Chapter 8 Troubleshooting|VP3000 
404 
 
IGBT over-heating 
warning   
(oH1)   
The AC motor drive detects over-heating of IGBT which exceeds the protection 
level of oH1 warning. (When Pr. H4-00 is higher than the IGBT overheating level, 
the drive shows oH1 error without displaying oH1 warning.) 
Immediately acts when IGBT voltage is higher than Pr. H4-00 
Warning Setting Parameter 
The drive auto-resets when IGBT temperature is lower than oH1 warning level 
minus (–) 5°C 
Check if the ambient temperature 
or temperature inside the cabinet 
is too high, or if there is 
obstruction in the ventilation hole 
of the control cabinet. 
1.  Check the ambient temperature. 
2.  Regularly inspect the ventilation hole of the control cabinet. 
3.  Change  the  installed  place  if  there  are  heating  objects,  such  as  braking 
resistors, in the surroundings. 
4.  Install / add cooling fan or air conditioner to lower the temperature inside the 
cabinet. 
Check if there is any obstruction 
on the heat sink or if the fan is 
running 
Remove the obstruction or replace the cooling fan. 
Insufficient ventilation space 
Increase ventilation space of the drive. 
Check if the drive matches the 
corresponded loading. 
1.  Decrease loading. 
2.  Decrease the carrier. 
3.  Replace with a drive with larger capacity. 
The drive has run 100% or more of 
the rated output for a long time 
Replace with a drive with larger capacity.