The detection and suppression of unbalanced magnetic pull in wound rotor induction motors using pole-specific search coils and auxiliary windings

This paper puts forward a concept for measuring rotor eccentricity in an wound rotor induction machines. The analysis is fully developed in the theory section then an experimental rig is described and measurements taken. These are compared to the calculated values. Using pole-specific search windings are necessary in a wound rotor machine because standard sideband current measurement techniques are only valid for cage induction machines. The search coils can also be used to suppress unbalanced magnetic pull if they have sufficient amp-turns and an analysis method is put forward.