Mitsubishi Electric FR-A700 Instruction Manual page 729

Troubleshooting
Major fault
When the protective function is activated, the inverter output is shut off and an alarm is output.
Operation Panel
Indication
Name
Description
Check point
Corrective action
Operation Panel
Indication
Name
Description
Check point
Corrective action
FR-A700 EC
E.OC1
Over current shut-off during acceleration
When the inverter output current reaches or exceeds approximately 220% of the rated cur-
rent during acceleration, the protective circuit is activated to stop the inverter output.
1) Check for sudden acceleration.
2) Check that the downward acceleration time is not long in vertical lift application.
3) Check for output short circuit.
4) Check that stall prevention operation is correct.
5) Check that the regeneration is not performed frequently. (Check that the output voltage
becomes larger than the reference voltage at regeneration and over current due to
increase in motor current occurs.)
6) Check that the power supply for RS-485 terminal is not shorted. (under vector control)
1) Increase the acceleration time. (Shorten the downward acceleration time in vertical lift
application.)
2) 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.
3) Check the wiring to make sure that output short circuit does not occur.
4) Perform a correct stall prevention operation. (Refer to section 6.7.4.)
5) Set base voltage (rated voltage of the motor, etc.) in Pr. 19 "Base frequency voltage".
(Refer to section 6.9.1.)
6) Check RS-485 terminal connection. (under vector control)
E.OC2
Over current shut-off during constant speed
When the inverter output current reaches or exceeds approximately 220% of the rated cur-
rent during constant speed operation, the protective circuit is activated to stop the inverter
output.
1) Check for sudden load change.
2) Check for output short circuit.
3) Check that stall prevention operation is correct.
4)Check that the power supply for RS-485 terminal is not shorted. (under vector control)
1) Keep load stable..
2) Check the wiring to avoid output short circuit.
3) Check that stall prevention operation setting is correct. (Refer to section 6.7.4.)
4) Check RS-485 terminal connection. (under vector control)
Causes and corrective actions
FR-PU04
OC during Accs
FR-PU07
FR-PU04
Stedy Spd OC
FR-PU07
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