Mitsubishi FR-A800

Causes and corrective actions
PROTECTIVE FUNCTIONS
653
6 5
Operation panel
indication
E.OV1 FR-PU07 OV During Acc
Name
Regenerative overvoltage trip during acceleration
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
• Check for too slow acceleration. (e.g. during downward acceleration in vertical lift load)
• 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.
Corrective action
• Set the acceleration time shorter.
Use the regeneration avoidance function (Pr.882 to Pr.886). (Refer to page 621.)
• 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
348.)
Operation panel
indication
E.OV2 FR-PU07 Stedy Spd OV
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
• 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.
Corrective action
• Keep the load stable.
• Use the regeneration avoidance function (Pr.882 to Pr.886). (Refer to page 621.)
• 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
348.)
• 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-PU07 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
• Check for sudden speed reduction.
• Check if the stall prevention operation is frequently activated in an application with a large load inertia.
Corrective action
• 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 621.)
• 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
348.)