Analysis and classification of bearingless machines with symmetric 3-phase concentrated windings

The paper deals with a classification for bearingless motors with separated 3-phase concentrated drive and bearing windings. Based on fundamental equations of the electrodynamics specific force equations are deduced, in order to develop lateral force properties in rotating machines. Furthermore, a new classification for 3-phase concentrated windings is proposed and adapted to bearingless motor theory. Based on that formalism the ordinal numbers and winding factors due to the winding scheme could be represented completely analytically. The deduced classification and formulas serve to obtain a relief in the practical design process of bearingless machines.