10-8
Table 2 Warning/Self-diagnosis and Corrective actions
LED display
Description
Cause
Possible solutions
OV (flash)
Over voltage
DC bus voltage exceeds the OV
detection level
：
200V class
：
410Vdc
400V class
：
820Vdc
(for 400V class, if input voltage
01-14 is set lower than 400V, the OV
detection value will is decreased to
700Vdc)
Deceleration time set too
short, resulting in
regenerative energy
flowing back from motor
to the inverter.
The inverter input voltage
is too high.
Use of power factor
correction capacitors.
Excessive braking load.
Braking transistor or
resistor defective.
Speed search parameters
set incorrectly.
Increase deceleration time
Reduce input voltage to comply
with the input voltage
requirements or install an AC
line reactor to lower the input
voltage.
Remove the power factor
correction capacitor.
Use dynamic braking unit.
Replace braking transistor or
resistor.
Adjust speed search
parameters.
UV (flash)
under voltage
DC bus voltage is lower than the UV
detection level or the pre-charge
contactor is not active while the
inverter is running.
190Vdc
：
200V class;
380Vdc
：
400V class
(the detection value can be adjusted
with parameter 07-13)
The input voltage is too
low.
Input phase loss.
Acceleration time set too
short.
Input voltage fluctuation.
Pre-charge contactor
damaged.
DC bus voltage feedback
signal value incorrect.
Check the input voltage.
Check input wiring.
Increase acceleration time.
Check power source
Replace pre-charge contactor
Replace control board or
complete inverter.
OH1 (flash)
Heatsink
overheat
The temperature of the heat sink is
too high.
Note: when OH1 fault occurs three
times within five minutes, it is
required to wait 10 minutes before
the inverter can be reset.
Ambient temperature too
high.
Cooling fan failed
Carrier frequency set too
high.
Load too heavy.
Install fan or AC to cool
surroundings.
Replace cooling fan.
Reduce carrier frequency.
Reduce load / Measure output
current
OH2 (flash)
Inverter over
Heating
warning
Inverters overheat warning.
Multi-function digital input set to 31.
(03-00~03-05=31)
Multifunction digital input
overheat warning active
Multi-function input function set
incorrectly.
Check wiring
