TM 9-4120-360-14
Section XXII. FAN MOTOR
5.111 Description
The fan motor is double shafted to drive the evaporator fan impeller at one end, and the condenser fan impeller at the
other. The motor contains two sets of windings, which permits two-speed operation. The speed, using one set of
windings, is 1725 rpm. When the second set of windings is switched on, the speed is doubled to 3450 rpm. The motor
contains permanently lubricated anti-friction bearings, and is protected against overheating by a thermal overload
protector.
5.112. Removal (See figure 5-13).
Remove the fan motor in accordance with the following procedure:
Disconnect power from the air conditioner before performing maintenance work on the electrical
system. The voltage used can be lethal.
a. Remove the evaporator intake grille by turning the six cam-lock studs 1/4-turncounter-clockwise to unlock,
then lift off the grille.
b. Remove the air falter retaining strip by removing two screws. Remove strip and air falter.
c. Remove eight screws from the evaporator fan inlet ring, and remove the inlet ring.
d. Loosen two setscrews in the hub of the evaporator fan impeller, and pull the impeller off the motor shaft. If the
impeller cannot be pulled off manually, thread two 5116-18 screws into the threaded holes in the face of the hub to use as
jackacrews or to attach a wheel puller.
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e. Remove eight screws and lock washers from the rim of the condenser fan guard, and remove the guard.
f. Loosen the two setscrews in the hub of the condenser fan impeller, and pull the impeller off the motor shaft. If
difficulty is encountered, the two 1/4-20 threaded holes in the faces of the hub can be used to attach a wheel puller.
g. Unscrew but do not remove four screws attaching the baffle (figure 5-13) to the mounting assembly. Remove
the baffle, with screws and spacers attached, as a unit.
h. Disconnect wiring harness plug, P9, from the receptacle, J9, on the motor junction box.
i. Carefully remove two socket head capscrews, lock washers, flat washers and bushings which secure the
motor mounting feet to the mounting crossbar.
j. Remove four self-locking nuts, flat washers, bushings and flat-head screws from the corners of the motor
mounting flange.
k. Carefully withdraw the motor through the condenser fan shroud.
5.113. Inspection/Test
Inspect the motor as follows:
a. Spin the rotor, and listen for bearing noise indicating rough operation. If present, turn the shaft slowly
backward and forward by hand to feel roughness. Replace bearings if roughness is evident.
b. Grip the rotor shaft, and attempt to pull it in and out to check for end-play. If there is, replace load spring or
shim(s).
