Failure of the AC BUS 2 with the APU Generator in Operation

TASK 24-50-00-810-811-A
Failure of the AC BUS 2 with the APU Generator in Operation

1. Possible Causes

BTC-2 [11XU2]
wiring
RELAY-GLC 2 AUX CTL [4XU2]
GLC-2 [9XU2]
RELAY-SMOKE [30XU2]
RELAY-BUS TIE [30XU1]
C/B-ELEC/GEN2/OFF/BTC2 SPLY [8XU]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 24-00-00-810-803-A	Circuit Breaker Tripped and/or C/B TRIPPED Warning
ASM 242203
AMM 24-22-34-000-001	Removal of the GCU-1(2)
AMM 24-22-34-400-001	Installation of the GCU-1(2)
AMM 24-22-55-000-001	Removal of the Contactors
AMM 24-22-55-400-002	Installation of the Contactors
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
AMM 31-60-00-860-001	EIS Start Procedure

3. Fault Confirmation
Subtask 24-50-00-860-068-A

A. Job Set-up
(1) Aircraft Maintenance Configuration
(a) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.
(b) Do the EIS start procedure (Upper ECAM DU and lower ECAM DU only)
AMM 31-60-00-860-001.

Subtask 24-50-00-710-070-A

B. Test
(1) Do this test:

ACTION	RESULT
1.On the ELEC panel 35VU: release the GEN1 and GEN2 pushbutton switches.	On the ELEC panel 35VU: the OFF legends of the GEN1 and GEN2 pushbutton switches come on. On the upper ECAM display unit: the ELEC AC BUS 2 FAULT warning comes into view.

4. Fault Isolation
Subtask 24-50-00-865-055-A

A. Table of the circuit breakers used in this procedure:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
122VU	ELEC/GEN2/OFF/BTC2 SPLY	8XU	T31

Subtask 24-50-00-810-060-A ** ON A/C NOT FOR ALL

B. If the test confirms the fault:

Do a check of the status of the circuit breaker (8XU).

(1) If the circuit breaker is closed:

Replace BTC-2 [11XU2] AMM 24-22-55-000-001 and AMM 24-22-55-400-002.

(a) If the fault continues:

Do a check and repair the wiring between the pin B/5 of BTC2 and pin AA/9C of GCU2 ASM 242203.

(b) If the fault continues:

Do a check for 28VDC:

1 If there is no 28VDC at the pin A/A2 of the relay (4XU2):

Replace the RELAY-GLC 2 AUX CTL [4XU2] .

a If the fault continues:

Repair the wiring between the circuit breaker ELEC/GEN2/OFF/BTC2 SPLY (8XU) and the pin A/A3 of the relay (4XU2) ASM 242203.

2 If there is no 28VDC at the pin B/6 of GLC2 (9XU2):

Replace GLC-2 [9XU2] AMM 24-22-55-000-001 and AMM 24-22-55-400-002.

a If the fault continues:

Repair the wiring between the pin A/A2 of the relay (4XU2) and pin B/8 of GLC2 (9XU2) ASM 242203.

3 If there is no 28VDC at the pin B/3 of BTC2 (11XU2):

Replace the RELAY-SMOKE [30XU2] .

a If the fault continues:

Repair the wiring between the pin A/A2 of the relay (4XU2) and pin B/8 of GLC2 (9XU2) ASM 242203.

4 If there is no 28VDC at the pin B/3 of BTC2 (11XU2):

Replace RELAY-BUS TIE [30XU1] .

a If the fault continues:

Do a check and repair the wiring between:
. Pin B/6 of GLC2 (9XU2) and pins A/B2 and A/X1 of the relay (30XU2) ASM 242203,
. Pin A/B3 of the relay (30XU2) and pin B/3 of BTC2 (11XU2) ASM 242203.

(2) If the circuit breaker is open:

Do the procedure (Ref. TSM TASK 24-00-00-810-803).

(a) If the fault continues:

Replace the C/B-ELEC/GEN2/OFF/BTC2 SPLY [8XU] .

Subtask 24-50-00-810-060-B ** ON A/C NOT FOR ALL

B. If the test confirms the fault:

Do a check of the status of the ELEC/GEN2/OFF/BTC2 SPLY circuit breaker (8XU).

(1) If the circuit breaker is closed:

Replace BTC-2 [11XU2] AMM 24-22-55-000-001 and AMM 24-22-55-400-002.

(a) If the fault continues:

Remove GCU2 AMM 24-22-34-000-001.
Do a check and repair the wiring between pin B/5 of BTC2 (11XU2) and pin AA/9A of GCU2 (1XU2) ASM 242203.
Install GCU2 AMM 24-22-34-400-001.

(b) If the fault continues:
1 Remove the GLC2 auxiliary control-relay (4XU2) and do a check for 28VDC at pin A/A3 on the base of the GLC2 auxiliary control-relay (4XU2).
a If there is 28VDC:

Replace the RELAY-GLC 2 AUX CTL [4XU2] .

b If there is no 28VDC:

Repair the wiring between the ELEC/GEN2/OFF/BTC2 SPLY circuit breaker (8XU) and pin A/A3 of the GLC2 auxiliary control-relay (4XU2) ASM 242203.

2 Do a check for 28VDC at pin B/22 of GLC2 (9XU2):
a If there is no 28VDC:

Replace GLC-2 [9XU2] AMM 24-22-55-000-001 and AMM 24-22-55-400-002.

b If the fault continues:

Repair the wiring between pin A/A2 of the relay (4XU2) and pin B/8 of GLC2 (9XU2) ASM 242203.

3 Do a check for 28VDC at the pin B/22 of BTC2 (11XU2):
a If there is no 28VDC:

Replace the RELAY-SMOKE [30XU2] .

b If the fault continues:

Repair the wiring between pin A/A2 of the GLC2 auxiliary control-relay (4XU2) and pin B/24 of GLC2 (9XU2) ASM 242203.

4 Do a check for 28VDC at pin B/3 of BTC2 (11XU2):
a If there is no 28VDC:

Replace RELAY-SMOKE [30XU2] .

b If the fault continues:

Do a check and repair the wiring ASM 242203 between:
. Pin B/22 of GLC2 (9XU2) and pins A/B1 and A/X1 of the smoke relay (30XU2)
. Pin A/B3 of the smoke relay (30XU2) and pin B/3 of BTC2 (11XU2).

(2) If the circuit breaker is open:

Do the circuit breaker tripped and/or C/B TRIPPED warning procedure (Ref. TSM TASK 24-00-00-810-803).

(a) If the fault continues:

Replace the C/B-ELEC/GEN2/OFF/BTC2 SPLY [8XU] .

Subtask 24-50-00-710-071-A

C. Do this test to make sure that the system operates correctly:

ACTION	RESULT
On the ECAM control panel: push the ELEC key to get the ELEC page.	On the lower ECAM display unit: the normal configuration comes into view.

5. Close-up
Subtask 24-50-00-860-069-A

A. Put the aircraft back to its initial configuration.
(1) On the ECAM control panel, set the UPPER DISPLAY and LOWER DISPLAY potentiometers to OFF.
(2) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.

[Rev.8 from Aug 2018] 2026.04.04 04:26:56 UTC