PROTECTIVE FUNCTIONS
168
Operation Panel Indication
E. OV3
FR-PU04
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.
Operation Panel Indication
E. THM
FR-PU04
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.
Operation Panel Indication
E. THT
FR-PU04
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.
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