Operating Instructions

Fault Codes
Digital Keypad
305 | 443
ID*
Display on LCD Keypad
Fault Name
Fault Descriptions
3
Over-current during steady
operation (ocn)
Output current exceeds three times of the rated current during
constant speed.
When ocn occurs, the drive closes the gate of the output
immediately, the motor runs freely, and the display shows an ocn
error.
Action and Reset
Action level
300% of the rated current
Action time
Immediately act
Fault treatment parameter
N/A
Reset method
Manual reset
Reset condition
Reset in five seconds after the fault is cleared
Record
Yes
Cause
Corrective Actions
Short-circuit at motor output due to poor
insulation wiring
Check the motor cable and remove causes of the short circuits, or replace the cable before turning
on the power.
Check for possible shaft lock, burnout or
aging insulation of the motor
● Troubleshoot the motor shaft lock.
● Check the motor insulation value with megger. Replace the motor if the insulation is poor.
Impulsive change of the load
Reduce the load or increase the capacity of AC motor drive.
Use special motor or motor with larger
capacity than the drive
Check motor capacity (the rated current on the motor’s nameplate should ≤ the rated current of
the drive)
Use ON/OFF controller of an
electromagnetic contactor at the output
(U/V/W) of the drive
Check the action timing of the contactor and Ensure it is not turned ON/OFF when the drive
outputs the voltage.
V/F curve setting error
Adjust the V/F curve settings and frequency/voltage. When the fault occurs, and the frequency
voltage is too high, reduce the voltage.
Torque compensation is too large.
Adjust the torque compensation (See Pr.07-26 torque compensation gain) until the output current
reduces and the motor does not stall.
Malfunction caused by interference
Verify the wiring of the control circuit and the wiring/grounding of the main circuit to prevent
interference.
The length of motor cable is too long
Increase the AC motor drive’s capacity.
Install AC reactor(s) on the output side (U/V/W).
Hardware failure
The ocn occurs due to the short circuit or ground fault at the output side of the drive.
Check for possible short circuit between terminals with the electric meter:
B1 corresponds to U, V and W; DC- corresponds to U, V, and W; corresponds to U, V, and
W.
If short circuits occurs, return to the factory for repair.