Failure of the DC NORM BUS 1 Switching Contactor

TASK 24-35-00-810-802-A
Failure of the DC NORM BUS 1 Switching Contactor

1. Possible Causes

CNTOR-DC NORM BUS 1 SWITCHING [1PC1]
wiring
C/B-ELEC/CNTOR/DC/BUS/TIE1 [9PC]

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 243502
AWM 243502
AMM 24-35-55-000-001	Removal of the Contactor
AMM 24-35-55-400-001	Installation of the Contactor
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
AMM 31-60-00-860-002	EIS Stop Procedure

3. Fault Confirmation
Subtask 24-35-00-860-052-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 (Lower ECAM DU only) AMM 31-60-00-860-001.

Subtask 24-35-00-710-054-A

B. Test

ACTION	RESULT
On the ECAM control panel: push the ELEC key to get the ELEC page.	On the lower ECAM display unit: the line between DC 1 and DC BAT buses goes out of view the line between DC 2 and DC BAT buses comes into view the DC ESS bus is supplied by the ESS TR.

4. Fault Isolation
Subtask 24-35-00-810-051-A

A. If the test confirms the fault:

Do a check for 28VDC between pins B/3 and B/5 of the DC NORM BUS 1 switching contactor (1PC1).

(1) If there is 28VDC:

Replace the CNTOR-DC NORM BUS 1 SWITCHING [1PC1] AMM 24-35-55-000-001 and AMM 24-35-55-400-001.

(2) If there is no 28VDC:

Do a check of the status of the circuit breaker (9PC).

(a) If the circuit breaker (9PC) is closed:

Do a check and repair the wiring :
. between the circuit breaker (9PC) and pin B/3 of the DC NORM BUS 1 switching contactor (1PC1)
. then between pin B/5 of the contactor (1PC1) and the ground point or terminal block ASM 243502 AWM 243502.

(b) If the circuit breaker (9PC) is open:

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

1 If the fault continues:

Replace the C/B-ELEC/CNTOR/DC/BUS/TIE1 [9PC] .

Subtask 24-35-00-710-055-A

B. Do the test given in Para. 3. and make sure that the normal configuration comes into view.

5. Close-up
Subtask 24-35-00-860-053-A

A. Put the aircraft back to its initial configuration.
(1) Do the EIS stop procedure
AMM 31-60-00-860-002.
(2) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.

[Rev.8 from Aug 2018] 2026.04.04 04:26:46 UTC