Mitsubishi Electric 700 Series Instruction Manual page 203

Causes and corrective actions
Operation panel
E.OC3
indication
Name
Overcurrent trip during deceleration or stop
When the inverter output current reaches or exceeds approximately 230% of the rated inverter current during
Description
deceleration (other than acceleration or constant speed), the protective circuit is activated and the inverter trips.
Check for sudden speed reduction.
Check for output short-circuit/ground fault.
Check point
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.
Increase the deceleration time.
Check the wiring to make sure that output short circuit/ground fault does not occur.
Corrective action
Check the mechanical brake operation.
Lower the setting of stall prevention operation level. (Refer to page 101).
Activate the fast-response current limit operation.
Operation panel
E.OV1
indication
Name
Regenerative overvoltage trip during acceleration
If regenerative energy causes the inverter's internal main circuit DC voltage to reach or exceed the specified value,
Description the protective circuit is activated and the inverter trips. The circuit may also be activated by a surge voltage produced
in the power supply system.
Check for too slow acceleration. (e.g. during downward acceleration in vertical lift load)
Check point
Check that the setting of Pr. 22 Stall prevention operation level is not too small.
Decrease the acceleration time.
Corrective action
Check that regeneration avoidance function (Pr. 882, Pr. 883, Pr. 885, Pr. 886) is used. (Refer to page 174).
Set the Pr.22 Stall prevention operation level correctly.
Operation panel
E.OV2
indication
Name 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,
Description 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 for sudden load change.
Check point
Check that the setting of Pr. 22 Stall prevention operation level is not too small.
Keep load stable.
Check that regeneration avoidance function (Pr. 882, Pr. 883, Pr. 885, Pr. 886) is used. (Refer to page 174).
Corrective action
Use the brake resistor, brake unit or power regeneration common converter (FR-CV) as required.
Set the Pr.22 Stall prevention operation level correctly.
Operation panel
E.OV3
indication
Name Regenerative overvoltage trip during deceleration or stop
If regenerative energy causes the inverter's internal main circuit DC voltage to reach or exceed the specified value,
Description
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 sudden speed reduction.
Increase the deceleration time. (Set the deceleration time which matches the moment of inertia of the load)
Longer the brake cycle.
Corrective action
Use regeneration avoidance function (Pr. 882, Pr. 883, Pr. 885, Pr. 886). (Refer to page 174).
Use the brake resistor, brake unit or power regeneration common converter (FR-CV) as required.
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