Installation of the AC ESS BUS Contactor

TASK 24-24-55-400-002-A
Installation 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	AR	ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE
No specific	AR	WARNING NOTICE(S)
No specific	Torque wrench: range to between 0.176 and 0.147 m.daN (15.58 and 13.01 lbf.in )

B. Work Zones and Access Panels

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

C. Referenced Information

REFERENCE	DESIGNATION
TASK 24-24-00-710-001-A	Operational Check of Emergency Generating System
TASK 24-28-00-710-001-A	Operational Test of the Static Inverter when the Aircraft Electrical Circuits are Energized from the External Power
TASK 24-28-00-710-001-A-01	Operational Test of the Static Inverter when the Aircraft Electrical Circuits are Energized from the APU
Contactor

3. Job Set-up
Subtask 24-24-55-860-053-A

A. Aircraft Maintenance Configuration
(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) Make sure that there is a WARNING NOTICE(S) in the cockpit 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 receptacle EXT PWR.
(4) Make sure that there is a WARNING NOTICE(S) on the access door 121AL to tell persons not to connect the external power connector.
(5) Make sure that the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE are in position at the access doors 812 and 822.
(6) Make sure that the access doors 812 and 822 are open.
(7) In the avionics compartment, make sure that the access panel (13) of the AC/DC emergency power center 106VU is open.

Subtask 24-24-55-865-054-A

B. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:

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

4. Procedure
Subtask 24-24-55-420-051-A

A. Installation of the Contactor

CAUTION: REFER TO THE MATCH MARKS MADE DURING THE REMOVAL WHEN YOU CONNECT THE ELECTRICAL WIRES. INCORRECT CONNECTION OF THE WIRES WILL CAUSE DAMAGE TO EQUIPMENT.

(1) Put the contactor (2) in position on the studs (3).
(2) Install the washers (1) and the nuts (12). Tighten the nuts.
(3) Install the crimped lugs (10) with the shunts (11).
(4) Install the retaining washers (9).
(5) Install the power supply wires (8).
(6) Install the washers (7) and the nuts (6). Tighten the nuts (6).
(7) TORQUE the nuts (6) to between 0.176 and 0.147 m.daN (15.58 and 13.01 lbf.in )

.
(8) Remove the CAP-BLANKING from each electrical connector and receptacle.
(9) Make sure that all the electrical connections are clean and in the correct condition.
(10) Connect the two electrical connectors (5).

Subtask 24-24-55-865-055-A

B. Remove the safety clip(s) and the tag(s) and close 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 24-24-55-710-051-A

C. Operational Tests
(1) Do the operational test of the emergency generation system (Ref. AMM TASK 24-24-00-710-001).
(2) Do the operational test of the static inverter (Ref. AMM TASK 24-28-00-710-001).

5. Close-up
Subtask 24-24-55-410-051-A

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the access panel (13) on the AC/DC emergency power center 106VU.
(3) Close the access doors 812 and 822.
(4) Remove the WARNING NOTICE(S).
(5) Remove the access platform(s).

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