78
1. MCCB trips.
Is MCCB of suitable rating?
YES
Is input/output terminal wiring correct?
YES
Does a ground fault exist in main circuit wiring?
YES
MCCB failure or inverter malfunction
(Contact Matsushita).
2.
Motor has over temperature
Is the motor overloaded?
YES
NO
Are V/F characteristics
correct?
NO
YES
Is the load factor reduction
correct for continuous
operation at low frequency?
NO
YES
Does an open phase exist in
the output of the inverter?
YES
Inverter malfunction
(Contact Matsushita).
Troubleshooting (2)
• Reduce the load factor.
• Increase the motor capacity.
(If the motor capacity exceeds the inverter
capacity, increase the latter as well).
Reduce V/F characteristics.
• Reduce the motor load factor, or carry out
forced cooling.
• Increase the motor capacity.
(If the motor capacity exceeds the inverter
capacity, increase the latter as well.)
• Check if output frequency can be increased
for use.
