Mitsubishi Electric FR-A800, Instruction Manual

Page: 909 / 1042

Protective functions Causes and corrective actions
FR-A800 6 - 21
Operation panel
indication
E.OV2 FR-LU-08 OV During Cnst Spd
Name Regenerative overvoltage trip during constant speed
Description
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 point
앫
Check for sudden load change.
앫
Check that the Pr. 22 "Stall prevention operation level" is not set to the no load current or
lower.
앫
Check if the stall prevention operation is frequently activated in an application with a large
load inertia.
앫
Check that acceleration/deceleration time is not too short.
Corrective action
앫
Keep the load stable.
앫
Use the regeneration avoidance function (Pr. 882 to Pr. 886). (Refer to page 5-685.)
앫
Use the brake unit or power regeneration common converter (FR-CV) as required.
앫
Set a value larger than the no load current in Pr. 22.
앫
Set Pr. 154 "Voltage reduction selection during stall prevention operation" = "10, 11".
(Refer to page 5-84.)
앫
Set the acceleration/deceleration time longer. (Under vector control or 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.)
Operation panel
indication
E.OV3 FR-LU-08 OV During Dec
Name Regenerative overvoltage trip during deceleration or stop
Description
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 point
앫
Check for sudden speed reduction.
앫
Check if the stall prevention operation is frequently activated in an application with a large
load inertia.
Corrective action
앫
Set the deceleration time longer. (Set the deceleration time which matches the moment of
inertia of the load.)
앫
Make the brake cycle longer.
앫
Use the regeneration avoidance function (Pr. 882 to Pr. 886). (Refer to page 5-685.)
앫
Use the brake unit or power regeneration common converter (FR-CV) as required.
앫
Set Pr. 154 "Voltage reduction selection during stall prevention operation" = "10, 11".
(Refer to page 5-84.)