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Failure Diagnosis
Failure Diagnosis of Inverter Unit
Caution
When performing an inspection or replacement, make sure to start working after the high
voltage danger indication light (red) has been turned off.
Capacitor discharge takes approx. 5 minutes.
Electric component layout of inverter unit
Left section of left side
of refrigeration unit
(1) When the refrigeration unit stopped by activation of the ground fault interrupter.
Possible cause is as follows. Check all of the following causes.
Cause
Compressor failure
Failure of an electric
component other than
compressor
Be sure to eliminate the cause of the failure before supplying the power (turning the ground fault
Caution
interrupter ON).
refrigeration unit
High voltage danger
indication light
Reactor
INV-F PCB
Power terminal block
Control terminal block
Heatsink temperature sensor
Method of Checking
1) Check insulation resistance between each phase
of compressor and case.
2) Less than 1 MΩ indicates motor failure.
1) Check the winding resistance of the compressor.
2) 0.15 Ω to 0.19 Ω (Ambient temperature 25°C)
indicates no problem.
1) Check the insulation resistance between each
terminal of the inverter-PCB and ground (G
terminal).
2) Less than 1 MΩ indicates insulation failure of the
inverter-PCB.
Check if any fused attachment or change of color
exists on the electromagnetic contactor.
1) Check if any anomalies exist in the resistance
value of diode.
2) Refer to "(4) Diode failure diagnosis".
1) Check if any anomalies exist in the IPM resistance
value of the INV-H PCB.
2) Refer to "(3) IPM (transistor)failure diagnosis".
Left side of
FM1
(Box back side)
INV-M
PCB
FC3-
PCB
INV-H PCB
From top F1, F2
Diode
F7
Front of
refrigeration unit
Operation
switch
CR2A-PCB
From left 1X1, 1X2, 1X3
Method of Action
Replace the compressor
Replace the compressor
Replace the inverter-PCB
Replace the electromagnetic
contactor.
Replace the diode.
Replace the INV-H PCB.
48
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