Mitsubishi Electric FR-F720P-0.75K to 110K Instruction Manual page 325

Causes and corrective actions
(4) Fault
When a fault occurs, the inverter trips and a fault signal is output.
Operation Panel
Indication
Name
Description
Check point
Corrective action
Operation Panel
Indication
Name
Description
Check point
Corrective action
314
E.OC1
Overcurrent trip during acceleration
When the inverter output current reaches or exceeds approximately 170% of the rated current during
acceleration, the protective circuit is activated to stop the inverter output.
· Check for sudden acceleration.
· Check that the downward acceleration time is not long in vertical lift application.
· Check for output short circuit.
· Check that the Pr. 3 Base frequency setting is not 60Hz when the motor rated frequency is 50Hz.(V/F
control, Simple magnetic flux vector control)
· Check if the stall prevention operation level is set too high.
· Check if the fast-response current limit operation is disabled. (V/F control, Simple magnetic flux vec-
tor control)
· Check that the regeneration is not performed frequently. (Check that the output voltage becomes
larger than the V/F reference voltage at regeneration and overcurrent occurs due to the high
voltage.) (V/F control, Simple 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.
· Increase the acceleration time.
(Shorten the downward acceleration time in vertical lift application.)
· When "E.OC1" is always lit at starting, disconnect the motor once and start the inverter.
If "E.OC1" is still lit, contact your sales representative.
· Check the wiring to make sure that output short circuit does not occur.
· Set the Pr. 3 Base frequency to 50Hz. (V/F control, Simple magnetic flux vector control) (Refer to page
98.)
· Lower the setting of stall prevention operation level. (Refer to page 91.)
· Activate the fast-response current limit operation. (V/F control, Simple magnetic flux vector control)
· Set base voltage (rated voltage of the motor, etc.) in Pr. 19 Base frequency voltage.(V/F control, Simple
magnetic flux vector control) (Refer to page 98.)
· 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.
E.OC2
Overcurrent trip during constant speed
When the inverter output current reaches or exceeds approximately 170% of the rated current during
constant speed operation, the protective circuit is activated to stop the inverter output.
· 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. (V/F control, Simple magnetic flux vec-
tor 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.
· Keep load stable.
· Check the wiring to avoid output short circuit.
· Lower the setting of stall prevention operation level (Refer to page 91.)
· Activate the fast-response current limit operation. (V/F control, Simple 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.
FR-PU04
OC During Acc
FR-PU07
(Refer to page 162.)
FR-PU04
Stedy Spd OC
FR-PU07
(Refer to page 162.)