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Chapter 4 Troubleshooting and Maintenance
4.1 Error display and corrective action
4.1.1 Manual Reset and Auto-Reset
Faults which can not be recovered manually
Display
content
Cause
Corrective action
-OV-
Voltage too high
when stopped
Detection circuit malfunction
Consult with the supplier
-LV-
Voltage too low
when stopped
1. Power voltage too low
2. Pre-charge resistor or fuse
burnt out.
3. Detection circuit
malfunction
1.Check if the power voltage
is correct
2.Replace the pre-charge
resistor or the fuse
3.Consult with the supplier
-OH-
The inverter is
overheated when
stopped
1. Detection circuit
malfunction
2. Ambient temperature too
high or bad ventilation
Improve the ventilation
conditions, if no result then
replace the inverter
OH-C
The inverter is
overheated
during running
1. IGBT temperature is too
high or bad ventilation
2. Temperature sensor error
or circuit malfunctions
1. Reduce carrier
frequency
2. Improve the ventilation
conditions, if no result
then replace the inverter
EPr
EEPROM
problem
Faulty EEPROM
Consult with the supplier
COt
Communication
error
Communication disruption
Check the wiring
CtEr
Current Sensor
detection error
Current sensor error or
circuit malfunction
Consult with the supplier
Err4
CPU Illegal
interrupt
External noise
If it occurs too often, please
consult with the supplier
r-OFF
power relay off
error
power relay or relative
circuit broken
Consult with the supplier
Faults which can be recovered manually and automatically
Display
content
Cause
Corrective action
OC-A
Over-current at
acceleration
1.Acceleration time too short
2.The capacity of the motor
exceeds the capacity of
the inverter
3.Short circuit between the
motor coil and the case
4.Short circuit between
motor wiring and ground
5.IGBT module damaged
1.Set a longer acceleration
time
2.Replace inverter with one
that has the same rating
as that of the motor
3.Check the motor
4.Check the wiring
5.Consult with the supplier
OC-C
Over-current at
fixed speed
1.Transient load change
2.Transient power change
1.Increase the capacity of
the inverter
2.Install inductor on the
power Supply input side
