Mitsubishi Electric FR-F820-00077 Instruction Manual page 832

Causes and corrective actions
Operation panel
indication
Name
Description
Check point
Corrective action
Operation panel
indication
Name
Description
Check point
Corrective action
Operation panel
indication
Name
Description
Check point
Corrective action
Resetting the inverter initializes the internal cumulative heat value of the electronic thermal O/L relay function.
6 - 20
E.OV2
Regenerative overvoltage trip during constant speed
If regenerative power causes the inverter's internal main circuit DC voltage to reach or exceed
the specified value, the protection 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 load change.
Check that the Pr. 22 "Stall prevention operation level" is not set to the no load current or
lower.
Check if the stall prevention operation is frequently activated in an application with a large
load inertia.
Check that acceleration/deceleration time is not too short.
Keep the load stable.
Use the regeneration avoidance function (Pr. 882 to Pr. 886). (Refer to page 5-560.)
Use the brake unit or power regeneration common converter (FR-CV) as required.
Set a value larger than the no load current in Pr. 22.
Set Pr. 154 "Voltage reduction selection during stall prevention operation" = "10, 11".
(Refer to page 5-180.)
Set the acceleration/deceleration time longer. (Under Advanced magnetic flux vector
control, the output torque can be increased. However, sudden acceleration may cause an
overshoot in speed, resulting in an occurrence of overvoltage.)
E.OV3
Regenerative overvoltage trip during deceleration or stop
If regenerative power causes the inverter's internal main circuit DC voltage to reach or exceed
the specified value, the protection 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.
Check if the stall prevention operation is frequently activated in an application with a large
load inertia.
Set the deceleration time longer. (Set the deceleration time which matches the moment of
inertia of the load.)
Make the brake cycle longer.
Use the regeneration avoidance function (Pr. 882 to Pr. 886). (Refer to page 5-560.)
Use the brake unit or power regeneration common converter (FR-CV) as required.
Set Pr. 154 "Voltage reduction selection during stall prevention operation" = "10, 11".
(Refer to page 5-180.)
E.THT
Inverter overload trip
When the temperature of the output transistor element exceeds the protection level while a
current flows at the rated output current level or higher without causing an overcurrent trip
(E.OC ), the inverter output is stopped. (Permissible overload capacity 120% 60 s)
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 the use under overload.
Set the acceleration/deceleration time longer.
Adjust the torque boost setting.
Set the load pattern selection setting according to the load pattern of the using machine.
Reduce the load.
Protective functions
FR-LU08 OV During Cnst Spd
FR-LU08 OV During Dec
FR-LU08 Inv. overload trip