Mitsubishi Electric FR-A820-00046 Instruction Manual page 1060

Causes and corrective actions
Operation panel
indication
Name
Description
Check point
Corrective action
Differs according to ratings. The rating can be changed using Pr. 570 "Multiple rating setting". (Refer to page 5-209.)
148% for SLD rating,170% for LD rating, 235% for ND rating (initial setting), and 280% for HD rating
6 - 20
E.OC2
Overcurrent trip during constant speed
When the inverter output current reaches or exceeds approximately 235%
during constant-speed operation, the protection circuit is activated and the inverter trips.
Check for sudden load change.
Check for output short-circuit.
Check if the stall prevention operation level is set too high. Check if the fast-response
current limit operation is disabled.
Check that the power supply for RS-485 terminal is not shorted (under vector control).
Check that the rotation direction is not switched from forward to reverse rotation (or from
reverse to forward) during torque control under Real sensorless vector control.
Check that the inverter capacity matches with the motor capacity.
(PM sensorless vector control)
Check if a start command is given to the inverter while the motor is coasting.
(PM sensorless vector control)
Keep the load stable.
Check the wiring to make sure that output short circuit does not occur.
Lower the stall prevention operation level. Activate the fast-response current limit
operation.
(Refer to page 5-325.)
Check RS-485 terminal connection (under vector control).
Prevent the motor from switching the rotation direction from forward to reverse (or from
reverse to forward) during torque control under Real sensorless vector control.
Choose inverter and motor capacities that match. (PM sensorless vector control)
Input a start command after the motor stops. Alternatively, use the automatic restart after
instantaneous power failure/flying start function. (Refer to page 5-590.)
(PM sensorless vector control)
Protective functions
FR-LU-08 OC During Cnst Spd
of the rated current