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PROTECTIVE FUNCTIONS
129
FR-PU04 Indication
Stedy Spd OV
Name
Regenerative overvoltage shut-off during constant speed
Description
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.
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 high power factor converter (FR-HC) as
required.
FR-PU04 Indication
OV During Dec
Name
Regenerative overvoltage shut-off during deceleration or stop
Description
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.
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 high power factor converter (FR-HC) as
required.
FR-PU04 Indication
Motor Overload
Name
Motor overload shut-off (electronic overcurrent protection) (Note 1)
Description
The electronic overcurrent protection in the inverter detects motor
overheat due to overload or reduced cooling capability during
constant-speed operation to stop the inverter output. When a multi-
pole motor or two or more motors are run, provide a thermal relay in
the output side of the inverter.
Check point
Check the motor for use under overload.
Corrective action
•
Reduce the load weight.
•
For the constant-torque motor, change the Pr. 71 setting to the
constant-torque motor setting.
FR-PU04 Indication
Inv. Overload
Name
Inverter overload shut-off (electronic overcurrent protection) (Note 1)
Description
If a current of more than 150% of the rated output current flows and
overcurrent shut-off does not occur (200% or less), inverse-time
characteristics cause the electronic overcurrent protection to be
activated to stop the inverter output in order to protect the output
transistors.
Check point
Check the motor for use under overload.
Corrective action
Reduce the load weight.
Note:1 Resetting the inverter initializes the internal heat integrating data of the
electronic overcurrent protection.