Mitsubishi Electric FR-A701 Instrucion Manual page 153

Causes and corrective actions
Operation Panel
Indication
Name
Description
Check point
Corrective action
Operation Panel
Indication
Name
Description
Check point
Corrective action
Operation Panel
Indication
Name
Description
Check point
Corrective action
146
E.OC3
Overcurrent trip during deceleration or stop
When the inverter output current reaches or exceeds approximately 220% of the rated inverter current 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.
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)
6. Check that the rotation direction is not switched from forward to reverse rotation (or from reverse to
forward) during torque control under real sensorless vector control.
1. Increase the deceleration time.
2. Check the wiring to make sure that output short circuit does not occur.
3. Check the mechanical brake operation.
4. Check that stall prevention operation setting is correct. (Refer to chapter 4 of
(applied).)
5. Check RS-485 terminal connection. (under vector control)
6. Prevent the motor from switching the rotation direction from forward to reverse (or from reverse to
forward) during torque control under real sensorless vector control.
E.OV1
Regenerative overvoltage trip during acceleration
If regenerative energy causes the inverter's internal main circuit DC voltage to reach or exceed the
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. Protective circuit may activate even
if the regeneration converter is not activated due to power supply failure (Input phase failure and
instantaneous power failure).
1. Check for power supply fault or wrong wiring.
2. Check for too slow acceleration. (e.g. during descending acceleration in vertical lift load)
3. Check that the Pr. 22 Stall prevention operation level is not lower than the no load current.
1. Perform wiring correctly.
2. · Decrease the acceleration time.
· Use regeneration avoidance function (Pr. 882 to Pr. 886). (Refer to chapter 4 of
manual (applied).)
3. Set a value larger than the no load current in Pr. 22 Stall prevention operation level.
E.OV2
Regenerative overvoltage trip during constant speed
If regenerative energy causes the inverter's internal main circuit DC voltage to reach or exceed the
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. Protective circuit may activate even
if the regeneration converter is not activated due to power supply failure (Input phase failure and
instantaneous power failure).
· Check for power supply fault or wrong wiring.
· Check for sudden load change.
· Check that the Pr. 22 Stall prevention operation level is not lower than the no load current.
· Perform wiring correctly.
· Keep load stable.
· Use regeneration avoidance function (Pr. 882 to Pr. 886). (Refer to chapter 4 of
manual (applied).)
· Set a value larger than the no load current in Pr. 22 Stall prevention operation level.
FR-PU04
OC During Dec
FR-PU07
FR-PU04
OV During Acc
FR-PU07
FR-PU04
Stedy Spd OV
FR-PU07
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