Delta MH300 Series - Page 730

Chapter 14 Fault CodesMH300
14-3
ID No. Display Fault Name Description
1
Over-current during
acceleration
(ocA)
Output current exceeds 3 times of the
rated current
during acceleration. When ocA
occurs, the drive
closes the gate of the output immediately, the
motor
runs freely, and the display shows an ocA 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 5 sec. after the fault is cleared.
Record Yes
Cause Corrective Actions
Acceleration time is too short.
1. Increase the acceleration time
2. Increase the acceleration time of S-curve
3. Set auto-acceleration and auto-deceleration parameter (Pr.01-44)
4. Set over-current stall prevention function (Pr.06-03)
5. Replace the drive with a larger capacity model
Short-circuit at motor output
due to poor insulation wiring.
Without considering the short circuits, check the motor cable or replace
the cable before turning on the power.
Check for possible burnout or
aging insulation of the motor
Check the motor insulation value with megger
. Replace the motor if the
insulation is poor.
The load is too large.
Check if the output current during
the whole working process exceeds the
AC motor drive’s rated current. If yes, replace the AC motor drive with a
larger capacity model.
Impulsive change of the load Reduce the load or increase the capacity of the 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 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 wiring/grounding of the
main
circuit to prevent interference.
The motor starts when in free
run.
Enable the speed tracking during start-up of Pr.07-12.