Mitsubishi Electric FR-D720S SC EC Instruction Manual page 447

Troubleshooting
Operation Panel
Indication
Name
Description
Check point
Corrective action
Operation Panel
Indication
Name
Description
Check point
Corrective action
Resetting the inverter initializes the internal thermal integrated data of the electronic thermal
relay function.
Operation Panel
Indication
Name
Description
Check point
Corrective action
Resetting the inverter initializes the internal thermal integrated data of the electronic thermal
relay function.
FR-D700 SC EC
E.OV3
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 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 for sudden speed reduction.
Increase the deceleration time. (Set the deceleration time which matches the inertia
moment of the load)
Use regeneration avoidance function (Pr. 882, Pr. 883, Pr. 885, Pr. 886). (Refer to
section 6.19.4.)
Use the brake unit or power regeneration common converter (FR-CV) as required.
E.THT
Inverter overload shut-off (electronic thermal relay function)
If the temperature of the output transistor element exceeds the protection level under the
condition that a current not less than the rated inverter current flows and overcurrent trip
does not occur (200% or less), the electronic thermal relay activates to stop the inverter
output. (Overload capacity 150% for 60s, 200% for 0.5s)
Check that acceleration/deceleration time is not too short.
Check that torque boost setting is not too large (small).
Check that load pattern selection setting is appropriate for the load pattern of the using
machine.
Check the motor for use under overload.
Check for too high ambient temperature.
Increase acceleration/deceleration time.
Adjust the torque boost setting.
Set the load pattern selection setting according to the load pattern of the using machine.
Reduce the load weight.
Set the ambient temperature to within the specifications.
E.THM
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 I²t value reaches 85% of the Pr. 9 "Electronic thermal O/L relay" setting
and the protection circuit is activated to stop the inverter output when the I²t value 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.
Check the motor for use under overload.
Check that the setting of Pr. 71 "Applied motor" for motor selection is correct.
(Refer to section .)
Check that the setting of Pr. 71 "Applied motor" for motor selection is correct.
(Refer to section 6.2.4.)
Reduce the load weight.
For a constant-torque motor, set the constant-torque motor in Pr. 71 "Applied motor".
Check that stall prevention operation setting is correct. (Refer to section 6.2.4.)
Causes and corrective actions
FR-PU04
OV During Dec
FR-PU07
FR-PU04
Inv. Overload
FR-PU07
FR-PU04
Motor Overload
FR-PU07
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