启动APU详细步骤以及火警测试时哪几个灯会亮？

zyz_92 · 发表于 2016-9-26 17:45:13

启动APU详细步骤以及火警测试时哪几个灯会亮？求详细解答

anan206001 · 发表于 2016-9-27 10:36:37

Ignition/Starting Function Sequence
This is the APU start sequence:
• The start sequence starts when the APU switch is put to the START
position and released to the ON position.
• The ECU turns on the oil pressure light on the P5 panel when the ECU
receives the start signal. The low oil pressure light goes out at 30-40 psi
oil pressure.
• The ECU opens the APU fuel shutoff valve and air inlet door. The inlet
door switch sends a door open signal to the ECU when the air inlet door
is open.
• At 0 percent speed and before the start system is energized, the ECU
energizes the ignition unit.
• If the air inlet door is open and the APU speed is less than 7 percent,
the ECU sends a start signal to the SCU. If the APU speed is more than
7 percent, the ECU waits until the speed is less than 7 percent.
• If 115v AC is available on transfer bus 1, the SCU sends a start signal to
the AC to DC converter in the SPU. The AC to DC converter gives 270v
DC power to the SCU.
• If 115v AC is not available on transfer bus 1, the SCU sends a start
signal to the DC to DC converter in the SPU. The DC to DC converter
gives 270v DC to the SCU. The SCU also has a control function to
prevent the DC to DC converter from depleting the battery below limits
(18v DC on ground, 20v DC in air) during a DC start attempt. The
proximity switch electronics unit (PSEU) provides the air/ground input.
• The DC to AC converter in the SCU changes the 270v DC power from
the SPU into three-phase start power. This power goes to the
starter-generator. The starter-generator turns the APU turbine shaft.
The SCU receives starter-generator rotor position from the
starter-generator resolver. The SCU uses this signal to synchronize the
three-phase start power to the starter-generator rotor position.
• At 7 percent speed, the ECU energizes the fuel solenoid which supplies
fuel for combustion.
• At approximately 30 percent speed, oil pressure goes above 30-40 psi.
The oil pressure switch removes the low oil pressure signal. The ECU
turns off the low oil pressure light.
• At 60 percent speed, the ECU de-energizes the ignition unit.
• At 70 percent speed, the ECU removes the start signal from the SCU.
The SCU removes the start signal from the SPU AC to DC and DC to
DC converters. This de-energizes the starter-generator.
• At 95 percent speed, plus two seconds, the ECU gives the ready to load
(RTL) signal to other airplane systems. This signals the airplane
systems that the APU is ready to accept pneumatic and electrical loads.
APU IGNITION AND START SYSTEM - FUNCTIONAL DESCRIPTION
737-600/700/800/900 AIRCRAFT MAINTENANCE MANUAL
49-40-00

口试请中签 · 发表于 2016-9-27 16:55:46

楼上的我要给你一个赞，好样的

夜雨769 · 发表于 2016-9-30 09:09:34

2楼，厉害啊！

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[70-80发动机CFM56-7] 启动APU详细步骤以及火警测试时哪几个灯会亮？

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