GROUND (WDM 49-31-01). IS THE CIRCUIT OK?
YES
Starter Motor Turns the APU Engine but There Is No Combustion (No Increase in EGT)
Figure 113A (Sheet 8)
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L38653
STARTER MOTOR CON- PREREQUISITES
TINUES TO TURN WHEN NONE
THE APU ENGINE SPEED
IS GREATER THAN 50%
POSSIBLE CAUSES:
1.
STARTER MOTOR, M161, PROBLEM (AMM 49-41-11/401)
2.
START RELAY, R5, PROBLEM (WDM 49-31-01)
3.
ELECTRONIC SPEED SWITCH, S634, PROBLEM (AMM 49-61-22/401).
FAULT ISOLATION:
YES
1 REMOVE THE COVER FOR THE
STARTER MOTOR BRUSHES.
ARE THE STARTER MOTOR BRUSHES WORN OR ARE THE INTER-NAL PARTS OF THE STARTER MOTOR DAMAGED FROM AN OVERSPEED CON-DITION?
THE START RELAY, R5, TERMINAL A1 TO GROUND (WDM 49-31-01). IS THERE AN OPEN CIRCUIT?
R5 (WDM 49-31-01).
Starter Motor Continues to Turn When the APU Engine Speed Is Greater Than 50%
Figure 114
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////////////////////////A / GTCP85-129 SERIES /737-300/400/500/ ENGINES /MAINTENANCE MANUAL ////////////////////////
PREREQUISITES
APU ENGINE ACCELER- MAKE SURE THIS SYSTEM WILL OPERATE:
ATES SLOWLY OR THE APU (AMM 49-11-00/201)
APU ENGINE SPEED MAKE SURE THE AIRPLANE IS IN THIS CONFIGURATION:
DOES NOT GET TO 100% ELECTRICAL POWER IS ON (AMM 24-22-00/201)
POSSIBLE CAUSES:
1.
APU BATTERY PROBLEM (AMM 24-31-11/201)
2.
CLOGGED FILTER ELEMENT FOR THE LOW-PRESSURE FUEL (AMM 49-31-22/401)
3.
CLOGGED FILTER FOR THE HIGH-PRESSURE FUEL (AMM 49-31-81/301)
4.
STARTER MOTOR, M161, PROBLEM (AMM 49-41-11/401)
5.
LEAKAGE FROM THE CONTROL AIR LINES
6.
FUEL CONTROL UNIT PROBLEM (AMM 49-31-11/401)
7.
BLEED AIR VALVE, V56, PROBLEM (AMM 49-52-11/401)
8.
COMBUSTOR UNIT PROBLEM (AMM 49-31-42/401)
9.
APU CONTROL THERMOSTAT PROBLEM (AMM 49-52-32/401)
10.
CLOGGED TEE FITTING FOR THE CONTROL AIR LINE
11.
3-WAY SOLENOID VALVE PROBLEM (AMM 49-52-61/401)
12.
APU INTERNAL DAMAGE (AMM 49-11-00/401).
FAULT ISOLATION:
NONO
1 START AND OPERATE THE APU
51 DO THE APU USUAL SHUTDOWN (AMM 49-11-00/201).
(AMM 49-11-00/201).
DOES THE "DC" AMMETER STAY
DO THIS PROCEDURE:
YES
ON THE NEGATIVE SCALE WHEN THESTARTER MOTOR TURNS THE APU APU ENGINE SPEED IS GREATER ENGINE BUT THERE IS NO COMBUS-THAN 50%? TION (NO INCREASE IN EGT)
(FIG. 113).
YES NO
SEE SHEET 2 22 DO THE APU USUAL SHUTDOWN
(BLOCK 2) (AMM 49-11-00/201).
DO THE APU DRY MOTORING
(AMM 49-11-00/201).
DO A CHECK OF THE VOLTAGE TO THE POSITIVE TERMINAL OF THE STARTER MOTOR, M161 (WDM 49-31-01).
IS THE VOLTAGE GREATER THAN 8V DC?
YES
SEE SHEET 2 (BLOCK 23)
APU Engine Accelerates Slowly or the APU Engine Speed Does Not Get to 100%
Figure 115 (Sheet 1)
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FROM SHEET 1 FROM SHEET 1 (BLOCK 1) (BLOCK 22)
YES
YES
NO
YES
YES
2 DO A CHECK OF THE FILTER ELEMENT FOR THE LOW-PRESSURE
FUEL (AMM 49-31-22/401).
IS THE FILTER ELEMENT CLOGGED?
NO
YES
3 DO A CHECK OF THE FILTERFOR THE HIGH-PRESSURE FUEL 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：737-300 400 500 AMM 飞机维护手册 AIRBORNE AUXILIARY POWER 1(35)
