Checking code Meaning, detecting method Cause Checking method & Countermeasure
1If VDC 150 V is detected
just before the inverter
starts.
2If VDC 400 V is detected
just before the inverter
starts.
3If the voltage of the INV
board’s sensor circuit input is
what it should not normally
be.
VDCsensor/
circuit trouble
4200 •Check if an instantaneous power
failure or power failure, etc. has oc-
curred.
•Check if the voltage is the rated
voltage value.
Check 1, the connections, 2, contact
at the connectors, 3 tightening
torque at screw tightened portions,
4, wiring polarities, 5, for broken
wires, and 6, for grounding in the fol-
lowing wiring.
TB1 ~ DS ~ POWER Board ~ 52C
~ R1 ~ DCL~C1 ~ IPM ~ G/A
Board (F1) ~ CNDC1 ~ CNDC2
wiring
✻Check if the wiring polarities are as
shown on the electric wiring dia-
gram plate.
To judge failure of R1, go to “Indi-
vidual Parts Failure Judgment Meth-
ods.”
To judge failure of the 52C, go to
“Individual Parts Failure Judgment
Methods.”
To judge failure of the DS, go to “In-
dividual Parts Failure Judgment
Methods.”
To judge failure of the DCL, go to
“Individual Parts Failure Judgment
Methods.”
If none of the items in 1) to 6) is ap-
plicable, and if the trouble reappears
even after the power is switched on
again, replace the INV board, (when
replacing the circuit board, be sure
to connect all the connectors, etc.
securely)
1) Power supply voltage is abnormal.
2) The wiring is defective.
3) The rush current prevention resis-
tors (R1) are defective.
4)The electromagnetic contactor
(52C) is defective.
5) The diode stack (DS) is defective.
6) The reactor (DCL) is defective.
7) The INV board is defective.
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