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Causes and corrective actions
(4) Fault
When a fault occurs, the inverter trips and a fault signal is output.
Operation Panel
Indication
E.OC1
FR-PU04
FR-PU07
OC During Acc
Name
Overcurrent trip during acceleration
Description
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 point
· 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.
Corrective action
· 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.
(Refer to page 162.)
Operation Panel
Indication
E.OC2
FR-PU04
FR-PU07
Stedy Spd OC
Name
Overcurrent trip during constant speed
Description
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 point
· 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.
Corrective action
· 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.
(Refer to page 162.)