Study On Electromagnetic Vibration And Noise Of Asynchronous Motor

As one of many motor types,squirrel-cage asynchronous motor has the advantages of low price,simple structure and high performance,and plays an important role in industrial production and transportation.With the development of science and technology,the noise and vibration problems of motors have gradually attracted the relevant researchers.At present,the electromagnetic noise problem of electrical machinery involves the theories of electromagnetism,mechanics,acoustics and other disciplines,and it is a problem involving the coupling of multiple physical quantities.This paper takes a Y-160M-4 squirrel-cage asynchronous motor as the research object.Based on the multi-physics coupling simulation platform,the electromagnetic characteristics,inherent mode,vibration response and noise radiation of the asynchronous motor are analyzed.The reasons for the electromagnetic vibration and noise of the motor are explored,and the electromagnetic characteristics of the asynchronous motor are analyzed.Based on the mathematical analytic method,the air-gap flux density and radial electromagnetic force of the asynchronous motor are calculated,and the main components of the harmonics of the air-gap flux density and electromagnetic force density curve of the asynchronous motor are solved.The finite element simulation software is used to build the two-dimensional electromagnetic model of the asynchronous motor under the condition of rated speed and no load.The electromagnetic characteristics of the asynchronous motor are calculated.And this article uses the two-dimensional Fourier transform tool to decompose the air-gap flux density and radial electromagnetic force wave in space and time to verify the analytical results.The three-dimensional model of the asynchronous motor is established.At the same time,the modal analysis is completed.Used the electromagnetic force as the excitation,the modal superposition is used to simulate the vibration of the motor,and the vibration response of the surface of the motor is obtained.A spherical air acoustic model is established,and the vibration acceleration of the motor shell surface is used as the excitation source to simulate the noise of sound pressure level of the asynchronous motor.Finally,the modal analysis,harmonic response analysis and harmonic acoustics of the induction motor are completed,and the inherent mode,modal frequency,vibration response and noise radiation are obtained.By building a test platform,the vibration test and noise test of the physical motor are completed,and it is verified that the simulation method has certain reliability.The influence of angle of the rotor skewed slot on electromagnetic vibration and noise of asynchronous motor is studied.Through the electromagnetic field simulation of the asynchronous motor with five different rotor skewed slot angles,the air-gap magnetic density and radial electromagnetic force characteristics are obtained.And the space-time decomposition is completed to explore the relationship between the skewed slot angle and the radial electromagnetic force waves of each order.Combined with the harmonic response analysis and harmonic acoustics of the asynchronous motor,the vibration acceleration results and the A-weighted sound pressure level distribution results are obtained.By comparing the five rotor skew conditions,it is found that when the noise is at the frequency of 3815 Hz,the noise radiation and vibration acceleration response of the 13.85° skewed motor keep a relatively low level.The maximum value of A-weighted sound pressure level is 86.396 d B,which is about 2.4d B lower than the maximum noise condition.This article describes the relationship between the width of the stator slot bottom and the electromagnetic vibration noise.And it is found that a larger slot bottom width can weaken the electromagnetic noise of the motor.As the width of the slot bottom increases,the harmonic amplitude of the air-gap flux density of the asynchronous motor will gradually decrease.And the same phenomenon exists in the harmonic amplitude of the radial electromagnetic force wave.Combined with the simulation results of vibration and noise,it is concluded that the electromagnetic vibration response of the asynchronous motor is inversely proportional to the width of the stator slot bottom.