APU Generator Phase Inversion

TASK 24-20-00-810-837-A
APU Generator Phase Inversion

1. Possible Causes

wiring
GCU-APU [1XS]
GEN-APU [8XS]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 242301
AMM 24-23-34-000-001	Removal of the GCU-APU
AMM 24-23-34-400-001	Installation of the GCU-APU
AMM 24-23-51-000-001	Removal of the APU Generator
AMM 24-23-51-400-001	Installation of the APU Generator
AMM 24-41-00-861-002	Energize the Aircraft Electrical Circuits from the External Power
AMM 24-41-00-862-002	De-energize the Aircraft Electrical Circuits Supplied from the External Power

3. Fault Confirmation
Subtask 24-20-00-700-078-A ** ON A/C NOT FOR ALL

A. Test
Not applicable.

NOTE: As the APU GEN was set to OFF because of a true failure, the fault confirmation is not necessary.

4. Fault Isolation
Subtask 24-20-00-810-076-A ** ON A/C NOT FOR ALL

A. If the fault symptom is identified by the CFDS message CHECK GEN APU PHASE SEQ and the upper ECAM DU warning APU GEN FAULT:

do a check of the wiring for phase inversion between respectively the APU generator pins T/1, T/2 and T/3 and the APU GLC pins A/F, A/E, A/D ASM 242301.

(1) If the wiring is not correct:

repair it.

(2) If the wiring is correct:

do a check of the wiring for phase inversion between respectively the APU GCU pins B/1A, B/2B, B/3A and the APU GLC pins A/F, A/E and A/D ASM 242301.

(a) If the wiring is not correct:

repair it.

(b) If the wiring is correct:

replace the GCU-APU [1XS] AMM 24-23-34-000-001 and AMM 24-23-34-400-001.

NOTE: Do not remove the APU GCU before you do the other steps of the trouble shooting.

(3) If the fault continues:

replace the GEN-APU [8XS] AMM 24-23-51-000-001 and AMM 24-23-51-400-001.

Subtask 24-20-00-810-076-B ** ON A/C NOT FOR ALL