Heat sink overtemperature

What does OH mean?

This fault indicates that the drive's heat sink temperature has exceeded its safe operating limit, typically due to insufficient cooling or excessive loading. By default, this critical condition triggers a full TRIP, inhibiting all ignition pulses and resetting the Ready signal to protect the drive's power semiconductors from thermal damage. Manual reset is required after the drive has cooled down and the cause is addressed.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Check ambient temperature: Ensure the operating environment temperature is within the drive's specified limits.

2. 4

   Reduce motor loading: Temporarily decrease the load on the motor to see if the temperature drops.

3. 5

   Inspect thermal paste/pads: If possible and safe, inspect the thermal interface material between power modules and the heatsink (requires power off and potentially disassembly).