Chapter 13 Warning CodesC2000 Plus 
 
ID No.  Display on LCD Keypad  Warning Name  Description 
9 
 
IGBT over-heating 
warning (oH1) 
The AC motor drive detects over-heating of IGBT
over the protection level of oH1 warning. (When Pr.06-
15 is higher than the IGBT over-heat
shows oH1 error without displaying oH1 warning.)   
Action and Reset 
Action condition  Pr.06-15 
Action time 
“oH1” warning occurs when IGBT temperature is higher than Pr.06-15 
value. 
Warning setting parameter  N/A 
Reset method  Auto-reset 
Reset condition 
The drive auto-resets when IGBT temperature is lower than oH1 warning level
minus (–) 5°C   
Record  N/A 
Cause  Corrective Actions 
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 
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.