Delta MS300 Series User Manual page 560

ID Display on LCD Keypad
3
Action Condition
Action Time
Fault Treatment Parameter
Reset Method
Reset Condition
Record
Cause
Short-circuit at motor output due to
poor insulation wiring
Check for possible shaft lock,
burnout or aging insulation of the
motor
Impulsive change of the load
Use special motor or motor with
larger capacity than the drive
Use ON/OFF controller of an
electromagnetic contactor at the
output (U/V/W) of the drive
V/F curve setting error
Torque compensation is too large.
Malfunction caused by
interference
The length of motor cable is too
long
Hardware failure
Fault Name
Over-current during
steady operation
(ocn)
Action and Reset
300% of the rated current
Immediately act
N/A
Manual reset
Reset in five seconds after the fault is cleared
Yes
Check the motor cable and remove causes of the short circuits, or replace the
cable before turning on the power.
Troubleshoot the motor shaft lock.
Check the motor insulation value with megger. Replace the motor if the
insulation is poor.
Reduce the load or increase the capacity of AC motor drive.
Check motor capacity (the rated current on the motor's nameplate should ≤ the
rated current of the drive)
Check the action timing of the contactor and make sure it is not turned ON/OFF
when the drive outputs the voltage.
Adjust the V/F curve settings and frequency/voltage. When the fault occurs, and
the frequency voltage is too high, reduce the voltage.
Adjust the torque compensation (refer to Pr.07-26 torque compensation gain)
until the output current reduces and the motor does not stall.
Verify the wiring of the control circuit and the wiring/grounding of the main
circuit to prevent interference.
Increase the AC motor drive's capacity.
Install AC reactor(s) on the output side (U/V/W).
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.
551
Fault Descriptions
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.
Corrective Actions
Chapter 14 Fault CodesMS300