TM 9-4120-357-14
4-45. Maintenance of Condenser Fan and Motor.
a. Access. In
order to
obtain access to
the condenser fan and motor assembly, the front access panel, junction box
and control panel, and the rear fan guard must be removed. Proceed in accordance with the following directions.
(1) Unscrew four panel fastener screws in the front access panel. Remove the panel.
WARNING
Disconnect power from the air conditioner before performing maintenance work
on the electrical system. The voltages used can be lethal.
(2) Disconnect all electrical plugs from their receptacles on
the junction box and control panel assembly.
(3) Loosen the small setscrew in
the core end fitting (14, figure 4-3) and slide the end fitting off of
the cable core.
(4) Remove two screws and washers from the hold-down clamp (16) near the top of the junction box. Remove
the clamp. Place the flexible cable to one side, out of the way.
(5) Remove six screws (7) on the left side of the casing, and remove two screws (8) and washers (9) from the
lower right corner bracket of the junction box. Remove the junction box and control panel assembly from the air condi-
tioner being careful to avoid kinking capillary tube from thermostat to sensing bulb. Store in a safe place.
(6) With fabric cover rolled up
and tied in
place, remove six screws from the looped ends of
the condenser fan
guards. Remove the guard.
b. Removal. Remove the condenser fan and motor from the air conditioner as
directed in
the following steps:
(1) Loosen two setscrews in
the hub of
the impeller (13, figure 4-4), and pull the impeller from the motor shaft.
Use a wheel puller if necessary. Tape key to motor shaft to prevent loss.
(2) Disconnect electrical plug, P2, from receptacle (3, figure 4-4) on
motor junction box (4).
(3) Remove four capscrews, washers and lock washers from the bottom of the motor mounting assembly, and
carefully remove the motor through the fan opening in back of the air conditioner. Identify for position, and retain shims
(11 & 12) if motor is to be re-installed.
c. Inspection/Test. Inspect and test the condenser fan motor as
follows:
(1) Inspect the motor and impeller for obvious damage, such as broken, gouged or bent parts. Replace the im-
peller if it is damaged.
(2) Check the shaft for freedom of
rotation and excessive side- or
end-play. Replace the bearings if
they are
rough or noisy.
(3) Using a surface plate and dial indicator, measure shaft runout. The OD of the shaft shall not indicate more
than 0.001 inch) (0.025 mm) TIR runout. Replace the rotor if runout is excessive.
(4) Using an
ohmmeter or
continuity tester, check continuity at
receptacle, J2
(3, figure 4-4). Check A to B, B to
C and C to A. Also check from each point to the motor frame or common ground. Continuity should be indicated in all
point-to-point checks, but should not be indicated from any point to ground.
d. Disassembly. Disassemble the condenser fan motor only to
the extent necessary lo
effect repairs. Proceed as
(1) Remove six screws from each end bell (1 & 10), and carefully remove end bells from the motor stator (5).
Use a brass drift and light hammer to tap around the edge of the end bell if difficult to remove.
(2) Withdraw the rotor (7) from the stator (5) and pull bearings (6) from end bell bearing cavities with a
bearing
puller if necessary.
4-54