Mitsubishi Electric FR-F800, Instruction Manual

Page: 737 / 834

Protective functions Causes and corrective actions
FR-F800 6 - 17
6.5.4 Fault
When a protective function activates, the inverter trips and a fault signal is output.
Operation panel
indication
E.OC1 FR-LU08 OC During Acc
Name Overcurrent trip during acceleration
Description
When the inverter output current reaches or exceeds approximately 170% (LD rating) / 148%
(SLD rating) of the rated current during acceleration, the protection circuit is activated and the
inverter trips.
Check point
Check for sudden speed acceleration.
Check if the downward acceleration time is too long in a lift application.
Check for output short-circuit.
Check that the Pr. 3 "Base frequency" setting is not 60 Hz when the motor rated frequency is
50 Hz.
Check if the stall prevention operation level is set too high. Check if the fast-response
current limit operation is disabled.
Check that the regenerative driving is not performed frequently. (Check if the output
voltage becomes larger than the V/F reference voltage at regenerative driving and
overcurrent occurs due to increase in the motor current.)
Check that the inverter capacity matches with the motor capacity. (PM motor control)
Check if a start command is given to the inverter while the motor is coasting. (PM motor
control)
Corrective action
Set the acceleration time longer. (Shorten the downward acceleration time of the lift.)
If "E.OC1" always appears at start, disconnect the motor once and restart the inverter.
If "E.OC1" still appears, contact your sales representative.
Check the wiring to make sure that output short circuit does not occur.
Set 50 Hz in Pr. 3 "Base frequency". (Refer to page 5-517.)
Lower the stall prevention operation level. Activate the fast-response current limit
operation. (Refer to page 5-175.)
Set the base voltage (rated voltage of the motor, etc.) in Pr. 19 "Base frequency voltage".
(Refer to page 5-517.)
Choose inverter and motor capacities that match. (PM motor control)
Input a start command after the motor stops. Alternatively, use the automatic restart after
instantaneous power failure/flying start function. (Refer to page 5-417.) (IPM motor control)
Operation panel
indication
E.OC2 FR-LU08 OC During Cnst Spd
Name Overcurrent trip during constant speed
Description
When the inverter output current reaches or exceeds approximately 170% (LD rating) / 148%
(SLD rating) of the rated current during constant-speed operation, the protection circuit is
activated and the inverter trips.
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.
Check that the inverter capacity matches with the motor capacity.
(PM motor control)
Check if a start command is given to the inverter while the motor is coasting.
(PM motor control)
Corrective action
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 5-175.)
Choose inverter and motor capacities that match. (PM motor control)
Input a start command after the motor stops. Alternatively, use the automatic restart after
instantaneous power failure/flying start function. (Refer to page 5-417.)
(PM motor control)