Heatsink Overtemperature Pre-alarm

What does OH mean?

An OH pre-alarm is issued when the heatsink temperature exceeds the L8-02 level, acting as an early warning before an OH2 fault trip. Depending on L8-03, the drive may continue running or continue running at a reduced speed. This signals that the heatsink is approaching its overtemperature limit and corrective action may be needed to prevent a full fault trip and subsequent shutdown.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Consider implementing load shedding or temporary speed reduction if the pre-alarm is frequent, to allow the drive to cool.

2. 4

   Review parameter L8-03 to understand the drive's configured behavior (continue, reduce speed) when this alarm is active.