Mitsubishi Electric FR-D720S SC EC Instruction Manual page 445

Troubleshooting
Fault
When a fault occurs, the inverter trips and a fault signal is output.
Operation Panel
Indication
Name
Description
Check point
Corrective action
Operation Panel
Indication
Name
Description
Check point
Corrective action
FR-D700 SC EC
E.OC1
Overcurrent shut-off during acceleration
When the inverter output current reaches or exceeds approximately 200% of the rated cur-
rent during acceleration, the protective circuit is activated and the inverter trips.
Check for sudden acceleration.
Check that the downward acceleration time is not long in vertical lift application.
Check for output short circuit/ground fault.
Check if the stall prevention operation level is set too high.
Check if the fast-response current limit operation is disabled.
Check that regeneration is not performed frequently. (Check that the output voltage
becomes larger than the V/f reference value at regeneration and overcurrent occurs due
to the high voltage.)
Increase the acceleration time. (Shorten the downward acceleration time in vertical lift
application.)
When "E.OC1" is always lit at starting, disconnect the motor once and start the inverter.
If "E.OC1" is still lit, contact your sales representative.
Check the wiring to make sure that output short circuit/ground fault does not occur.
Lower the setting of stall prevention operation level.
Activate the fast-response current limit operation. (Refer to section 6.2.4).
Set base voltage (rated voltage of the motor, etc.) in Pr. 19 "Base frequency voltage".
(Refer to section 6.4.1.)
E.OC2
Overcurrent shut-off during constant speed
When the inverter output current reaches or exceeds approximately 200% of the rated cur-
rent during constant speed operation, the protective circuit is activated and the inverter
trips.
Check for sudden load change.
Check for output short circuit/ground fault.
Check if the stall prevention operation level is set too high.
Check if the fast-response current limit operation is disabled.
Keep load stable.
Check the wiring to make sure that output short circuit/ground fault does not occur.
Lower the setting of stall prevention operation level.
Activate the fast-response current limit operation. (Refer to section 6.2.4).
Causes and corrective actions
FR-PU04
OC During Acc
FR-PU07
FR-PU04
OC During Dec
FR-PU07
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