Generalised rotating-field theory of wound-rotor induction machines having asymmetry in stator and/or rotor windings

Rotating-field concepts are utilised to develop a generalised theory of induction machines having asymmetrical windings on both the stator and the rotor. No constraint has been put on the type of asymmetry present; both the differing number of turns in the phase windings and their nonuniform spatial displacement have been included. Asymmetry is shown to produce currents of various frequencies which are dependent on the speed of the machine. Symmetry on either side of the gap considerably reduces the number of such generated frequencies. A few examples are given to illustrate that earlier published analyses of the behaviour of asymmetrical induction machines are but special cases of the generalised theory.