Fault Message:

GEN4 DELTA CURRENT FAULT

Fault Code:

2424118LPS

Associated CAS:

GEN 4 FAIL
(Advisory)

The Generator Control Unit (GCU) 4 detects between two phases a difference in output current larger than 35A±5A.

• Variable Frequency Generators (VFG) 4 (G4)
• Generator Control Unit (GCU) 4 (A59)
• AC Power Center (ACPC) (A54)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

A GCU patch cable (GSE REF # 24X-24-02) can be used to swap GCUs 1, 4 and 5 into position 2 or 3 (for troubleshooting only).

The GCU NVMs can only be downloaded at position #2 or #3.

1. Check for CAIMS message related to the ACPC short circuit fault. Clear/troubleshoot the message first if existed.

   1. If system checks are good, do close out.
   2. If fault remains, continue with next step.

2. Swap the GCU 4 with GCU 2 (physically or using the GCU patch cable).
   NOTE: Use PMAT to monitor the fault on GCU.

   1. If system checks are good, replace GCU 4 and do close out.
   2. If fault remains, continue with next step.

3. Disconnect T1, T2, T3 and G at VFG 4.
4. Perform continuity check (closed circuit= failure) at the terminal block of VFG 4 as follows:

   From	To	Result
   G4-T1	Ground
   G4-T2	Ground
   G4-T3	Ground

   1. If there is continuity, go to step 25.
   2. If there is no continuity, continue with next step.

5. Perform wiring checks (open circuit= failure) between VFG 4 and ACPC as follow:

   From	To	Result
   G4-T1	ACPC VFG4-T10
   G4-T2	ACPC VFG4-T11
   G4-T3	ACPC VFG4-T12

   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.

6. Disconnect connector G4P1 on the VFG 4.
7. Perform continuity check (open circuit= failure) within VFG 4 as follows:

   From	To	Result
   G4P1-F	G4P1-D
   G4P1-E	G4P1-D
   G4P1-J	G4P1-D

   1. If there is no continuity, go to step 25.
   2. If there is continuity, continue with next step.

8. Perform continuity check (closed circuit= failure) on VFG 4 and ground as follows:

   From	To	Result
   G4P1-F	Ground
   G4P1-E	Ground
   G4P1-J	Ground
   G4P1-D	Ground

   1. If there is continuity, go to step 25.
   2. If there is no continuity, continue with next step.

9. Disconnect GCU 4 connector A59P2.
10. Perform continuity check (open circuit= failure) between G4P1 and A59P2 as follows:

    From	To	Result
    G4P1-F	A59P2-41
    G4P1-E	A59P2-42
    G4P1-J	A59P2-50
    G4P1-D	A59P2-40

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

11. Perform wiring checks (closed circuit= failure) between G4P1 and ground as follow:

    From	To	Result
    G4P1-F	Ground
    G4P1-E	Ground
    G4P1-J	Ground

    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.

12. Disconnect ACPC connector A54P2.
13. Perform continuity check (open circuit= failure) between A59P2 and A54P2 as follows:

    From	To	Result
    A59P2-49	A54P2-E
    A59P2-57	A54P2-F
    A59P2-63	A54P2-G
    A59P2-62	A54P2-H

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

14. Perform wiring checks (closed circuit= failure) between A59P2 and ground as follow:

    From	To	Result
    A59P2-49	Ground
    A59P2-57	Ground
    A59P2-63	Ground

    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.

15. Perform continuity check (open circuit= failure) between VFG 4 and K13 as follows:

    From	To	Result
    G4-T1	K13-A1
    G4-T2	K13-B1
    G4-T3	K13-C1

    1. If there is continuity, go to step 17.
    2. If there is no continuity, continue with next step.

16. Repair wiring (including inside ACPC) between VFG 4 and K13 as follows:

    From	To	Result
    G4-T1	K13-A1
    G4-T2	K13-B1
    G4-T3	K13-C1

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.
       NOTE: Call Bombardier for decision to repair ACPC wiring or replace ACPC.

17. Perform wiring checks (closed circuit= failure) between VFG 4 and ground as follow:

    From	To	Result
    G4-T1	Ground
    G4-T2	Ground
    G4-T3	Ground

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

18. On current transducer 4 (LCTA 4), disconnect connector PL4.
19. Perform continuity check (open circuit= failure) in ACPC as follows:

    From	To	Result
    A54P2-E	PL4-1
    A54P2-F	PL4-2
    A54P2-G	PL4-3
    A54P2-H	PL4-4

    1. If there is no continuity, go to step 26.
    2. If there is continuity, continue with next step.

20. Perform continuity check (open circuit= failure) between ACPC and ground as follows:

    From	To	Result
    A54P2-E	Ground
    A54P2-F	Ground
    A54P2-G	Ground

    1. If there is continuity, go to step 26.
    2. If there is no continuity, continue with next step.

21. Perform continuity check (open circuit= failure) at connector PL4 as follows:

    From	To	Result
    PL4-1	PL4-4
    PL4-2	PL4-4
    PL4-3	PL4-4

    1. If there is no continuity, go to step 23.
    2. If there is continuity, continue with next step.

22. Perform continuity check (short circuit= failure) at connector between JL4 and ground as follows:

    From	To	Result
    JL4-1	Ground
    JL4-2	Ground
    JL4-3	Ground

    1. If there is no continuity, go to step 24.
    2. If there is continuity, continue with next step.

23. Replace LCTA 4.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

24. Replace GLC 4 (K4).

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

25. Swap VFG 4 with VFG 3.

    1. If system checks are good, replace VFG 4 and do close out.
    2. If fault remains, continue with next step.

26. Replace ACPC.
27. Do close out.