TM 9-4120-357-14
b. Removal (See figure 4-15.) Remove the evaporator fan and motor assembly from the air conditioner as follows:
WARNING
Disconnect power from the air conditioner before performing maintenance work
on the electrical system. The voltages used can be lethal.
(2) Remove four screws and eight washers from the flange of each inlet ring (12 & 13, figure 4-15) and remove
the inlet rings.
(3) Remove four capscrews and washers from the motor support (2). Carefully lift out fan and motor assembly.
(1) Loosen two socket-head setscrews in the hubs of both centrifugal fan impellers (10,11), and slide the cen-
trifugal fan impellers from the motor shaft. Use two 5/16-18 screws as jackscrews in the hub flange if the centrifugal fan
impellers are difficult to remove. Tape keys (14,15) to the shaft to prevent loss.
(2) Remove four capscrews, washers and lock washers from the support plate (2). Remove the motor.
(3) Remove four screws from each end bell (4,9). Carefully remove end bells. Use a brass drift, tapping it
around the circumference of each end bell to break it loose from the motor stator (3) if necessary.
CAUTION
Do not clean bearings with solvent. Bearings are permanently lubricated and
sealed at time of manufacture.
(5) If bearings are to be re-used, place them in clean plastic bags or wrap them in grease-proof paper until
needed.
(6) Remove four screws from the corners of the junction box (16). Carefully lift the junction box away from mo-
tor stator (3).
(7) Remove two screws from the thermal overload protector (17). Tag wires for identification, and disconnect
them from overload protector.
(8) Remove four screws. Remove the receptacle (18) from the junction box (16).
d. Inspection/Test. Inspect/test the evaporator fan and motor assembly as directed in the following steps:
(1) Inspect the impellers for dents, nicks, gouges or deformation. Replace them if damage is sufficient to cause
imbalance or interference.
(2) Inspect the motor shaft for end-play, side-play or runout, and listen for clicking or grinding noises when being
rotated by hand. If runout exceeding 0.001-inch (0.025mm) TIR exists, replace the rotor. If other indications are found,
replace the bearings.
(3) Using an ohmmeter or continuity tester, check continuity at receptacle (18, figure 4-15) from points A to B, B
to C and A. If continuity does not exist in one or more pairs, remove the thermal overload protector and test each pair of
contacts for continuity. If continuity does not exist in one or more pairs, replace the thermal overload protector. Check
continuity of each pair of winding leads, and of each lead to the motor frame. If continuity does not exist in one or more
pairs, or if continuity does not exist between any lead and the motor frame, replace the motor.
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