Delta VFD1A5MS43ANSAA User Manual

Chapter 14 Fault CodesMS300
551
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 Condition
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 make sure 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 (refer to 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.

Delta VFD1A5MS43ANSAA Specifications

General

Brand	Delta
Model	VFD1A5MS43ANSAA
Category	DC Drives
Language	English