Analysis of asymmetrical induction-motor windings

Recently, a number of single-winding multispeed induction motors have been devised in which some unbalance of the windings has been inevitable. This paper sets out to analyse such windings using the balanced applied voltage as the reference. The criteria necessary to form asymmetrical windings which will draw balanced currents are obtained. Particular attention is directed towards the pole-amplitude-modulated type of winding, in which two phases are alike and placed symmetrically about the third. Experimental verification of the theoretical results obtained is given for this type of winding.