Mitsubishi Electric FR-A800 Series Instruction Manual page 788

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
Operation panel
indication
Name
Description
Check point
Corrective action
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E.OV1
Regenerative overvoltage trip during acceleration
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 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.
• Set the acceleration time shorter.
Use the regeneration avoidance function (Pr.882 to Pr.886). (Refer to
• Set a value larger than the no load current in Pr.22.
• Set Pr.154 Voltage reduction selection during stall prevention operation = "10 or 11". (Refer to
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
• Use the brake unit, multifunction regeneration converter (FR-XC), 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 or 11". (Refer to
• 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.)
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
• Use the brake unit, multifunction regeneration converter (FR-XC), or power regeneration common converter
(FR-CV) as required.
• Set Pr.154 Voltage reduction selection during stall prevention operation = "10 or 11". (Refer to
E.THT
Inverter overload trip (Electronic thermal O/L relay)
If the temperature of the output transistor elements exceeds the protection level with a rated output current or
higher flowing without the overcurrent trip (E.OC[]), the inverter output is stopped. (Overload capacity 150% 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.
• Check that the encoder wiring and the specifications (encoder power supply, resolution, differential/
complementary) are correct. Check also that the motor wiring (U, V, W) is correct (under Vector control).
• 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.
• Check the wiring and specifications of the encoder and the motor. Perform the setting according to the
specifications of the encoder and the motor (under vector control). (Refer to
search engine
FR-LU08 indication OV During Acc
page 732.)
FR-LU08 indication OV During Cnst Spd
page 732.)
FR-LU08 indication OV During Dec
page 732.)
FR-LU08 indication Inv. overload trip
*4
page
6. PROTECTIVE FUNCTIONS
6.5 Causes and corrective actions
page 431.)
page 431.)
10
page 431.)
87.)
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