Medium voltage motor harmonic heating, torques and voltage stress when applied on VFDs

The increase in the application of medium voltage variable frequency drives to AC motors has raised concerns regarding the effects the drives have on the motors. Most of the published data available is for low voltage motors and drives, which are not necessarily accurate for the medium voltage applications. We address the harmonic heating, torques and voltage stress that are induced on the motors when they are applied on various types of drives. Results from both modelling and field measured data is used to provide general guidelines.