Mitsubishi Electric FR-A720-0.4K Instruction Manual page 403

Operation Panel
Indication
Name
Regenerative overvoltage shut-off during acceleration
If regenerative energy causes the inverter's internal main circuit DC voltage to reach or exceed the
Description specified value, 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. (e.g. during descending acceleration in vertical lift load)
· Decrease the acceleration time.
Corrective action
· Use regeneration avoidance function (Pr. 882 to Pr. 886). (Refer to page 366.)
Operation Panel
Indication
Name
Regenerative overvoltage shut-off during constant speed
If regenerative energy causes the inverter's internal main circuit DC voltage to reach or exceed the
Description specified value, 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.
· Keep load stable.
Corrective action · Use regeneration avoidance function (Pr. 882 to Pr. 886). (Refer to page 366.)
· Use the brake unit or power regeneration common converter (FR-CV) as required.
Operation Panel
Indication
Name
Regenerative overvoltage shut-off during deceleration or stop
If regenerative energy causes the inverter's internal main circuit DC voltage to reach or exceed the
Description
specified value, 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 inertia of moment of
Corrective action
· Decrease the braking duty.
· Use regeneration avoidance function (Pr. 882 to Pr. 886). (Refer to page 366.)
· Use the brake unit or power regeneration common converter (FR-CV) as required.
Operation Panel
Indication
Name Inverter overload shut-off (electronic thermal relay function)
If a current not less than 150% of the rated output current flows and overcurrent shut-off does not occur
Description
(220% or less), inverse-time characteristics cause the electronic thermal relay to be activated to stop
the inverter output in order to protect the output transistors. (overload immunity 150% 60s)
Check point Check the motor for use under overload.
Corrective action Reduce the load weight.
Operation Panel
Indication
Name
Motor overload shut-off (electronic thermal relay function)
The electronic thermal relay function in the inverter detects motor overheat due to overload or reduced
cooling capability during constant-speed operation and pre-alarm (TH display) is output when the
temperature reaches 85% of the Pr. 9 Electronic thermal O/L relay setting and the protection circuit is
Description
activated to stop the inverter output when the temperature reaches the specified value. When running
a special motor such as a multi-pole motor or multiple motors, provide a thermal relay on the inverter
output side since such motor(s) cannot be protected by the electronic thermal relay function.
1. Check the motor for use under overload.
Check point
2. Check that the setting of Pr. 71 Applied motor for motor selection is correct. (Refer to page 180.)
3. Check that stall prevention operation setting is correct.
1. Reduce the load weight.
Corrective action 2. For a constant-torque motor, set the constant-torque motor in Pr. 71 Applied motor.
3. Check that stall prevention operation setting is correct. (Refer to page 148.)
*1 Resetting the inverter initializes the internal thermal integrated data of the electronic thermal relay function.
E.OV1
E.OV2
E.OV3
the load)
E.THT
E.THM
Causes and corrective actions
FR-PU04
OV During Acc
FR-PU07
FR-PU04
Stedy Spd OV
FR-PU07
FR-PU04
OV During Dec
FR-PU07
FR-PU04
Inv. Overload
FR-PU07
*1
FR-PU04
Motor Overload
FR-PU07
*1
5
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