Mitsubishi Electric FR-A820-00046 (0.4K) Instruction Manual page 751

Operation panel
indication
Name
Description
Check point
Corrective action
*2 Differs according to ratings. The rating can be changed using Pr.570 Multiple rating setting. (Refer to
148% for SLD rating,170% for LD rating, 235% for ND rating (initial setting), and 280% for HD rating
Operation panel
indication
Name
Description
Check point
Corrective action
*3 Differs according to ratings. The rating can be changed using Pr.570 Multiple rating setting. (Refer to
148% for SLD rating,170% for LD rating, 235% for ND rating (initial setting), and 280% for HD rating
752
6. PROTECTIVE FUNCTIONS
6.5 Causes and corrective actions
E.OC2
Overcurrent trip during constant speed
When the inverter output current reaches or exceeds approximately 235%
speed operation, the protection circuit is activated and the inverter output is shut off.
• Check for sudden load change.
• Check for a short-circuit in the output 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
409.)
• 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
E.OC3
Overcurrent trip during deceleration or stop
When the inverter output current reaches or exceeds approximately 235%
deceleration (other than acceleration or constant speed), the protection circuit is activated and the inverter output
is shut off.
• Check for sudden speed reduction.
• Check for a short-circuit in the output circuit.
• Check for too fast operation of the motor's mechanical brake.
• 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)
• Set the deceleration time longer.
• Check the wiring to make sure that output short circuit does not occur.
• Check the mechanical brake operation.
• Lower the stall prevention operation level. Activate the fast-response current limit operation. (Refer to
409.)
• 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
FR-LU08 indication
page 604.) (PM sensorless vector control)
FR-LU08 indication OC During Dec
page 604.) (PM sensorless vector control)
Overcurrent trip during constant
speed
*2
of the rated current during constant-
page
page 326.)
*3
of the rated current during
page
page 326.)