TM 5-4520-241-14
(2) After the armature has been tightened by torquing nut (18), rotate the armature several turns to check for
binding in the fan assemblies.
(3) If a new motor is being installed, cut one black lead and splice in the thermal overload protector using two butt
connectors. Fasten the protector to the motor field with Ty-rap.
8-4.
VENTILATING MOTOR.
a. Test the operation of the ventilating motor by installing the fan and connecting the motor to an AC ammeter in
series with a 120 VAC, 50 or 60 Hz, single phase source.
b. With the motor operating under the fan load, current draw shall not exceed 3.4 amperes. Use a tachometer to
check motor speed. It must be approximately 1,425 rpm when operating at 50 Hz and 1,725 rpm when operating at 60
Hz.
c. Replace the motor if the current draw is too high or the speed is too low. No repair is authorized.
8-5.
FUEL PUMP POWER SUPPLY.
a. Disassembly.
(1) Remove hardware (1, 2, and 3, fig. 8-3) to remove the assembled fuel pump power supply bracket (4) from
the heater case.
(2) If the rectifier is to be replaced, remove nut (5), lock washer (6), and screw (7) to remove rectifier (8).
Unsolder all four wires from the terminal strip (12).
(3) Remove nut (9), lock washer (10), and screw (11) to remove terminal strip (12).
(4) Remove the white lead (13), ray lead (14), and yellow lead (15) from their connecting points. The gray lead
(14) is connected to the lower overheat thermostat, which must be removed from the bulkhead before pulling off the
terminal.
(5) Remove grommet (16). Remove nut (17), lock washer (18), and s rew (19) to remove transformer (20).
c
Unsolder the two red wires (21) from the terminal strip.
b. Cleaning and Inspection.
WARNING
Clean parts in a well-ventilated area. Avoid inhalation of solvent fumes and
prolonged exposure of skin to cleaning solvent. Wash exposed skin thoroughly.
Dry cleaning solvent (fed. spec. P-D-680) used to clean parts is potentially
dangerous to personnel and property. Do not use near open flame or excessive
heat. Flash point of solvent is 100 F (38 C).
8-7
