Warning 66 in VLT FC301/ FC302 : Heat Sink Temperature Low - comes when the drive is too cold to operate. This warning is based on the temperature sensor in the IGBT module.

1. Increase the ambient temperature of the unit.
2. Supply a trickle amount of current to the drive whenever the motor is stopped by setting parameter 2-00 DC Hold/Preheat Current to 5% and parameter 1-80 Function at Stop.