TM 9-4110-256-14
4-21. CIRCUIT BREAKER CB1 TESTING AND REPLACEMENT.
This task covers:
a. Testing
b. Removal
c. Installation
INITIAL SETUP
General Safety Instructions:
Equipment Conditions:
WARNING
disconnected.
High voltage and exposed rotating parts are used in
the refrigeration unit. Personal injury can result if
power is connected.
Materials / Parts:
Lock Washers (2)
Lock Washers (6)
Marker Tags (6)
(1)
Be sure power has been disconnected at the source and remove two bolts (1) and lock washers (2).
Discard lock washers.
(2)
Carefully pull circuit breaker cover (3) out to expose circuit breaker (4) terminals.
(3)
Using multimeter set to measure continuity, check circuit breaker (4) continuity between terminals Al to
A2, B1 to B2, and C1 to C2 with circuit breaker in both ON and OFF position. Continuity should be
indicated only when circuit breaker (4) is in the ON position. If continuity was indicated in the OFF
position or if no continuity was indicated in the ON position, Replace circuit breaker (4).
(4)
If no failure was indicated, carefully push circuit breaker cover (3) into place and install two new lock
washers (2) and bolts (1).
b. Removal.
(1)
Be sure power has been disconnected at the source and remove two bolts (1) and lock washers (2).
Discard lock washers.
(2)
Remove six screws (5), lock washers (6), and circuit breaker cover (3). Discard lock washers.
(3)
Check gasket (7) material for damage. If damaged, notify direct support maintenance to replace it.
NOTE
Terminal hardware is supplied with circuit breaker.
(4)
Tag wire lead terminals (8) and remove six nuts (9), lock washers (10), and wire lead terminals.
4-41