Analysis and Study of Skewed Slot Tooth Distance on Low Electromagnetic Noise of Three-Phase Induction Motor with Squirrel Cage Rotor

This paper studies the electromagnetic noise and vibration of three-phase induction motor with squirrel cage rotor affected by different skewed slots tooth distance. For low electromagnetic noise motor, a traditional method which recommending skewed slot tooth distance of the rotor is equal to one pitch of the stator is not optimal. A new method is proposed in which the coefficient factor is coupled to the stator when considering the behavior of the skewed slot by theoretical derivation and analysis in the influence of skewed slot rotor on the radial magnetic force. It is easy and effective to analyze the harmonic Magnetic Motive Force(MMF) and estimate the effect of skewed slot on reducing main magnetic noise caused by some specific electromagnetic force harmonic when the proper skewed slot tooth distance is selected. Electromagnetic finite analysis coupling electromagnetic field-circuit based on "multi-slice method" is investigated on skewed slot squirrel cage rotor, and simulation on three different skewed slots motor is discussed by this method. Three prototype machines using rotors with different skewed slots tooth distance are developed to validate the applicability of this method and examine the accuracy of the simulation results. In conclusion, its calculation results agree with the test results well.