PROTECTIVE FUNCTIONS
183
Operation Panel
Indication
E.OC3
FR-PU04
OC During Dec
Name
Overcurrent shut-off during deceleration
Description
When the inverter output current reaches or exceeds approximately 200% of the
rated 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.
Check for too fast operation of motor's mechanical brake.
Corrective action
Increase the deceleration time.
Check mechanical brake operation.
Operation Panel
Indication
E.OV1
FR-PU04
OV During Acc
Name
Regenerative overvoltage shut-off during acceleration
Description
A prealarm (RB indication) occurs if the inverter's internal main circuit DC voltage
reaches 85% of the specified value due to regenerative energy. If that voltage
reaches or exceeds the specified value, the protective circuit is activated to stop
the inverter output. It may also be activated by a surge voltage generated in the
power supply system.
Check point
Check for too slow acceleration.
Corrective action
Decrease the acceleration time.
Operation Panel
Indication
E.OV2
FR-PU04
Stedy Spd OV
Name
Regenerative overvoltage shut-off during constant speed
Description
A prealarm (RB indication) occurs if the inverter's internal main circuit DC voltage
reaches 85% of the specified value due to regenerative energy. If that voltage
reaches or exceeds the specified value, the protective circuit is activated to stop
the inverter output. It may also be activated by a surge voltage generated in the
power supply system.
Check point
Check for sudden load change.
Corrective action
•
Keep load stable.
•
Use the brake unit or power regeneration converter (FR-RC) as required.
Operation Panel
Indication
E.OV3
FR-PU04
OV During Dec
Name
Regenerative overvoltage shut-off during deceleration or stop
Description
A prealarm (RB indication) occurs if the inverter's internal main circuit DC voltage
reaches 85% of the specified value due to regenerative energy. If that voltage
reaches or exceeds the specified value, the protective circuit is activated to stop
the inverter output. It may also be activated by a surge voltage generated in the
power supply system.
Check point
Check for sudden speed reduction.
Corrective action
•
Increase the deceleration time. (Set the deceleration time which matches the
inertia moment of the load)
•
Decrease the braking duty.
•
Use the brake unit or power regeneration converter (FR-RC) as required.
5
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