Message Name:

HYD PUMP 3A CIRCUIT BREAKER TRIPPING

AC Power Center (ACPC) Secondary Logic Card (SLC) 4 reported AC Motor Pump (ACMP) 3A Circuit Breaker (CB) tripped.

• AC Power Center (ACPC) Relay (K24)
• AC Power Center (ACPC) Contactor (K13)
• AC Motor Pump (ACMP) 3A (B53)
• AC Power Center (ACPC) Secondary Logic Card (SLC) 4
• AC Power Center (ACPC) Electromagnetic Interface (EMI) Filter
• AC Power Center (ACPC) (A54)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. Perform CAIMS Hydraulic Pump Phase Current Check:
   NOTE: Perform this check if the hydraulic pump circuit breaker does not trip every time or if there is a delay between the time when the pump is turned ON and when the pump circuit breaker trips.

   • Using the PMAT, access CAIMS
   • Select SYSTEM DIAG
   • Select ATA 24
   • Select AC POWER CENTER ACPC_A (B)
   • Select LRU TEST
   • Select HYDRAULIC PUMP SYSTEM DATA
   • Select CONFIRM to go to page 3/4
     

2. Turn ON the hydraulic pump and look at the three phase's current value.

   1. If there is a phase (A, B or C) that displays no current or a different current value than the other two phases, continue with next step and if needed, go to step 8 and if still required go to step 16.
   2. If the current value is the same on all three phases, continue with next step.

3. For hydraulic pump check, disconnect hydraulic pump 3A connector (B53P1).
4. On the EMS CDU set the HYD PUMP 3A Circuit Breaker (CB) to IN.
5. Set hydraulic pump 3A to ON via the Hydraulic Control Panel.
6. Perform the voltage check as follows:

   From	To	Expected Result	Result
   B53P1-A	B53P1-E	115 VAC
   B53P1-B	B53P1-E	115 VAC
   B53P1-C	B53P1-E	115 VAC

   1. If the voltage is not as specified above or the circuit breaker is tripping, go to step 10.
   2. If the voltage is as specified above, continue with next step.
      NOTE: Presence of voltage does not eliminate the electrical system as a possible cause. High resistance of a single phase contact on any multiphase contactor will cause the remaining phases to go HIGH. This will result in the CB tripping.

7. Set hydraulic pump 3A to OFF.
8. For hydraulic versus electrical Isolation Test, with hydraulic pump 3A switch set to OFF, perform a continuity check between B53P1 connectors as follows:

   From	To	Expected Result	Result
   B53P1-A	B53P1-E	Open
   B53P1-B	B53P1-E	Open
   B53P1-C	B53P1-E	Open
   B53P1-A	B53P1-B	Open
   B53P1-A	B53P1-C	Open
   B53P1-B	B53P1-C	Open

   1. If there is continuity, repair defective wiring as required and do close out.
   2. If there is no continuity, continue with next step.

9. After all the other checks in the sections below have been performed, if a cause was not identified, you may elect to swap hydraulic pump 3A and 3B to isolate if the pump is defective.
10. For Secondary Logic Card, swap the ACPC Secondary Logic Card (SLC) 4 with SLC 1.

    1. If the system checks are good, replace ACPC Secondary Logic Card (SLC) 4 and do close out.
    2. If the fault remains, continue with next step.

11. Reset the hydraulic pump 3A circuit breaker to IN.
12. Set the hydraulic pump 3A switch to ON.

    1. If the HYD PUMP 3A circuit breaker trips, set the hydraulic pump 3A switch to OFF and go to step 16.
    2. If the HYD PUMP 3A circuit breaker does not trip, continue with next step.

13. Set the hydraulic pump 3A switch to OFF.
14. Set the hydraulic pump 3B switch to ON.

    1. If the HYD PUMP 3B circuit breaker does not trip, set the hydraulic pump 3B switch to OFF, do close out and monitor.
    2. If the HYD PUMP 3B circuit breaker trips, continue with next step.

15. Set the hydraulic pump 3B switch to OFF.
16. For Relay and contactor check, access the ACPC secondary power assembly and swap relay K24 with relay K14.
    NOTE: You may perform a 115 VAC voltage check directly on the contactors phase contacts to see if a phase is missing. If a phase is missing, check to see if problem originates upstream of the affected contactor. If the contactor is found to be causing the phase drop, replace contactor.

    1. If the system checks are good, replace relay K24 and do close out.
    2. If fault remains, continue with next step.

17. Reset the hydraulic pump 3A circuit breaker back to IN.
18. Set the hydraulic pump 3A switch to ON.

    1. If the HYD PUMP 3A circuit breaker does not trip, set the pump to OFF, replace the defective relay and do close out.
    2. If the HYD PUMP 3A circuit breaker trips, set the hydraulic pump 3A switch to OFF and continue with next step.

19. Access the ACPC primary power assembly and swap contactor K13 with K5.

    1. If the system checks are good, replace contactor K13 and do close out.
    2. If fault remains, continue with next step.

20. Reset the hydraulic pump 3A circuit breaker back to IN.
21. Set the hydraulic pump 3A switch to ON.

    1. If the HYD PUMP 3A circuit breaker does not trip, set the pump to OFF, replace the defective contactor and do close out.
    2. If the HYD PUMP 3A circuit breaker trips, set the hydraulic pump 3A switch to OFF and continue with next step.

22. For EMI filter check, perform a wiring check of the EMI filter.
    NOTE: The picture 5 and 6 depicts SLC 3 connector P310 and is shown for reference since it has the same layout as SLC 4 connector P410.

    1. If wiring checks are not good, repair defective wiring as required and do close out.
    2. If wiring checks are good, continue with next step.

23. Remove SLC 4.
24. Perform a continuity check at connector P410 as follows:

    From	To	Result
    P410-22	Ground

    1. If there is continuity, go to step 28.
    2. If there is no continuity, continue with next step.

25. Perform a continuity check at connector P410 as follows:

    From	To	Result
    P410-22	P410-25
    P410-22	P410-28
    P410-22	P410-31

    1. If there is no continuity, go to step 28.
    2. If there is continuity, continue with next step.

26. Install SLC 4.
27. Retest Hydraulic pump 3A.
28. Replace ACPC.
29. Do close out.