N3 OV and LV errors 
Replace fuse
No 
Apply power
No 
Yes
Is the Fwd LED on ? 
Yes
The inverter is faulty. 
Perform a detailed check.
Yes
Inverter is functioning normally
No 
Fig. 22.3  OV and LV Error Troubleshooting 
Is the main circuit fuse 
ok ?
Replace control board
Yes
Is there motor output voltage at 
terminals  U, V & W ?
Input frequency command
No 
Yes
Does the inverter function 
normally after replacement  
?
Yes
Any faults displayed ?
Are there any visual 
abnormalties ?
Replace faulty parts
Are there any  
abnormal indications ?
Input operational command
Yes
No 
Replace control board
Is the output frequency displayed 
on the digital operator ?
Yes
Replace control board
No 
No 
Replace control board
Connect the motor and run
Yes
Are the current 
detectors ok  ?
No 
No