An analysis is developed for induction motors having any number of asymmetrical primary windings and any symmetrical or asymmetrical power supply, with any symmetrical or asymmetrical impedances connected to the motor terminals, provided that symmetrical polyphase secondary windings are utilised. The basis of the analysis is the transformation of the asymmetrical primary windings to their equivalent tapped-quadrature windings, which has the advantage of facilitating the application of 2-phase rotating-field theory to the asymmetrical machine. All the parameters involved in the generalised analysis can be calculated from the design details of the motor, and its validity is demonstrated by the performance prediction of the shaded-pole type of single-phase motor.