Fault Message:

GEN3 DELTA CURRENT FAULT

Fault Code:

2423118LPS

Associated CAS:

GEN 3 FAIL
(Advisory)

The Generator Control Unit (GCU) 3 detects between two phases a difference in output current larger than 35 A ±5 A.

• AC Power Center (ACPC) (A54)
• Generator Control Unit (GCU) 3 (A58)
• Variable Frequency Generator (VFG) 3 (G3)
• 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 GCU 3 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 3 and do close out.
   2. If fault remains, continue with next step.

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

   From	To	Result
   VFG 3-T1	Ground
   VFG 3-T2	Ground
   VFG 3-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 3 and ACPC VFG 3 as follow:

   From	To	Result
   VFG 3-T1	ACPC VFG 3-T7
   VFG 3-T2	ACPC VFG 3-T8
   VFG 3-T3	ACPC VFG 3-T9

   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 G3P1 on the VFG 3.
7. Perform continuity check (open circuit= failure) on VFG 3 as follows:

   From	To	Result
   G3P1-F	G3P1-D
   G3P1-E	G3P1-D
   G3P1-J	G3P1-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 3 as follows:

   From	To	Result
   G3P1-F	Ground
   G3P1-E	Ground
   G3P1-J	Ground
   G3P1-D	Ground

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

9. Disconnect GCU 3 connector A58P2.
10. Perform continuity check (open circuit= failure) between G3P1 and A58P2 as follows:

    From	To	Result
    G3P1-F	A58P2-41
    G3P1-E	A58P2-42
    G3P1-J	A58P2-50
    G3P1-D	A58P2-40

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

11. Perform wiring checks (closed circuit= failure) as follow:

    From	To	Result
    G3P1-F	Ground
    G3P1-E	Ground
    G3P1-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 A54P3.
13. Perform continuity check (open circuit= failure) between A58P2 and A54P3 as follows:

    From	To	Result
    A58P2-49	A54P3-E
    A58P2-57	A54P3-F
    A58P2-63	A54P3-G
    A58P2-62	A54P3-H

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

14. Perform wiring checks (closed circuit= failure) as follow:

    From	To	Result
    A58P2-49	Ground
    A58P2-57	Ground
    A58P2-63	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 VFG3 and K10 as follows:

    From	To	Result
    VFG 3-T1	K10-A3
    VFG 3-T2	K10-B3
    VFG 3-T3	K10-C3

    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 VFG3 and K10 as follows:

    From	To	Result
    VFG 3-T1	K10-A3
    VFG 3-T2	K10-B3
    VFG 3-T3	K10-C3

    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) as follow:

    From	To	Result
    VFG 3-T1	Ground
    VFG 3-T2	Ground
    VFG 3-T3	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.

18. On current transducer 3 (LCTA3), disconnect connector PL3.
19. Perform continuity check (open circuit= failure) in ACPC between A54P3 and PL3 as follows:

    From	To	Result
    A54P3-E	PL3-1
    A54P3-F	PL3-2
    A54P3-G	PL3-3
    A54P3-H	PL3-4

    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) in ACPC between A54P3 and ground as follows:

    From	To	Result
    A54P3-E	Ground
    A54P3-F	Ground
    A54P3-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 PL3 as follows:

    From	To	Result
    PL3-1	PL3-4
    PL3-2	PL3-4
    PL3-3	PL3-4

    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 JL3 and ground as follows:

    From	To	Result
    JL3-1	Ground
    JL3-2	Ground
    JL3-3	Ground

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

23. Replace LCTA3.

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

24. Replace GLC3 (K10).

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

25. Swap VFG 3 with VFG 4.

    1. If system checks are good, replace VFG 3 and do close out.
    2. If fault remains, continue with next step.

26. Replace ACPC.
27. Do close out.