Study On The Electromagnetic Vibration Of Asynchronous Motor In Asymmetric Operation

With the development of industry, the motor as an equipment for power exportation ismore and more important. Therefore, to ensure safe and reliable operation of the motor hasbeen the focus of attention. The resonance by changing electromagnetic force is a primaryfactor for causing the accident. Therefore, the study on factors affecting air-gap magneticfield changes and the vibration of rotor when it subjected to electromagnetic force hasimportant theoretical and practical significance.As the motor supported by asymmetry run-time working, this paper has studied theelectromagnetic vibration when the rotor is subjected to heterogeneous air-gapelectromagnetic force and the electromagnetic damping force. Firstly, according to theKirchhoff’s low, it has obtained the symmetric run phase stator voltage equation and theequivalent. And on this basis, the paper has analyzed the asymmetric operation of thecircuit, it has obtained current and voltage equations, thus obtained sequence and reversemagnetic potential when it is in the asymmetric run-time.Secondly, according to the basic electromagnetic theory and energy method, thepaper has obtained the electromagnetic force and the electromagnetic damping force innon-uniform air-gap magnetic field when the motor on the asymmetry running. on thebasis of the programming calculation, draw in different asymmetric case, electromagneticforce, electromagnetic damping force and electromagnetic energy curve changing withtime, and discuss the outer voltage and rotor eccentric mass effectOnce again, According to the Lagrange equations of non-conservative system, it hasobtained the electrical vibration equation when the motor has no load. To a specific type ofelectric motor as an example, through the calculation, taking into account the differentsituation, caused by different asymmetric magnetic potential, at different voltages andeccentric cases draw the vibration displacement versus time curve, rotor phase diagram,the graph of the rotor motion. And qualitative analysis of the graph has been done.Finally, based on the energy method and average method, inherent frequency is closeto the excitation frequency is derived when the parameters of vibration equation. Takingthe motor for example, its amplitude-frequency curve has been mapped out, and the analysis of the variation rule has been done.