Installation of the Contactors

TASK 24-42-55-400-001-A
Installation of the Contactors

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: 212
FIN: 12XX
FIN: 14XX

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 1M (3 FT)-ADJUSTABLE
No specific	AR	WARNING NOTICE(S)
No specific	Torque wrench: range to between 15.93 and 13.28 lbf.in (0.18 and 0.15 m.daN )
No specific	Torque wrench: range to between 0.3 and 0.27 m.daN (26.55 and 23.89 lbf.in )

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
212	COCKPIT
121AL

C. Referenced Information

REFERENCE	DESIGNATION
TASK 20-21-15-912-001-A	Tightening Torques for Electrical Component Fasteners
TASK 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
TASK 24-42-00-862-001-A	De-energize the Ground Service Network Supplied from the External Power
TASK 24-42-58-400-001-A	Installation of the AC Service Bus Contactor Module
TASK 25-11-41-000-001-A	Removal of the Third Occupant Seat
TASK 25-11-41-400-001-A	Installation of the Third Occupant Seat
Contactors ** ON A/C NOT FOR ALL
Contactors ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 24-42-55-860-050-A

A. Aircraft Maintenance Configuration
(1) In the cockpit, make sure that the third occupant seat is removed (Ref. AMM TASK 25-11-41-000-001).
(2) In the cockpit, in the L lower section of the panel 120VU, make sure that the access panel of the panel 123VU is removed.
(3) Make sure that the ACCESS PLATFORM 1M (3 FT)-ADJUSTABLE is in position at the access door 121AL.
(4) Make sure that the access door 121AL is open.
(5) Make sure that the external power connector is not connected to the aircraft receptacle.
(6) Make sure that a WARNING NOTICE(S) is in position on the access door 121AL to tell persons not to use the external power receptacle.
(7) In the cockpit, on the overhead ELEC panel 35VU, make sure that these pushbutton switches are released:

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

(8) In the cockpit, make sure that a WARNING NOTICE(S) is in position to tell persons not to operate the pushbutton switches on these overhead panels:

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

(9) In the cockpit, on the APU section of the overhead panel 25VU, make sure that a WARNING NOTICE(S) is in position to tell persons not to start the APU.

Subtask 24-42-55-865-051-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
122VU	ELEC/EXT PWR/LT CLT/NOT IN/USE	6XG	X30

4. Procedure
Subtask 24-42-55-420-052-A ** ON A/C NOT FOR ALL

A. Installation of the Contactor Base

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) Install the contactor base (1) in correct position.
(2) Install the washers (3) and the screws (4) and tighten them.
(3) Make sure that the electrical cables (5) are clean and in correct condition.
(4) Installation of the electrical cables (5).
(a) Install the washers (6) and the nuts (7).
(b) TORQUE the nuts (7) to between 0.3 and 0.27 m.daN (26.55 and 23.89 lbf.in )

.
(5) Install the jumpers (14) between the contactor base (1) and the adjacent base.
(6) Install the washers (13) and the nuts (12) and tighten them (Ref. AMM TASK 20-21-15-912-001).

Subtask 24-42-55-420-050-A ** ON A/C NOT FOR ALL

B. Installation of the contactor

CAUTION: MAKE SURE THAT THE CONTACTOR LOCATING PIN IS CORRECTLY ENGAGED IN ITS RECESS LOCATED IN ONE POWER TERMINAL. THIS PREVENTS DAMAGE TO THE LOCATING PIN WHEN YOU APPLY THE TORQUE.

(1) Install the contactor (11) on the 6 tapped barrels (2) of the contactor base (1).
(2) TORQUE the captive screws (8) to between 15.93 and 13.28 lbf.in (0.18 and 0.15 m.daN )

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

Subtask 24-42-55-420-052-B ** ON A/C NOT FOR ALL

C. Installation of the Module 20XX

NOTE: The installation of a module is necessary only if it was removed.

(1) Install the module 20XX (Ref. AMM TASK 24-42-58-400-001).

Subtask 24-42-55-420-050-B ** ON A/C NOT FOR ALL

D. Installation of the Contactor

CAUTION: MAKE SURE THAT THE CONTACTOR LOCATING PIN IS CORRECTLY ENGAGED IN ITS RECESS LOCATED IN ONE POWER TERMINAL. THIS PREVENTS DAMAGE TO THE LOCATING PIN WHEN YOU APPLY THE TORQUE.

(1) Install the contactor (3) on the module 20XX (4).
(2) TORQUE the captive screws (2) to between 15.93 and 13.28 lbf.in (0.18 and 0.15 m.daN )

.
(3) Remove the blanking caps from the electrical connector (1) and the electrical receptacle.
(4) Make sure that all the electrical connections are clean and in the correct condition.
(5) Connect the electrical connector (1) to the contactor (3).

Subtask 24-42-55-865-052-A

E. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
122VU	ELEC/EXT PWR/LT CLT/NOT IN/USE	6XG	X30

Subtask 24-42-55-710-050-A

F. Operational Test
(1) Energize the ground service network
(Ref. AMM TASK 24-42-00-861-001).
(2) On the FWD attendant panel 120RH:

Push the MAIN ON membrane switch.
Make sure that all the entrance and cabin lights come on.

5. Close-up
Subtask 24-42-55-862-050-A

A. Put the aircraft back to its initial configuration.
(1) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).

Subtask 24-42-55-410-050-A

B. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the front panel of the panel 123VU.
(3) Install the Third Occupant seat (Ref. AMM TASK 25-11-41-400-001).
(4) Remove the WARNING NOTICE(S).
(5) Close the access door 121AL.
(6) Remove the access platform(s).

[Rev.10 from 2021] 2026.03.31 23:24:34 UTC