Cause : DC bus over temperature- The OHt dc bus trip indicates a DC bus component over temperature based on a software thermal model. The drive includes a thermal protection system to protect the DC bus components within the drive.

1. This includes the effects of the output current and DC bus ripple.
2. The estimated temperature is displayed as a percentage of the trip level in Pr 07.035.
3. If this parameter reaches 100 % then an OHt dc bus trip with sub-trip 200 is initiated.
4. The drive will attempt to stop the motor before tripping.
5. If the motor does not stop in 10 seconds the drive trips immediately.
6. Check the AC supply voltage balance and levels.
7. Check DC bus ripple level.
8. Reduce duty cycle.
9. Reduce motor load.
10. Check the output current stability.