Delta VP3000 Series - Page 503

Chapter 8 Troubleshooting｜VP3000
494
ID No.
Fault Name
Descriptions
3
Over-current during
steady operation
(ocn)
Output current exceeds 1.9 times of rated current at 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 Condition
190% of the rated current
Action Time
Immediately act
Fault Treatment Parameter
No
Reset Method
Manual reset
Reset Condition
Reset in 5 sec. 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 the 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 make sure it is not turned ON / OFF
when the drive outputs the voltage.
V/F curve setting error
Adjust V/F curve setting 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 (refer to Pr. E0-16 torque compensation gain)
until the current reduces and the motor does not stall.
Malfunction caused by
interference
Verify the wiring of the control circuit and wiring/grounding of the main circuit to
prevent interference.
The length of motor cable is too
long
Enlarge the AC motor drive’s capacity.
Install AC reactor(s) on the output side (U/V/W).
Hardware failure
The ocA occurs due to short circuit or ground fault at the output side of the drive.
Check for possible short circuits between terminals with the electric meter
corresponds to U, V and W.
If short circuit occurs, return to the factory for repair.