Maintenance Solar

7302019 Maintenance Solar

httpslidepdfcomreaderfullmaintenance-solar 117

Turbomachinery Technology Seminar

Quality in Maintenance

CsTERPllLARSolarrdquo Turbines



Contents

INTRODUCTION

MAINTENANCE OBJECTIVES

MAINTENANCE APPROACHES

MAINTENANCE PLANNING

AVAILABLE TECHNOLOGIES

INTEGRATED GAS TURBINE CONTROL

CONDITION MONITORING SYSTEMS

SUMMARY

ACKNOWLEDGEMENTS

REFERENCES

Page

81-I

81-1

81-I

81-4

81-6

81-14

81-14

81-14

81-15

Cat and Caterpillar are trademarks of Caterpillar Inc

Solar Saturn Centaur Taurus Mars Turbotronic and SoLoNOx are trademarks of Solar Turbines IncorporatedSpecifications subject to change without notice Printed in USA

Copyright Q 1992 by Solar Turbines Incorporated

-l-l-S81 492




CS Woods

ManagerCustomer Services Technical Center

WJ BlissSenior Engineer

Customer Services Technical Support

INTRODUCTION

Gas turbines have a number of advantages that

distinguish them from many other power sources

including greater reliability and lower overall life-

cycle cost A quality maintenance program is

essential to benefit fully from these attributes In

recent years significant advancements have been

made in both the concepts and technologies used

in maintaining gas turbines

This paper addresses aspects of establishing

an effective efficient maintenance program for

small and medium-sized gas turbines In touch-

ing upon the goals of a quality maintenance

program it discusses what should be maintain-

ed when it should be done and how it can be

accomplished by employing the various technol-ogies available including lube oil analysis vibra-

tion analysis gas turbine performance analysis

borescopic inspection and trending of operating

parameters


Different operators have different needs and will

often emphasize different objectives in their

maintenance programs including

l Availabi lity

l Maximized production

l Optimized efficiency

Control of operating costs

Although operators assign varying levels of im-

portance to each of these objectives if thought-

fully designed a quality maintenance program

can achieve all of them

Availability The simplest definition of avail-

ability is ldquoreadiness to runrdquo Availability can be

quantified using the following formula (Chandler

1984)

Availabili ty ( ) =Period - (SD + UD) x 1oo

Periodwhere

Period = Length of time defined in either

hours or days

SD = Scheduled Downtime

UD = Unscheduled Downtime

Maximized Production This means attaining

the largest gross output over a given period of

time whether the output is kilowatts of electricity

produced or millions of cubic meters of gas

moved down a pipeline

Optimized Efficiency Highest efficiency isachieved when the minimum energy is used to

realize the desired level of production

Control of Operating Costs A well -designed

maintenance program helps to minimize the cost

of operation over the gas turbinersquos life cycle

Among the elements that can be controlled are

overhaul cycles resources (equipment and

people) and inventory (replacement parts)


Essential to a quality maintenance program is

determining what to maintain and then decidingwhen to do it Three different approaches to main-

tenance timing can help solve these problems

+ Unscheduled Maintenance - Maintenance

performed only when an incident occurs

l Scheduled Maintenance -Also called preven-

tive maintenance this approach consists of

a schedule of periodic maintenance tasks

designed to preclude failures

81-I



l On-Condition Maintenance (Predictive Main-

tenance) - Planned monitoring of package

condition Maintenance is then scheduled

based upon the equipmentrsquos health Not only

are costly surprises avoided but unneeded

maintenance can often be deferred When

the measurements of machine condition aretrended over a period of time they can be

used to anticipate failures well before they

occur For this reason on-condition mainte-

nance is also called predictive maintenance

Several factors must be weighed to determine

which approach should be used for each systemor component These include the criticality of the

system or component the relative costs of apply-

ing each maintenance concept and the acces-sibility of both the component and the site

Items that are not expensive or critically im-

portant may fall into the unscheduled category

and can be repaired when they fail As cost or criticality increase preventive maintenance be-

comes desirable Components that are even

more costly or critical or both (Figure I) are

generally monitored more carefully using predic-tive maintenance technologies

For gas turbine packages the biggest most

important components are often the most reliableand require the least maintenance The best ex-

ample is the gas turbine itself Though it contains

thousands of individual parts its maintenance is

relatively simple Since it is very critical and the

most costly part of the package it warrants care-ful monitoring The same is true of the driven

equipment (generator gas compressor or pump)

However the gas turbine is just one part of the

overall package If not given proper attention

minor components can cause serious problems

Predictive

CRITICALITY-wgure I - Maintenance Concepts

81-OO M

For instance a loose compressor dischargepressure (Pcd) line to the fuel control can prevent

the gas turbine from starting

Ancillary equipment used to ensure the quality

of air fuel and water should be part of a quality

maintenance plan Al so many co mponen ts

mounted off the gas turbine skid have a vitaleffect on the operation of the gas turbine andits driven equipment Examples include switch-

gear for generator sets as well as gas coolers

scrubbers and yard valves for compressor sets

Various process valves and associated equip-

ment are important to the proper operation of

other types of driven equipment such as pumps

Most manufacturers provide recommended

maintenance procedures and some schedules

based upon the design of the gas turbine equip-

ment However they may not meet all the needs

of a specific installation A few manufacturers

offer standard maintenance tables that indicatewhich components should be checked or main-

tained along with a suggested schedule (Table 1)

Some manufacturers develop application or site-

specific maintenance tables that typically include

elements of both scheduled and on-condition

maintenance Such information should be used

as a starting point when planning any quality

maintenance program

Operating Experience

Actual operating exper ience provides one of

the best guides as to which components need

attention Frequently a vast amount of useful

knowledge exists at all levels within the userrsquos

maintenance department Gas turbine user groups

and associations can provide valuable infor-

mation as well Other operators rely upon con-

tractors to define what requires maintaining Still

others have found that relying on the gas turbinemanufacturerrsquos expertise is very helpful Ideally

experience from all sources should be con-

sidered when designing a quality maintenance

program

Operating Conditions

A harsh operating environment or unique oper-ating conditions may necessitate modifications

once a basic maintenance program has been

outlined For example dirty fuel gas may make it

necessary to remove inspect and clean the fuel

injectors more frequently than if very clean fuel

was used Additional modifications may be re-

quired due to trends detected through predictivemaintenance

81-2



Tabe 1 Excerpt from Maintenance Table

Semi-

Periodic Checks continued

Air Systems

Daily Monthly Annually Annually

8 Check air inlet system for obstructions or

contamination record differential pressure

X

9 If air dryer is installed check operation

10 Check inlet guide vanes for position

check torque paint on full-open stops

and actuator cylinder linkage

X

X

11 Inspect gas turbine compressor variable vane

mechanism for wear Check for bent arms

loose linkages loose bushings Ensure stop

settings are correct Check for damaged signal

wires to actuator (if applicable)

X

12 Inspect bleed valve actuator mechanism for

proper operation

X

13 Inspect intake and exhaust systems for

damage leaks debris

X

Lube Oil amp Servo Oil Systems

14 Check oil tank level every 24 hours Record oil

consumption

X

15 Verify proper operation of oil makeup system

(if installed)

X

81-026M

In addition to air fuel and water quality local

environmental conditions can be a major con-

sideration The typically salt-laden atmospherefound in most offshore installations or the higher

pollution levels found in industrial areas require

closer monitoring of gas turbine performance

More frequent compressor cleaning may be

needed due to salt and hydrocarbon ingestion

into the gas turbinersquos compressor Extremes in

ambient temperature and humidity also influence

needed maintenance These modifications to main-

tenance plans may be permanent or seasonal

Trending

The backbone of all predictive maintenance

programs is the detection of trends within theparameters being monitored The observation of

an adverse trend provides the second reason to

modify maintenance schedules If routine vibra-

tion measurements (either on-line or periodic)

indicate an increase in vibration closer scrutiny

may be warranted (Figure 2) A steady rise in the

amount of a wear metal detected in the lube oil

may suggest a need to increase the frequency of

oil sampling Wear in a particular bearing for

example may produce some amount of copper

or lead Such modifications to planned schedules

are usually only temporary lasting until thesuspected problem is identified and solved

Modifications to schedules due to environment

or predictive maintenance trends can also be

positive Intake air that is particularly dry and

clean air can allow extended time between in-

gestive cleaning of the gas turbinersquos compressor

section Monitoring the machinersquos health may

allow the time between overhauls to be extended

Deciding what to maintain and when to do it

requires consideration of numerous factors on a

system-by-system basis

Most of the recent technological advancements

in gas turbine maintenance take advantage of trend analysis This consists of monitoring the

changes in important measurements over time

Analyzing the results can help detect and predict

potential problems in time to avert them

Whatever the parameter being tracked a

baseline value should be first established The

baseline values of a specific parameter may

vary between similar units due to manufacturing

tolerances operating hours and maintenance

81-3



05

s00 04

z

g 03

cn

rrdquo0 02

Z-

01

SHUTDOWN SETPOINT-______----_----------_

WARNING SETPOINT

I I I I I I I I I I

J F M A M J J A S O81-002M

a Overall Vibration (No 3 Bearing)

E 3 0

aa0o 2 0

IO


b Spectrochemical Oil Analysis

Fgure 2 Adverse Operating Trends Maintenance Program Example

schedules The absolute level of the baseline is

not essential as long as it falls within acceptable

operating limits for that parameter

What is important is the occurrence of diver-

gence from the baseline Such trends are a direct

reflection of changes within the machine and can

be important in planning maintenance and reach-

ing established maintenance goals For some

parameters such as a bearing temperature or a

vibration level any divergence from baseline

may be significant In other cases a change in

the rate of divergence may signal a potential

problem such as a performance decrease due

to blade tip rub

Operating conditions such as temperatures

pressures and speeds will vary and these changes

affect trends For instance different speeds and

loads alter measured vibration levels While it is

seldom possible to duplicate operating condi-

tions exactly data for trending should be taken

under conditions as nearly identical as possible

Even when some variables cannot be controlled

recording important operating conditions allows

them to be considered when analyzing the trends


Once the tasks have been defined and a sched-

ule has been established the operator is faced

with two more key decisions about how to best

accomplish the diverse set of maintenance

goals First the level of operator involvement in

the maintenance program must be defined in

terms of

Number of machines versus expense of

hiring training and equipping qualified

personnel

l Relative costs of doing maintenance inter-

nally versus contracting

Q Complexity of tasks better done by othersWith only one machine it may be better both

technically and financially to have an experi-

enced contractor perform at least some of the

maintenance as opposed to hiring training and

equipping a maintenance staff With a number

of machines investing in developing internal

maintenance capabilities could yield lower main-

tenance costs Even with in-house staff per-

forming all of the maintenance the operator may

choose to seek assistance in more complex

aspects of the program

A good example of a focused and well thought-

out maintenance program is one developed by

the gas operations division of a European oil

and gas company operating a large number of

gas turbine-powered natural gas compressors

ranging in size from 820 to 22370 kW (1100 to

30000 hp)

Within the maintenance department respon-

sible for gas turbines and reciprocating engines

is a specialized Engine Diagnosis group This

group carries out a wide variety of predictive

maintenance work on a scheduled basis Among

the data used by the mechanical and electrical

engineers involved are the results of lube oil

analysis (both spectrochemical and wear particle

analysis) borescope inspections gas tu bine

performance and extensive vi bration analysis

In a unique approach to conducting predictive

maintenance work this group has built two spe-

cialized vans (Figure 3) that are driven to the work

sites These vans are equipped with an array of

81-4



FFT analyzer

Oscilloscope

Digital vector filter

8-channel DAT recorder

Printer

Plotter

Cable storage (on drums)

Two-way radioDesk and bench spaces

Runout compensator

PC computer and monitor

Switching matrix

Various filters

Selection of transducers

Transducer shaker table

Proximity probe testing device

Batteries and charger

Acoustic and ultrasonic tools

Tool tape and manual storage

Laser alignment system Among the unique features of this instrumen-

tation is a switching matrix that allows great

flexibility and ease in connecting various input

signals from the gas turbines to the different

electronic devices in the van Cables are run from

the various transducers and measuring devices

on the gas turbine package directly to the van

where they are attached to a number of inputconnectors wired to the switching matrix Inside

the van the diagnostic tools are also wired to the

matrix While making measurements and diag-

nosing the results the operator can then connect

any transducer to any device in the van by merely

inserting pegs in the appropriate matrix holes

The matrix can also be controlled by computer

programs written for use in the van These

programs largely automate the collection and

analysis of data the comparison with earlier data

(from digital audio tapes) the calibration of

transducers and other tasks

The Engine Diagnosis group also makes use

of laser alignment tools eliminating the wide as-

sortment of mechanical alignment tools required

to service a diverse fleet of gas turbines Acous-

tic and ultrasonic measurements and other in-

strumentation for maintaining both gas turbine

and reciprocating equipment are also used

Such an investment in equipment and the per-sonnel to use it is not a viable option for all gas

turbine users but it does serve as an example of

a commitment to quality maintenance on the part

of one operator of a large number of gas turbines

Regardless of the approach taken by others it is

important for the operator to assess internal capa-

bilities when designing a maintenance program

Figure 4 Diagnostic Van (Interior)

81-5




Once it has been determined to what extent the

staff will be involved in the maintenance program

the operator must decide which of the many

powerful technologies that are now available will

be employed includingl Spectrochemical lube oil analysis

l Computer-aided vibration data collection

and analysis

l PC-based performance analysis and trending

l Borescope inspection and graphical docu-

mentation

Monitoring miscellaneous parameters (man-

ually or with integrated controlcondition moni-

toring systems)

Lube Oil Analysis

Perhaps the easiest and most cost-effective form

of predictive maintenance is lube oil analysis

Periodically a sample of lube oil is taken from the

gas turbine for spectrochemical oil analysis The

amounts of various elements in the oil are

trended including a number of wear metals Part

of each sample is used for physical properties

tests to monitor the lubricating quality of the oilitself

The frequency at which samples should be

taken can vary depending on the operating

profile and environment If a gas turbine is started

and stopped frequently subjected to large am-bient temperature swings or operated in a dirty

environment samples should be taken every

month A sample taken every three months may

be acceptable for a gas turbine running con-

tinuously in a relatively clean environment Sam-

pling each six months would be suitable for gas

turbines in standby applications or operated in-

frequently

Wear metal levels in reciprocating engine oil

typically trend upward over time (Figure 5) An

increase in the rate of wear gives early indication

of potential problems Wear metals in gas turbine

oil typically reach equilibrium quickly then remainessentially constant over time Any significant

divergence from this flat trend curve warns the

analyst of potential problems

Key elements in ensuring quality lube oil

analysis are proper sampling technique and the

selection of a quality laboratory to conduct the

analysis After the oil has been mixed by running

the machine samples should be taken from the

oil tank in a manner that will not pick up sediment

in the bottom of the tank Taking separate sam-

ples from several different drain locations on the

machine does not help to identify the area in the

machine where the wear metals originate This is

due to typically low wear rates and low con-

centrations of wear metals in the oil

Filtration does not have a measurable impact

on spectrochemical oil analysis in gas turbines

This type of analysis measures particles ranging

up to about 5 microns in size Typical gas turbine

oil filters have a nominal media rating of 10

microns (Figure 6)

Certain physical property tests can be done

along with spectrochemical analysis These in-

clude measuring the samplersquos viscosity Total

Acid Number and water present Experience has

proven that along with adequate oil filtrationthese tests allow the quality of the oil to be mon-

itored adequately so that oil can be used in-definitely without changing Unlike reciprocating

Reciprocating Engine

TIME-Figure 5 Wear Metal Trends

100 I-7 - - - - --

Spectrometer

I

I

Ferrograph

Typical Filter

I I I I

01 1 10 100 1000

WEAR PARTICLE SIZE pm 81-006M

Figure 6 Wear Particle Sizes

81-6



engines the levels of wear metals and con-

taminants do not usually increase over time in

gas turbines Typical criteria for oil replacement

in a mid-size gas turbine are given in Table 2

Table 2 Typical Oil Replacement Criteria forMid-Size Gas Turbine

Lubricant

Type

Synthesized

Hydrocarbon

MIL-L-23699

and MIL-L-7808

Petroleum

Fire-Resistant

Viscosity

Change

Limits

+25 -10

+15 -15

+25 - 10

+15 -15

Total Acid Water Content

Number Parts per

Max Million Max

40

20

1 o

30

2000

2000

2000

2000

81-027M

While spectrochemical analysis is most appro-

priate for trending purposes (due to its simplicity

and low cost) additional tests are readily avail-able from most commercial labs to assist in diag-

nosing problems These include ferrographic

(wear particle) analysis and foaming charac-

teristics tests

Vibration Analysis

Many gas turbines are now equipped with on-line

vibration monitors with the dual purpose of get-ting the operatorrsquos attention thus warning him of

a problem and actually shutting the unit down to

prevent a destructive failure These are important

roles but they do not contribute significantly to a

good predictive maintenance program

By the time a monitor is in alarm the problemmay be fairly severe it may be too late to avoid

an unscheduled shutdown The monitor can still

provide sufficient warning to avoid secondary

damage Newer integrated Programmable Logic

Controller (PLC)-based controlmonitoring sys-

tems can offer an improvement by trending such

things as overall vibration levels Even thesehowever do not trend frequency-specific vibra-

tion data that can better detect not only the exist-

ence of a potential problem but can help identify

the specific faultIn addition to on-line monitoring vibration data

collection and analysis systems are now avail-

able which help to overcome this lack of frequen-

cy-specific analysis capability Typically such a

computer-aided system would include a portable

analyzerdata collector a set of PC software and

a variety of transducers and accessories (Figure

7) Properly implemented computer-based vibra-

tion programs permit the detection and correc-

tion of problems before they impact production or

maintenance costsGenerally vibration analysis involves con-

sideration of not just the level (amplitude) of vibration but also the frequency at which vibra-

tion occurs The amplitude is a measure of vibra-

tion severity while the frequency is used to

determine the cause of the vibration Specific

mechanical faults generate characteristic fre-

quency signatures Knowledge of these signa-tures is the basis of spectral vibration analysis

A quality vibration trending system will allow

the periodic collection of spectral vibration data

which are essential to detecting and correcting

potential vibration problems at the earliest indica-tion In this way both initial and secondary

damage can be limited or even prevented entire-ly In addition to helping to gather and store

spectral data these systems allow semiauto-

mated analysis and trending of specific vibration

parameters (Figure 8)

81-007

Figure 7 Depiction of Vibration Data Collection

System

81-7



18

16

v) 14r-

5 12I -

2

2 lsquo-O5 0 8a

2 0 6cJ0 0 4CL

No 1 Bearing (Horizontal) Prox Probe A

lx Ngp Speed

0 100 200 300 400 500 600 700

DAYS 81-009M

Figure 8 Vibration Parameter Trends Figure 9 Vibration Parameters

When the vibration data base is set up in the

computer each gas turbine package is dividedinto a series of measurement points At each

measurement point a spectrum will be acquired

when vibration data are collected In addition to

storing the spectrum itself the program stores

and trends 4 to 6 vibration parameters at each

measurement point Each parameter consists of

a measurement of overall vibration within a nar-

row frequency band Each band is designed to

encompass a spectral peak at a frequency that

might occur at that point on the machine if a

specific problem occurred For example im-

balance or bearing damage in a gas turbine

would be observed at its running speed whileeach gear-type pump would have a specific

meshing frequency that can reveal internal

problems The vibration levels within these bands

are then trended over time and the vibration

analyst is notified if they exceed any of several

types of preset alarm levels (Figure 9) Thus

trending the parameter can provide early detec-

tion and identify a specific problem should it arise

Should an alarm occur the analyst can then

retrieve and closely scrutinize spectral data

waveforms and other information to help diag-

nose the problem At this point the analystrsquos

training and experience are of utmost impor-tance While the computer-based systems allow

the analyst to process large quantities of data

and make the job much easier eventually it is the

analyst who must decide what if anything is

wrong and the action to recommend

Vibration analysis requires training and exper-

ience Excellent training is commercially avail-

able With this training a technician who is not

an expert in vibration analysis can adequately

Warning Level I

FREQUENCY (Hz) OR ORDERS 81-O OM

detect and diagnose about 80 of the problems

that will likely be encountered With experiencethis percentage will improve

One point that cannot be overemphasized is

that the value of a vibration program is directly

related to the quality of the raw data Items critical

to high quality accurate vibration data include

l Selecting good measurement points

l Choosing appropriate vibration transducers

l Ensuring proper mounting of transducers

l Selecting appropriate analyzers

Measurement Points

Care must be taken when selecting measurement

points in order to allow a direct mechanical pathto the object being monitored (a bearing for

instance) Transducers must not be placed on

parts of the machine which will resonate such as

flexible metal and loose structural pieces Also

important to selecting good measurement points

is the choice of the proper direction of measure-

ment Imbalance for example is usually mani-

fested radially while misalignment often shows

up axially

It is important to choose enough measurement

points to adequately monitor all key parts of the

machine but too many measurement points

should be avoided Excessive measurementpoints result in additional instrumentation ex-

pense data collection and analysis effort and

computer memory use while providing little ad-

ditional insight into the machinersquos health Figure

IO shows the measurement points for a typical

mid-sized gas turbine package Measurements

are taken at each major part of the package and

the points are carefully chosen to monitor the

most likely types of potential vibration problems

81-8



MEASUREMENTPOINTS 1 2 34 5 6 7 8 9

I Point I Description Transducer

Accessory Drive Gearbox (Axial)Gas Producer (Horizontal)Power Turbine (Vertical)Gearbox (Vertical)Compt-Fssor Beying (X t Y)

Accelerometer VelocityVelocity

Accelerometer Proximity Probe

8 I

81-011

Figure IO Typical Vibration Measurement Points

Transducer Types

A second factor essential to accurate vibration

data is choosing the proper transducer type

Generally there are three types of transducers

each with its own advantages and disadvantages

l Displacement probes

l Velocity transducers

l Accelerometers

Displacement Probes Displacement probes (also

called proximity or eddy current probes) measure

the relative displacement between a shaft and

the transducer mount Many mid-size industrial

gas turbines now make use of internal displace-

ment probes Due to a drop in signal strength asfrequency increases the upper useful frequency

of these transducers is about 1000 Hz

Velocity Transducers Velocity transducers con-

sist of a permanent magnet suspended within a

coil by springs The movement of the magnet

within the coil creates a voltage signal proportional

to vibration velocity The moving components give

the transducer a low resonant frequency By

design this natural resonance is highly damped

This limits the lowest frequency at which they can

be used Typically their useful frequency range

runs from 10 to 2000 Hz ( Figure 11)Accelerometers Accelerometers contain a fixed

mass and a piezoelectric crystal The mass

applies a force to the crystal when exposed to

vibration An electrical charge is produced

proportional to the force and hence the accel-

eration Since they contain no moving parts they

are rugged and long lasting Being fairly stiff

they have a high resonant frequency which limits

their upper useful frequency A typical frequency

range would be 5 to 10000 Hz (Figure 12)

though a wide choice is available Their frequen-

cy response makes them particularly sensitive to

proper mounting technique (Hewlett-Packard

Co 1983)

Decision Path Figure 13 illustrates a flow dia-gram depicting the decision path for choosing

the proper transducer type for a particular appli-

cation In the past either proximity probes or

velocity transducers have been used on gas tur-

bines themselves Accelerometers are generally

used on gearboxes because of their ability to

measure high frequency gear meshing The

present trend for gas turbines is away from

velocity transducers and toward accelerometers

due to their greater reliability Aero-deriviative

gas turbines are normally equipped with roller

bearings Since faults within roller bearings

generate very high frequencies accelerometersshould be used on these gas turbines

Natural Resonant Frequency (Damped)

Useful Range

0 500 1000 1500 2000

FREQUENCY Hz 81-012M

Figure I I Frequency Response of Typical Velocity

Transducer

J

0 5000 10000 15000 20000


Figure 12 Frequency Response of TypicalAccelerometer

81-9



r MEASURE

RELATIVE NO

DISPLACEMENT

OR CRITICAL

CLEARANCE HNEED TO

TRANSMITTED MEASURE

TO MACHINE ABOVE

1000 Hz

YES 1 Y E S 1rdquordquo NO 1

I DISPLACEMENT

I IUSE

PROBE ACCELEROMETER I IUSE A VELOCITY

TRANSDUCER I I I I I

81-014M

Figure 13 Decision Path for Transducer Selection

Transducer Mounting

One of the major sources of inaccurate vibration

data is improper transducer mounting It is es-

sential that all transducers be mounted rigidly

Proximity probes are usually embedded in bear-

ing housings or otherwise mounted rigidly within

the machine by the manufacturer

Velocity transducers and accelerometers are

mounted externally on the machine casing For

gas turbines hard-mounted transducers should

be used versus hand-held or magnetically

mounted ones Figure 14 illustrates the response

of an accelerometer attached to a shaker table

by various means The response is basically flat

to 10000 Hz when the transducer is f irmly

mounted using a stud mount The quality of the

response degrades with other mounting tech-

niques A magnetic mount yields inaccurate

results beginning at about 4000 Hz The hand-

held transducer is unusable above 1000 Hz

(often as low as 500 Hz)

In addition to the inaccurate results obtained

from hand-held and magnetically mounted trans-

ducers the results are generally unrepeatable

Figure 15 depicts a series of vibration spectra

taken from the same point on the same machine

and by the same person using a hand-heldtransducer It is evident that the spectra are not

at all the same This becomes a serious problem

when attempting to employ computer-based

trending systems Such variances defeat the

trending capabilities of the program

For accelerometers a stud mount is typically

used (Figure 16) Ideally this stud mount should

be applied on a machined surface The quality of

the surface is very important it should be smooth

and the studrsquos perpendicularity to the surface

should be assured This is particularly important

because the accelerometer is often used to

measure very high frequencies

For velocity transducers various valid mount-

ing arrangements are possible (Figure 17) Spe-

cially designed mounting blocks can be bolted or

even glued to the machine Any mount should be

thoroughly tested before selection Knowing how

well it transmits vibration is important and it is

critical to ensure that its own mounted resonant

frequency is not within the frequency range to be

measured

Selection of Analyzers

Once good measurement points have been

chosen appropriate transducers selected and

proper mounting techniques defined the appro-

I Hand-held Probe

g +I0

ki2 00-2z -10

-20

I I I I I

0 2 4 6

FREQUENCY kHz

8 10

81-015M

Figure 14 Frequency Response from DifferentMounting Techniques

PLOT

SPQN

2 4

0i

I I 1 I

0 2000 4000 6000 8000 10000

FREQUENCY IN HZ

81-016

Figure 15 Spectra from Hand-Held Transducer

Data (5-3-89)

81-10



81-021

Figure 16 Accelerometer with Stud Mount

81-020

Figure 17 Typical Velocity Transducer Mounts

(Blocks)

priate vibration analyzer must be selected For-

tunately a wide variety of excellent instrumenta-

tion is now available Some analyzers are

intended for sophisticated design and diagnostic

work while others are intended specifically for

predictive maintenance Setting up a quality

maintenance program should focus on analyzers

intended for predictive maintenance particularlyif many machines are to be monitored Typically

those designed for use in machine condition

monitoring are less complex smaller more

rugged and less expensive (Figure 18) Current

technology has made many analyzers available

the better of which are

0 True FFT (Fast Fourier Transform) analyzers

Some devices currently on the market are

merely sweeping-filter recorders that measure

vibration with a fairly wide moving filter FFT

analyzers digitally simulate hundreds of

very precise fixed-frequency filters This

vastly improves frequency resolution mak-

ing analysis much more precise

Data collectors with sufficient memory for the anticipated amount of data

Analyzers capable of measuring and record-

ing phase information which is needed to

accomplish trim balancing Some analyzers

have the capability to perform the trim

balancing calculations If waveform analysis

is desired the analyzer should also be

capable of storing such data

Analyzers capable of being used with a

variety of transducers

Most analyzerdata collectors are part of an

integrated PC-based system The analyzers are

used to collect and analyze data at the machinesite while the computer programs are used to

program the analyzers and establ ish and

manage vibration data bases In these data

bases the trending of vibration data is accom-

plished (Figure 19)

81-022

Figure 18 Vibration Analyzer

81-11



0 3 LOAD DATA INTO PC

0 1 PROGRAM ANALYZER 0 2 COLLECT DATA FROM PACKAGE

Figure 19 lntegra tion of Analyzer PC and Software

Properly established a PC-based system al-

lows the trending and semiautomated analysis of

large quantities of data It will warn the analyst of

adverse trends and can enable maintenance per-sonnel to play a more active role in monitoring the

condition of machinery

If several machine types are to be monitored

or if the vibration program will be established at

separate geographic sites ldquomasterrdquo data basesshould be considered The use of master data

bases accomplishes several major things Firstit encourages correct standardized data collec-

tion and analysis at all levels of the organization

Second it ensures compatible data for the free

exchange of information within the organization

Finally it facilitates refinement of the program by

allowing each participant to learn from the collec-

tive experience of all

Gas Turbine Performance Analysis

Some gas turbine manufacturers offer computer

programs for trending performance These pro-

grams may be run on a personal computer or may

be incorporated into a PLC-based controlcondi-tion monitor system for early detection of perfor-

mance degradation

Performance parameters are periodically taken

from existing machine-mounted instrumentation

Since operating conditions are seldom constant

performance parameters taken at one time can-

not be compared directly with those from another

time The computer program calculates what the

performance parameters of a like-new gas turbine

81-019M

04 TREND AND 05 GENERATE REPORTS

ANALYZE DATA

would be under those same operating conditionsthen compares those to the actual performanceparameters from the machine

The percentage variances from nominal (usedas a reference point) are then trended over timeThe resulting trends show the performance

degradation that is recoverable and nonre-

coverable (Odom 1989)

For example Figure 20 illustrates the perfor-

mance degradation due to contaminants being

ingested by the compressor Figure 21 depictsthe gradual nonrecoverable performance degra-

dation that occurs during the time between over-

haul (TBO) Figure 22 displays the combined

losses The sawtooth effect is due to the oc-casional ingestive cleaning of the compressor to

I-

A

1

T

ENGINE OPERATING HOURS-wgure 20 Recoverable Performance Degradation

81-12



ENGINE OPERATING HOURS-Figure 2 I Nonrecoverable Performance

Degradation

ENGINE OPERATING HOURS-El-025

Figure 22 Total Performance Degradation

optimize gas turbine performance efficiency

and exhaust emissions

Cleaning the gas turbinersquos compressor section

with water and appropriate solvents while crank-

ing the gas turbine on the starter (or at low idle

speed) is a proven method to recover most lost

performance and is the preferred method of in-

gestive cleaning However if ldquoon-linerdquo cleaning

(cleaning at normal operating speed) is to bedone it is essential to adhere to the recommen-

dations of the gas turbine manufacturer

Computer performance analysis programs

allow monitoring of nonrecoverable performance

loss over time This can be valuable in timing

overhauls to control life-cycle costs As with other

forms of predictive maintenance the absolute

values calculated by the programs are not sig-

nificant nor are their absolute relationships to

nominal values The key is to monitor changes in

each trend over time

Borescope Inspection

Periodic inspection of a gas turbinersquos hot section

is used to detect and trend thermal wear and

damage Certain types of problems such asclogged fuel injectors can be detected in this

way and corrected to prevent more serious faults

Trending the condition of internal gas turbine

components helps in the orderly planning of over-

hauls allowing them to be done when needed

rather than too soon or too late

Among the problems that can be detected by

this type of inspection are hot section thermal

damage and wear clogged or damaged fuel in-

jectors and contamination in the aft compressor

stages

Damaged blades or nozzles can affect perfor-

mance Damagedclogged fuel injectors or adamaged combustor liner can affect emissions

as well as cause thermal wear of the gas turbine

blades and nozzles Contamination in the aft

stages of the compressor may also indicate a

degradation of performance

Some smaller gas turbines can be internally

inspected by partial disassembly but most gas

turbines are now equipped with ports to allow

borescope inspections

Documentation of the findings from borescope

inspections is essential to good trending Three

basic methods are available

l Hand-drawn depictions supported by written

description

l Videotaped inspections

l Photographic documentation

Although hand-recorded documentation can

be effective it is subject to individual inter-

pretation Today the trend is toward optically

recorded documentation Systems are available

for videotaping inspections as they are per-

formed Their primary disadvantage is the need

to view much unnecessary footage to arrive at

the few discrepancies which require monitoringand trending Still-photographic documentation

solves both problems by being objective and by

focusing only on the problem areas requiring

attention

Monitoring Miscellaneous Parameters

Experience shows that trending a variety of mis-

cellaneous parameters can also be a valuable

part of a condition monitoring program Although

81-13



these vary from machine to machine some useful

examples are

Lube Oil Tank Back Pressure - Trending this

parameter gives early warning of worn

seals Seal air moving across the worn seal

flows with the oil into the tank and slightly

raises tank pressure It can also indicate the

need to service a dirty or clogged oil-mist

precipitator in the oil tank vent

Filter Differential Pressures - These offer an

excellent method of monitoring the need to

change various filters

Oil Consumption - Trending oil consumption

can help detect a faulty seal-oil separator on

a compressor set

Gas Turbine Inlet Temperature Spreads -

On machines with multiple thermocouple

indications monitoring the temperature

spread between thermocouples can be use-

ful in detecting fuel injector or combustor

problems



The advent of control systems based upon pro-

grammable logic controllers offers the oppor-

tunity to expand upon and automate the trending

of a variety of parameters The latest generation

of such systems offers combined gas turbine

control and condition monitoring capabilities

extending to the driven equipment and other

process controls (DeMoss 1992) They allow

monitoring of the gas turbine package on a real-

time basis and allow the past history of a variety

of parameters to be called up and displayed

Several parameters can be recalled and shown

in ldquostrip-chartrdquo format Also the systems can be

used to trend gas performance and to visually

display a gas boost compressor operating

map showing the current operating point of

the package Predictive emission monitoring is

incorporated into some such systems (Hung

1992)These systems cannot perform all of the in-

depth analysis and trending that are needed in a

quality maintenance program but they can cer-

tainly enhance such an effort For example they

do not perform sophisticated vibration analysis

such as FFT spectral analysis or orbit analysis

Oil samples for spectrochemical analysis must

still be taken and periodic borescope inspections

are still required

The future for combined controlcondition

monitoring systems is promising They offer great

flexibility for enhancements such as on-line FFT

vibration analysis and trending

SUMMARY

A quality maintenance program has a significant

impact on the reliability and life-cycle cost of the

gas turbine package Varying applications oper-

ating environments and duty cycles make it

difficult to develop a single program with set

schedules to meet every operatorrsquos needs

Operator goals also vary widely but generally

fall into the four categories of availability produc-

tion efficiency and operating cost

There are many steps in developing a main-

tenance program including determining what to

maintain and when and how to do it The com-

plexity of a gas turbine package requires aquality maintenance program that includes a mix-

ture of unscheduled scheduled and on-condi-

tion maintenance

Selecting an approach to maintaining a given

component of a gas turbine package should be

driven by criticality relative costs and acces-

sibility Other variables need to be taken into

account such as operating experience and

conditions

The use of trending technology allows oper-

ators to optimize their programs with more on-

condition maintenance Trending also provides

more information to track the results to measurechanges in operating and environmental condi-

tions and to identify adjustments required in

maintenance schedules

Great care must be taken to ensure that con-

sistent high quality data are taken whenever

trending technologies are applied Failure to do

so will result in misleading trends that could leave

an impending failure undetected or result in un-

necessary maintenance

With proper planning and the application of

todayrsquos maintenance technologies a quality main-

tenance program can be assured A thoughtfully

designed program can achieve al l of the

operatorrsquos diverse maintenance goals

ACKNOWLEDGEMENTS

The authors would like to gratefully acknowl-

edge the assistance of Mr Gerhard Stich Mr

Herbert Blach and Mr Herbert Rohrbacher

(OMV Aktiengesellschaft) for their kind assistance

in preparing this paper

81-14



REFERENCES

Chandler AL 1984 ldquoTurbomachinery Main-

tenance Planning rdquo TTS8 Turbomachinery Tech-

nology Seminar Solar Turbines IncorporatedSan Diego California

DeMoss SH 1992 ldquoGas Turbine Control

Enhancements and Networksrdquo TTS72 Turbo-

machinery Technology Seminar Solar Turbines

Incorporated San Diego California

Hewlett-Packard Company 1983 ldquoEffective

Machinery Maintenance Using Vi bration Anal-

ysisrdquo Application Note 243-1 Hewlett-Packard

San Jose California

Hsu LL 1989 ldquoGas AirFuelWater Manage-

mentrdquo TTS54 Turbomachinery Technology Semi-

nar Solar Turbines Incorporated San DiegoCalifornia

Hung WSY 1992 ldquoPredictive NOx Mon-

itoring System An Alternat ive to In-Stack

Continuous Emission Monitoringrdquo TTS83 Turbo-machinery Technology Seminar Solar Turbines


Odom FM 1989 ldquoOptimizing the Efficiency

of Gas Compressor Packagesrdquo TTS57 Turbo-





Contents

INTRODUCTION







SUMMARY

ACKNOWLEDGEMENTS

REFERENCES

Page

81-I

81-1

81-I

81-4

81-6

81-14

81-14

81-14

81-15

Cat and Caterpillar are trademarks of Caterpillar Inc

Solar Saturn Centaur Taurus Mars Turbotronic and SoLoNOx are trademarks of Solar Turbines IncorporatedSpecifications subject to change without notice Printed in USA

Copyright Q 1992 by Solar Turbines Incorporated

-l-l-S81 492




CS Woods




INTRODUCTION


















parameters





l Availabi lity











1984)


Periodwhere


hours or days


























81-I

































Predictive


81-OO M
























maintenance program













program









81-2




Semi-


Air Systems




X





X

X






X


proper operation

X


damage leaks debris

X



consumption

X


(if installed)

X

81-026M












Trending


































81-3



05

s00 04

z

g 03

cn

rrdquo0 02

Z-

01


WARNING SETPOINT

I I I I I I I I I I



E 3 0

aa0o 2 0

IO

















to blade tip rub


















terms of



personnel




















30000 hp)















81-4



FFT analyzer

Oscilloscope



Printer

Plotter



Runout compensator


Switching matrix

Various filters









































81-5










and analysis



mentation



toring systems)

Lube Oil Analysis



















frequently

























microns (Figure 6)









100 I-7 - - - - --

Spectrometer

I

I

Ferrograph

Typical Filter

I I I I

01 1 10 100 1000



81-6








Lubricant

Type

Synthesized

Hydrocarbon

MIL-L-23699

and MIL-L-7808

Petroleum

Fire-Resistant

Viscosity

Change

Limits

+25 -10

+15 -15

+25 - 10

+15 -15


Number Parts per

Max Million Max

40

20

1 o

30

2000

2000

2000

2000

81-027M






teristics tests

Vibration Analysis









































81-007


System

81-7



18

16

v) 14r-

5 12I -

2

2 lsquo-O5 0 8a

2 0 6cJ0 0 4CL


lx Ngp Speed

0 100 200 300 400 500 600 700

DAYS 81-009M




































Warning Level I












Measurement Points










up axially













81-8








8 I

81-011


Transducer Types







l Accelerometers






























Co 1983)















Useful Range

0 500 1000 1500 2000



Transducer

J

0 5000 10000 15000 20000



81-9



r MEASURE

RELATIVE NO

DISPLACEMENT

OR CRITICAL

CLEARANCE HNEED TO

TRANSMITTED MEASURE

TO MACHINE ABOVE

1000 Hz


I DISPLACEMENT

I IUSE



81-014M


Transducer Mounting















































measured





I Hand-held Probe

g +I0

ki2 00-2z -10

-20

I I I I I

0 2 4 6

FREQUENCY kHz

8 10

81-015M


PLOT

SPQN

2 4

0i

I I 1 I

0 2000 4000 6000 8000 10000

FREQUENCY IN HZ

81-016


Data (5-3-89)

81-10



81-021


81-020


(Blocks)






































plished (Figure 19)

81-022


81-11


























mance degradation








81-019M


ANALYZE DATA











I-

A

1

T


81-12




Degradation



































stages















description













attention





81-13




examples are













a compressor set






problems





























are still required





SUMMARY















tion maintenance






conditions


















ACKNOWLEDGEMENTS






81-14



REFERENCES











San Jose California















CS Woods




INTRODUCTION


















parameters





l Availabi lity











1984)


Periodwhere


hours or days


























81-I

































Predictive


81-OO M
























maintenance program













program









81-2




Semi-


Air Systems




X





X

X






X


proper operation

X


damage leaks debris

X



consumption

X


(if installed)

X

81-026M












Trending


































81-3



05

s00 04

z

g 03

cn

rrdquo0 02

Z-

01


WARNING SETPOINT

I I I I I I I I I I



E 3 0

aa0o 2 0

IO

















to blade tip rub


















terms of



personnel




















30000 hp)















81-4



FFT analyzer

Oscilloscope



Printer

Plotter



Runout compensator


Switching matrix

Various filters









































81-5










and analysis



mentation



toring systems)

Lube Oil Analysis



















frequently

























microns (Figure 6)









100 I-7 - - - - --

Spectrometer

I

I

Ferrograph

Typical Filter

I I I I

01 1 10 100 1000



81-6








Lubricant

Type

Synthesized

Hydrocarbon

MIL-L-23699

and MIL-L-7808

Petroleum

Fire-Resistant

Viscosity

Change

Limits

+25 -10

+15 -15

+25 - 10

+15 -15


Number Parts per

Max Million Max

40

20

1 o

30

2000

2000

2000

2000

81-027M






teristics tests

Vibration Analysis









































81-007


System

81-7



18

16

v) 14r-

5 12I -

2

2 lsquo-O5 0 8a

2 0 6cJ0 0 4CL


lx Ngp Speed

0 100 200 300 400 500 600 700

DAYS 81-009M




































Warning Level I












Measurement Points










up axially













81-8








8 I

81-011


Transducer Types







l Accelerometers






























Co 1983)















Useful Range

0 500 1000 1500 2000



Transducer

J

0 5000 10000 15000 20000



81-9



r MEASURE

RELATIVE NO

DISPLACEMENT

OR CRITICAL

CLEARANCE HNEED TO

TRANSMITTED MEASURE

TO MACHINE ABOVE

1000 Hz


I DISPLACEMENT

I IUSE



81-014M


Transducer Mounting















































measured





I Hand-held Probe

g +I0

ki2 00-2z -10

-20

I I I I I

0 2 4 6

FREQUENCY kHz

8 10

81-015M


PLOT

SPQN

2 4

0i

I I 1 I

0 2000 4000 6000 8000 10000

FREQUENCY IN HZ

81-016


Data (5-3-89)

81-10



81-021


81-020


(Blocks)






































plished (Figure 19)

81-022


81-11


























mance degradation








81-019M


ANALYZE DATA











I-

A

1

T


81-12




Degradation



































stages















description













attention





81-13




examples are













a compressor set






problems





























are still required





SUMMARY















tion maintenance






conditions


















ACKNOWLEDGEMENTS






81-14



REFERENCES











San Jose California












































Predictive


81-OO M
























maintenance program













program









81-2




Semi-


Air Systems




X





X

X






X


proper operation

X


damage leaks debris

X



consumption

X


(if installed)

X

81-026M












Trending


































81-3



05

s00 04

z

g 03

cn

rrdquo0 02

Z-

01


WARNING SETPOINT

I I I I I I I I I I



E 3 0

aa0o 2 0

IO

















to blade tip rub


















terms of



personnel




















30000 hp)















81-4



FFT analyzer

Oscilloscope



Printer

Plotter



Runout compensator


Switching matrix

Various filters









































81-5










and analysis



mentation



toring systems)

Lube Oil Analysis



















frequently

























microns (Figure 6)









100 I-7 - - - - --

Spectrometer

I

I

Ferrograph

Typical Filter

I I I I

01 1 10 100 1000



81-6








Lubricant

Type

Synthesized

Hydrocarbon

MIL-L-23699

and MIL-L-7808

Petroleum

Fire-Resistant

Viscosity

Change

Limits

+25 -10

+15 -15

+25 - 10

+15 -15


Number Parts per

Max Million Max

40

20

1 o

30

2000

2000

2000

2000

81-027M






teristics tests

Vibration Analysis









































81-007


System

81-7



18

16

v) 14r-

5 12I -

2

2 lsquo-O5 0 8a

2 0 6cJ0 0 4CL


lx Ngp Speed

0 100 200 300 400 500 600 700

DAYS 81-009M




































Warning Level I












Measurement Points










up axially













81-8








8 I

81-011


Transducer Types







l Accelerometers






























Co 1983)















Useful Range

0 500 1000 1500 2000



Transducer

J

0 5000 10000 15000 20000



81-9



r MEASURE

RELATIVE NO

DISPLACEMENT

OR CRITICAL

CLEARANCE HNEED TO

TRANSMITTED MEASURE

TO MACHINE ABOVE

1000 Hz


I DISPLACEMENT

I IUSE



81-014M


Transducer Mounting















































measured





I Hand-held Probe

g +I0

ki2 00-2z -10

-20

I I I I I

0 2 4 6

FREQUENCY kHz

8 10

81-015M


PLOT

SPQN

2 4

0i

I I 1 I

0 2000 4000 6000 8000 10000

FREQUENCY IN HZ

81-016


Data (5-3-89)

81-10



81-021


81-020


(Blocks)






































plished (Figure 19)

81-022


81-11


























mance degradation








81-019M


ANALYZE DATA











I-

A

1

T


81-12




Degradation



































stages















description













attention





81-13




examples are













a compressor set






problems





























are still required





SUMMARY















tion maintenance






conditions


















ACKNOWLEDGEMENTS






81-14



REFERENCES











San Jose California















Semi-


Air Systems




X





X

X






X


proper operation

X


damage leaks debris

X



consumption

X


(if installed)

X

81-026M












Trending


































81-3



05

s00 04

z

g 03

cn

rrdquo0 02

Z-

01


WARNING SETPOINT

I I I I I I I I I I



E 3 0

aa0o 2 0

IO

















to blade tip rub


















terms of



personnel




















30000 hp)















81-4



FFT analyzer

Oscilloscope



Printer

Plotter



Runout compensator


Switching matrix

Various filters









































81-5










and analysis



mentation



toring systems)

Lube Oil Analysis



















frequently

























microns (Figure 6)









100 I-7 - - - - --

Spectrometer

I

I

Ferrograph

Typical Filter

I I I I

01 1 10 100 1000



81-6








Lubricant

Type

Synthesized

Hydrocarbon

MIL-L-23699

and MIL-L-7808

Petroleum

Fire-Resistant

Viscosity

Change

Limits

+25 -10

+15 -15

+25 - 10

+15 -15


Number Parts per

Max Million Max

40

20

1 o

30

2000

2000

2000

2000

81-027M






teristics tests

Vibration Analysis









































81-007


System

81-7



18

16

v) 14r-

5 12I -

2

2 lsquo-O5 0 8a

2 0 6cJ0 0 4CL


lx Ngp Speed

0 100 200 300 400 500 600 700

DAYS 81-009M




































Warning Level I












Measurement Points










up axially













81-8








8 I

81-011


Transducer Types







l Accelerometers






























Co 1983)















Useful Range

0 500 1000 1500 2000



Transducer

J

0 5000 10000 15000 20000



81-9



r MEASURE

RELATIVE NO

DISPLACEMENT

OR CRITICAL

CLEARANCE HNEED TO

TRANSMITTED MEASURE

TO MACHINE ABOVE

1000 Hz


I DISPLACEMENT

I IUSE



81-014M


Transducer Mounting















































measured





I Hand-held Probe

g +I0

ki2 00-2z -10

-20

I I I I I

0 2 4 6

FREQUENCY kHz

8 10

81-015M


PLOT

SPQN

2 4

0i

I I 1 I

0 2000 4000 6000 8000 10000

FREQUENCY IN HZ

81-016


Data (5-3-89)

81-10



81-021


81-020


(Blocks)






































plished (Figure 19)

81-022


81-11


























mance degradation








81-019M


ANALYZE DATA











I-

A

1

T


81-12




Degradation



































stages















description













attention





81-13




examples are













a compressor set






problems





























are still required





SUMMARY















tion maintenance






conditions


















ACKNOWLEDGEMENTS






81-14



REFERENCES











San Jose California














05

s00 04

z

g 03

cn

rrdquo0 02

Z-

01


WARNING SETPOINT

I I I I I I I I I I



E 3 0

aa0o 2 0

IO

















to blade tip rub


















terms of



personnel




















30000 hp)















81-4



FFT analyzer

Oscilloscope



Printer

Plotter



Runout compensator


Switching matrix

Various filters









































81-5










and analysis



mentation



toring systems)

Lube Oil Analysis



















frequently

























microns (Figure 6)









100 I-7 - - - - --

Spectrometer

I

I

Ferrograph

Typical Filter

I I I I

01 1 10 100 1000



81-6








Lubricant

Type

Synthesized

Hydrocarbon

MIL-L-23699

and MIL-L-7808

Petroleum

Fire-Resistant

Viscosity

Change

Limits

+25 -10

+15 -15

+25 - 10

+15 -15


Number Parts per

Max Million Max

40

20

1 o

30

2000

2000

2000

2000

81-027M






teristics tests

Vibration Analysis









































81-007


System

81-7



18

16

v) 14r-

5 12I -

2

2 lsquo-O5 0 8a

2 0 6cJ0 0 4CL


lx Ngp Speed

0 100 200 300 400 500 600 700

DAYS 81-009M




































Warning Level I












Measurement Points










up axially













81-8








8 I

81-011


Transducer Types







l Accelerometers






























Co 1983)















Useful Range

0 500 1000 1500 2000



Transducer

J

0 5000 10000 15000 20000



81-9



r MEASURE

RELATIVE NO

DISPLACEMENT

OR CRITICAL

CLEARANCE HNEED TO

TRANSMITTED MEASURE

TO MACHINE ABOVE

1000 Hz


I DISPLACEMENT

I IUSE



81-014M


Transducer Mounting















































measured





I Hand-held Probe

g +I0

ki2 00-2z -10

-20

I I I I I

0 2 4 6

FREQUENCY kHz

8 10

81-015M


PLOT

SPQN

2 4

0i

I I 1 I

0 2000 4000 6000 8000 10000

FREQUENCY IN HZ

81-016


Data (5-3-89)

81-10



81-021


81-020


(Blocks)






































plished (Figure 19)

81-022


81-11


























mance degradation








81-019M


ANALYZE DATA











I-

A

1

T


81-12




Degradation



































stages















description













attention





81-13




examples are













a compressor set






problems





























are still required





SUMMARY















tion maintenance






conditions


















ACKNOWLEDGEMENTS






81-14



REFERENCES











San Jose California














FFT analyzer

Oscilloscope



Printer

Plotter



Runout compensator


Switching matrix

Various filters









































81-5










and analysis



mentation



toring systems)

Lube Oil Analysis



















frequently

























microns (Figure 6)









100 I-7 - - - - --

Spectrometer

I

I

Ferrograph

Typical Filter

I I I I

01 1 10 100 1000



81-6








Lubricant

Type

Synthesized

Hydrocarbon

MIL-L-23699

and MIL-L-7808

Petroleum

Fire-Resistant

Viscosity

Change

Limits

+25 -10

+15 -15

+25 - 10

+15 -15


Number Parts per

Max Million Max

40

20

1 o

30

2000

2000

2000

2000

81-027M






teristics tests

Vibration Analysis









































81-007


System

81-7



18

16

v) 14r-

5 12I -

2

2 lsquo-O5 0 8a

2 0 6cJ0 0 4CL


lx Ngp Speed

0 100 200 300 400 500 600 700

DAYS 81-009M




































Warning Level I












Measurement Points










up axially













81-8








8 I

81-011


Transducer Types







l Accelerometers






























Co 1983)















Useful Range

0 500 1000 1500 2000



Transducer

J

0 5000 10000 15000 20000



81-9



r MEASURE

RELATIVE NO

DISPLACEMENT

OR CRITICAL

CLEARANCE HNEED TO

TRANSMITTED MEASURE

TO MACHINE ABOVE

1000 Hz


I DISPLACEMENT

I IUSE



81-014M


Transducer Mounting















































measured





I Hand-held Probe

g +I0

ki2 00-2z -10

-20

I I I I I

0 2 4 6

FREQUENCY kHz

8 10

81-015M


PLOT

SPQN

2 4

0i

I I 1 I

0 2000 4000 6000 8000 10000

FREQUENCY IN HZ

81-016


Data (5-3-89)

81-10



81-021


81-020


(Blocks)






































plished (Figure 19)

81-022


81-11


























mance degradation








81-019M


ANALYZE DATA











I-

A

1

T


81-12




Degradation



































stages















description













attention





81-13




examples are













a compressor set






problems





























are still required





SUMMARY















tion maintenance






conditions


















ACKNOWLEDGEMENTS






81-14



REFERENCES











San Jose California





















and analysis



mentation



toring systems)

Lube Oil Analysis



















frequently

























microns (Figure 6)









100 I-7 - - - - --

Spectrometer

I

I

Ferrograph

Typical Filter

I I I I

01 1 10 100 1000



81-6








Lubricant

Type

Synthesized

Hydrocarbon

MIL-L-23699

and MIL-L-7808

Petroleum

Fire-Resistant

Viscosity

Change

Limits

+25 -10

+15 -15

+25 - 10

+15 -15


Number Parts per

Max Million Max

40

20

1 o

30

2000

2000

2000

2000

81-027M






teristics tests

Vibration Analysis









































81-007


System

81-7



18

16

v) 14r-

5 12I -

2

2 lsquo-O5 0 8a

2 0 6cJ0 0 4CL


lx Ngp Speed

0 100 200 300 400 500 600 700

DAYS 81-009M




































Warning Level I












Measurement Points










up axially













81-8








8 I

81-011


Transducer Types







l Accelerometers






























Co 1983)















Useful Range

0 500 1000 1500 2000



Transducer

J

0 5000 10000 15000 20000



81-9



r MEASURE

RELATIVE NO

DISPLACEMENT

OR CRITICAL

CLEARANCE HNEED TO

TRANSMITTED MEASURE

TO MACHINE ABOVE

1000 Hz


I DISPLACEMENT

I IUSE



81-014M


Transducer Mounting















































measured





I Hand-held Probe

g +I0

ki2 00-2z -10

-20

I I I I I

0 2 4 6

FREQUENCY kHz

8 10

81-015M


PLOT

SPQN

2 4

0i

I I 1 I

0 2000 4000 6000 8000 10000

FREQUENCY IN HZ

81-016


Data (5-3-89)

81-10



81-021


81-020


(Blocks)






































plished (Figure 19)

81-022


81-11


























mance degradation








81-019M


ANALYZE DATA











I-

A

1

T


81-12




Degradation



































stages















description













attention





81-13




examples are













a compressor set






problems





























are still required





SUMMARY















tion maintenance






conditions


















ACKNOWLEDGEMENTS






81-14



REFERENCES











San Jose California



















Lubricant

Type

Synthesized

Hydrocarbon

MIL-L-23699

and MIL-L-7808

Petroleum

Fire-Resistant

Viscosity

Change

Limits

+25 -10

+15 -15

+25 - 10

+15 -15


Number Parts per

Max Million Max

40

20

1 o

30

2000

2000

2000

2000

81-027M






teristics tests

Vibration Analysis









































81-007


System

81-7



18

16

v) 14r-

5 12I -

2

2 lsquo-O5 0 8a

2 0 6cJ0 0 4CL


lx Ngp Speed

0 100 200 300 400 500 600 700

DAYS 81-009M




































Warning Level I












Measurement Points










up axially













81-8








8 I

81-011


Transducer Types







l Accelerometers






























Co 1983)















Useful Range

0 500 1000 1500 2000



Transducer

J

0 5000 10000 15000 20000



81-9



r MEASURE

RELATIVE NO

DISPLACEMENT

OR CRITICAL

CLEARANCE HNEED TO

TRANSMITTED MEASURE

TO MACHINE ABOVE

1000 Hz


I DISPLACEMENT

I IUSE



81-014M


Transducer Mounting















































measured





I Hand-held Probe

g +I0

ki2 00-2z -10

-20

I I I I I

0 2 4 6

FREQUENCY kHz

8 10

81-015M


PLOT

SPQN

2 4

0i

I I 1 I

0 2000 4000 6000 8000 10000

FREQUENCY IN HZ

81-016


Data (5-3-89)

81-10



81-021


81-020


(Blocks)






































plished (Figure 19)

81-022


81-11


























mance degradation








81-019M


ANALYZE DATA











I-

A

1

T


81-12




Degradation



































stages















description













attention





81-13




examples are













a compressor set






problems





























are still required





SUMMARY















tion maintenance






conditions


















ACKNOWLEDGEMENTS






81-14



REFERENCES











San Jose California














18

16

v) 14r-

5 12I -

2

2 lsquo-O5 0 8a

2 0 6cJ0 0 4CL


lx Ngp Speed

0 100 200 300 400 500 600 700

DAYS 81-009M




































Warning Level I












Measurement Points










up axially













81-8








8 I

81-011


Transducer Types







l Accelerometers






























Co 1983)















Useful Range

0 500 1000 1500 2000



Transducer

J

0 5000 10000 15000 20000



81-9



r MEASURE

RELATIVE NO

DISPLACEMENT

OR CRITICAL

CLEARANCE HNEED TO

TRANSMITTED MEASURE

TO MACHINE ABOVE

1000 Hz


I DISPLACEMENT

I IUSE



81-014M


Transducer Mounting















































measured





I Hand-held Probe

g +I0

ki2 00-2z -10

-20

I I I I I

0 2 4 6

FREQUENCY kHz

8 10

81-015M


PLOT

SPQN

2 4

0i

I I 1 I

0 2000 4000 6000 8000 10000

FREQUENCY IN HZ

81-016


Data (5-3-89)

81-10



81-021


81-020


(Blocks)






































plished (Figure 19)

81-022


81-11


























mance degradation








81-019M


ANALYZE DATA











I-

A

1

T


81-12




Degradation



































stages















description













attention





81-13




examples are













a compressor set






problems





























are still required





SUMMARY















tion maintenance






conditions


















ACKNOWLEDGEMENTS






81-14



REFERENCES











San Jose California



















8 I

81-011


Transducer Types







l Accelerometers






























Co 1983)















Useful Range

0 500 1000 1500 2000



Transducer

J

0 5000 10000 15000 20000



81-9



r MEASURE

RELATIVE NO

DISPLACEMENT

OR CRITICAL

CLEARANCE HNEED TO

TRANSMITTED MEASURE

TO MACHINE ABOVE

1000 Hz


I DISPLACEMENT

I IUSE



81-014M


Transducer Mounting















































measured





I Hand-held Probe

g +I0

ki2 00-2z -10

-20

I I I I I

0 2 4 6

FREQUENCY kHz

8 10

81-015M


PLOT

SPQN

2 4

0i

I I 1 I

0 2000 4000 6000 8000 10000

FREQUENCY IN HZ

81-016


Data (5-3-89)

81-10



81-021


81-020


(Blocks)






































plished (Figure 19)

81-022


81-11


























mance degradation








81-019M


ANALYZE DATA











I-

A

1

T


81-12




Degradation



































stages















description













attention





81-13




examples are













a compressor set






problems





























are still required





SUMMARY















tion maintenance






conditions


















ACKNOWLEDGEMENTS






81-14



REFERENCES











San Jose California














r MEASURE

RELATIVE NO

DISPLACEMENT

OR CRITICAL

CLEARANCE HNEED TO

TRANSMITTED MEASURE

TO MACHINE ABOVE

1000 Hz


I DISPLACEMENT

I IUSE



81-014M


Transducer Mounting















































measured





I Hand-held Probe

g +I0

ki2 00-2z -10

-20

I I I I I

0 2 4 6

FREQUENCY kHz

8 10

81-015M


PLOT

SPQN

2 4

0i

I I 1 I

0 2000 4000 6000 8000 10000

FREQUENCY IN HZ

81-016


Data (5-3-89)

81-10



81-021


81-020


(Blocks)






































plished (Figure 19)

81-022


81-11


























mance degradation








81-019M


ANALYZE DATA











I-

A

1

T


81-12




Degradation



































stages















description













attention





81-13




examples are













a compressor set






problems





























are still required





SUMMARY















tion maintenance






conditions


















ACKNOWLEDGEMENTS






81-14



REFERENCES











San Jose California














81-021


81-020


(Blocks)






































plished (Figure 19)

81-022


81-11


























mance degradation








81-019M


ANALYZE DATA











I-

A

1

T


81-12




Degradation



































stages















description













attention





81-13




examples are













a compressor set






problems





























are still required





SUMMARY















tion maintenance






conditions


















ACKNOWLEDGEMENTS






81-14



REFERENCES











San Jose California





































mance degradation








81-019M


ANALYZE DATA











I-

A

1

T


81-12




Degradation



































stages















description













attention





81-13




examples are













a compressor set






problems





























are still required





SUMMARY















tion maintenance






conditions


















ACKNOWLEDGEMENTS






81-14



REFERENCES











San Jose California















Degradation



































stages















description













attention





81-13




examples are













a compressor set






problems





























are still required





SUMMARY















tion maintenance






conditions


















ACKNOWLEDGEMENTS






81-14



REFERENCES











San Jose California















examples are













a compressor set






problems





























are still required





SUMMARY















tion maintenance






conditions


















ACKNOWLEDGEMENTS






81-14



REFERENCES











San Jose California














REFERENCES











San Jose California












Maintenance Solar

Documents

Transcript of Maintenance Solar