Mitsubishi Electric FR-A700 Series Instruction Manual page 140

(4) Major fault
When the protective function is activated, the inverter output is shut off and an alarm is output.
Operation Panel
Indication
Name Overcurrent shut-off during acceleration
When the inverter output current reaches or exceeds approximately 220% of the rated current during
Description
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 the Pr. 3 Base frequency setting is not 60Hz when the motor rated frequency is 50Hz.
Check point
5. Check that stall prevention operation is correct.
6. Check that the regeneration is not performed frequently. (Check that the output voltage becomes
7. Check that the power supply for RS-485 terminal is not shorted. (under vector control)
1. Increase the acceleration time.
2. When "E.OC1" is always lit at starting, disconnect the motor once and start the inverter.
3. Check the wiring to make sure that output short circuit does not occur.
Corrective action
4. Set the Pr. 3 Base frequency to 50Hz. (Refer to page 50.)
5. Perform a correct stall prevention operation. (Refer to
6. Set base voltage (rated voltage of the motor, etc.) in Pr. 19 Base frequency voltage. (Refer to
7. Check RS-485 terminal connection. (under vector control)
Operation Panel
Indication
Name
Overcurrent shut-off during constant speed
When the inverter output current reaches or exceeds approximately 220% of the rated current during
Description
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.
Check point
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.
Corrective action
3. Check that stall prevention operation setting is correct. (Refer to
4. Check RS-485 terminal connection. (under vector control)
Operation Panel
Indication
Name
Overcurrent shut-off during deceleration or stop
When the inverter output current reaches or exceeds approximately 220% of the rated inverter current
Description
during deceleration (other than acceleration or constant speed), the protective circuit is activated to
stop the inverter output.
1. Check for sudden speed reduction.
2. Check for output short circuit.
Check point 3. Check for too fast operation of the motor's mechanical brake.
4. Check that stall prevention operation setting is correct.
5. Check that the power supply for RS-485 terminal is not shorted. (under vector control)
1. Increase the deceleration time.
2. Check the wiring to avoid output short circuit.
3. Check the mechanical brake operation.
Corrective action
4. Check that stall prevention operation setting is correct.(Refer to
5. Check RS-485 terminal connection. (under vector control)
Operation Panel
Indication
Name Regenerative overvoltage shut-off during acceleration
If regenerative energy causes the inverter's internal main circuit DC voltage to reach or exceed the
Description
specified value, the protective circuit is activated to stop the inverter output. The circuit may also be
activated by a surge voltage produced in the power supply system.
Check point
Check for too slow acceleration. (e.g. during descending acceleration with lifting load)
· Decrease the acceleration time.
Corrective action
· Use regeneration avoidance function (Pr. 882 to Pr. 886). (Refer to
E.OC1
larger than the V/F reference voltage at regeneration and overcurrent due to increase in motor
current occurs.)
(Shorten the downward acceleration time in vertical lift application.)
If "E.OC1" is still lit, contact your sales representative.
Instruction Manual (applied).)
E.OC2
E.OC3
E.OV1
Causes and corrective actions
FR-PU04
OC During Accs
FR-PU07
Instruction Manual (applied).)
FR-PU04
Stedy Spd OC
FR-PU07
Instruction Manual (applied).)
FR-PU04
OC During Dec
FR-PU07
Instruction Manual (applied).)
FR-PU04
OV During Acc
FR-PU07
Instruction Manual (applied).)
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