Fault - Mitsubishi Electric FR-A820-00046 Instruction Manual

Protective functions
6.5.4

Fault

When a protective function activates, the inverter trips and a fault signal is output.
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
FR-A800
E.OC1
Overcurrent trip during acceleration
When the inverter output current reaches or exceeds approximately 235%
during acceleration, the protection circuit is activated and the inverter trips.
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 power supply for RS-485 terminal is not shorted (under vector control).
Check that the encoder wiring and the specifications (encoder power supply, resolution,
differential/complementary) are correct. Check also that the motor wiring (U, V, W) is correct
(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)
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 5-690.)
Lower the stall prevention operation level. Activate the fast-response current limit
operation. (Refer to page 5-325.)
Set the base voltage (rated voltage of the motor, etc.) in Pr. 19 "Base frequency voltage".
(Refer to page 5-690.)
Check RS-485 terminal connection (under vector control).
Check the wiring and specifications of the encoder and the motor. Perform the setting
according to the specifications of the encoder and the motor (under vector control).
(Refer to page 2-71.)
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.) (IPM sensorless
vector control)
Causes and corrective actions
FR-LU-08 OC During Acc
of the rated current
6 - 19