Class II Division 2 Occupancy Sensors - ECE Senior...

Class II Division 2 Occupancy

Sensor

James Fisher

Michael Gazda

Russell Gee

JoAnne Hitchcock

Gledi Progonati

Christopher Zannoni

Dr. George Lykotrafitis (ME)

Dr. Sung Yeul Park (EE)

Presented on March 6, 2013 by:

Senior Design 2012-2013

Overview Background

Design Approach

FM Approvals

Final Design

FEA Testing

Electrical Engineering Role

Circuit Redesign

Dust Circulation Chamber

Future Planning

Senior Design 2012-2013 2

Background

What are occupancy sensors?

Project Task

Modify for Class II Division 2 Environment


Class II Division 2 Safety

What is it?

○ Explosive Dusts abnormally present

cause ignition

○ Warehouses/Storage areas


Design Approach


Design Approach

Three initial designs

FM Approvals

Nationally Recognized Testing Laboratory


FM Approvals Meeting

Explained the testing process

4 static tests, 1 dynamic test

Intrinsic Safety Test

Gave feedback on design

Correct specifications


Final Design


Finite Element Testing

4 static tests

Torque Test

Crush Test

Pullout Conduit Test

Bending Moment Test

1 dynamic test

Impact Test


Torque Test

Applied torque of 113 N-m on conduit

entrance

Max Equivalent Stress: 22.9 MPa


Crush Test

A crushing force of 444 Newtons applied

to top



Pullout Conduit Test

Pullout force of 890 Newtons applied to

conduit entrance

Max Equivalent Stress: 13 MPa


Bending Moment Test

Deflection of 10 ft. conduit to 10 in.



Impact Test


Impact Test

Max Equivalent Stress:

21.1 MPa


Dust Circulation Chamber


Chamber will:

Circulate Talcum powder

Draw 0.3psi below atm

vacuum inside enclosure

Monitor enclosure

pressure and air flow

Dust Chamber Design

Volumetric

Sensor

Vacuum

Pump

Pressure

Sensor

Valve

Filter

Fans

Clear Plastic

Air Tight Box

Controller

Relay 5 volts

120 volts


Dust Chamber Initial Flow Analysis

Senior Design 2012-2013

Front View of Chamber Side View of Chamber

Enclosure Enclosure

19

Talcum powder stays air born at about 1m/s

Circuit Flowchart

AC

Filter

Step-Down to

12V

Step-Down

to 3.2V

Microcontroller

12-20V LED Circuit Control/Switch for

Output

One-Shot

Circuit

INPUT

Relay

OUTPUT

PIR

LIGHTS


Capacitive Circuit Ignition Curves (A.3)


Ca

pa

cit

an

ce (

uF

)

Voltage (V)

Intrinsic Safety Testing of

Capacitors Voltage Across C (V) Max Allowed Voltage (V)

Capacitors

(µF)

1 2 3 No Safety

Factor

Safety

Factor of 1.5

220 19.42 12.25 3.18 6 4.2

4.7 11.72 - - 14 9.33

0.068 12.25 - - 45 30

1 1.3m - - 20 13.33

0.01 421.6m - - 39 26

0.47 18.92 - - 24 16

Table: “Intrinsic Safety of Initial Capacitors from A.3”


Resistive Circuit Ignition Curves (A.1)


Cu

rre

nt

(A)

Voltage (V)

Intrinsic Safety Testing of

Resistors R Voltage Across Resistors (V) Current Across Resistors (A)

100k

19.116

8

527.69

m

1.113 18.8 8.87m 141.1u 5.19u 11.12u 204.6f 837.6f

1.11m 13.2m 12.46m 19.25 - 228.4p 138.8u 144.3u 200u -

10k 1.511m - - - - 154.3n - - - -

120 3.3102

m

- - - - 27.53u - - - -

1M 11.132 7.7m 33.5m 3.16 - 11.12u 211.4p 18.67p 3.133u -

750k 8.592 - - - - 11.41u - - - -

1.2M 2.285 421.6m - - - 1.904u 348.5n - - -

470k 894.6m 3.2 204m 225.4m - 1.902u 19.79p 509.1p 489.9p -

47k 19.34 19.45 - - - 17.84p 293.6u - - -

2.4 14.7m - - - - 434.4u - - - -

3.3k 18.3 - - - - 5.54m - - - -

10M 18.835 - - - - 1.352u - - - -

Table: “Intrinsic Safety of Initial Resistors from A.1”


Project Timeline

January (Wks)

February (Wks)

March (Wks)

April (Wks) May

1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1

ANSYS Testing

Design Dust Chamber

Build Dust Chamber

Intrinsic Safety Spec Analysis

Redesign Circuit

Prototype Circuit

PCB design

PCB Fabrication

Test Prototype Circuit

Test Enclosure in Chamber

Finalize Project

Make Presentations and Reports


Questions?


Class II Division 2 Occupancy Sensors - ECE Senior...

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