TM 5-4520-253-13
TEST VENTILATING AIR MOTOR (CONT)
4.
5.
6.
7.
8.
9.
10.
Disconnect red wire (7) of ventilating air motor (8) from red wire (9) of PC board (10).
Connect ac ammeter (11) in series with red wires (7 and 9).
Plug in power cable at POWER RECEPTACLE and position HEATER-OFF-FAN switch to FAN.
With motor (8) operating under fan load, current draw shall not exceed 5.4 amperes.
Use tachometer to check motor speed.
Motor speed should be 2950 rpm at 50 Hz and 3500
rpm at 60 Hz.
If current draw is too high or motor speed is too low, test motor capacitor (12) in accordance
with TEST VENTILATING AIR MOTOR CAPACITOR, TESTING, page 4-60. If capacitor is
good and motor (8) still does not meet requirements, replace motor. No repair is authorized.
If motor (8) does not start when HEATER-OFF-FAN switch is turned to FAN, use tool and
manually spin fan blades. If motor starts, replace capacitor and then follow above testing
procedure.
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