Removal of the TR 1 and TR 2 Contactors and the TR 2/AC Service Bus Normal Supply Contactor

TASK 24-32-55-000-001-A
Removal of the TR 1 and TR 2 Contactors and the TR 2/AC Service Bus Normal Supply 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: 212
FIN: 14PU
FIN: 5PU1
FIN: 5PU2

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	CAP - BLANKING
No specific	AR	WARNING NOTICE(S)
FOR [5PU1] (CNTOR-TR 1)
FOR [5PU2] (CNTOR-TR 2)
No specific	AR	CAP - BLANKING

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
212	COCKPIT
121AL

C. Referenced Information

REFERENCE	DESIGNATION
TASK 25-11-41-000-001-A	Removal of the Third Occupant Seat
Transformer Rectifier Contactors - Location ** ON A/C NOT FOR ALL
Transformer Rectifier Contactors - Location ** ON A/C NOT FOR ALL
TR 2/AC Service Bus Normal Supply Contactor ** ON A/C NOT FOR ALL
TR 1 and TR 2 Contactors ** ON A/C NOT FOR ALL
TR 2/AC Service Bus Normal Supply Contactor ** ON A/C NOT FOR ALL
TR 1 and TR 2 Contactors ** ON A/C NOT FOR ALL
FOR [13PN] (MODULE-DC BUS 1 CNTOR)
TASK 24-61-58-000-001-A	Removal of the DC Bus 1 Contactor Module
FOR [14PN] (MODULE-DC BUS 2 CNTOR)
TASK 24-61-58-000-002-A	Removal of the DC Bus 2 Contactor Module
FOR [20XX] (MODULE- AC SVCE BUS CNTOR)
TASK 24-42-58-000-001-A	Removal of the AC Service Bus Contactor Module
FOR [5PU1] (CNTOR-TR 1)
FOR [5PU2] (CNTOR-TR 2)
TR 1 and TR 2 Contactors ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 24-32-55-010-050-A

A. Get Access

Transformer Rectifier Contactors - Location ** ON A/C NOT FOR ALL

(1) Remove the Third Occupant seat (Ref. AMM TASK 25-11-41-000-001)
(2) In the cockpit:

(a) FOR [14PU] (CNTOR-TR 2/AC SVCE BUS NORM SPLY)
remove the front panel of the panel 123VU.

(b) FOR [5PU1] (CNTOR-TR 1), [5PU2] (CNTOR-TR 2)
on the left lower side of the panel 120VU, remove the access door.
(3) Put the ACCESS PLATFORM 1M (3 FT)-ADJUSTABLE in position on the access door 121AL.
(4) Open the access door 121AL.

Subtask 24-32-55-860-050-A

B. Safety Precautions
(1) Make sure that the external power connector is not connected to the aircraft EXT PWR receptacle.
(2) Put warning notice(s) in position on the access door 121AL to tell persons not to connect the external power connector to the aircraft EXT PWR receptacle.
(3) In the cockpit, on the ELEC panel 35VU, make sure that these pushbutton switches are released:

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

(4) In the cockpit, put WARNING NOTICE(S) in position to tell persons not to operate the pushbutton switches on these overhead panels:

21VU (EMER ELEC PWR section),
25VU (APU section),
35VU (ELEC).

4. Procedure
Subtask 24-32-55-020-050-A ** ON A/C NOT FOR ALL

A. Removal of the Contactor

CAUTION: REMOVE THE CONTACTOR ONLY AND NOT THE BASE OR THE MODULE WHERE THE WIRES ARE CONNECTED.

(1) Disconnect the electrical connector (9).
(2) Put CAP - BLANKING on the disconnected electrical connector (9) and the electrical receptacle (8).
(3) Loosen the captive screws (7).

NOTE: Do not remove the captive screws (7) and the spring washers from the contactor (10).

(4) Remove the contactor (10).

Subtask 24-32-55-020-053-A ** ON A/C NOT FOR ALL

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

B. Removal of the Contactor Base

NOTE: The removal of the contactor base is necessary only if it is damaged.

(1) Remove the nuts (11) and the washers (12).
(2) Disconnect the cables (13) from the contactor base (1).
(3) Remove the nuts (6) and the washers (5).
(4) Remove the jumper (4) from the contactor base (1) and from the adjacent contactor base.
(5) Remove the screws (3) and the washers (2).
(6) Remove the contactor base (1).

Subtask 24-32-55-020-050-B ** ON A/C NOT FOR ALL

CAUTION: REMOVE THE CONTACTOR ONLY AND NOT THE BASE OR THE MODULE WHERE THE WIRES ARE CONNECTED.

C. Removal of the Contactors

TR 2/AC Service Bus Normal Supply Contactor ** ON A/C NOT FOR ALL

(1) FOR [5PU1] (CNTOR-TR 1), [5PU2] (CNTOR-TR 2)

TR 1 and TR 2 Contactors ** ON A/C NOT FOR ALL

(a) Disconnect the electrical connector (4).
(b) Put CAP - BLANKING on the disconnected electrical connector (4) and the electrical receptacle (2).
(c) Loosen the captive screws (3).

NOTE: Do not remove the captive screws (3) and the spring washers from the contactor (5).

(d) Remove the contactor (5).

Subtask 24-32-55-020-053-B ** ON A/C NOT FOR ALL

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

D. Removal of the Modules 20XX, 13PN and 14PN

NOTE: The removal of the modules is necessary only if they are damaged.

(1) FOR [20XX] (MODULE- AC SVCE BUS CNTOR)

Remove the module 20XX (Ref. AMM TASK 24-42-58-000-001).

(2) FOR [13PN] (MODULE-DC BUS 1 CNTOR)

Remove the module 13PN (Ref. AMM TASK 24-61-58-000-001).

(3) FOR [14PN] (MODULE-DC BUS 2 CNTOR)

Remove the module 14PN (Ref. AMM TASK 24-61-58-000-002).

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