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5.2 Faults which can be auto-reset or reset by manual operation
Fault Code
Content
Probable Cause
What to do
OC-S
Over Current
during Starting
1. Motor is short circuited
2. Motor has ground fault
3. Inverter transistor
module is damaged
1. Check and fix motor
2. Remove the grounding point
3. Change transistor module
OC-A
Over Current
during Accel.
1. Accel. time is set too
short
2. Inappropriate V/F
pattern selection
3. Motor capacity exceeds
Inverter rating
1. Extend accel. time
2. Select the optimum V/F pattern
3. Select a larger WATT-tronic
Inverter
OC-C
Over Current
during Constant
speed
1. Load changes
excessively
2. Input voltage fluctuates
excessively
1. Check load condition
2. Install a reactor between power
supply and Inverter
OC-d
Over Current
during Decel.
1. Decel. time is set too
short
1. Extend decel. time
OC-b
Over Current
during Braking
1. Braking freq. is set too
high
2. Braking voltage is set
too high
3. Braking time is set too
long
1. Reduce braking freq.
2. Lower braking voltage
3. Shorten braking time
OV-C
Over Voltage
during Constant
speed
1. Decel. time is set too
short or load inertia is
too high
2. Input voltage fluctuates
1. Extend decel. time
2. Set Fn_48 = xxx0
3. Add external braking resistor or
module
4. Install a reactor between power
supply and Inverter
5. Select a larger WATT-tronic
Inverter
