Hitachi UTOPIA RAS-4HVRP2E - Checking Procedure for the Inverter PCB

10 Troubleshooting
Checking procedure for main parts
SMGB0136 rev.0 - 07/2021
313
10
10.4.1.5 Checking procedure for the inverter PCB
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Fault diagnosis of DC fan motor
When Alarm 04 or 53 is indicated and some PCB is faulty, it may have been caused due to faulty fan motor. If PCB
operates with a faulty fan motor, it can be damaged. Therefore, check the fan motor as explained below when replacing
the faulty PCB.
! CAUTION
• Turn OFF main power before start working.
• Working and checking with the power ON may disturb correct diagnosis and may result in failure.
Procedure in case of error diagnosis
1 Disconnect the fan motor connectors from its respective PCB and remove the propeller fan. Then, turn the fan motor
shaft by hand.
Normal Fan motor shaft turns smoothly
Faulty
No continuous rotary torque movement felt when turning the motor by hand. This occurs because the
internal magnet of the fan motor breaks the movement when the internal electronic circuit of the fan
motor has a short-circuit fault.
2 Measure the fan motor resistance:
Measurement procedure
1 Ensure that the fan motor connectors have been correctly disconnected as explained above.
2 Connect the black test lead of the tester to the black wire pin of the fan motor connector.
3 Connect the red test lead to the wire connector pin to be checked.
Results
Normal Observed values will be close to the normal values in the table below.
Faulty
Observed values will be deviated from the normal values in the table below. (Generally, an open-
circuitfaultshows∞,andashort-circuitfaultshowsseveralΩ-kΩ).
Internal electronic circuit fault of the fan motor including short-circuit and breakage can be checked.
Motor model
Wire colour for checking (Normal value)
Red-black White-black Yellow-black Blue-black
RRMB4415 13.5-14.4kΩ 1MΩorgreater 225-226kΩ 1MΩorgreater
SIC-68FV-D851-18 1MΩorgreater 26-50kΩ 168-312kΩ 1MΩorgreater
SIC-68FV-D851-17
1MΩorgreater 42-78kΩ 168-312kΩ 1MΩorgreater
SIC-81FV-D8138-1
Values are shown for referential purpose. While actual values may vary depending on the type of the tester, any tester
canbeusedtodetermineanyshort-circuitorbreakagebasedon∞orseveralΩor0Ωor∞.