Accidental Disconnection of the IDG1

TASK 24-20-00-810-807-A
Accidental Disconnection of the IDG1

1. Possible Causes

RELAY-IDG 1 DISC CTL [3XT]
wiring
P/BSW-ELEC/IDG 1 [5XT]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 24-21-00-710-040	Operational Test of the IDG Disconnect and Reconnect (Reset) Function - Engine Static
ASM 242101
AMM 24-41-00-862-002	De-energize the Aircraft Electrical Circuits Supplied from the External Power
AMM 71-00-00-710-003	Engine Automatic Start
AMM 71-00-00-710-028	Engine Shutdown

3. Fault Confirmation
Subtask 24-20-00-700-103-A ** ON A/C NOT FOR ALL

A. Test
Not applicable, you cannot confirm this fault on the ground.

4. Fault Isolation
Subtask 24-20-00-810-092-D ** ON A/C NOT FOR ALL

A. If the fault symptom is identified by the CFDS message IDG1 DISCONNECTED and the warning ELEC GEN1 FAULT on the upper ECAM display unit:
(1) If the IDG1 has been disconnected intentionally, that is if this CFDS message is associated with other CFDS messages such as:
. IDG1 LOW OIL PRESSURE
. IDG1 (OVERTEMP)
. IDG1 HIGH DELTA TEMP
. IDG1 BULB TOLERANCE
. other messages.

no trouble shooting is necessary.

(2) If the IDG1 has not been disconnected intentionally:

reconnect the IDG1: for this, reset the disconnect system AMM 24-21-00-710-040 (the warning ELEC GEN1 FAULT is no longer shown of the upper ECAM display unit and the DISC indication is no longer shown on the lower ECAM display unit).

(a) If the IDG1 disconnects again (the warning GEN1 FAULT is shown again on the upper ECAM display unit and the DISC indication is shown again on the lower ECAM display unit):

replace the RELAY-IDG 1 DISC CTL [3XT] .

1 If the fault continues:

do a check and repair the wiring for abnormal 28VDC between the pin A/A1 of the relay (3XT) and the pin A/12 of the IDG1 ASM 242101.

(b) If the IDG1 does not disconnect:

on the circuit breaker panel 122VU, open, safety and tag the circuit breaker ELEC/GCU/1 (2XU1).

1 If the IDG1 disconnects (the warning GEN1 FAULT is shown on the upper ECAM display unit and the DISC indication is shown on the lower ECAM display unit).

replace the P/BSW-ELEC/IDG 1 [5XT] .

a If the fault continues:

do a check and repair the wiring for abnormal 28VDC between the pin A/B1 of the pushbutton switch (5XT) and the pin A/X1 of the relay (3XT) ASM 242101.

2 If the IDG1 does not disconnect:

stop the trouble shooting and on the circuit breaker panel 122VU, remove the safety clip and tag and close the circuit breaker (2XU1).

Subtask 24-20-00-710-079-A ** ON A/C NOT FOR ALL

B. Do this test to make sure that the system operates correctly:
(1) Make sure that the circuit breaker 2XU1 is closed.
(2) On the overhead panel, on the ELEC panel 35VU:

push, release and push again the ELEC/GEN1 pushbutton switch (3XU1).

(3) Start the engine 1 AMM 71-00-00-710-003.
(4) Do this test:

ACTION	RESULT
On the ECAM control panel: push the ELEC key to get the ELEC page.	On the lower ECAM display unit: the correct electrical parameters of the GEN1 are shown and the AC1 busbar is supplied by the GEN1.

5. Close-up
Subtask 24-20-00-860-107-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.
(1) Stop the engine 1 AMM 71-00-00-710-028.
(2) On the ECAM control panel, set the UPPER DISPLAY and LOWER DISPLAY potentiometers to OFF.
(3) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.

[Rev.8 from Aug 2018] 2026.04.04 04:26:10 UTC