t - up t o a v o i d d i s c o n n e c t i n g t h e b a t t e r y b e f o r e t h e sys tem power i s adequa te t o supp ly t h e l o a d . Power f o r t h i s c o n t r o l i s s u p p l i e d d i r e c t l y from t h e b a t t e r y . A l s o , t h i s i s r e q u i r e d t o p r o v i d e b a t t e r y power f o r t h e con- t r o l s t o pe r fo rm a s t a r t - u p .

The m o n i t o r i n g p a n e l ( F i g u r e 5-15) p r o v i d e s r e a d o u t and a la rms f o r sys tem p a r a m e t e r s n o t r e a d o u t on t h e c o n t r o l p a n e l . I n a d d i t i o n , r e a d o u t f o r m u l t i p l e s i g n a l pa ramete r s i s p rov ided where o n l y one o f a r edundan t set i s d i s p l a y e d on t h e c o n s o l e . The m o n i t o r i n g p a n e l a l s o s e r v e s a s a b u f f e r e d m o n i t o r i n g c e n t e r f o r a l l s i g n a l s between t h e s i g n a l c o n d i t i o n e r and t h e c o n t r o l c o n s o l e . These s i g n a l s a r e a v a i l - a b l e on t h e t e s t p a n e l and on a c o n n e c t o r p a n e l f o r d i s t r i b u t i o n t o remote d a t a a c q u i s i t o n .

The m o n i t o r i n g p a n e l i s a supplement t o t h e c o n t r o l p a n e l and n o t needed f o r sys tem c o n t r o l . The m o n i t o r i n g p a n e l p r o v i d e s t h e o p e r a t o r a d d i t i o n a l s t a t u s and a la rm c o n d i t i o n d u r i n g BPS development t e s t s . The m o n i t o r i n g p a n e l does n o t o p e r a t e o f f e c g i n e power b u t i s s u p p l i e d from 110-vac f a c i l i t y power.

The m o n i t o r i n g p a n e l i s 19 i n . wide by 19 i n . h i g h . Mounted on t h i s p a n e l a r e s i x d u a l - s c a l e m e t e r s , one th ree -pen t r e n d r e c o r d e r , and 1 2 pa ramete r a l a r m s . The r e c o r d e r w i l l mon i to r any t h r e e o f 80 a n a l o g c h a n n e l s . The a la rms a r e a d j u s t a b l e from t h e r e a r o f t h e p a n e l . The d u a l - s c a l e m e t e r s a r e connec ted t o m u l t i p l e p u s h b u t t o n s t o p r o v i d e r e a d o u t of a l l s i g n a l s n o t r e a d o u t on t h e c o n t r o l p a n e l .

F u n c t i o n a l D e s c r i p t i o n

The major r e q u i r e m e n t s f o r t h e moni to r p a n e l a r e :

(a) To p r o v i d e a n a u d i b l e and v i s u a l a l a rm sys tem and s t a t e - p o i n t s t a t u s i n d i c a t i o n f o r p a r a m e t e r s n o t accounted f o r on t h e c o n t r o l p a n e l

Page 5-37

( b ) To p r o v i d e an i s o l a t i o n a m p l i f i e r b u f f e r e d parameter o u t p u t t e r m i n a l board and connec to r p a n e l f o r i n t e r f a c i n g w i t h a cus tomer - fu rn i shed D i g i t a l Data A c q u i s i t i o n System

Mete r ina Svstem

Analog s i g n a l s f o r t h e pa ramete r s moni tored a t t h e v a r i o u s c y c l e s t a t e p o i n t s , a s shown on t h e P and I diagram and n o t accounted f o r on t h e c o n t r o l p a n e l , a r e b rough t t o t h e moni to r ing p a n e l v i a t h e c o n t r o l p a n e l . I n t h e c a s e of t r i p l e - r e d u n d a n t c i r c u i t s , m a j o r i t y v o t e r l o g i c i n t h e c o n t r o l p a n e l i s used t o select a s i g n a l f o r con- t r o l and d i s p l a y . A l l t h r e e s i g n a l s may be observed on t h e m o n i t o r i n g p a n e l . Meters on t h e moni to r ing p a n e l a r e t h e same a s i n t h e c o n t r o l p a n e l . They a r e 2 p e r c e n t of f u l l - s c a l e m e t e r s . A l l ana log s i g n a l s , i n c l u d i n g t h e redundant c i r c u i t s , a r e b rough t th rough i s o l a t i o n ampli- f i e r s t o a t e r m i n a l board mounted a t t h e back o f t h e moni to r ing p a n e l . The t e r m i n a l board p r o v i d e s a c c e s s t o each channe l from t h e s i g n a l c o n d i t i o n e r ; t h i s i n c l u d e s a l l a n a l o g s i g n a l s , d i s c r e t e p o s i t i o n s i g - n a l s f o r v a l v e and r e l a y p o s i t i o n s , e t c . , and a l l command s i g n a l s t o t h e s i g n a l c o n d i t i o n e r . Connectors a r e p rov ided f o r c a b l i n g t o a remote d a t a - a c q u i s i t i o n system.

Alarm System

The a la rm sys tem p r o v i d e s t h e n e c e s s a r y c i r c u i t r y f o r t h e opera- t o r t o se t a v a r i a b l e s e t - p o i n t t h a t t r i p s an a larm i f a system paramete r i s above o r below t h e d e s i r e d o p e r a t i n g range . The cir- c u i t r y i s i n Row F of t h e c a r d f i l e . The c a r d f i l e tester i s used t o a d j u s t a l a rm s e t - p o i n t . The a la rms a r e i d e n t i c a l t o t h o s e on t h e c e n t r a l p a n e l .

A l l me te r ing and r e c o r d i n g c i r c u i t s a r e i s o l a t e d by t h e ampli- f i e r s . T h i s r educes t h e p o s s i b i l i t y of a c c i d e n t a l s h o r t i n g and a s s u r e s t h a t module removal w i l l n o t a f f e c t sys tem o p e r a t i o n .

Power Supply

F a c i l i t y 110-v, 60-Hz power i s r e q u i r e d f o r o p e r a t i o n of t h e moni to r ing p a n e l . T h i s power i s used t o o p e r a t e +15, -15, and +5 v r e f e r e n c e s u p p l i e s f o r t h e moni to r ing p a n e l c i r c u i t s . The 110-v f a c i l i t y power i s b rough t th rough an i s o l a t i o n t r a n s f o r m e r t o a l low e x t e r n a l measurements t o be made s a f e l y .

Page 5-39

The c a l i b r a t o r t e s t e r c o n s i s t s of a combinat ion DVM/EPUT COUNTER (mounted d i r e c t l y o v e r t h e c a r d f i l e i n Bay 2 ) and a t e s t e r module (mounted i n t h e t o p of t h e c a r d f i l e ) . The t e s t e r module c o n s i s t s of t h e s e l e c t o r s w i t c h e s , i n d i c a t o r lamps, p c board c o n n e c t o r s , and c i r - c u i t r y n e c e s s a r y t o a d j u s t t h e v a r i o u s t i m e r s and compara tors o f t h e sys tem. Although i t s pr imary purpose i s t o c a l i b r a t e BCS c i r c u i t r y , t h e t e s t e r a l s o a c t s a s an i n t e r f a c e t o t h e DVM/EPUT COUNTER when pe r - forming normal t r o u b l e s h o o t i n g p r o c e d u r e s .

Drawing 306623 shows t h e l o c a t i o n of t h e t e s t e r , PC board l o c a - t i o n and t y p e , and a l i s t o f board t y p e s v e r s u s f u n c t i o n . S p e c i f i - c a l l y , t h e t e s t e r p r o v i d e s s e t t i n g s f o r t h e f o l l o w i n g BCS f u n c t i o n a l c i r c u i t s :

( a ) Comparators

( b ) Comparators w i t h a larms

( c ) Timers and d e l a y s

( d ) Gain f o r s e t - p o i n t p r e s s u r e s P2 and P8

( e ) H y s t e r e s i s s e t t i n g f o r P2

( f ) Vol tage measuring d u r i n g t r o u b l e s h o o t i n g

I n a d d i t i o n t o t h e s p e c i a l l o g i c c i r c u i t s r e q u i r e d f o r s p e c i f i c c o n t r o l f u n c t i o n s , s e v e r a l c i r c u i t boards were d e f i n e d f o r u t i l i z a t i o n . S p e c i f i c a l l y t h e s e c i r c u i t s a r e a s f o l l o w s :

( a ) Analog r e c e i v e r s ( 6 p e r board)

( b ) Comparators ( 4 p e r board)

( c ) Comparators w i t h a larms ( 3 p e r board)

( d ) Analog s e l e c t o r (1 p e r board)

(e ) Contac t i n t e r f a c e ( 1 2 p e r board)

Page 5-40

? = z C C C C C C C C C w .s w w w w w m w 0 0 0 0 0 0 0 0 0 n n n n n n n n n

ADHESIVE B A C K I N G .

Of t h e s e v e n t y - e i g h t c o n t r o l l o g i c p r i n t e d c i r c u i t boards i n t h e c o n s o l e c a r d f i l e , 50 a r e of t h e above d e s i g n s .

The a n a l o g r e c e i v e r p r o v i d e s a d i f f e r e n t i a l i n p u t f o r a l l a n a l o g s i g n a l s from t h e s i g n a l c o n d i t i o n e r and p r o v i d e s an o u t p u t s i g n a l r e f e r e n c e d t o t h e c o n s o l e s i g n a l ground. Th i s e l i m i n a t e s t h e e r r o r from ground p o t e n t i a l d i f f e r e n t i a l s t h a t would o t h e r w i s e o c c u r . T e s t p o i n t s on t h e boards p r o v i d e conven ien t b u f f e r e d a c c e s s t o t h e a n a l o g s i g n a l s f o r maintenance.

The comparator board h a s an a d j u s t a b l e r e f e r e n c e f o r each com- p a r a t o r c i r c u i t . This may b e used a s a h igh o r low r e f e r e n c e . The moni tored a n a l o g s i g n a l i s compared t o t h e r e f e r e n c e , and when it r e a c h e s t h e s e t - p o i n t , t h e o u t p u t of t h e comparator changes s t a t e . The c i r c u i t has a 30-mv a d j u s t a b l e h y s t e r e s i s t o p r e v e n t o s c i l l a t i o n .

The comparator-with-alarm i s s i m i l a r t o t h e comparator and i n c l u d e s a la rm c i r c u i t r y . When t h e ana log s i g n a l goes o u t of t o l e r - ance , a p u l s a t i n g 28-v s i g n a l i s a p p l i e d t o an o u t p u t p i n f o r connec- t i o n t o an a larm l i g h t . The o u t p u t c o n t i n u e s t o p u l s a t e u n t i l t h e a larm i s acknowledged. I t i s t h e n main ta ined a t 28 vdc c o n t i n u o u s l y u n t i l t h e o u t - o f - t o l e r a n c e c o n d i t i o n i s c o r r e c t e d .

The ana log s e l e c t o r boards moni tor t r i p l e - r e d u n d a n t ana log s i g n a l s . I f a l l t h r e e s i g n a l s a g r e e , one c i r c u i t i s s e l e c t e d f o r l o g i c and moni to r ing c i r c u i t s . I f one of t h e s i g n a l s d e v i a t e s from t h e o t h e r two by more t h a n a p r e s e t d i f f e r e n t i a l , t h e d i s c r e p a n t s i g - n a l i s d i s c a r d e d and a v a l i d s u b s t i t u t i o n made. A l o g i c s i g n a l i s p rov ided f o r a n n u n c i a t i n g t h e d i s c r e p a n c y .

C o n t a c t i n t e r f a c i n g f u r n i s h e s a n o i s e - f r e e i n t e r f a c e f o r p o s i t i o n s i g n a l s from c o n t r o l r e l a y s , v a l v e s , and p r e s s u r e s w i t c h e s .

The c o n t r o l p a n e l u t i l i z e s power from t h e t28-vdc BPS bus . Swi tch ing r e g u l a t o r s a r e used t o d e r i v e t h e pr imary t15- and +5-vdc power f o r t h e c o n t r o l c i r c u i t r y . These pr imary power s u p p l i e s a r e p h y s i c a l l y i s o l a t e d from t h e c a r d f i l e t o s h i e l d t h e conduc to r s c a r r y i n g s w i t c h i n g c u r r e n t s .

For redundancy, s i m p l i f i e d , less e f f i c i e n t series r e g u l a t o r s a r e p rov ided f o r backup of t h e 515- and +5-vdc supp ly buses . These a r e d ioded i n and g i v e no power u n l e s s t h e bus v o l t a g e d rops below t h e normal e s t a b l i s h e d by t h e pr imary s u p p l i e s . Loss o f any pr imary o r backup supp ly i s annunc ia ted on t h e CPM.

Page 5-41

A 5-v reference for comparators is provided by redundant series regulators in the card file.

This power system was selected for the control in preference to triple-redundant supplies to minimize hardware. This approach is possible, because the circuitry is accessible for maintenance. The supplies are packaged in modular form to improve maintainability.

Page 5-42

TESTS

Two complete Brayton control systems were acceptance-tested prior to shipment to NASA. Testing consisted of extensive functional checks at ambient temperature and pressure, nominal power, and maximum and minimum stress. This was accomplished by using a load simulator described later, in conjunction with detailed test procedures. In additon, calibration data for analog signals were recorded at four points within the analog range at various stress levels.

The control system contract described specific test requirements to be met by each unit delivered. The requirements are presented in the following section.

The contractor, as a part of Task 11, shall prepare a detailed test plan for acceptance-testing of each completed Brayton Engine Control System prior to delivery.

These tests shall be designed to demonstrate compliance with all control system specifications and to eliminate infant mortality failures. To implement these tests, the contractor shall construct a system instrumentation and load simulator which will furnish, at each Brayton Engine Control System terminal, an appropriate signal or load.

If a failure or malfunction occurs, the acceptance test shall be discontinued and the trouble corrected (always accompanied by a malfunction report indicating the failure mode, cause of failure, and corrective action taken). Unless granted an exception by the NASA Project Manager, the entire test sequence shall be repeated until successfully completed. Since the signal conditioner is engine- mounted, it shall be subjected to a simulated space environment of

torr during all acceptance tests.

The tests shall include, but not be limited to, the following:

(a) Each module shall be inspected for compliance with design specifications.

(b) Each module shall be subject to a 168-hr power aging to be run at maximum module stress within specifications. At the completion of the aging, each module shall be tested at minimum dc voltage and temperature for correct operation. In the case of redundant circuitry, each subcircuit shall be tested to ensure no part-failure within the module.

Page 6-1

(c) The Engine Control System shall be assembled and inspected for workmanship and compliance with design specifications and subjected to the following tests:

The system shall be tested for proper operation by individually exercising each input signal. This test shall be run at the extremes of maximum stress and minimum margin to assure compliance over the range of control system specifications, The maximum stress shall be defined as that combination of control system specifications that is most likely to cause permanent damage to the system. Minimum margin is defined as that combination of control system specifications that is most likely to cause improper system operation but not result in permanent damage. The contractor shall determine what combinations of specifications shall be used for maximum stress and minimum margin tests. These selections are to be submitted to NASA for approval with the contractor's reasons for the particular selections.

(2) The system shall be tested for proper operation and for a simulated instrument transducer failure at each control input signal terminal.

(3) The system shall be tested for false or extraneous control commands or false readouts when subjected to dc bus noise. For this procurement, dc bus noise shall be specified as 75-v transients (positive on the +28- vdc bus and negative on the minus-dc bus) with a 10- psec duration and a repetition rate of 10 pulses/sec.

A load simulator (LS) was designed for testing the delivered Brayton Control Systems. It was a contract requirement that the LS be able to simulate every signal that can be received by the BCS when it is connected to the Brayton Power System. This means that the LS must be capable of sending and receiving all signals to and from the BCS, thereby, exercising all the logic. The LS must act upon these signals and return the correct feedback information. For example, when the BCS sends a signal to operate a valve, the LS must receive this signal, simulate the valve load, and return a feedback signal indicating that the valve has operated.

Simulation is performed for every valve, relay, and pressure switch on the BPS, Also, all signal outputs from thermocouples, pressure transducers, flowmeters, electrical voltages, and current

Page 6-2

t r a n s f o r m e r s a r e s i m u l a t e d by t h e LS t o t h e p r o p e r BCS i n p u t . The P and I diagram a t t h e end of t h e r e p o r t shows e v e r y s i g n a l and l o a d s i m u l a t e d by t h e LS.

The l o a d s i m u l a t o r a l s o s u p p l i e s a l l t h e power t o t h e BCS. T h i s i s t h e nominal 528-vdc bus . To meet t h e c o n t r a c t r e q u i r e m e n t s , t h i s bus f o r s t e a d y - s t a t e t a s k s must r ange from i25.75 t o i 3 2 v. The LS i s a b l e t o p r o v i d e + 4 8 v on t h e d c bus f o r 3 s e c and +75-v p u l s e s on t h e bus a t t h e r a t e of 10 p u l s e s / s e c .

The LS was d e s i g n e d a s a one-person o p e r a t i o n and was packaged i n a s e p a r a t e compact c o n s o l e ( F i g u r e 6 - 1 ) . The LS i s connected t o t h e BCS th rough a s p e c i a l c a b l e h a r n e s s between t h e l o a d s i m u l a t o r and t h e s i g n a l c o n d i t i o n e r . T h i s c a b l e r e p l a c e s t h e a c t u a l BPS c a b l e t h a t w i l l c o n n e c t t h e s i g n a l c o n d i t i o n e r t o t h e BPS. The BCS t r a n s m i s s i o n c a b l e c o n n e c t s t h e s i g n a l c o n d i t i o n e r t o t h e c o n t r o l and m o n i t o r i n g p a n e l s .

Procedure

A d e t a i l e d 29-page checkout p rocedure was w r i t t e n t o f a c i l i t a t e complete f u n c t i o n a l t e s t i n g o f each c o n t r o l sys tem. T h i s p rocedure p r o v i d e s t h e o p e r a t o r w i t h s t ep -by-s tep i n s t r u c t i o n s f o r s e t t i n g up t h e LP p r i o r t o s t a r t i n g t e s t s , s e t t i n g up t h e BCS, and c o n d u c t i n g a comple te s i m u l a t e d s t a r t - u p . Next , t h e s e i n s t r u c t i o n s e n a b l e check- i n g o u t e v e r y c i r c u i t and p i e c e of hardware i n t h e BCS. Th i s i s f o l - lowed by a s i m u l a t e d shutdown p r o c e d u r e . The f i r s t t h r e e pages o f t h e checkout p r o c e d u r e s a r e shown on t h e f o l l o w i n g pages t o i l l u s t r a t e t h e comple teness o f t h e checkou t .

Each manual s t e p i n t h e p rocedure i s s e p a r a t e d and numbered a s shown i n t h e f i r s t column. I n t h e second column, t h e l o c a t i o n i s shown f o r pe r fo rming e a c h o p e r a t i o n , f o r o b s e r v i n g t h e p o s i t i o n o f a c o n t r o l , i n d i c a t o r , o r s i g n a l , and f o r r e a d i n g t h e magnitude o f t h e p a r a m e t e r . Automatic r e s p o n s e s o r o p e r a t i o n s a r e shown i n t h e t h i r d column by lower c a s e l e t te rs i n p a r e n t h e s i s , and a b r i e f d e s c r i p t i o n of t h e f u n c t i o n o r o p e r a t i o n . A s a f i n a l i t e m , a check e n t r y i s r e q u i r e d of t h e o p e r a t o r t o show t h a t t h e i t e m h a s been performed o r obse rved .

System No. 1 R e s u l t s

The f o l l o w i n g i s a b r i e f d e s c r i p t i o n o f t h e r e s u l t s o b t a i n e d d u r i n g t e s t i n g t h e f i r s t BCS. The comple te sys tem, i n c l u d i n g c o n t r o l and m o n i t o r i n g p a n e l s , t r a n s m i s s i o n c a b l e , s i g n a l c o n d i t i o n e r , and l o a d s i m u l a t o r were connec ted f o r t h e f i r s t t i m e on A p r i l 6 , 1969. I n i t i a l t e s t i n g r e v e a l e d an o s c i l l a t i o n problem i n t h e s i g n a l cond i - t i o n e r b u f f e r a m p l i f i e r s . Th i s was c o r r e c t e d by c o n n e c t i n g h igh- f r equency compensat ion network c a p a c i t o r s t o t h e a m p l i f i e r s . Capaci- t o r s were a l s o added t o t h e o u t p u t t o r educe n o i s e .

Page 6-3

AIREmCAWCH MANUFACTURINO COMPANY DP ARIZONA . DIVI.1OU Or .*I *A ..ST. SB".O..llrn*

.*111*1.. ..1,0*.

ITEM

BCS CHECKOUT PROCEDURE DATA SHEET -- OF

PRESTART C H E C K L I S T FOR LOAD SIMULATOR

PRESSURE AND DC SIMULATION PANEL

CONTROL S E T T I N G

( a ) PRESSURE A D J * p o t e n t i o m e t e r ( 0 )

( b ) DC V O L T S * - - p o t e n t i o m e t e r ( 0 1

(c) A l l toggle s w i t c h e s UP

E- PUT COUNTER ON

AC - DVM ON

AC - DVM ON

METER SELECTOR PANEL

( a ) E-PUT SELECTOR FLOW

( b ) AC-DVM FLOW

( c ) DC-DVM TEMP

RELAYS + PRESSURE SWITCHES PANEL

( a ) SWP2A and SWP2B OPEN

( b ) SWP3Al SWP3BI and SWP4 CLOSED

PRIMARY AND SECONDARY FLOW PANEL

( a ) PUMP s w i t c h e s O F F

( b ) A l l ALTERNATOR, COLD PLATE

and BHXU switches ON

CHECK

TECHNICIAN ENGINEER Q . A . DATE

Page 6-5

PRESTART CHECKLIST FOR ELECTRONIC CONTROL

NOTE

B e f o r e p e r f o r m i n g the f o l l o w i n g p r e s t a r t

checkl is t , be s u r e BATTERY CONTROL s w i t c h i s

O F F t o p r e v e n t u n d e s i r a b l e a l a r m s .

PRIMARY PUMP

SECONDARY PUMP

~ 8 / 1 0 S E T P O I N T A D J U S T

S V ' s 6, 8, 5 & 9

S V ' s 4 , 1, 7 , 10 & 3 GBM L O G I C

HEAT SOURCE

F I ELD CONTROL

VRE AUX POWER

VRE I N M I B I T

VEHICLE LOAD

TECHNICIAN EWGImER Q . A . BATE

Page 6-6

AIWtBEARCH MANUFACTURINO COMPANY OF ARlZhaNA A D I Y b m I P W O I 1 U I .a.a.IV G D . L O I I 7 I D M

r"ol*l. *.,.our

1 ITEM I LOCATION

L S

GBM

GBM

LS

GBM

LS

GBM

S CHECKOUT PROCEDUIRE: DATA SHEET -- O F

1 FUNCTION AND RESULT

NORMAL STARTUP PROCEDURE

NOTE

B e f o r e t he procedure i s a t t e m p t e d , the PRE-

START C H E C K L I S T S for the load s i m u l a t o r and

E C S should be p e r f o r m e d .

I nc rease T 1 2 HEAT SOURCE o u t p u t u n t i l the

HEAT SOURCE WARM f l a g changes t o GREEN

on the STTM

Change GBM L O G I C s w i t c h t o AUTO

A c k n o w l e d g e the f o l l o w i n g f lags:

( a ) S V 5 & S V 6 f l ags - YELLOW

O p e n and close SWP3A

( a ) S V 8 & S V 9 f l ags - YELLOW

A c k n o w l e d g e GEM a l a r m

O p e n and close SWP3B

A c k n o w l e d g e GEM a l a r m

O p e n and close SWP4

A c k n o w l e d g e GBM a l a r m

Additional preliminary checkout revealed a noise problem in the thermocouple signal conditioning circuits. Filters were tried on several of the circuits but did not reduce the noise sufficiently.

Further system tests showed that some of the noise was coming from the load simulator and interconnecting cable. To correct this problem, all thermocouple (TC) inputs were removed from the load simulator. All TCs but those for automatic control were welded to a steel plate in the vacuum chamber. Thermocouple inputs to the signal conditioner for automatic control were provided from precision battery mil- livolt supplies, thus eliminating the noise problem.

The preliminary checkout also showed that two of the six flow circuits were not signal-conditioning properly. This was caused by a noise problem that was quickly rectified by replacing all the flow signal leads from the LS to the signal conditioner with shorter shielded leads.

With these modifications to the input for the signal conditioners, the noise problems were reduced considerably but were still evident. Testing showed the source was the switching regulator power supplies in the signal conditioners. The ripple from the power supplies was not within specification. Also during this checkout, excessive component failures occurred in the signal conditioner. These appeared to be related to faulty power supply operation. One power supply in the signal conditioner failed completely. The failed components were replaced and lab power supplies substituted. Further checkout revealed no component failures and significantly reduced noise in the analog circuits. To expedite delivery of the first control system, NASA gave approval to complete the acceptance tests without the signal- conditioner supplies.

Ambient Test: Functional and calibration tests were first made at ambient conditions. The signal conditioner and control and monitoring panels were tested at standard atmospheric pressure and temperature and the dc bus was held at t28 v. A complete functional checkout was made, using the procedures previously described. All start-up, shutdown, control, and protection circuits operated correctly with a few minor discrepancies. These were noted and corrected.

All control and monitoring panel meters, card file test parts, and digital data acquisition system output were monitored for input of 0, 30, 60, and 100 percent full scale. All readings were within the required t2 percent of full-scale accuracy. However, the system is easily capable of achieving '1 percent full-scale accuracies.

Page 6-8

Maximum Stress: Functional and calibration tests were then made at maximum stress. This is defined as operating the signal conditioner at 150 microns with a coolant discharge temperature of 115OF; the card file at ambient pressure and at 90°F; and system operating power at 32 vdc. The system performance at maximum stress duplicated the results obtained at ambient conditions.

Minimum Stress: Functional and calibration tests were also made at minimum stress. This is defined as operating the signal conditioner at 150 microns with a coolant discharge temperature of -65OF, card file at ambient pressure and temperature, and system operating power at 24 vdc. All data atminimum stress duplicated results obtained at ambient conditions.

System No. 2 Results

A'functional test was successfully completed on September 17, 1969. This included a complete checkout of all operational procedures, as described in the test instructions.

The environmental box on the control panel card file was fabri- cated, and checkout was completed. The unit was run at low temperatures (+36OF) and high temperatures (+lOO°F). Problems were noted with condensation, and changes were made in the setup to correct this condition.

The load simulator was modified to separate the thermocouple wiring to the signal conditioner from the other cabling. This resulted in the addition of Connector J113 to the load simulator. The panel was used to confirm wiring; however, because the noise level was still excessive, all thermocouples but the triple-redundant circuits were spot-welded to a plate for the aging and functional tests. The triple-redundant circuits were fed from battery-powered potentiometers. Testing was conducted and completed under the following schedule for 1969 :

Function Date and Time

(a) Functional checkout at room September 18, 2:00 p.m. temperature and pressure-- began chamber evacuation, temperatures increasing

(b) Functional checkout at maximum stress

(1) Prepare for checkout September 18, 3:30 p.m.

Page 6-9

Function Date and Time

(2) Completed 91.5-hr burn- in and calibration

(3) Start checkout at maximum stress

(c) Functional checkout at minimum stress

(1) Begin chilling

(2) Start checkout at minimum stress

(d) Functional checkout of system

(1) Complete checkout of spare signal conditioner boards

September 22, 5:00 a.m.



September 22, 4:00 p.m.

September 23, 5:00 p.m.

(2) Final test using burned- September 23, 8:00 a.m. in boards

(3) Completed final func- September 26, 11:OO a.m. tional test

During testing, intermittent failure of T12B was noted. Inspec- tion, after completion of the test, showed that the connection at the reference junction terminal for T12B was loose. This was tightened, and no further problem developed.

Slowly increasing the speed through the "VRE Speed" set-point, prevented the K502 relay from closing. This resulted when the redundant VRE speed comparators were set slightly different. The relays operate from 0.5-sec, one-shot pulse signals. The close signal is via two series circuits, each operated from a separate VRE speed comparator. Unless the pulses are synchronous, the close signal will not be effected. The VRE speed comparators were reset to coincide and operate properly.

Valve SV-4 and relay K503 would not actuate during an emergency shutdown, Checking after shutdown disclosed a wiring error on circuit A1 of Board A7. The discrepancy was corrected, and the fault was cleared.

Page 6-10

Testing was conducted with the EMES override circuit installed, and the circuit functioned properly under all conditions. The set- point varied from -18.6 and +19.7 vdc at -65OF coolant discharge to -18.6 and +18.0 vdc at ambient, and -22.6 and +19.6 vdc at 115OF coolant discharge. Further testing on this circuit is to be performed by NASA.

Final Status: Most circuits and hardware were operational with the exception of the speed signal, Sp40C, which would not function. Extensive troubleshooting efforts resulted in extreme damage to the board. Because of the urgency for completing the checkout, permission was received from NASA to ship. the second ECS; the speed circuit would be repaired at NASA. Calibration data for the second control system met the t2 percent full-scale- accuracy requirements.

Page 6-11

31 SCUSS! OII OF RESULTS

T h i s c o n t r a c t r e s u l t e d i n t h e sh ipmen t o f two Brayton power con- t r o l sys t ems t o NASA. The f i r s t c o n t r o l s y s t e m h a s been i n s t a l l e d a t t h e NASA-LeRC Plumbrook Space Power F a c i l i t y and is b e i n g used t o con- t r o l a Bray ton Power System p r e s e n t l y unde r deve lopment t e s t . The second Brayton c o n t r o l sys t em h a s been i n s t a l l e d i n a t e s t c e l l a t L e R C and i s b e i n g s u b j e c t e d t o tes ts w i t h o t h e r Bray ton power s y s t e m e lec t r i ca l subsys t ems .

To d a t e , t h e f i r s t c o n t r o l sys t em h a s been used t o make 1 2 suc - c e s s f u l s t a r t - u p s and shutdowns of a Brayton Power System. The s y s - t e m h a s per formed w e l l a s a compact c o n t r o l f o r t h e power s y s t e m and h a s p r o v i d e d most o f t h e development s y s t e m e l e c t r i c a l d a t a t h r o u g h i t s b u f f e r e d o u t p u t .

The g a s i n v e n t o r y module c o n t r o l h a s been used e x t e n s i v e l y ; t h e o v e r l o a d c o n t r o l p r e v e n t e d an e n g i n e shutdown; and t h e unde r speed pro- t e c t i o n t u r n e d on j ack ing -gas t o p r o t e c t t h e BRU b e a r i n g s when needed . The BCS, t o d a t e , h a s been s u c c e s s f u l . Very few BCS component f a i l - u r e s have been d e t e c t e d d u r i n g t h e 2561-hr deve lopment t e s t i n g . The o n l y ma jo r a r e a s r e q u i r i n g f u r t h e r e f f o r t a r e t h e power s u p p l i e s and t h e s p e e d s e n s i n g c i r c u i t s i n t h e s i g n a l c o n d i t i o n e r .

Some o f t h e problems e n c o u n t e r e d d u r i n g t e s t i n g w e r e t h e r e s u l t o f t h e e l e c t r i c a l s i m u l a t i o n s p r o v i d e d by t h e l o a d s i m u l a t o r . T h i s was p a r t i c u l a r l y t r u e o f t h e thermocouple s i m u l a t o r . I n f u t u r e t e s t s , it i s recommended t h a t a c t u a l t r a n s d u c e r s b e used where p o s s i b l e . Thermocouples c o u l d b e p l a c e d i n a c o n t r o l l a b l e env i ronmen t box, and p r e s s u r e t r a n s d u c e r s c o u l d b e mounted on c o n t r o l l a b l e p r e s s u r e h e a d e r s . A l i q u i d l o o p w i t h a c t u a l f low t r a n s d u c e r s s h o u l d b e u s e d . T h i s t y p e o f l o a d s i m u l a t o r would more a c c u r a t e l y r e p r e s e n t t h e a c t u a l c o n d i t i o n s and would e l i m i n a t e many of t h e problems e n c o u n t e r e d w i t h e l e c t r i c a l s i m u l a t i o n s .

The w r i t t e n check-ou t p r o c e d u r e s worked v e r y w e l l and a r e recommended f o r any f u t u r e t e s t i n g .

Page 7-1

The engine-mounted siynal conditioner provides the interface between the BPS and the control system. Six types of signal- conditioning units were designed to provide 0- to 5-v signal input to the control panel from the power system transducers. These circuits include:

(a) Thermocouple conditioner and reference temperature junction

(b) Buffer amplifiers for 0- to 5-v input signals (pressure transfucer, dc bus, and battery voltages)

(c) AC voltage and current

(d) AC three-phase power

(e) Frequency to dc conditioners (0.05 to 200 v)

All of the above signal-conditioning circuits met the required accuracy of +2 percent of full-scale. In fact, most of the circuits provided +1 percent of full-scale over the -65' to +115OF calibration tests. Also, signal-conditioning circuits were developed for actual control hardware on the power system, as commanded by 0- or 5-v signals from the control panel. These circuits included:

(a) Triple-redundant valve drivers

(b) Dual-redundant parallel and series fail-safe valve and relay drivers

(c) Emergency shutdown override logic

All of the above driver circuits have performed properly during acceptance-testing and actual system operation.

During the initial system acceptance-testing some component failures occurred, probably due to infant mortality. However, no signal- conditioner component failures have been detected during the 2561-hr tests at the Space Power Facility.

The only two areas in the signal conditioners which should be considered for further improvement are the power supplies and the frequency-to-dc conditioners. The power supply problem was discussed in the Acceptance Testing section. The frequency-to-dc conditioners

Page 7-2

do m e e t t h e r e q u i r e d accuracy of k.2 p e r c e n t o v e r t h e range of C - t o 120-percent speed; however, above 120-percent speed , t h e s e condi- t i o n e r s e x h i b i t r a p i d r o l l - o f f . This r e s u l t e d i n f a i l u r e t o p r e v e n t t h e l o s s of a BRU when a th ree -phase s h o r t o c c u r r e d d u r i n g t e s t s a t t h e Space Power F a c i l i t y . Due t o waveform d i s t o r t i o n , t h e f requency appeared much h i g h e r t h a n it a c t u a l l y was. Because of t h e r o l l - o f f c h a r a c t e r i s t i c , t h e ana log o u t p u t i n d i c a t e d approximate ly 50 p e r c e n t of r a t e d speed , which, i n t u r n , r e s u l t e d i n i n c o r r e c t c o n t r o l a c t i o n . An a l t e r n a t e f requency- to-dc c o n d i t i o n e r has been recommended t h a t does n o t e x h i b i t t h i s r o l l - o f f c h a r a c t e r i s t i c .

The t r a n s m i s s i o n sys tem f o r connec t ing t h e engine-mounted s i g n a l c o n d i t i o n e r t o t h e c o n t r o l p a n e l c o n s i s t s of 11 hard-wired c a b l e s . These c a b l e s t r a n s m i t a l l t h e t r a n s d u c e r s i g n a l s , commands, and d c power t o and from t h e c o n t r o l c o n s o l e . The c a b l e sys tem has caused no problems d u r i n g accep tance and power system development tes ts . Noise l e v e l s were moni to red , and no a p p r e c i a b l e n o i s e was recorded by t h e c a b l e system. For t h e power system development t e s t , t h i s c a b l e i s 400 f t long and goes th rough two vacuum-chamber bulkhead feed- th roughs .

I f , i n a f u t u r e space sys tem, t h e c o n t r o l p a n e l and s i g n a l - c o n d i t i o n e r can be l o c a t e d c l o s e t o g e t h e r , a hard-wired c a b l e sys tem shou ld be adequa te . However, shou ld weight r e d u c t i o n be n e c e s s a r y , a m u l t i p l e x e d t r a n s m i s s i o n sys tem should be i n v e s t i g a t e d .

The c o n t r o l p a n e l p r o v i d e s compact c o n t r o l l o g i c , manual over- r i d e s and sys tem s t a t u s r e a d o u t s . The e x t e n s i v e human f a c t o r d e s i g n e f f o r t has r e s u l t e d i n a compact d e s i g n t h a t i n c o r p o r a t e s f l i g h t - t y p e hardware and modular concep t s i n a v e r s a t i l e c o n f i g u r a t i o n a l l o w i n g t h e f l e x i b i l i t y of o p e r a t i o n r e q u i r e d of a development system. The c o n t r o l p a n e l o p e r a t e s from t h e system d c bus .

The f r o n t p a n e l i s s e p a r a t e d i n t o subsystem modules w i t h sub- g r a p h i c s f o r r a p i d comprehension. L i g h t s a r e l i m i t e d t o a n n u n c i a t o r s f o r abnormal c o n d i t i o n s t h a t r e q u i r e r a p i d o p e r a t o r r e s p o n s e . F l a g s i n d i c a t e v a l v e and r e l a y p o s i t i o n s t a t u s . Swi tches e n a b l e t h e opera- t o r t o manual ly o r a u t o m a t i c a l l y c o n t r o l a l l pumps, v a l v e s , r e l a y s , and c o n t r o l o v e r r i d e s .

Page 7-3

Automatic c o n t r o l i s provided by l o g i c and implemented wi th i n t e - g r a t e d c i r c u i t r y on p r i n t e d c i r c u i t boards l o c a t e d i n a c a r d f i l e a t t h e back of t h e c o n s o l e . A combinat ion d i g i t a l v o l t m e t e r , c o u n t e r , and t e s t e r i s l o c a t e d above t h e c a r d f i l e t o a l l o w t h e o p e r a t o r t o v a r y t h e comparator and t i m e r s e t - p o i n t s , t o check t e s t p o i n t s , and t o i s o l a t e annunc ia ted f a u l t s . B u i l t - i n t e s t c i r c u i t r y p rov ides t h e a n n u n c i a t o r l o g i c . Manual o v e r r i d e s a l low replacement of f a i l e d com- ponen t s . The l o g i c i s f u n c t i o n a l l y modular ized t o maximize i n t e r - c h a n g e a b i l i t y and t o minimize s p a r e s r equ i rements . Of t h e seventy- e i g h t 4.5 x 6 . 5 p r i n t e d c i r c u i t boards i n t h e c o n t r o l p a n e l c a r d f i l e , 2 6 a r e unique; t h a t i s , t h e y perform s p e c i f i c l o g i c f u n c t i o n s . The remain ing 52 a r e comprised of s i x board d e s i g n s . These s i x p r o v i d e t h e f o l l o w i n g f u n c t i o n s :

( a ) F i v e - v o l t r e f e r e n c e ( 3 p e r board)

( b ) Con tac t i n t e r f a c e ( 1 2 p e r board)

( c ) Analog r e c e i v e r ( 6 p e r b o a r d )

( d ) Analog s e l e c t o r (1 p e r b o a r d )

( e ) Comparator ( 4 p e r board)

( f ) Comparator w i t h a larm ( 3 p e r board)

No major problems w i t h t h e d e s i g n have developed d u r i n g t e s t i n g . For a f l i g h t sys tem, c o n s i d e r a b l e r e d u c t i o n i n s i z e could be r e a l i z e d . A s s t a t e d , t h i s system i n c o r p o r a t e s many f e a t u r e s t o f a c i l i t a t e f l e x i - b i l i t y f o r t h e development of t h e Brayton Power System. For i n s t a n c e , t h e s t a r t and s t o p modules cou ld be f u l l y automated f o r t h e f l i g h t sys tem. The BCS has a complete p a n e l f o r m3nual c o n t r o l of s t a r t - u p and shutdown. Logic is i n c o r p o r a t e d t h a t would a l low au tomat ic s t a r t - up and shutdown wi th a minimum of r e w i r i n g . The meter r e a d o u t s c o u l d b e r e p l a c e d w i t h a h i g h d e n s i t y d i s p l a y such a s a s i n g l e d i g i t a l o r CRT w i t h s e l e c t o r s . The c i r c u i t r y i s des igned f o r a c o n t r o l room environment; however, i t could be repackaged t o d i s s i p a t e h e a t t o a c o l d p l a t e , shou ld t h i s be d e s i r a b l e . The c i r c u i t r y i s a l s o compat- i b l e w i t h medium and l a r g e - s c a l e i n t e g r a t i o n .

Page 7 - 4

T h i s r e p o r t documents t h e r e q u i r e m e n t s , d e s i g n , f a b r i c a t i o n , and c h e c k o u t o f t h e c o n t r o l s f o r a Bray ton Power System. Two c o n t r o l s y s - t e m s were b u i l t and t e s t e d . The f i r s t h a s s u c c e s s f u l l y c o n t r o l l e d a B r a y t o n Power System f o r 12 o p e r a t i n g c y c l e s , t o t a l l i n g 2561 h r ; t h e s econd i s b e i n g e v a l u a t e d i n an e l e c t r i c a l subsys t em t e s t . The con- t r o l s y s t e m c o n s i s t s o f a n engine-mounted s i g n a l c o n d i t i o n e r c o n n e c t e d b y a 400- f t t r a n s m i s s i o n c a b l e t o a c o n t r o l c o n s o l e i n t h e c o n t r o l room.

The c o n t r o l s y s t e m p r o v i d e s power s y s t e m s t a r t - u p and shutdown l o g i c , a u t o m a t i c s t e a d y - s t a t e c o n t r o l and p r o t e c t i o n , s i g n a l c o n d i - t i o n i n g o f a l l power s y s t e m t r a n s d u c e r s , s y s t e m s t a t u s , and a u t o m a t i c and manual c o n t r o l o f a l l power sys t em ha rdware . The c o n t r o l s y s t e m i s d e s i g n e d t o p r o v i d e t h e s e f u n c t i o n s f o r 5 y r o r l o n g e r . T h i s i s accompl i shed by u s i n g in t eg ; a t ed c i r c u i t r y and " h i g h r e l " e q u i v a l e n t components and by p r o v i d i n g redundancy o f a l l c r i t i c a l c o n t r o l c i r - c u i t s . The c o n t r o l sys t em was d e s i g n e d t o l e r a n t of f a i l u r e s t o e n s u r e t h a t no s i n g l e f a i l u r e w i l l d e g r a d e t h e Bray ton Power Sys tem power o u t p u t .

Conso le ha rdware and c i r c u i t r y i n c l u d e s e l f - t e s t c i r c u i t r y t o i s o l a t e f a i l u r e s . I n t e r c h a n g e a b l e modules were u s e d e x t e n s i v e l y i n t h e d e s i g n t o min imize s p a r e s r e q u i r e m e n t s and t o s i m p l i f y ma in t enance . The s i g n a l c o n d i t i o n e r u t i l i z e s t r i p l e - r e d u n d a n t c i r c u i t r y t o a l l o w u n a t t e n d e d o p e r a t i o n i n t h e power s y s t e m vacuum, t e m p e r a t u r e , a n d n u c l e a r env i ronmen t . Long-term m i s s i o n s u c c e s s would b e enhanced by a c c e s s t o t h e s i g n a l c o n d i t i o n e r f o r r e p l a c e m e n t of f a i l e d components .

A c a b l e s y s t e m i s u t i l i z e d f o r t r a n s m i t t i n g d a t a and commands be tween t h e s i g n a l c o n d i t i o n e r and t h e c o n s o l e ; however, t h e i n t e r - f a c e s a r e a l l 0 t o 5 v t o f a c i l i t a t e t h e u s e o f m u l t i p l e x i n g o r t e l e m - e t r y .

The c o n s o l e f r o n t p a n e l was d e s i g n e d t o m e e t deve lopment - type c o n t r o l r e q u i r e m e n t s w i t h f l i g h t - t y p e c o n c e p t s . The f i n a l f l i g h t - t y p e v e r s i o n would b e f u r t h e r au toma ted and would r e q u i r e much less f r o n t - p a n e l a r e a . The c o n t r o l c i r c u i t r y i s c o m p a t i b l e w i t h m i c r o m i n i a t u r - i z a t i o n , w i t h t h e c i r c u i t r y and c o n t r o l c o n c e p t s d i r e c t l y a p p l i c a b l e t o f u t u r e s p a c e power s y s t e m s .

Page 8-1

9 , REFERENCES

1. " R a d i a t i o n E f f e c t s , " P h y s i c s of F a i l u r e i n E l e c t r o n i c s , V o l . 5 , U . S . D e p a r t m e n t of C o m r n e r c e / B a t t e l l e , S e c t i o n IVA, J u n e 1, 1 9 6 7 .

2 . " R a d i a t i o n E f f e c t s , S t a t e - o f - t h e - A r t 1 9 6 5 - 1 9 6 6 , " R a d i a t i o n E f f e c t s I n f o r m a t i o n C e n t e r / B a t t e l l e , R E I C R e p o r t No. 4 2 d , J u n e 3 0 , 1 9 6 6 .

P a g e 9 - 1

APPENDIX A

CONTROL SYSTEM CONTRACT SPECIFICATIONS

(EXHIBIT A) 1 7 Pages

APPENDIX A COPJTROL SYSTET'I CONTRACT SPEC I F 1 CATIONS

I. SCOPE OF WORK

The c o n t r a c t o r s h a l l r i lrnish t h e pe rsonne l , i a c l l I t less, s c r v l c c ~ s , n ~ l d m a t e r i a l s necessary to d e s i g n , Tabr icatc , asscln~l) l y , t 1 . s ~ n11d dl1 l i vc.1- t w o ( 2 ) Engine Control Systenls. Each Engine C o ~ ~ t r o l Sy~tciII s l ~ ; ~ l l c o n s i s t o f a Cont ro l Panel and i t s a s s o c i a t e d m o d ~ ~ l c s , 11 Moni t o r l n g Pancl , and i t s a s s o c i a t c d modules, a S i g n a l Conditioner and a l )prol) r lu tc c a b l i n g between t h e Control P a n e l , Monitoring P a n c l , and tllc S l g n a l Condi t ioner .

11. ENGINE CONTROL SYSTEM SPECIFICATIONS

A. General S p e c i f i c a t i o n s

1. The Engine Cont ro l System s h a l l be an i n t e g r a l clemcnt i n the s e l f - c o n t a i n e d Brayton engine p r e s e n t l y under developolcnt. I n t h i s c o n f i g u r a t i o n , the Control System s h a l l operate d i r e c t l y From eng ine D .C . power. The Contro L and Monitoring pi~nch l s slla 1 1 bc connected t o the s i g n a l c o n d i t i o n e r tllrough a n i n s tru~ul~uL c a b l e and a command c a b l e . The con t ro l s y s t e ~ ~ ~ s h a l l ol)ctr;~til independently or any ground support ~>owc~~- o r i 11s t i - t ~ ~ t ~ c ~ ~ l t i ~ t i 0 1 1 .

Tlic des ign sha 11 inc l ude an engine) 111oun~c*d S ig1111 1 C o ~ t c l i t i o ~ i t ~ l .

and rclmotcly loca ted Control and Monitoring pilncsls.

2 . Thc Control and Monitoring pane l s slla L 1 1 ) ~ s dcs i gnitd L o 1.1111 L I I ( ~ engine development tc ls ts . The c o n t r a c t o r slio I I des ig11 l l c ,

c o n t r o l c i r c u i t s so t h a t t h e c i r c u i t concc.pts s h a l l bra 11si1al)Lc i n a f u t u r e [ l i g h t c o n t r o l system.

3 . The S i g n a l Condi t ioner s h a l l be designc*d and b u i l t t o the. e ~ ~ g i n c ? environmental s p e c i f i c a t i o n s .

4 . The Engine Control Systems s h a l l bc dcsigncd i n accordilnci. with paragraphs a . through d. below:

a . R e l i a b i l i t y - A l l c o n t r o l systc.m c i r c t ~ i t s and co~i~ l )on~~i l l :i

s h a l l be designed f o r 5 ycar c o n t i n u o t ~ s o l x ~ r i t t i o ~ l . No l ) t ~ r t s h a l l be designed i n t o t h e s y s t c * ~ ~ ~ wl~lcll i s Itnow~l LO I I ; I V L * LI

wear-out l i f e s h o r t e r than SLvcb y e a r s . Tlic conti-(1 l syst c > o i

s h a l l be designed so no one p a r t f i l l l 1lrc w l l 1 rclHII I L 1 11 LI

c a t a s t r o p h i c f a i l u r e o f t he engino.

b. - The Control Moni Lor lng I ' l~tt ;~ls ::I111 I I IN.

ab le I rom t h e r r o n t of the pane, La. Ally 111odt1 I i s :;I111 I I I ) ( ) r ep l aceab le wi thout causing anothcr I I I I ) ~ I I l cs L O I I I L I I I I I I I C t I O I I .

c . Fa i l Safe1 - The1 Engine. Cont ro 1 Sys ti1111 t i l l i t 1 1 hl' d ~ t : ~ ig11~5d [(>I- t l ~ , eugl uc t o c\pclratc norma L Ly w l L ~ I :) I 1 c t ) n t r o l s l gnu \ 3 de-encnrgized so t h a t a power Tn i l11rc. t o Lhcs coi1~1-1)l systcnl w i l l n o t r c s u l t i n a n eng ine sliutdown. Any Ta i l r ~ r ~ > wi t l i i n a modulc s h a l l r e s u l t i n t h e modulr I ;ti l i ng i n t o ; I sa 1 mode, a s i n d i c a t e d i n each oC t h e ct)tlLroL iltodulc, w r i tcLrll)s. The c i r c u i t r y i n e a c h c o n t r o l ~tiodule s h a l l be dc,s ignod t o check i t s o p e r a t i o n ; any f a i l u r e s s h a l l be annot1ncc.d by a l a r m s on t h e c o n t r o l p a n e l .

d . - The C o n t r a c t o r s h a l l u se t h e l a t e s t t echno logy a v a i l a b l e f o r c i r c u i t s and p a r t s whprc\ t h e p o t e n t i a l f o r h i g h r e l i a b i l i t y e x i s t s i n t h e n e a r f u t u r e .

B . Per formance S p e c i f i c a t i o n s

L . The Engine C o n t r o l System s h a l l c o n s i s t of a Con t ro l Panc.1 and Moni to r ing P a n e l connec ted t c - , t h e eng inc through a c o n t r o l c a b l e and S i g n a l C o n d i t i o n e r , a s shown i n f igr~rc . 2A. Tho C o n t r o l Pane l s h a l l c o n t a i n s t a r t , s t o p , and p ro t ccL ivc n ~ c ~ d u l c s . The Moni to r ing Pane 1 s h a l l p rov idc rchadot~ t o I ;I tt~inin~tlnt 0 1 i o r t y (40) eng ine i n s t r u n i c n t a t i o n 1 ) o i n ~ ~ . 'f11el S Y S L ~ S I I I gIli11 I l)ca i l l accordance w i t h t11c. r c ~ q t ~ i r e m c n t s s t n t ~ t l I)ca l o w .

2 . The c o n t r a c t o r s h a l l c o n s t r u e ttic Logic 1)iagrallls i n c l ~ ~ d c l d I ~ c l - c i n o n l y t o deterl t t ine how e a c h c o n t r o l modulc s h a l l f u n c t i o n .

3 . The c o n t r o l s s h a l l be des igned s o t h a t normal sys tem ope>]-a t ion w i l l n o t be a f f e c t e d when t h e Con t ro l Panc'l i s turnc>d o i f .

4. The C o n t r o l System s h a l l opclratc tltc valvc!s and r e l ; ~ y s ;is i n d i c a t e d on F i g u r e L .

The c o n t r a c t o r s h a l l use t h e a u x i l i a r y c o n t a c t s on tllcl vaLvcss and r e l a y s t o i n d i c a t e on t h e pane l e i t h c ~ r a n open o r c 1osc.d p o s i t i o n o i t h e valvcb o r r e 1 a y .

5 . A l l t imer and comp:~rator s e t t i n g s s l lnl l I,c w i t l l i ~ l t l l c > C O I ~ L I - ~ ~ ~

111odu1es and n o t on t l ~ e pclric 1 d i s p 1 ay . 'L'liclsc : ~ t l l t t s t 1 1 1 c ~ 1 1 t s s11;1 L 1 bc made w i t h t h e a i d o i self-contained L(*.rt ('(lr1ll)lltc111 I C ) C . ; I t c ~ d i n t h e c o n s o l e .

6 . The sys t em s h a l l be i n accordancca w l t l i ~ l i c * ~ ( ~ ( ~ I I ~ ~ ~ ~ I I I ( ~ I I ~ ti ; I I I

s p e c i f i e d below:

a . - An eng ine rnounic~d A ign :~ l C O I I C I 1 t i O I I ~ I. s h a l l be b u i l t t o s i g n a l c o n d i t i o n in:itrt~rnc~nt:~L i o 1 1 H ~ J : I I , I I : I f o r t r a n s m i t t a l t o thc, Cont ro l ; ~ n d M o l l i Lor i I I ~ I ) C I I I I . l :, , , I I I ~

distribute' and s i g n a l cc~nd i t i o n wl~can i ~ c - c ~ t l c ~ t l C O I I L I I ~ I ~ , I I L ~ I t o t h e eng ine rrom th(5 Contro l !)anen l . I S : , I ~ I I W I ~ i 1 1 I igrr~ I , ? A .

1) . - The S ignn 1 (:olitll t I onclr S I I I I l I I ) ( $ d[*s Igi~ed a s thc e l e c t r i c a l i n t e r f a c e bctwcen t l ~ c j cnginc mountc~d 111- - s t ruments and a c t u a t e d c o n t r o l d e v i c r s on one s i d c , nnd the Control Panel and Monitoring Panel on thc o t h e r . Thc s i g n a l s from the ins t ruments s h a l l bc ampl i l i i*d , L i n c a r i z i ~ d , c a l - i b r a t e d , and cond i t ioned t o a s t a n d t ~ r d vo l tage rongc l o r t r a n s m i t t a l t o t h e Cont ro l and Monl t o r l n g Panels . Thcl con- t r a c t o r s h a l l provide a means f o r r c ~ f c ~ r e n c i n g a l l thcr i~~ocoul>lc j u n c t i o n s on t h e S i g n a l Condi t ioncr .

c. S i g n a l s from t h e Control Panel yhal l I)c powi3r ill1111 l ii-iild ilnd condi t ioned t o d r i v e t h e appropriate, control . dcviccxs O I I t l1c1 engine . The c o n t r a c t o r s h a l l s igna l c0ndi.t ion ;I I I C O I I L I - I I I s i g n a l s for opening and c l o s i n g la te l l ing rc,l.uys so t l ~ ; ~ t these s i g n a l s arc a p p l i e d f o r l e s s than 15 second:;. ' l ' l ~ t ~

s i g n a l cond i t ion ing rcquiremcnts f o r L I I ~ o c t u n t i ~ d cc rn~ro l dev iccs s h a l l bc i n accordance wi th Figurc 3 .

d . Thc S i g n a l Condi t i o n e r s h a l l b t dcsiglwd I-or cng inc l l~or~nt i ng i n accordance wi th Figure 3a. S i g n a l s t o he scblit bitclc i~nd f o r t h between t l i c t Contrc:l and Monittrr l 11g Pane 1s illid L I I ( * s i g n a l cc)ndi t ioncr shn L l be i c d v ia c r ~ b l c s not t o c~xcc~c(l 400 I c e t i n l eng th .

. Thc~ c o n t r a c t o r s l ~ a l L I t ~ r n i s l i t11c c i~l) l c l t i c*clulplx~d wl t11 11 l u g ~ which s h a l l bc i n s e r t n b l c i n t o o t l t l c t s located ; ~ t t l t c , Plum Brook Space Power FaciLi t y .

Thc c o n t r a c t o r s11all c v a l u a t e tllc r e l i ~ t i v t ' lllcr i t s of v i ~ r i ous conununicrttion systclns talting i n t o i1cc111lnL s11c11 i i ~ c t o r s ;is n o i s c , c r o s s t a l k , l i n c ~ d rop , cctse 0I' Ins ta l lu t i{ in and r~~rrin- ' tcnance , and r c l i a b i l i t y .

Thc Power Amp1 i f y ing and the S i g n a l Condi t i oning cqrl i l)loi>nt f o r t h e s i g n a l s opera t ing the ac tua ted con t ro 1 deviccts sha L l be loca tcd i n the S i g n a l Condi t ioncr .

The number of i n p u t s and ou tpu t s t o t l i i b S ignnl Conditionclr a r c i n d i c a t e d i n Figurc 3.

f . The S i g n a l Condi t ioning o f thc BRU sl>c~cud s igna l S I I ~ I I 1 I N ' designed t o provide a s i g n a l to t l ~ i l Control SYH L I ~ I I I i t 11 (1c* i R I I ope ra t ing c o n d i t i o n s and dur ing a1 l I,car 111dr1 of ol~c+rill I I I I I . There s h a l l be emergency sh~ltdown I og lc I ocr~tcad O I I L I I I . S i g n a l Condi t ioner . This s i ~ a l l provldc "dl r i ~ c t w l rc~tl" 11vc.1 - speed p r o t e c t i o n .

g . Whil e the s igna l condJ$ioncsr w l I 1 I I I I I - I I I I I l l y o l ~ t ~ ~ 11 1 c . t l I 1 1 ; I

vaclltirrt, i t shn l l bet dcs i gncbd t.0 opcar;l 1 I , i 11 r l l I- :I 1 I I I I I , I I i l l l c l r r - phcrc..

11. Fal I-Safc. - Eacll c o n t r o l s i g n a l t o :lilt1 11-on1 Llio S 1gri:il Con- d i t i o n e r sl ial l be eval uatcd t o de t c ' i - I H l t i c ' 011 npl)roi)r l iitc Cal L - s a l e mode. When p o s s i b l e , de tcxction 01' f i ~ i l u r c o f t r ansduccrs s h a l l be incorporated i n t h e S i g n a l Condi t ioner . Thrl con- t r a c t o r s h a l l ident!.fy i n t h e Pre l iminary Design a l l t rnns - ducers f o r which a f a i l u r e i s d e t c c t a b l c .

i . - The S igna l Condi t ioner s h a l l be cooled hy conduct iok of t h e generated h e a t t o a Cold P l a t e . The Cold P l a t e s h a l l be cooled by a l i q u i d c o o l a n t c i r c u l a t i n g through i t . The c o o l a n t f l u i d s h a l l be Dow Corning 200, which i s :I s i l i c o n c l i q u i d wi th a s e l e c t e d v i s c o s i t y of 2 c c ~ n t i s t r o k r ~ s a t 7 7 ' ~ and having a s p e c i f i c h e a t of 0.45 B T ~ J / ~ ~ . ~ ~ ~ - ~ F . Thc S i g n a l Condi t ioner s h a l l be designed f o r 0111~ (1) Ilour opera t i on w i t h a coo lan t i n l e t temperature oS - 0 5 " ~ and f o r cont i ~ l r ~ o u s o p c r a t i o n Lor a f i v e (5 ) year l i t e wi th a coo lan t t r t l L 1 c . L

t emperature of + 1 3 0 ° ~ . The c o n t r a c t o r sho 1 l condtlc t 11 Is thermal a n a l y s i s f o r con t inuotls +150"1~ coo lnn t d i schcirgi~ temperature . The c o n t r a c t o r i s t o provide i t t lc.ast 15 rll~ll-- mocouples l o r determining r c p r c s e n t a t ivc tctnpcrn tr trcs o I t h e S i g n a l Condi t ioncr . Thc t h c r m o c o ~ i p l ~ o r ~ t p u t s sllal 1 not be s i g n a l cond i t ioncd .

j . Environmcnt - Thc S i g n a l Condi t ioncr s h n l l Iw Il iglit- p ro to type equiplncnt. The S igna L Cond i t 1 onc.1- sliit l l Ixs dl-s iglli'd i n accordance wi th NASA 1,eRC S p e c i f i c i ~ t i uns P 1 2 2 4 - 1, P I 1)24- I Supplement 1, and P1224-2.

The c o n t r a c t o r s h a l l provide s u C f i c i c > l ~ t Locnl sliicxLdi~lg t c ) a s s u r e r e l i a b l e perlorniance t o r a 111lnia1rai1 0 1 ' T ivcb (5) yc,ilrs f o r each p a r t or s u b - c i r c u i t . The c l c c t r o l i i c p;lr ts i l i thil S i g n a l Condi t ioncr s h a l l be capoblc oC nicletlng tit(\ l ivcs (5) y e a r minimum o p e r a t i o n per iod cvcn i l c~xposcd cant 11i r10t1 ; i ly t o a r a d i a t i o n dosage o l 5 x l o i o nv t ( f a s t ) and !, x 10' rild 1

( c ) *

7 . Monitoring Panel - A Monitoring Panel slin l 1 bc, d t~s ignc~d t o con- t i n u o u s l y d i s p l a y the o p e r a t i o n a l s t a t t l s of t l l c , engi nc..

a . The Monitoring Panel s l i a l l c o n s i s t 0 1 il 11i1111( of i ~ i d i ~ i ~ l c ~ r ~ , m e t c r s , and recorders and d j spl ny tl~in I ) ~ I I i l ~ ~ l ( ' t l l Y : i :il)c8t' i l It'd i n Figurc 3. The f r o n t Taccs 0 1 Llica M o ~ ~ i l o ~ . l ~ ~ f i I ' r ~ l ~ c ' l : ~ l r i t 1 1 bc ar ranged i n a convc~~i lvn t 1,111 corl~l,r~c*t I I I : I I I I I ~ ~ I . 1111 t l i a l 1111-d and approvcd by the I,el(C Pro,]cc.L Mr t~ i r~y , , , c~ r .

b . Each channel fro111 t l ~ c s igna l condl L i ~ ~ r i c ~ t - ::I~:I I I 11111 ( l c t I I V I I I I - a b l e on an e x t c ~ r n a l tcrlriinal b l oclc I I I I I I I I ~ L ~ ~ ~ ~ O I I L l l c - I I I O I I I I 1 1 1 - 1 I I K pane l . These e x l c r n a l tct-nil 1x1 l 1101 I I ~ t i : i l r , ~ l l I N , t l r 1 vc I I I I ~ i s o l a t i o n amp1i f ic . r~ s o L l ~ l i t Lc.1-rr1111.t l f i l l o l - t I I I K , }:I O I I I I ( I , I J I -

a p p l i c a t i o n of c'xk~rncll vol t,igcs s l ~ a l l lioi i t i t c a t - i 1 . i i s w i I 1 1 normal c o n t r o l and rlioni t o r j n g ol)cur;lLiori.

a . The Control Panel s h a l l be comprised o r tllc followlllg:

(1) Control Modules

( 2 ) A Readout Module

(3) A c h a s s i s which s h a l l be wired f o r power and s i g n a l d i s t r i b u t i o n t o t h e modules. Thc modules s h a l l bc i n s e r t e d i n t o t h i s c h a s s i s .

(4) An a la rm system

(5) The Control Pancl and the Monitoring Panel s l ~ a l l l ,~-ovidi* an o p e r a t o r s t a t i o n f 01- rrkrnotcb con t ro l o l t l l c * e~q: i 11c dur ing devc Lopmrnt t e s t s .

1). Control Modules - A l l con t ro L ~ilod~ll t ' ~ H ~ I ~ I l l b ~ t d i l ~ Jgtl(*d 8 0

i t i s p o s s i b l e t o rcloovcs any u f thcs t* 111oclt11 C H w I L l~o i~ i a f f e c t i n g the Brayton cnginc o l ) e r a t l t ) t ~ .

c . Alarms - Any f o i l u r c 0 1 t h c elc.cLronlce in rl11y 0 1 t l ~ i , I I ~ I J ~ ~ I ~ L ~ H

r e fe renced i n t h i s c o n t r a c t s h a l l ~ - c * . q t ~ L t i l l an 31 I I ~ I I I idc911L- i i y i n g i n d i v i d u a l l y thc p a r t i c t ~ l a r ~ ~ ~ o d u l ~ , t h a t I ;I I 1c.d. A1 1 alarm systems s h a l l c o n s i s t of both an a u d i b l e and a visible warning system. Two different aud ib le sounds s h a l l bc. oro- v ided ; one f o r an engine mal Iunc t ion , thc. o the r f o r a c o n t r o l c i r c u i t malfunct ion. The aud ib le a lorm silo 11 bc b o t l ~ ncous t i c and e l e c t r i c a l f o r connect ion i n t o a n aud io conununicotion channel . The aud ib le a larm s i g n a l s h a l l bc designed s o t h a t an a u d i b l e a larm s h a l l be s i l e n c e d by p i e s s i n g a b u t t c ~ n s p e c i f i c t o t h e even t which caused t h e a larm but r e t a i n i n g the v i s i b l e s i g n a l u n t i l t h e a larming s i t u a t i o n is c o r r ~ ) c t e d . These a la rms , once a c t i v a t e d , s h a l l n o t t u r n o i f u n t i l i~cknow- ledged by t h e o p e r a t o r .

d . Readout Module - The readout module s h a l l c o n s i s t o l illctcrs read ing out inpu t paramc t e r s t o thc c.c)ntro 1 nlodu l ( > s . S u f f i c i c n t - i n f o r ~ n a t i o n s h a l l be providcsd t o tl1t1 i)ptXi-ittor so L l ~ t can ef f e c t i v c l y opera te t l i c ~ systcin Inantrrl 1 l y .

I e . Ma j n powcar - Thcsre sha l l I>c :I l l lrc'cb-l)o~ 1 1 l o n t l t i t 1 1 1 I1tlwc.r H W J 1.~1)

on tht: Ct)ntrol Panel which controltc t irnd -Y8 v o l 1 w I ) . ( : . (-8 +40%) power t o th(8 cornponc.nts 0I ' L l ~ h r i~t~otrt;~ L 1 c coril 1.0 l l o g i c . The t h r e e p o s i t i o n s s h a l l I N ) : ( I ) O f S ; (:>) AttLl~; ( 3 ) On.

' l ' l l t~ I op, I c b I I1 t I l C t l l l c K I ~ 1 I1 , : i P411:1 I I I ) ( % t I c * 1 4 I ~ 1 1 t Y I P I \ \ t l l i l I < I i I 1 ~ ~ i l l l -

ot~Ls and : ~ l : r r ~ i ~ s w i l l I)cb opcr:~tlvc ' L J I I ~ > I I Cilia I I I ~ I ~ I I l ) r , W c t l - t witch i s i n t l ~ e "AU'l'Ot' o r "ON" p o s i t i o n .

Thc c o n t r a c t o r s h a l l provide a volt:igc~ r e g u l a t o r t o l u ; ~ i ~ ~ t a i n a s t eady c o n t r o l panel vo l t age dur ing D.C. bus t r n n s i c n t s i f necessa ry .

l . - The contr;1cLor s h n l l dcs ign t l ~ c t Con t ro l Pane l Por use i n a ground c o n t r c ~ l s t a t i o n . Tl~cs Cont ro l Pane l s h a l l be of a compact des ign a s d c ~ c r m i n c ~ d by t h e LeRC P r o j e c t Manager. Thc contr: lctor s h a l l d1spL:iy a l l i n f o r m a t i o n i n a c o n c i s e e a s i l y i n t c r p r c t c d monncr rind inltc p r e c a u t i o n s t o prevent: swi tches fro111 being ncc i den ta l ly opcra ted .

Thc C o n t r t ~ l and Monitoring Panol s s l ~ : ~ l 1 Iw dcsignctd a s :I

two man s t a t i o n c o n v e r t i b l e t o onc 111an opcru t ion I'or c~l?d~rr- ance t e s t i n g .

9. S t a r t Modulc

a . Thc c o n t r a c t o r s l i a l l dcs ign and f a h r i c a t ( , tllc S t ; ~ r t Modtt Le i n accordance with Figure 4 w11 i ch i s i ncorporn tcad I l c s ~ - c * i 11.

b . I n a d d i t i o n t o those requirements a s s p c c i r i e d 01.1 F i g u r t ~ 4 , t h c S t a r t Modulc s h a l l bc fu rn i shcd i n uccordancc, wi t i 1 i hc 101 lowing:

(1) An i n d i c a t i o n t h a t thc Sr~nc t ions on tllc p r ~ l - s t a r t c:heclc- l i s t I~avc bclen c o ~ ~ i p l e t c d .

( 2 ) An i n d i c a t i o n t l ~ ; ~ t t l ~ c * I'trnc t i o n s on tl1c8 1)o:iL.-st:trl checli 1 is t Iiavc be8cn cori~l) 1 o Lcxd.

( 3 ) A l i g h t e d ~ , ~ l s l ~ b u t i o n Tor i l ldici~ L l ng w11ct11 Lo I)clfil ti s t a r t u p .

(4 ) I n d i c a t o r s f o r n o t i l y i n g i l ~ opcr:ator o f t l ~ c rlc i i on of c r i t i c a l conlponents dur ing tllc .r t o r t u p .

(5) Automatic a c t i o n of c r j t icrll con~l)ot~c~nl H dt~r. l11g :il ( 1 1 L I I I I .

a . The c o n t r a c t o r s h a l l d e s i g n and fabricate t h e S t o p Module i n acco rdance w i t h F i g u r e 5 which i s i n c o r p o r a t e d h e r e i n .

/ /

b. I n a d d i t i o n t o tho& r e q u i r e m e n t s a s s p e c i l i e d on F i g u r c 5 , t h e S t o p Module s h a l l be f u r n i s h e d i n acco rdance w i t h t h e f o l l o w i n g :

(1) An i n d i c a t i o n t h a t t h e f u n c t i o n s on t h e p r c - s t o p check- l i s t have been completed.

(2) I n d i c a t o r s f o r n o t i f y i n g t h e o p e r a t o r of t h c a c t i o n o i c r i t i c a l components d u r i n g shutdown.

( 3 ) A l i g h t e d pushbu t ton f o r i n d i c a t i n g when t o begin s h u t - down.

(4) Automat ic a c t i o n of c r i t i c a l conlponcnts d u r i n g s l ~ t ~ ~ d o w l ~ .

c . F a i l - S a f e Mode - I f a c i r c u i t I ' a i l u r c o c c u r s , t l l c b S t o p Module w i l l be des igned t o t a k e no a c t i o n i . c . , a l l c o ~ i t r o l o u t p u t s shou ld become de -ene rg ized .

a . The c o n t r a c t o r s h a l l d e s i g n and f a b r i cu t e t h e Eillel'gclncy Sliut- down Module i n acco rdance w i t h F i g u r e 2g which is inccir l)orotcd h e r e i n .

b. I n a d d i t i o n t o t h o s e r e q u i r e m e n t s as s p c c i r i c d on It'igtiro 2g, t h c Emergency Shutdown Module s h a l l bc. f u r n i s h p d in ; i c c ~ ~ r d a ~ ~ c c a w i t h t h e Io l lowing :

(1) T h i s module s h a l l be des igned tc~ r e a l i z e cxtl-clmc rc.1 i- a b i l i t y s u b j e c t t o t h e approval o r disnpprov:rL 0 1 tlic LeRC P r o j cc t Manager.

(2) I n t h e e v e n t o f a f a i l u r e In t l i c b c i r c t ~ l t r y 1 1 1 t l l l : ~ rnodulcl , t l ic Cai l u r e sho l l no t c 8 1 1 c . l gJ zca S J ~ , I I : I I s L 1 1 tli(1

v a r i o u s c o n t r o l ~ ) o l n t s .

c . The emergency shutdown c i r c u i t ~ 1 1 ; ) l l I ) ( ! 1 I I C l ~id(a(l : I I I ; I l l 1 1 1 . L

of t h e engine-mounted S i g n a l Cond i t i t r i 1 c . r . '1'111 s c I rc11 i H I I ~ I I I be d i r e c t w i red t o t h e a p p r o p r j i ~ t c eng in< , cc)nLrt,l tlc.vicc,:~ i r l ~ t l

s h a l l be a c t i v a t e d by eng ine overspccbtl or IllclnuaI l111)111 1 1 - 0 1 1 1

t h e c o n t r o l p a n e l .

d . F,t I I -Sal C- El~tdi* - 11 fi ciucti l t i :r l I t1r.c t 1 t - i itr R , Y i i t > It:\\ir$k.&~>t\tqy

Slzutdown Module s h a l l be desigt7c.d L o Calcc. nc, i l c t i O ~ I , i , c , , a l l c o n t r o l outpi lcs s h a l l become dc -cnesg ized .

1 2 , Heat Source Module -- -

a . The c o n t r a c t o r s h a l l d e s i g n and i a b r i c a t e t h e heat: sou rce module i n acco rdance w i t h t h e f a l l o w i n g :

( I ) A swiLch s h a l l be p rov ided For lteat sou rcc opercxtic~rz,

( 2 ) An a l a r m i n d i c a t i n g n~odu lc f a i l u r e s slrtall bc. provided.

( 3 ) An i rnd ica t ion of t h e h e a t sou rcc r e l a y p o s i t i o n sl l r t l l be provided .

O the r pararnetcrs i n t h e h e a t sourccx olodule s h a l l bc ~ i i s l ) i ayc \ t l by t h e c r i t i c a l pa ra r r~e te r s rirodtllc ,

b . The Heat Source Module s h a l l r e q u i r e pane l read or^ t s , . I l '~riii:; , h i g h r e l i a b i l i t y c i r c u i t s and f a i l - s a f e p r o t e c t i o n ,

a , The c o n t r a c t o r s l r a l l d e s i g n and f a b r i c a t e tlic G ~ i s Invc~l i~ tory Mndr~le i n accordance w i t h F i g u r e 2cl which i s i n c o r p o r a t e d h e r e i n ,

b . L n a d d i t i o n t o t h o s e reqwircnicxn& ns spc.ci l i c d i 11 1 1 1 ~ 1 1 1 ~ ' Ld , tilts Gas I n v e n t o r y Module shi l l 1 be Luri~islked i n ticeordaiicc. w i t i t t h e Lo 1 lowing:

( I ) The r c l e rcncc ! p r e s s u r e sh:tll bc! Pro111 Lhi. 1'1-ol~t o f i h t ' pane 1.

( 2 ) Therc sha l L be conti isuous o p c r a l l on u l iirrlrs I t )r i I I C - i i i i t k t - -

up and b l ccd valve.

c , Thc Comparator U(badband shu l l l r i j ad j t t u talrlil frolii 1 /2 L lti-(>rig11 5 p s i a .

F a i 1 -Sa fe - 'L'hc sniall i n j c c l i 01, itlid t i i ~ r i t i i vcbnl vtr I vt. : t i r i t 1 1 d . -- r e t u r n t o t h e i r normal ly e lo8cd porrj Llo~ltl I I Lllca ( : l l H I ~ i v t . i ~ L 1 1 1 y Plodrl l e f a i l s ,

14. Gas -

1). I n o d d i t i o n t o tlic)sc r cc l~~ i rc .~~ icn t t l r ~ ! i til,ctc I l lcd I I I k' I H I I I . ~ ~ 2 0 , the Gas Bearing Modblc s h a l l bc* Surtr 1 t + l ~ i * t l 111 r ~ c ~ o t ' c l t ~ t r ~ ~ c w l tlr t h e fo l lowing:

I n t h e e v e n t of a f a i l u r e i n t l ~ c Loglc oC t l i i s rnodttli~, the s i g n a l t o t h e j ack ing gas va lvc sliul l f a l l o l f If L t i s o f f and [ a i l on i f i t i s on a t t h e tiluc tlrc I ogic Pill l urrt occurs .

15 . Valve Module

a . The c o n t r a c t o r s h a l l d e s i g n and Labr l c11 trl L l i i ~ VII l vc. M o t l ~ i 111 i n accordance wi th F igure 2c wlilcll I H Lncorl>nrciLc.tl 11clt.ct l n.

b . I n a d d i t i o n t o those requirc lncnts ; IS ~ p c c i 1 icd 111 I?lgllrcs 2c , the Valve Module s h a l l bc l urnis11c.d i n uccord;lncca w l t i i t h c fo l lowing :

(1) I n the e v e n t of a f a i l u r e i n onc of thc clionnc~Ls 0 1

t h i s modulc, the module s h a l l f n i L i n n 1nanni.r so Lliu t no a c t i v a t i n g s i g n a l i s sent t o thc valve i n t l i i i t

channel w i t h t h c e x c e p t i o n of tl1c1 jaclting gas va lvcb l o g i c .

(2) I n the evvnt of rt fa i l t~ rca i n t l ~ c s j acking ga:; valvc0 Logic, the, Jacking gas v a l v e s s l ~ a l l rcxrnain i n thcs p o s i t i o n i n which they wcrc i n a t thc t i m c b tlic l o g i c f a i l u r e occurs .

a . The c o n t r a c t o r s h a l l d e s i g n and f a b r i c a t e the Gas Ovc~r- p r r3ssure Module i n accordancc w i t h P igurc 2b wliicli i s i n c o r p o r a t e d h e r e i n .

b . I n a d d i t i o n t o those requirclncnts a s speciLied i n F igurc 2b, t h e Gas Overpressure Module s h a l l bc fu rn i shed i n accordancc w i t h the fo l lowing :

I n the e v e n t of a f a i l u r e i n t l ~ c Logjc ctf thc' Gas Ovc,l-- p r e s s u r e Module , the c i r c u i t r y sha l l C u i 1 In a I I I ~ I ~ ~ I ~ C ' I - : i t )

t h a t no s i g n a l i s s e n t to a c t i v ~ l t c ~ l ~ c . 1;11-gi. vc2111 va l vt .

1 7 . E l e c t r i c a l Mod11 l e

a . The c o n t r a c t o r s t ~ a l l des ign i ~ r i c i Jiil)r l(,lllt- I I r c , I C l ~ a t l I I 1 / I l Module i n accordancc wj t i 1 FJgilri~ 0 wlt l c.11 1 1 1 I I I ( . , I I I ) O I 1 1 I t a i l

h e re i n .

b . I n addi t ion t o bIiou(! . r c s c l ~ ~ i J - C I I I I , I I ~ 1 4 I I I I I I I I I . ~ . I I l c * ( l 1 1 1 1; I ~ , I I I I , 0 , t h i s mod111 s h : ~ l l b(0 I ttrli Iu11c.d 1 1 1 ~ I ( : ~ . o I ( I ; I I I ( . I . ' W I I 11 I 1 1 1 .

l o I. I owing :

(1 ) 'I'iiu i~vc~rell)er*d ~ j r o t c - c t l o l ~ ~ I l l l 1 1 i i ~ ~ ( + r ~ t t t * w l t i t 1 1 1 I / 0 1 I L N s e t 1x ) ln t f o r a maximunl ovcrul)oi-ti rtr LL* 06 l O'd , / N ~ I .

second ,

( 2 ) L t l t i le e v e n t oll a f a i l u r e i n L I I C ~ lClccir iccil mod ti^<-, a1 1 outp t r t s s h a l l be dcten~brg I ~ c b t l , 'l'ltt- d ~ c ~ ~ c ~ i - g i zc,d Fa i l . -Safe Mode s h a l l m a i n t a i n L l ~ c $ e n g i r ~ c :iLiitt~s I ~ ~ I C )

wit i t t h e e x c e p t i o n of t h e specd c o n t r o l o v c ~ t - ~ - l d c ,

a . The c o n t r a c t o r s h a l l d e s i g n and Lnbr i cu tc tlxe 1,lqirid 1 , c t ~ ~ l )

Module i n acco rdance w i t h the Lo1 L o w l I I ~ :

( I ) P r o v i d e maiiual c o n t r o l f o r earl t o r t l r c t pni~ll>s,

( 2 ) P r o v i d e S l o w r e a d o u t ar. t l i r ce ,lcus l or cacll oi ~ l l c l i q u i d l o o p s ,

( 3 ) Provide low Tlaw alarrns f o r ecicll l i c l t ~ i d 1o01).

(4) P r o v i d e r e a d o u t i o r each I-lot s p o t t c ~ t ~ ~ l x ~ r a t t ~ r ~ ~ .

( 5 ) P r o v i d e s c i ~ o r a t c a l a r r i ~ f o r u a c l ~ 11ot s l i c ) L L c ~ ~ n l ) t ~ r - ; i l ~ i i c ~ .

1 I n the. e v e n t of '1 f a i l u r e i n tllc ~ o ~ ~ l r c ) l l o g i c , Ll lc ' I I I c t i l l uy s l i a l l f a i l i n strcll a niailner s o tlraL ito s i g ~ ~ i i l s ,ire. :,( I I L t i - o m

t h ( , ~irodrr Les t o Clic coo 1 a n t prniil>s . I . - 1% Lank Modttlcns - Two ( 2 ) modttl c s w i t l l 1) I ;i11Ic 11-011 L I < ICC, : I s11,i 1 1 lx*

l o c a t e d i n t h e C o n t r o l PancL of on(, systr-in.

1 . The phi l i sophy of d e s i g n and t h e gcsnc1r-ti l rc'qujrcsinclnts o r 111i' Brayton Engine C o n t r o l S y s t e n ~ s h a l L bc j r t i t ccordi~ncc wit l i MIL-E-8189, E l e c t r o n i c s Equipment, I n L ~ I L ~ e v e n t 01 con1 l l c 1 b(>tween diny documents a s i nco rporn ted I ~ ~ i - c ~ l n , Ll1c1 ~ - c ~ c l r i i u ~ ~ ~ i ~ c ~ l l t s a s s t a t t d i n l l l is Stdtemc.t~C of Worlc s11;11 i Itavc, ~ ~ r e ~ c c ~ c l c ~ r r i c ~ , ' d ' l t c s

I < ~ t e s t l s s t r t . , i n e i f ( l c t on tlte tl;t~ib 0 1 rchtlt~c::i I o r 1 1 l : l l~ii:-i,i l , ( $ 1 the, s p e c i f i c a t j o n s , stant l : i rds, dr;rwlltg:i, ilnd O L l ) c s r - I I I I I I I i c . I I 1 ~ 1 1 l r i

I i t i t L o r i I I i I I I I J I Al ly deviation i r i j ~ n this U t , C a 1 l ccl Spec. l 1 I C ~ I I f I O I I I I r l l ~ i l I I 1 1 1 11111 1 ( I O I I I y by r i r j t t ( ~ z a i l t l~or- iz , t t l t rn o r t I 1 c 1 Nh!;A P r l t r \ ~ * c . t flft~irrp,c-~

2, {;cncr:iL - The i%rayto~-i Eng i 1 1 ~ C o j > ~ r o I S y ~ t ~ * I I I ; i l i ! i I I I N , I I I I . I I 6 ~ i l i t b i l -- as a comptetc, e n d i t c , m wli.iclr R I I ; I I I 11i)t: T ( * ~ / I I 1 1 . 1 : L ( * I . v / I , i I)&$, , i t : ! j 1 1 1 i f - 111c.1it o r ~ t ~ o d i Cic:;~t.iorl bc!i (11. ! i a ~ - i t l : : ! ! t I I;II [ I I I I . ' l ' i ~ i s (1111i i 8 - 0 1

Plodtil(~:i s11~iL 1 I>(: dcss igric~d i 11 O ~ L I I Z I . LII:IL. c I I , ~ , I I i ! c ~ l i : i i i ~ ~ , t f ~ i ( , ; i ~ t I I ~ ~ ~ilade convenient l y .

MIL,-K-38101, R e s i s t o r s

MIL-R- 38102, C a p a c i t o r s

(d ) JPL-ZPP-2061-PPL

( i ) T a b l c l (High I ~ c L i i i l > I l l ~ y )

( F i ) Tab le 2 ( S p a c c l c r a f ~ )

( e ) GSFC-PPL

( f ) ANA U I I I l e t i n 400 , E l ( ~ e t r c ~ n l c 1Ccl11 I l>nlcbnt

( g ) MIL,-S- 19500 , Scrniconcl~~ctol-- I)ctvicc)

d , A l l c Lec t ron ic p , i r t s s l la l 1 1 ~ s citl)ol)lc OI ol)ccr.it I ilg i 1 1 1

tclill)cLraturc' envi i -onmt~nt of Lllc. S iglri~ l Cond i L l I I I ~ l irk; I I I I I ( ~ I I l c *

wllich is coo L1.d I)y il I 1 ( l id tind C O V ~ ~ I - P I tlit. Lcstl~l)(bi.ilL~lr ( 1.~!13g(~ Srorr~ - 6 5 " ~ Lo L50°F.

The> c o n t r a c t o r s l l a l l i n s p c c t 11aclr ~x i r t : u s c d I n t l 1 c 1 corttl-01 sys t em c i r c u i t s L o instii-c t h a t i t nrcets t lcslgn sl)cBc i I i c < i t l o n s .

b ru 6 . - The Bray ton Lrlgi.nc1 ( : c )n t ro l S y s tcin s l ~ ; ~ l l L ) C L t l ~ - s i g~ic.d

2% .. tc) opc>ra t c fro111 a nolninal + ;ind/or- -28 v o l t 1).(:. b t ~ s ; I S 111. iilt;~~-y

7 Ix)wcr and opcnra t e ilunlunc t o l,us n o l s c s . ' I ' l i i b 1)11s s1i;i I I I ) < , I - C ~ ~ ; I I I : I L t s c l

<;;.tc/ wi t l i i n -8'L and +40'%, of noininal vol t-ilgo st(*t idy s t i t t c w i L I I : I I I I ~ ~ X -

a ~ , ~ b - ~ ? , . iinurn n o i s e spec iSic ; i t i .on or 75 v o l t I - J I I I S , * S 0 1 t ~ n I I I ~ C I O S ~ ~ C O I K I d u r a t i o n a t o r a t e 01' 10 p u l s e s licl' sc~cond 011 c- i th(11- I- or - 2 8 v o l t D . C . bus .

7 . - 'l'hct cng i nc,-mounted lnorlt! 1 c s slta 1 L I ) ( > c l t > s i glic'd t o o p e r a t f f o r f i v c ( 5 ) y c a r s i n a H ~ ~ ~ I C L ' (~nvirori111~11t L J ~ ~ ~ I O I I L

herme t i c s e a l i n g . The packages ~ 1 1 ' 1 L 1 1 ) ~ C ' I IC I O S C ~ L C ) I I I C ~ i I I ~ , I i 11

c l e a n l i n e s s and exc l l lde any forca ig~l ~ i r a t i ~ ~ i , ~ I s ,

8 . E x t e r n a l Te rmina l s - '1'11(2 I x l cLrrl;i l I { . I I I I 1 1 r i 1 l ti hI1,i 1 1 I ) , $ , I I I I ~ I I 01 H

o r s t u d s L o which I c <id:$ rri,ly I ) ( # WI I t f ( + t i . ' l ' l ~ t , : * I t16 i : i t > l i t t I I I ! , threaded s o t h a t tc,rriy~ornry I (+:rdri c . : l l r I ) ( , 1 1 1 t i ~ c . l i c * t l 1 1 1 1 1 I . I I ~ I J I I I - p o s e s . N i ) r i ~ t a t i o n cjr cjl_lic,r I O O ( ~ ( S I I 1 1 1 ) : i l l 11 ( I , I 1 1 1 l i i ~ i l i ; i : l i l y

f i x e d p o r t i o n o f a tc . rrni~ia 1 s i i i ~ 1 l I ) ( * c i~l~ri t - t l I t y I I I / ~ ~ . I . I I , I l l l 8 1 w o r s h r i r~kage t ~ r any norr :~i~ I i t t t ~ ~ l t i ~ ~ ~ I [:a i I C I I - ~ ~ I ~ ~ I 1 I I V ~ I I v i , t l 1 1 1

C O I I I I C C L ~ O ~ I or c! i s c o ~ ? n ~ @ c L j o r ~ Ll i~- i )~~g! io~tL I 1 1 I ! , I * ! 1 1 1 1 t ~ ! i k 8 , I I , , , c o n t r o l :;ystcrrr.

Fin i s l l - Finis11 o r tcxrminalcr s l~c~l 1 r n c * ~ ~ L 11k$ l ) ~ ~ ~ ' i t r t ' ~ i ~ t l ~ i c * c ~ a . P

rcqt l i rei i lc~nts s l ~ e c l t i e d I n p:lrugrnplr I I l o w .

b . - Termina l s s h a l l br? du rab ly and l i g i b l y ~ i~ur l t cd .

9 . B r a z i n g - Nonc a l lowed u n l e s s s p e c i f i c a l ly a1)l)rovcd by t l l c s NASA P r o j e c t Manager.

10 . ,Welding - Welding s h a l l comply w i t 1 1 tl1i8 r c q t ~ i i * c ~ l l c ~ ~ l t s i f i t i l ) c S c . I - f i c a t i o n s MIL-W-8611A and S t a n d a t d o r M11,-R- I 1468.

11, E l e c t r o n i c C i r c u i t Connec t ions - A l l c l c c t r o ~ l i c c i r c u i t r c . s i u t - ance we ld ing s h a l l be i n accordances w i t 1 1 hIL-W-8939 (ASG). O the r mc thods of making e l e c t r i c a l c o n n e c t i o n s sha L l ~ ' c l ~ ~ i l i r c ~ a p p r o v a l of t h e NASA P r o j e c t Manager.

12 . Conforntal C o a t i n g - A l l a s p e c t s of c o n i o r ~ n a l c o a t i n g ;IS st11)- a l i t t e d by t h e c o n t r a c t o r a r e s u b j e c t t o a p p r o v a l by tllc NASA P r o j e c t Managcr.

13 . Radio I n t e r f e r c ~ n ~ ~ - Designcd i n accordance witti Spec i Tic.:~l ion P 1224- I Siipp lcnicnt 1 .

1 4 A 1<11viro1111icllt - The S i g n a 1 Condi t 1 oncQr- :i11;1 1 1 IN. tlcs 1gllc.tl I 1 1 i~i.col-tl- nnce w i t h envi ronnlcnta l s p c c i r i c a t l o n u 1'1 224- 1 and 1'1 :!2/t-2. Tl~ca Con t ro l and Morlitor i ng Panc 1s s h n l l bc dcbsig~lcd i n :rcc.ortl;l~lcc~ w i t h envi ronelcnta l s p e c i l ' i c o t i o ~ i s P1224.11 Sul)purtS 2.1 , 2 . 2 . 2 and P 1224-2 S u b p a r t s 2.0 (31 1 1 , ;~r tu) o n l y .

15. Packaging Tor D e l i v c ~ r ~ - Each E11gi1lc C O I I ~ r o l Sys tc t r r~ :;/la l l I ) ( . packed i n s e p a r a t e , s e a l c d , dus t-1,rool' col l ta incsrs ; \ ~ l d adt.cltl.1 t c s 1 y ~ ' r o t c c t e d a g a i n s t ddlnage d t t r ing s h i pitic3nl kind s Lotagc3. Piirl(ctging s l l a l l be i n a nlanncr t o i n s u r e n c c c l l ) t a ~ t c ~ ~ by coaunon c i l r r i i ~ l - i'or sh ipmcnt by bcs t colluncrcial t r a n s p o r t a t io11.

16. P r i n t e d C i r c u i t s - P r i n t e d t i r c r t i t board LayouL and d c s i g u s h a l l 11e i n acco rdance w i t h MSFC-STD- 154.

1 . Acceptance T( . s t Sl)cac i l i c ; ~ t i orlrj - ' j ' l i r . c.0111 I r l c I 1 1 1 r c r r I I I I I I I t 1 1 1

Task 11 sha l I preparc4 a d ( ~ ~ ; l i Itq(1 t , h ~ i ~ l , l ; ~ ~ ~ 1 1 1 1 11c .1 1 , 1 1 1 I I I I I 1 , 1 1 1 i 1 I I I ~ ,

o f each completed Braytort lingin(, C0ntr111 : ;y r r l l . 1 1 1 Ijr 1 1 1 1 1 1 1

d e l i v e r y .

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s i g n a l o r l o a d .

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t h e t c s t s h a l l be d i s c o n t i n t l e d and thcx LI-oitb l ( n c%orrctc ~ ~ s t l ( , I I w'ly 5

accoul l~ .~~r ic~d I)y a Ina 1 lunc t l o n re1)or t i nd i c . I L i u g Llicl I ' I i l 111 ( ~iitido , c~ i l l s c O i i a i \ t i r e , 31id c o r r c c t i v P ; le t ioli t t~ l<c~l t ) . 1111Ic~:~> C I n ~ ~ ~ L ( x d an c x c c ~ l ~ t l o n by t l l c . NASA P r o j e c t M;lnagctl- L l l c h c ~ t ~ L l r c ~ L c , : l l S C > ( I I I C I I C C ~

s h a l l bc r e p e n t e d t t n t i l s ~ l c c c s s l 1 1 1 l y cc~rlllile~tc~d. S i lice, 1111 : iJg- n n l Ce)ntiitioncbr i s c,nginc.-lnountt.d, i t s l ~ ; ~ l l I ) ( . !iull jtsc.~(ld L O 11

s i111ulntc1d spaccx environliic~nt o; lo- ' t o r r ( I L I I - i lib: ii I 1 : I ( c ( I ~ L I I I I C I '

L c s t s .

2 . Tllc) accc31-ttarice t c l s t s skiall i nc l t~dc , b i ~ t I ~ O L Il111iL~ttl L O t l i ,

I ( 1 1 lowing:

1) . ECICII I I I O ~ I I I ( $ s l i : ~ 1 I bt- s(~l),jclct. to i i I OH I I O I I I - S I I O L ~ I ~ I - ; I& i I I ~ L o b(> 1.1111 a t 11laxi11lt11n iiiodtllc~ s t l - cxs s w i L l l 1 1 1 sl)c<c i I i c ; ~ L ii111:~. At the. co~np l r , t i o n o I- thck a g i n g , c9:lctl I I I O ~ I I l ( , s l~ i l l l I ) ( $ t1.s 1 ( , ( I ;I L 111in it1111nr I). C . vo I tagc> ; I I I ~ 111in ~ I I ~ ( I I I I ~ ~ ~ I I I ~ ) ~ ~ ~ - ; I L I I I ~ ( ~ i 01. c o r ~ - ~ , c , I

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c i r c u i t s1r;ill 1 , ~ ' t e s t c d t o i nsilrc! 110 parL i n i l t~rcss w i 111 i l l

t l ~ c 111odu I t m .

c . Tltcs Engi ncs Contra 1 Sy s tc~nl slr;l 1 1 i l ~ ~ ( ' l l l l ) 1 c'd ill icl I I I : ; ~ I ( c . 1 (8d i 01- worknl;~nship and C O I I I ~ ) l ioncc, w i tlb tit*:; ign sl)cbc i l i C ; I L iolrs .

( 1 ) 'L'he systciii s l ~ a l l 1x1 testcld I 01- j i l - t r l ) c q l - ol)ili-ilt i o l l I)p i l l -

d i v i d i ~ a l l y 1 ,xerc i :; i ng c.<1c11 i 11l) t r 1 sign;^ l . '1'11 i s 1 (,:; 1 S I I ~ I I I be rl1n a t Llru cxLt'c8r~~cs oi lltiix ~ I I I ~ I I I I s l I - I . S S i l l 1 1 1 I I I i 1 1 ~ I I I I I I I I

( 2 ) llqli'l Systc~lll :+\la1 I 1x1 ~ U S L C ~ C I llll. \ ) l ~ l ~ \ ) l S 1 ~ op,*l.;lL 1 1 ~ 1 1 1 0 , . il s imula ted ins t runlent t r a n s d u c c l ~ I n l 1 tire a t ~ ' i ~ c l l v o i \ t r r ~ l i n p u t s i g n a l t e r m i n a l .

( 3 ) The systelns s h a l l be t e s t c d l o r itlldc! o r cxtrahcorls c o n t r o l coan~ands o r f a l s e rcaklot~ts wiic~n subjcctcld to D.C. bus n o i s e . For t h i s p focur~*mcnt , Odd, bus no i se s h a l l be s p e c i f i e d a s 75 v o l t t r a n s i e n t s ( p o s i t i v e on t h e p o s i t i v e 28 v o l t D.C. bus and ncgar ivc on the n e g a t i v e D,C . bus) w i t h a 10 mitrosccodd dttrakion and a r e p e t i t i o n r a t e of 10 puLscs per sccond.

111. S p e c i f i c Requirenients

A, Taslc 1 - P r c Linlinary Dcsign Report

1 , Thcl c o n t r a c t o r sha 1 l per rorrt~ a P r i ~ l i111i rli~ry Dcs ign I(c.l)otlL tits l I n 1 I I ~

t l l e ~ desigri s p c r i f i c a t i o n s 1 or the king i n c ~ ( ! o n t r ~ ~ l S ~ : : L I I I I ~ , l l i l sllal 1 st111111it t o thcb NASA ~ r o j c c k Milnngr.t- I o r itlIprovir l SOIII . (4) c o ~ ~ ~ l i l o t o s ~ t s 1, l ti9 ;I r c p r o d t ~ c i b l c3 sc$t o i ringi ~ i c ~ c t ~ i ~ i ~ ; rlri~wi II}:S i 11 . agrpentclnt w i t h spec i 1 i C a t i o n M11,-D- I OOO C:l tilgc~ry A , I ~ C I ~ I I I '1, ;IIIC) 4 1 i l L 1 1

i n suf f j c i e n t d e t a i l t o d e s c r i b e nccur:tLc ly t l ~ c s tlcs I K I I i l r l c l

assembly de t o i l s oC khc E ~ g i n e Contro 1 Sy:; tc.111. Tltc, lil'c* l 1111 l rlrtry Dcsign Rclport s l la l 1 inc lude a l l t l l c , c r i L ~ U I - ~ L I I1stc.d 1111th1r "(!onk i ' t ~ l Sys te i~i S l ~ c c i i i c a t i o n s ' ' o r t l l i s exlti I i i L ;IS wc.1 l ;IS r'i-i l ( '1 ' i . 1 ! : ( + I - c3ctcd by the c o n t r a c t ~ ) r , T11r dr~lottttt i ) l i l ~ ~ t r k t ~ n c l n t a t itb, i I IC l lldltig redundancy, r e q u i r e d t o nwe t thc. 1-12 [ i n b i l i t y oh j c c t i vcss slba l l btl dc~tcrmined i n t h i s Pre l i ln inary Dcsj gn Study .

2 . T ~ I C c o n t r a c t o r s h d l l prepmc1 a coarprel~c~~ls i vr* progrilnl pldn us ing n i ormat of h i s own ~ h o o s i n ~ and dots i l i ng n l l ~ ~ l c r n i ~ n ~ ~ c l C c s i l 'ort nc8ccssary t o c o ~ l \ p l ~ t c ~ t h i s pro j cc t . ti ti^ l>rc~griiiil 1) I i l i t ~ 1 1 ; t i I drlsoribc, d e t a i l e d p lans and phasing, ;I ~)rr~l)osr .d Y ~ ) L # I I ~ i11g scIrc*dti l il, and R e l i a b i l i t y and q u a l i t y Assutoncr~ Hi*rli~irc~rni-ilts i l l ~ C C I ~ I ' ( I ~ I I I C I ~ w i t h E x l ~ i h i t l3, paragral)h 2 .4 . Th i s I ) ~ I ) ~ I ' ; I I I I ~ 1 1 ~ 1 1 1 I ) t s S I I ~ ) I I I i L tc'd I o r approva l t o t h c NASA P r o j e c t Miltlaginr I'ol-ty- l LVi* (115) tlifys a i t e r award of c o n t r a c t .

3 , A formal 1)esign Revictw wi I l bi> 111, l tl i 11 t r c ~ ~ t ~ r d ~ ~ t t c c * wi L I I 111t.

r ~ q u i r ~ ~ ~ ~ ~ c ~ ~ i t s of Exhihi t B , ~ ~ a r o g r i l l ~ l ~ 2 .{I . 4. Within th ree ( 7 ) wc~(~ks ol L i t ( , C I ~ I I C ' I I I H 1 1 1 1 , 1 1 1 LOc . I)I.:I I H I I I t t * v I ~ . w

t c q u i r c d by t h i s t i t s k , t l ~ c a c.ontr;icl 1 1 1 r r l ~ i l l 1 rrtt11111 I I 1 . 1 1 c 0 1 1 1 I,:$

0 1 a co~r~[)rc!h(*nb ive S1111mary l{r*por L I 1 8 I 1 1 t - l,t*lU; I ' I * I I ] 1 8 c . t P ~ I I I I : I ~ , I * I . This rcLpor t S ~ I ~ A 1 I. J ncor l)trr:llc* arty c l i u ~ ~ g t * r ~ I I I I ~ I / o r I t - v 1 1 1 ltrll:~ 1 1111 I rrlay re . r~ i l t frr)r~l th( . Prc3lllllill;lry l)(v:ilg~~ I ( I~ I I I I~ .L ; I I I ( ~ ( 1 1 t ' I ~ O I I I I ~ I I I>cs i g n Iteview as rc~co~~rmcnd(~tl I)y i l l ( + I,rll{(: I ~ ~ I I J c s c . 1 M I I I I , I ~ , I ~ I .

B . Tnslc I I - Dc~ta l l ~ ~ t l - l ) c ~ s I = - 1 . Inurlcdiatc l y upon r c s ~ c * i p t 0 1 approv.l l ( 1 1 '1':1sI< 1 , t l t c ~ c c ~ l i t ~ - , i c ~ o a :

s h a l l pcriorili a d e t a i l d e s i g n Lor tllr ICng l n c l C o t ~ t r o l S ~ ~ C ( , I I I based oil t h e r e s u l t s oC t h e p r e l i ~ i i i n a r y dclsign v r - r o r t upl)lovc.tl in Task I .

2 . . P r io r t o p r o c u r c m n t * of t o o l i n g , r ~ i w n ~ ~ l L ~ , l - i i t l s , or L I I ~ \ I <ll)r i - c a t i o n (1; p a r t s the- c o n t r a c t o r slla l 1 r l l r l i lslr L l 1 1 5 NASA P r o i c ' ( ' L Managcr- I ou r (4) c o ~ ~ i l > l c t c > s c t s p111s :I i -c~l~r~c~drlc i l ~ l c ' s c . ~ 0 1 c>ngincel i n g d rawings i n agreement wi t11 s ~ ) t ' c l 1 i c i l t i111 t blll,-I)- 1000 Ca tego ry f%E , Forn~ 3 , f o r approva L t o ~ t~-oc~oc~cI . Inci i v I ~ L I , I I d rawings s h a l 1 be I or-wardcd as co1111) lcb tc,d i 11 o r d e r tIlnL c1:11- l l (.st ~ x ) s s i b l c ~ a p p r o v a l luay bc. g r a n t e d .

3. Due, t o t h e r e l i a b i 1 i t y rcquircnlcsnts , t l ~ o c o n t r : l c t o r h l l i ~ l l , I l s o S I I ~ I I ~ ~ L l o r r e v i e w by t h e NASA P r o jcsct M;~li~lgc~r . I 1 I d t s ~ , ~ i l t tl

s l x , c i I i c a tions and pi-occ.drlrc.s h(t w i l l t r b c > i n t l ~ t . I ,ll)r i C , I L I 1 1 1 1

1 1 1 theh ICnginc Con t ro l Systr'lti.

4 . ' 1 ' 1 1 ~ 1 c o n t r ; ~ c t o ~ - sha l l a l s o 101- i l l i l l , I L ~ a 'i'cbs~ PI ; ) I ) . ' t ' l l t , 'rca: ,~ I'l ,in slt'~ l 1 i n c l r ~ d r 1111 I I ~ I ~ I I I I I I t ( * s t : , c<IIt:ii '~Ll l i t w i I 1 1 ~ ) I - ~ ~ v i lip, 1 / 1 1

coit~pi i , i i ~ c ~ ~ t o t h i s s l ) ( , c j I i c <1Lio11 0 1 L / I ( , clcss i g t ~ 1 1 1 L J I C , C I I I I ~ t - ~ ~ i

. ' Sys t e l~ l . Il'hc c o n t r , l ~ l o r h l ~ , l l l 3111)1111L L I I C ' '1'cst I ' I , I I I t o t l ~ c . NASA P r o j e c t t4onagc.r I o r ctl>prova i .

, 5 , .A Forlilal l l c s ign Kc.vit w w i 1 1 be 11ctld i n , lccort l , t~icc~ w i t l l L l l c

r c ~ q ~ i r ~ l i l c ~ n t s 0 1 Exhi b i t : A , pnragral)lt L . C t .

6 . Wi th in t l i r c~e ( 3 ) wcelcs 0 1 t l r t . c o t ~ c l11sic111 ( 1 1 t l ~ c I)c>s igli I < t v1t.w rc-quircld by t h i s t a s k , t l~c ' c o ~ ~ t r ~ ~ c t or :71~ci l l sttl)liri t ~ 1 ~ 1 1 ell11 i t 9 5

o l a C o ~ ~ ~ p r e h c n s i v c Slalmlary liepol- t LO L l i t * l,tlli(: I'ro jc>c L Mali:~g(~L'. T h i s r e p o r t s h a l l incorpor:lLc. any c~lii~iigc~s ; ~ ~ l t l / t ) r ~ . ~ * v i : , i o ~ i : ? Lhnt niay rest11 t fro111 t h c P r e 1 i a l inary Iles ign Iicxl)or t ;1nd t l i c l l'orlllo l Des ign Review a s reco1nn1cndc.d by t h c ~ T,eliC P ro J e c t Mnn:lgc,l-.

7 . A s p a r t O L Task 11, t h e c o n t r a c t o r s h a l 1 subtilit a d ( . t , l i l c $ t l l i s t o f reco~~unended s p a r e \ , i n c l u d i n g b ~ r t n o t l in l i t t>d to e m l o c t i - i c , ~ l components ,' p a n e l hardware , and c i rcrliL c r ssclrlb l i e s I o r itl)l)rova 1 by t h e NASA LcRC P r o j e c t Manngc3i .

C . Task trc'nt Con t ro l Sy stc4111s ---

1: T a s k I P 1 A -- !mi : ; ~ : ~ l ~ ! l l l : , ~ b ' # l I l l i ( a l l l ~ l l l

l J l ) o r ~ rc cc.1 pt o i api)t-l~v;i I 0 1 ! / I ( . I ) ( $ ( 11 I I l j r - I : l p , i ~ I 1 1 $1' t ~ . l ~ I I , l l l r

o n t o 1 I 1 I I - 1 I ( l l l I t I $ 1 I I L W I ? ( ' j

Irngi~ic ( : o r ~ t t ~ , l . ' > ~ S ~ ( I I I ~ ? . I - I - I I , , I I I ~ . I I I I I Y I I I l l ~ ~ ~ t ~ t ~ t ( I

i 1 1 adv<illc c oi . I ~ I [ ) ~ L I V < I I 0 1 t 111 Ilc*~ . I r l I ) c ~ c , i ;:II w I I 1 1 L 1 1 1 , ( 1 1 1 1 I I I I I I I ( 1

0 1 thc 1,ASA 1'1-o j e c L I ~ I ~ I I I ~ I ~ ; ( ~ I < I I I ~ , 1 1 1 1 1 1 O V , I I 1111 I 1 1 1 ( ; O I I I I , I ( 1 I I I ~ ,

Of Liccct .

The c o n t r a c t o r s h a l l conduct thc. acccll>t:liic[' L r 5 9 L s , alili~-ovc~tl 111

t he Taslc I1 T c s t P l a n , on t h e two ( 2 ) I<ngl tic) C o ~ l t r o l SysLt1111s f a b r i c a t e d i n Task I I I A .

3 . Task I I I C - Engine C o n t r o l Systeins

Two ( 2 ) Engine C o n t r o l Systems s h a l l bc dcxlivercd t o NASA-Levis Research C e n t e r f o l l o w i n g t h e accep tance t e s t prograoi a t t h V c o n t r a c t o r ' s l a c i l i t y .

4 . Each Engine Contrcll System s h a l l bc accoilipanicd by two ( 2 ) complc. t e s e t s p l u s a r c p r o d u c i b l c s c t o i csngini>er i ng c l r t ~ w i ~ i g s i n agreelricnt w i t h 's1)eciCicat ion MIL-D- I000 Cit tvgory I b E , Fort11 3 . These, drawings shril 1 show t l > ~ I J ~ j n l c o n r j g ~ i r i ~ t i o ~ i o i t h c Engincs C o n t r o l Sys tciii. A L L d c l ~ j a t ions o l thcl d e l l vc'i-c'd ctquiprnent fro111 t h e s e drawings s h a l l b r l i s t e d .

The c o n t r a c t o r slit11 1 l u r n i s h to NASA LtsItC L I I O t iystc~~il 111!il i.u111(~111:1t lrlii and 1 oad s i l l lulator d e s c r ibcd i 11 pnri~gr:il)ll 11 . I ) . I .

E . Task V - Manuals

The c o n t r a c t o r s h a l l fu t -n ish I n s t a l l a t i t l n and O p e r a t i o n nranuals for the 1)evclol)luent C o n t r o l Sys tc i~ l . F ivc (5) ~~ l i lnua l s s h a l l be d c l i vcred w i t h cxach ISnginc. C o n t r o l System. Tllc format and c o n t e n t fdr t h c s e nianunls s h a l l be s u b j c c t t o thcx approva l o r tllc 1,cltC P r o j e c t Mollagcr.

The c o n t r d c t o r s h a l l sl-?pLy NASA a l l ql):zrrl p:ltAts ; I S nppr-v('d i l l

Tasrc I;.

BRAYTON CYCLE CONTRACTS

BASIC FINAL REPORT DISTRIBUTION LISTS

NASA Lewis Resea rch C e n t e r 21000 Brookpark Road C l e v e l a n d , Ohio 44135 A t t e n t i o n :

C o n t r a c t Manager ( 5 ) M a i l S t o p 500-201

Bray ton P r o j e c t O f f ice (77 ) M a i l S t o p 500-201

H . O . S lone i 1) M a i l S t o p 500-201

D . R . Packe (1) M a i l S t o p 500-201

R . E . E n g l i s h (1) M a i l S t o p 500-201

B . Lubarsky M a i l S t o p 3-3

J. E . D i l l e y (1) M a i l S t o p 500-309

D . C . Beremand (1) M a i l S t o p 500-201

W . T . Wintucky (1) M a i l S t o p 500-201

V. F . H l a v i n M a i l S t o p 3-14

NASA Lewis Resea rch C e n t e r Plum Brook S t a t i o n T a y l o r Road Sandusky, Ohio 44870 A t t e n t i o n : J . C . N e t t l e s ( 2 )

Ma i l S t o p 1441-1

P . A . T h o l l o t (1) M a i l S t o p 500-201

A . S . V a l e r i n o (1) M a i l S t o p 500-202

H . A . Shumaker (1) M a i l S t o p 500-202

W . L. S t e w a r t (1) Mai l S t o p 77-2

L i b r a r y Mai l S t o p 60-3

R e p o r t C o n t r o l O f f i c e (1) Mai l S t o p 5-5

R e l i a b i l i t y & Q u a l i t y Assurance O f f i c e

M a i l S t o p 500-111

Technology U t i l i z a t i o n O f f i c e (1) Mai l S t o p 3-19

N a t i o n a l A e r o n a u t i c s & Space Adm. Washington, D . C . 20546 A t t e n t i o n : P . R . M i l l e r (1)

Code RNP

H . D . Rochen (1) Code RNP

NASA S c i e n t i f i c & T e c h n i c a l I n f o r m a t i o n F a c i l i t y P o s t O f f i c e Box 5700 C o l l e g e P a r k , Maryland 20740 A t t e n t i o n : A c q u i s i t i o n s Branch (SQT-34054) (1 + r e p r o d u c i b l e )

NASA A m e s Resea rch C e n t e r M o f f e t t F i e l d , C a l i f o r n i a 94035 A t t e n t i o n : L i b r a r y (1)

NASA F l i g h t Resea rch C e n t e r P o s t O f f i c e Box 273 Edwards, C a l i f o r n i a 93523 A t t e n t i o n : L i b r a r y (1)

NASA Goddard Space F l i g h t C e n t e r G r e e n b e l t , Maryland 20771 A t t e n t i o n : L i b r a r y (1)

J e t P r o p u l s i o n L a b o r a t o r y 4800 Oak Grove D r i v e Pasadena , C a l i f o r n i a 91103 A t t e n t i o n : L i b r a r y (1)

NASA Lang ley Resea rch C e n t e r Lang ley S t a t i o n Hampton, V i r g i n i a 23365 A t t e n t i o n : L i b r a r y (1)

NASA Manned S p a c e c r a f t C e n t e r Hous ton , Texas 77058 A t t e n t i o n : L i b r a r y (1)

A . Redding - EP-5 (1)

NASA M a r s h a l l Space F l i g h t C e n t e r M a r s h a l l Space F l i g h t C e n t e r , A l a .

35812 A t t e n t i o n : L i b r a r y (1)

A e r o j e t - G e n e r a l C o r p o r a t i o n 1100 West H o l l y v a l e Azusa, C a l i f o r n i a 91702 A t t e n t i o n : L i b r a r y (1)

Aerospace C o r p o r a t i o n P o s t Off ice Box 95085 Los Ange le s , C a l i f o r n i a 91745 A t t e n t i o n : L i b r a r y (1)

AiResearch M a n u f a c t u r i n g Co. 402 Sou th 36 S t r e e t Phoenix , A r i z o n a 85034 A t t e n t i o n : L i b r a r y (1)

L y l e S i x (1)

AiResearch M a n u f a c t u r i n g Co. 9851 Sepulveda Bou leva rd Los Ange le s , C a l i f o r n i a 90009 A t t e n t i o n : L i b r a r y (1)

AiResearch M a n u f a c t u r i n g Co. 2525 W . 190 S t r e e t T o r r a n c e , C a l i f o r n i a 90509 A t t e n t i o n : L i b r a r y (1)

B a t t e l l e Memorial I n s t i t u t e 505 King Avenue Columbus, Ohio 43201 A t t e n t i o n : L i b r a r y (1)

Bendix R e s e a r c h Labs D i v i s i o n D e t r o i t , Michigan 48232 A t t e n t i o n : L i b r a r y (1)

Boe i n g Company Aerospace D i v i s i o n P o s t O f f i c e Box 3707 S e a t t l e , Washington 98124 A t t e n t i o n : L i b r a r y (1)

Borg-Warner C o r p o r a t i o n P e s c o P r o d u c t s D i v i s i o n 24700 Nor th M i l e s Road B e d f o r d , Ohio 44146 A t t e n t i o n : L i b r a r y

Bureau o f Naval Weapons Depar tment o f t h e Navy Washington , D . C . 20025 A t t e n t i o n : Code RAPP (1)

C o n t i n e n t a l A v i a t i o n & E n g i n e e r i n g Corp .

12700 K e r c h e v a l Avenue D e t r o i t , Michigan 48215 A t t e n t i o n : L i b r a r y (1)

C u r t i s s - W r i g h t C o r p o r a t i o n Wr igh t Aero D i v i s i o n Main & P a s s a i c S t r e e t s Woodridge, New J e r s e y 07075 A t t e n t i o n : L i b r a r y (1)

G e n e r a l Dynamics C o r p o r a t i o n 16501 Brookpark Road C l e v e l a n d , Ohio 44142 A t t e n t i o n : L i b r a r y (1)

G e n e r a l E l e c t r i c Company Mechan ica l Technology L a b o r a t o r y R & D C e n t e r S c h e n e c t a d y , New York 12301 A t t e n t i o n : L i b r a r y (1)

G e n e r a l E l e c t r i c Company Space D i v i s i o n C i n c i n n a t i , Ohio 45215 A t t e n t i o n : L i b r a r y (1)

G e n e r a l E l e c t r i c Company Re-en t ry & Env i ronmen ta l S y s . Div 3198 C h e s t n u t S t r e e t P h i l a d e l p h i a , Pa . 19104 A t t e n t i o n : L i b r a r y (1)

G e n e r a l Motors C o r p o r a t i o n I n d i a n a p o l i s , I n d i a n a 46206 A t t e n t i o n : L i b r a r y (1)

Hughes A i r c r a f t C o r p o r a t i o n Cen t inda & T e a l e Avenue C u l v e r C i t y , C a l i f o r n i a 90230 A t t e n t i o n : L i b r a r y (1)

I n s t i t u t e f o r Defense Ana lyses 400 Army-Navy D r i v e A r l i n g t o n , V i r g i n i a 22202 A t t e n t i o n : L i b r a r y (1)

Lea r S i e g l e r , I n c . 3171 S . Bundy D r i v e S a n t a Monica, C a l i f o r n i a 90406 A t t e n t i o n : L i b r a r y (1)

Lockheed Miss i les & Space Co. P o s t O f f i c e Box 504 Sunnyva le , C a l i f o r n i a 94088 A t t e n t i o n : L i b r a r y (1)

McDonnell Douglas A s t r o n a u t i c s Co. 5301 Bo l sa Avenue Hun t ing ton Beach, C a l i f o r n i a 92645 A t t e n t i o n : L i b r a r y (1)

McDonnell Douglas A s t r o n a u t i c s Co. 3000 Ocean P a r k Boulevard S a n t a Monica, C a l i f o r n i a 90406 A t t e n t i o n : L i b r a r y (1)

M a s s a c h u s e t t s I n s t i t u t e o f Technoloc Cambridge, M a s s a c h u s e t t s 02139 A t t e n t i o n : L i b r a r y (1)

Mechanica l Technology I n c o r p o r a t e d 968 Albany-Shaker Road Latham, New York 12110 A t t e n t i o n : L i b r a r y (1)

Nor th American Rockwell Corp . Atomics I n t e r n a t i o n a l D i v i s i o n P . 0 . Box 309 Canoga P a r k , C a l i f o r n i a 91304 A t t e n t i o n : T. A . Moss (1)

Nor th American Rockwell Corp. Space D i v i s i o n 122 14 Lakewood Bou leva rd Downey, C a l i f o r n i a 90241 A t t e n t i o n : L i b r a r y (1)

N o r t h e r n R e s e a r c h & E n g i n e e r i n g Co.

219 V a s s a r S t r e e t Cambridge, M a s s a c h u s e t t s 02139 A t t e n t i o n : L i b r a r y (1)

Power Informa t i o n C e n t e r U n i v e r s i t y o f P e n n s y l v a n i a 3401 Marke t S t r e e t , Room 2107 P h i l a d e l p h i a , P e n n s y l v a n i a 19104

S o l a r D iv . o f I n t e r n a t i o n a l H a r v e s t e r 2200 P a c i Eic Highway San Diego , C a l i f o r n i a 92112 A t t e n t i o n : L i b r a r y (1)

Space Systems D i v i s i o n Los Angeles A i r F o r c e S t a t i o n Los Ange le s , C a l i f o r n i a 90045 A t t e n t i o n : L i b r a r y (1)

S u n s t r a n d Denver 2480 West 70 Avenue Denver , Co lo rado 80221 A t t e n t i o n : L i b r a r y (1)

TRW Sys t e m s One Space Park Redondo Beach; C a l i f o r n i a 90278 A t t e n t i o n : L i b r a r y (1)

U . S . Army Eng inee r R & D Labs Gas T u r b i n e T e s t F a c i l i t y F o r t B e l v o i r , V i r g i n i a 22060 A t t e n t i o n : W . C r i m

U n i t e d A i r c r a f t C o r p o r a t i o n P r a t t & Whitney A i r c r a f t Div. 400 Main S t r e e t E a s t H a r t f o r d , Conn. 06108 A t t e n t i o n : L i b r a r y (1)

U n i t e d A i r c r a f t R e s e a r c h Lab E a s t H a r t f o r d , Conn. 06108 A t t e n t i o n : L i b r a r y (1)

West inghouse E l e c t r i c Corp. A s t r o n u c l e a r L a b o r a t o r y P o s t Off ice Box 10864 P i t t s b u r g h , P e n n s y l v a n i a 15236 A t t e n t i o n : L i b r a r y (1)

W i l l i a m s Resea rch Wal l ed Lake, Michigan 48088 A t t e n t i o n : L i b r a r y (1)

TRW A c c e s s o r i e s D i v i s i o n 23555 E u c l i d Avenue C l e v e l a n d , Ohio 44117 A t t e n t i o n : L i b r a r y (1)

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