Chapter 13. Troubleshooting & Maintenance
13.2 Fault Remedy
Protective
functions Cause Remedy
CAUTION:
When an overcurrent fault occurs, operation must be started after the cause is removed to
avoid damage to IGBT inside the inverter.
Overcurrent z Accel/Decel time is too short compared to
the GD2 of the load.
z Load is greater than the inverter rating
z Inverter output is issued when the motor is
free running.
z Output short circuit or ground fault has
occurred.
z Mechanical brake of the motor is operating
too fast.
) Increase the Accel/Decel time.
) Replace the inverter with appropriate
capacity.
) Resume operation after stopping the motor
or use H22 (Speed search) in Function group
2.
) Check output wiring.
) Check the mechanical brake.
Ground fault
current
z Ground fault has occurred at the output
wiring of the inverter
z The insulation of the motor is damaged due
to heat.
) Check the wiring of the output terminal.
) Replace the motor.
Inverter
overload
Overload trip
z Load is greater than the inverter rating.
z Inverter capacity is incorrectly selected.
z Torque boost scale is set too large.
) Upgrade the capacity of motor and inverter
or reduce the load weight.
) Select correct inverter capacity.
) Reduce torque boost scale.
Heat sink
overheat
z Cooling system has faults.
z An old cooling fan is not replac ed with a
new one.
z Ambient temperature is too high.
) Check for alien substances clogged in the
heat sink.
) Replace the old cooling fan with a new one.
) Keep ambient temperature under 40°C.
Output Phase
loss
z Faulty contact of magnetic switch at output
z Faulty output wiring ) Make connection of magnetic switch at
output of the inverter securely.
) Check output wiring.
Cooling fan
fault
z An alien substance is clogged in a
ventilating slot.
z Inverter has been in use without changing a
cooling fan.
) Check the ventilating slot and remove the
clogged substances.
) Replace the cooling fan.
Over voltage
z Decel time is too short compared to the
GD2 of the load.
z Regenerative load is at the inverter output.
z Line voltage is too high.
) Increase the Decel time.
) Use Dynamic Brake Unit.
) Check whether line voltage exceeds its
rating.
Low voltage
z Line voltage is low.
z Load larger than line capacity is connected
to line (ex: welding machine, motor with high
starting current connected to the commercial
line).
z Faulty magnetic switch at the input side of
the inverter.
) Check whether line voltage is below its
rating.
) Check the incoming AC line. Adjust the line
capacity corresponding to the load.
) Change a magnetic switch.
Electronic
thermal
z Motor has overheated.
z Load is greater than inverter rating.
z ETH level is set too low.
z Inverter capacity is incorrectly selected.
z Inverter has been operated at low speed for
too long.
) Reduce load weight and operating duty.
) Change inverter with higher capacity.
) Adjust ETH level to an appropriate level.
) Select correct inverter capacity.
) Install a cooling fan with a separate power
supply.
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