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Causes and corrective actions
(4) Fault
When a fault occurs, the inverter trips and a fault signal is output.
Operation Panel
Indication
E.OC1
FR-PU04
FR-PU07(-01)
OC During Acc
Name
Overcurrent trip during acceleration
Description
When the inverter output current reaches or exceeds approximately 170% of the rated current during
acceleration, the protective circuit is activated to stop the inverter output.
Check point
Check for sudden acceleration.
Check that the downward acceleration time is not long in vertical lift application.
Check for output short circuit.
· Check if the stall prevention operation level is set too high.
· Check if the fast-response current limit operation is disabled.
Check that the regeneration is not performed frequently. (Check that the output voltage becomes
larger than the V/F reference voltage at regeneration and overcurrent occurs due to the high
voltage.)
Corrective action
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 does not occur.
· Lower the setting of stall prevention operation level. (Refer to page 74.)
· Activate the fast-response current limit operation.
Set base voltage (rated voltage of the motor, etc.) in Pr. 19 Base frequency voltage. (Refer to page 82.)
Operation Panel
Indication
E.OC2
FR-PU04
FR-PU07(-01)
Stedy Spd OC
Name
Overcurrent trip during constant speed
Description
When the inverter output current reaches or exceeds approximately 170% of the rated current during
constant speed operation, the protective circuit is activated to stop the inverter output.
Check point
Check for sudden load change.
Check for output short circuit.
· Check if the stall prevention operation level is set too high.
· Check if the fast-response current limit operation is disabled.
Corrective action
Keep load stable.
Check the wiring to avoid output short circuit.
· Lower the setting of stall prevention operation level. (Refer to page 74.)
· Activate the fast-response current limit operation.
Operation Panel
Indication
E.OC3
FR-PU04
FR-PU07(-01)
OC During Dec
Name
Overcurrent trip during deceleration or stop
Description
When the inverter output current reaches or exceeds approximately 170% of the rated inverter current
during deceleration (other than acceleration or constant speed), the protective circuit is activated to
stop the inverter output.
Check point
Check for sudden speed reduction.
Check for output short circuit.
Check for too fast operation of the motor's mechanical brake.
· Check if the stall prevention operation level is set too high.
· Check if the fast-response current limit operation is disabled.
Corrective action
Increase the deceleration time.
Check the wiring to avoid output short circuit.
Check the mechanical brake operation.
· Lower the setting of stall prevention operation level. (Refer to page 74.)
· Activate the fast-response current limit operation.
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