TM 9-4120-357-14
e. Assembly. Assemble the evaporator fan and motor assembly in accordance with the following instructions: (see
(1) Install receptacle (18) in junction box (16). Secure with fours screws.
(2) Install the thermal overload protector (17) in
the junction box (16), and solder connections. (See figure 4-16,
Wiring Diagram.) Secure it to the junction box with two screws.
(3) Install the junction box (16, figure 4-15) on
the motor stator (3) and secure it
with four screws.
(4) Slide a bearing (6) and two load springs (8) onto fan end of rotor (5), and slide a bearing onto other end of
rotor. Insert rotor into motor frame.
(5) Carefully install the end bells over the ends of
rotor and bearings, aligning screw holes in
end bells and
frame. Secure with four screws at each end.
NOTE
Balance fans and motor as an assembly in a two plane running balance to a
maximum allowable unbalance of 0.03 ounce inches per plane at the high
operating speed of the motor. Balancing weights shall be tight on fans and shall
not be capable of falling off due to fan rotation.
(6) Orient the motor support (2) with the two nut plates forward, and attach the motor with its electrical recepta-
cle facing forward. Secure with four capscrews, lock washers and flat washers.
CAUTION
The right and left centrifugal impellers are mirror images of each other. Make that
each is installed on the correct end of the motor. Looking into the open ends of
the impellers, the right-hand one must have the blades angled with the leading
(outer) edge clockwise from the trailing edge.
(7) Align keyways, and press impellers onto motor shaft. Surface of hub should be flush with end of motor shaft.
Tighten setscrews in the hub of each impeller. Then install fan and motor assembly in air conditioner.
f. Installation. Install the evaporator fan and motor assembly in air conditioner as follows:
(1) Position the assembly in the air conditioner, and secure with two screws and flat washers through the casing
partition into the nut plates of the support, finger tight. Install two screws and flat washers through the upper flange of the
support into the nut plate of the casing, finger tight. Tighten all four screws.
(2) Install inlet rings (12 &
13, figure 4-15) through holes in
air intake plenums. Secure with four screws and
eight washers through the flange of each inlet ring.
(3) Check clearances between impellers and inlet rings, and tighten capscrews through motor support plate.
(4) Connect electrical plug, P15, to the receptacle on the motor. Connect power to the air conditioner, turn the
mode selector switch to VENTILATE, and check the operation of the fan and motor assembly. If airflow is low or non-
existent, remove the assembly and interchange impellers. If rubbing, grating or binding is evident, adjust clearance as
necessary.
(5) Position the top panel on the air conditioner. Secure it with 31 screws through the top and rear flange.
(6) Position the evaporator air discharge grille on
the air conditioner. Secure it
with 16
screws and washers.
(7) Position the two evaporator air intake grilles on
the air conditioner. Secure each with 12
screws and wash-
ers.
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