本次问题来自这篇文章:《737NG EMDP压力低故障分析》
有小伙伴问: 在RESET前,为什么要脱开EMDP电插头呢?是怕对泵造成损伤吗,拔跳开关也行啊。
这个CAUTION来自于AMM SDS 29-10-00:
同样的内容在FIM 29-10 TASK 803/804也有:
但是FIM的初始评估里并没有要求RESET前脱开EMDP电插头,而在后续的排故程序里有要求。
那么现在问题来啦:RESET前到底要不要脱开EMDP电插头呢?
由于涉及线路问题,我们要去看看WDM或SSM手册:
这里以B系统EMDP为例,泵三相电源继电器R318的吸合供电由图中红线的28V直流电控制。

AMM SDS 29-10-00
如果 P5板相应EMDP电门在OFF位,复位 Ground Fault Detector 后,三相电源也无法加到EMDP上。
所以,我们平常只要把P5板EMDP电门放OFF位,就可以去复位相应的Ground Fault Detector,而无需脱开EMDP上电插头。
最后,针对此问题解释如下:
AMM SDS 29-10-00里的这个CAUTION是多余的FIM 29-10 TASK 803/804 Initial Evaluation 是正确的,此时只要P5板 EMDP电门在OFF位,无需去EMDP上脱开电插头,可以直接复位GFDFIM 29-10 TASK 803/804 Fault Isolation Procedure 也是正确的,因为执行此步时,P5板EMDP电门在ON位
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我给波音的SR内容如下:
DESCRIPTION:
Description
======================
In AMM SDS 29-10-00:
CAUTION : DO NOT PUSH THE RESET SWITCH ON THE GROUND FAULT DETECTOR BEFORE YOU DISCONNECT ELECTRICAL CONNECTOR FROM THE EMDP.
Desired Action
======================
When the ELEC HYD PUMP switches set in off position,the hydraulic pump relay contacts open and stop 115v ac power to the EMDP.
Why did there need disconnect electrical connector from the EMDP before reset the ground fault detector?
Purchase Order Number (if required)
======================
RESPONSE AND/OR REQUIRED ACTION :
RESPONSE:
The caution note in AMM SDS 29-10-00 is not necessary. This note would be associated when doing FIM Troubleshooting for Electrical Power to the System A or B EMDP Problem - Fault Isolation in FIM 29-10 Tasks 803 and 804.
A request has been submitted to remove the caution note from the AMM SDS. Boeing will advise the AMM revision schedule by 14 July 2016.
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