TM 9-4120-388-14
b. Fan inspection (Installed)
This task consists of:
a. Motor Test (Installed)
c. Removal
d. Clean
e. Installation
INITIAL SET-UP:
Equipment Condition
Radio Frequency Filter removed (4-44).
Evaporator fan and evaporator fan inlet bell removed (4-62).
Rear panel removed (4-31 ).
Conditioned air filter removed (4-33).
Special tool:
6 inch(152 mm) long arm hex "L" type key (hex head wrench)
Personnel required: 2
Disconnect input power to the air conditioner before performing any internal
maintenance. Voltages used can KILL. Shutting the unit off at the control panel
does not disconnect unit power.
a. Motor test (installed).
(1)
Be sure that power has been disconnected.
(2)
Check motor for rotational freedom by spinning fan. If there is any stiffness or binding, notify your supervisor.
Check motor bearings for shaft end play. If there is excessive end play, notify your supervisor.
(3)
(4)
Electrically test motor as follows:
(a) Disconnect motor cable connector (P12).
(b) Use a multimeter set on lowest OHMS scale to check continuity between pins A and B, A and C, and
B and C in motor connector (J1 2). If there is no continuity between any pair of pins, the motor winding
is open. Replace motor.
(c) Use a multimeter set on high OHMS scale to test stator insulation by checking between each pin in
connector (A, B, and C) and motor housing. A reading of less than 500,000 ohms indicates insulation
failure. Replace motor.
NOTE
If all of the above inspections and tests are satisfactory, but the motor will still not operate
properly, notify direct support maintenance, who may desire to make further tests before
the motor is removed.
b. Fan inspection (installed).
(1) Check fan for dents, bent or loose fan blades, and that hub is securely attached. Replace if damaged.
(2) Check inlet bells for dents or any distortion that would cause interference with fans. Replace if damaged.
