Harmonic restraint technique of stator core shape and non uniform air-gaped universal motors for vacuum cleaner

This paper focuses on the restraint method of the 3rd harmonics current, in which close attention has been paid to the iron core shape of the universal motor for power vacuum cleaners. In this paper, the gap permeance, magnetic saturation of an iron core, and the influence that a slot ripple has on harmonic current were verified using FEM electromagnetism analysis. As the result, stator core shape proved quantitatively that a restraint of harmonic current has an effect. The authors think assert that a design manual should be adapted to create an international standard about a restraint of the harmonic current of a universal motor.