Fault Message:

GEN4 OVERCURRENT FAULT

Fault Code:

2424115LPS

Associated CAS:

GEN 4 FAIL
(Advisory)

Generator Control Units (GCU) 4 has reported an overcurrent on one phase of the Generator 2.

• Generator Control Units (GCU) 4 (A59)
• Main Generator 4 (G4)
• AC Power Center (ACPC) (A54)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

Over current detection specification:

• The output current on one phase of the GEN 4 is more than 185 Amps.

CAUTION: Due to the nature of this CAIMS message, wiring checks should be performed prior to swapping any LRUs in order to prevent damage to LRUs or aircraft.

1. Perform a visual inspection for arcing evidences of ACPC primary section. GCU 4 and GEN 4 feeder cables.

   1. If arcing evidence is found, repair/replace damaged components.
   2. If fault remains, continue with next step.

2. Check for short circuit on GEN 4.

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

   1. If short circuit is found, go to step 8.
   2. If there is no short circuit, continue with next step.
      NOTE: Disconnect the power feeder cables on studs T1, T2, T3 and the ground cable (G) for short circuit test.

3. Disconnect the connector A59P1 of the GCU 4.
4. Perform wiring checks between the Generator 4, ACPC contactor K4, K13, K6 and the GCU 4 on each phase.

   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.
      NOTE: Call Bombardier for decision to repair ACPC wiring or replace ACPC.

5. Disconnect the connector A59P2 of the GCU 4.
6. Check for short circuit of GCTA wiring interface between the Generator 4 and the GCU 4.

   1. If short circuit is found, go to step 8.
   2. If there is no short circuit, continue with next step.

7. Swap GCU 4 with GCU 2.

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

8. Replace GEN 4.

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

9. Replace ACPC.
10. Do close out.