Check Method Of Dc Fan Motor - Mitsubishi Electric PUMY-P250YBM Technical & Service Manual

Check method of DC fan motor (fan motor/outdoor multi controller circuit board)
1. Notes:
· High voltage is applied to the connector (CNF1, 2) for the fan motor. Pay attention to the service.
· Do not pull out the connector (CNF1, 2) for the motor with the power supply on.
(It causes trouble of the outdoor multi controller circuit board and fan motor.)
2. Self check
Symptom: The outdoor fan cannot rotate.
Fuse check
Check the fuse (JP50) on outdoor
multi controller circuit board.
Did the fuse blow?
No
Wiring contact check
Contact of fan motor connector
(CNF1, 2)
Is there contact failure?
No
Power supply check (Remove the connector (CNF1, 2))
1 While the breaker is OFF, disconnect the compressor wirings (U/V/W) from the outdoor power circuit board.
2 While the breaker is OFF, disconnect the fan motor connector CNF1, 2.
3 When 5 minutes have passed since turning ON the breaker, turn SW7-1 ON.
4 Check the voltage of the outdoor multi controller circuit board.
Measure the voltage in the outdoor controller circuit board.
TEST POINT 1: V (between 1 (+) and 4 (−) of the fan connector): 310–340 VDC (3-phase)
DC
: V (between 1 (+) and 4 (−) of the fan connector): 290–330 VDC (when PAM stops),
DC
TEST POINT 2: V (between 5 (+) and 4 (−) of the fan connector): V
CC
TEST POINT 3: V (between 6 (+) and 4 (−) of the fan connector): V
CC
Is the voltage normal?
No
Replace the outdoor multi
controller circuit board.
Check the operation.
Fail
Replace the defective fan motor.
Note: Turn SW7-1 OFF after the troubleshooting completes.
The fan sometimes starts on-off cycle operation during low-load operation or cooling at low ambient temperature.
It is not abnormal; the operation ensures reliability of the product.
OCH760
Disconnect the FAN motor
Yes
connector and measure the
resistance of connector pins.
Refer to "8-6. HOW TO
CHECK THE PARTS".
Yes
Correct the wiring.
Yes
Replace the defective fan motor.
Check the operation of fan.
Replace the outdoor
multicontroller circuit board.
OK
Complete.
Is the fan motor normal?
No
Replace the outdoor multi controller circuit
board (MULTI.B.) and the defective fan motor.
380 VDC (when PAM is operating) (Single phase)
15 VDC
CC
0–6.5 VDC
CC
Yes
OK
Fail
98
Yes
Replace the outdoor multi
controller circuit board (MULTI.B.).
Complete.