Mitsubishi Electric FR-CS84-012 Instruction Manual page 215

 Fault
When a protective function is activated, the inverter output is shut off and a fault signal is output.
Operation panel
indication
Name
Description
Check point
Corrective action
Operation panel
indication
Name
Description
Check point
Corrective action
Operation panel
indication
Name
Description
Check point
Corrective action
214
6. PROTECTIVE FUNCTIONS
6.5 Causes and corrective actions
E.OC1
Overcurrent trip during acceleration
When the inverter output current reaches or exceeds approximately 200% of the rated current during
acceleration, the protection circuit is activated and the inverter output is shut off.
• 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.)
• 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
• Lower the stall prevention operation level. Activate the fast-response current limit operation. (Refer to
119.)
• Set the base voltage (rated motor voltage, etc.) in Pr.19 Base frequency voltage. (Refer to
E.OC2
Overcurrent trip during constant speed
When the inverter output current reaches or exceeds approximately 200% of the rated current during constant-
speed operation, the protection circuit is activated and the inverter output is shut off.
• 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.
• 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
119.)
E.OC3
Overcurrent trip during deceleration or stop
When the inverter output current reaches or exceeds approximately 200% of the rated current during
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 output short-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.
• 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
119.)
FR-LU08 indication Overcurrent trip during acceleration
page 194.)
Overcurrent trip during constant
FR-LU08 indication
speed
FR-LU08 indication OC During Dec
page
page 194.)
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