Removal of the AC ESS BUS Contactor

TASK 24-24-55-000-002-A
Removal of the AC ESS BUS Contactor

WARNING: MAKE SURE THAT NO AC OR DC POWER IS CONNECTED TO THE AIRCRAFT ELECTRICAL CIRCUITS. THERE IS A RISK OF ELECTROCUTION IF THE AC OR DC POWER STAYS CONNECTED.

ZONE: 125
FIN: 15XE

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE
No specific	AR	CAP - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
125	LATERAL AVIONIC COMPARTMENT
812, 822

C. Referenced Information

REFERENCE	DESIGNATION
Contactor

3. Job Set-up
Subtask 24-24-55-941-052-A

A. Safety Precautions
(1) In the cockpit, on the overhead panel 35VU, make sure that these pushbutton switches are released:

BAT 1, BAT 2,
GEN 1(2), APU GEN,
EXT PWR.

(2) In the cockpit, put a WARNING NOTICE(S) to tell persons not to operate the pushbutton switches on the overhead panels:

21VU (EMER ELEC PWR),
35VU (ELEC).

(3) Make sure that the external power connector is not connected to the aircraft receptable EXT PWR.
(4) Put a WARNING NOTICE(S) on the access door 121AL to tell persons not to connect the external power connector.

Subtask 24-24-55-010-051-A

B. Get access to the avionics compartment.
(1) Put an ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE at the access doors 812 and 822.
(2) Open the access doors 812 and 822.

Subtask 24-24-55-865-053-A

C. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
106VU	AC ESS/BUS/EMER/CNTOR/SPLY	15PC	C08
106VU	AC ESS BUS/EMER/STBY/CNTOR/SPLY	10XE	C06

Subtask 24-24-55-010-053-A

D. Get Access
(1) In the avionics compartment, remove the access panel (13) from the AC/DC emergency power center 106VU.

4. Procedure

CAUTION: MAKE MATCH MARKS ON ALL THE ELECTRICAL WIRES BEFORE YOU DISCONNECT THEM. INCORRECT CONNECTION OF WIRES WILL CAUSE DAMAGE TO EQUIPMENT.

Subtask 24-24-55-020-051-A

A. Removal of the Contactor
(1) Disconnect the two electrical connectors (5).
(2) Put CAP - BLANKING on the electrical connectors (5) and the electrical receptacles (4).
(3) Loosen the nuts (6).
(4) Remove the nuts (6) and the washers (7).
(5) Remove the power supply wires (8) and the retaining washers (9).
(6) Remove the crimped lugs (10) with the shunts (11) and but do not discard them.
(7) Loosen the 4 nuts (12).
(8) Hold the contactor (2).
(9) Remove the 4 nuts (12) and washers (1).
(10) Remove the contactor (2).

[Rev.10 from 2021] 2026.03.31 23:22:46 UTC