Characterization of a single-phase induction motor due to the effect of slot opening

This work investigates the effect of the slot opening on the torque and efficiency of a single-phase induction motor. The time-stepping finite element method is used to solve the electromagnetic coupled field in a single-phase induction motor, and then, the Maxwell stress tensor is used to investigate the mechanism of torque production and, eventually, to improve the efficiency. It shows that torque is produced in the vicinity of the slot opening as the rotating magnetic field revolves. It also shows that double layer slots, which have the main and auxiliary windings together, produce a significant amount of negative torque. This research designs the slots of the stator by controlling the slot opening as well as by appropriately introducing slot closure in such a way as to minimize negative torque so that it increases the efficiency of a single-phase induction motor.