Damper winding for noise and vibration reduction of induction machine under sinusoidal conditions

Abstract : The flux density harmonics in the air-gap of AC machines have many origins. They generate electromotive forces and current harmonics, Maxwell forces, noise and vibrations. The principle of the presented method is to use a new auxiliary stator winding, connected to capacitors. The induced current harmonics generate flux density components in opposition to the initial ones, creating a damping effect. The study presented in this paper concerns an induction machine and particularly focus on flux density harmonics generated by slotting effects. The method allows to reduce the sound pressure level main lines of about 15dBA. The vibrations are reduced too. Moreover the stator current harmonics are attenuated, and the power factor is significantly improved.