Mitsubishi City Multi P500YEM-A, Service Handbook, Page: 79 / 145

–78–
Remedies for a Main Power Breaker Trip
3)
Check item Symptom Remedy
[5]
Check the in-
verter circuit
trouble. 1
Check to see if the IPM screw
terminal is securely tightened.
3
Check the resistances be-
tween each terminal of IPM.
Refer to
¶
[1] (5) 5) for de-
tails on IPM troubleshooting.
2
Check the exterior of the IPM.
1
Screw terminal is loose. · Check all IPM screw terminals and tighten
them.
2
IPM is cracked due to swelling.
3
Resistance error between each
terminal of IPM.
4
All normal for items
1
-
3
above
· IPM replacement
Check the operation in [3] or [4] after
replacing the IPM.
In the case of an output voltage
unbalance or error recurrence
Replace the G/A board
In the case of an output voltage unbalance
or error recurrence after replacement:
Replace the INV board
· IPM replacement
Check the operation in [3] or [4] after
replacing the IPM.
In the case of an output voltage
unbalance or error recurrence:
Replace the G/A board
In the case of an output voltage unbalance
or error recurrence after replacement:
Replace the INV board
· IPM replacement
In the case of an output voltage unbalance
or error recurrence after replacement:
Replace the G/A board
In the case of an output voltage unbalance
or error recurrence after replacement:
Replace the INV board
Check item
[1]
[2]
[3]
Symptom Remedy
Perform Meg check between the
terminals in the power terminal block
Tba.
Turn on the power again and check
once more.
Turn on the outdoor unit and check
that it operates normally.
1
Zero to several ohm, or Meg
failure.
1
Operates normally without tripping
the main breaker.
2
Main power breaker trip
1
Main power breaker trip
2
No remote control display
Check each part in the main inverter circuit.
* Refer to “Simple Checking Procedure for
individual component of main inverter circuit”.
a. Diode Stack
b. IPM
c. Rush current protection resistor
d. Electromagnetic relay
e. DC reactor
f. Noise filter
a. There is a possibility that the wiring shorted
momentarily.
Trace the short and repair.
b. If item a. above is not the case, there is a
possibility that there was a compressor
failure.
· A compressor ground fault can be suspected.
Go to (2)-[2].