MITSUBISHI ELECTRIC FR-S520 - Manual (Page 147)

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Operation Panel Indication OC2 FR-PU04 Stedy Spd OC
Name Overcurrent cut-off during constant speed
Description
When the inverter output current reaches or exceeds
approximately 200% of the rated inverter 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/ground fault.
Corrective action Keep load stable.
Operation Panel Indication OC3 FR-PU04 OC During Dec
Name Overcurrent cut-off during deceleration
Description
When the inverter output current reaches or exceeds
approximately 200% 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/ground fault.
Check for too fast operation of motor's mechanical brake.
Corrective action
Increase the deceleration time.
Adjust brake operation.
Operation Panel Indication OV1 FR-PU04 OV During Acc
Name Regenerative overvoltage cut-off during acceleration
Description
When the main circuit DC voltage in the inverter rises to or above
the specified value due to excessive regenerative energy during
acceleration, 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.
Corrective action
Decrease the acceleration time.
Install a power factor improving reactor.
Operation Panel Indication OV2 FR-PU04 Stedy Spd OV
Name Regenerative overvoltage cut-off during constant speed
Description
When the main circuit DC voltage in the inverter rises to or above
the specified value due to excessive regenerative energy during
constant speed, 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 load change.
Corrective action
Keep load stable.
Install a power factor improving reactor.