Mitsubishi Electric FR-F700PJ Instruction Manual page 307

Causes and corrective actions
Operation panel
E.OC2
indication
Name Overcurrent trip during constant speed
When the inverter output current reaches or exceeds approximately 170% of the rated current during constant speed
Description
operation, the protective circuit is activated and the inverter trips.
 Check for sudden load change.
 Check for output short-circuit/ground fault.
 Check if the stall prevention operation level is set too high.
Check point  Check if the fast-response current limit operation is disabled. (V/F control, General-purpose magnetic flux vector
control)
 Check that the inverter capacity matches with the motor capacity. (IPM motor control)
 Check if a start command is given to the inverter while the motor is coasting. (IPM motor control)
 Keep load stable.
 Check the wiring to make sure that output short circuit/ground fault does not occur.
 Lower the setting of stall prevention operation level. (Refer to page 103.)
Corrective action  Activate the fast-response current limit operation. (V/F control, General-purpose magnetic flux vector control)
 Choose inverter and motor capacities that match. (IPM motor control)
 Input a start command after the motor stops. Alternatively, set the automatic restart after instantaneous power
failure/flying start function. (IPM motor control)
Operation panel
E.OC3
indication
Name
Overcurrent trip during deceleration or stop
When the inverter output current reaches or exceeds approximately 170% of the rated inverter current during
Description
deceleration (other than acceleration or constant speed), the protective circuit is activated and the inverter trips.
 Check for sudden speed reduction.
 Check for output short-circuit/ground fault.
 Check for too fast operation of the motor's mechanical brake.
 Check if the stall prevention operation level is set too high.
Check point
 Check if the fast-response current limit operation is disabled. (V/F control, General-purpose magnetic flux vector
control)
 Check that the inverter capacity matches with the motor capacity. (IPM motor control)
 Check if a start command is given to the inverter while the motor is coasting. (IPM motor control)
 Increase the deceleration time.
 Check the wiring to make sure that output short circuit/ground fault does not occur.
 Check the mechanical brake operation.
 Lower the setting of stall prevention operation level. (Refer to page 103.)
Corrective action
 Activate the fast-response current limit operation. (V/F control, General-purpose magnetic flux vector control)
 Choose inverter and motor capacities that match. (IPM motor control)
 Input a start command after the motor stops. Alternatively, set the automatic restart after instantaneous power
failure/flying start function. (IPM motor control)
Operation panel
E.OV1
indication
Name
Regenerative overvoltage trip during acceleration
If regenerative energy causes the inverter's internal main circuit DC voltage to reach or exceed the specified value,
Description
the protective circuit is activated and the inverter trips. 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 point
 Check that the setting of Pr. 22 Stall prevention operation level is not too small.
 Check if the stall prevention operation is frequently activated in an application with a large load inertia.
 Decrease the acceleration time.
 Use regeneration avoidance function (Pr. 882, Pr. 883, Pr. 885, Pr. 886). (Refer to page 262)
Corrective action
 Set the Pr.22 Stall prevention operation level correctly.
 Set Pr.154 Voltage reduction selection during stall prevention operation = "11".
302
FR-PU04
Stedy Spd OC
FR-PU07
(Refer to page 161.)
FR-PU04
OC During Dec
FR-PU07
(Refer to page 161.)
FR-PU04
OV During Acc
FR-PU07