Research On Vibration Response In Middle And Small Size Induction Motor Based On The Rotor Dynamic Characteristics

With the continuous development of the motor industry and the continuous progress in the key technology of the motor, the vibration and noise of the motor has become an important index to measure the quality of the motor. This makes the research and control of the vibration and noise of the motor has a considerable practical and economic benefits, the merits of the motor noise control will become the main factor in the market competition, therefore, in the new century, one of the key developments and promotion of product will be the low noise motor. Based on the dynamic characteristics of the motor rotor, the vibration response of the induction motor is well analyzed. The main work is divided into the following aspects:Firstly, the stator, winding, end cover, frame and the hole motor were accurately modelled by the application of the three dimensional modeling software Pro/Engineer, in order to calculate the corresponding modal analysis, the finite element software Workbench is well used, and the corresponding modal shapes and natural frequencies are obtained, the influence of different parts of the motor on the natural frequency is also analyzed, which provides the analysis basis for further improve motor from the structure to reduce vibration and noise. The accuracy of the finite element calculation result is verified by the hammer modal test method.Secondly, Based on the mechanism of induction motor electromagnetic vibration, the theoretical expression of the air gap magnetic density and electromagnetic force wave is derived from the magnetic potential. And with the help of the finite element software Ansoft Maxwell, according to the simulation of induction motor model, the magnetic distribution of the motor, air gap magnetic density distribution and the electromagnetic force generated by the air gap magnetic density were calculated by FEM and the vibration response of the motor was calculated in the large-scale commercial software ANSYS, at the same time the motor in static state when eccentric was also analyzed. And the finite element simulation results were verified by the vibration experiment.Finally, according to the actual situation of the motor rotor, the rotor-bearing dynamic analysis model is established. The calculation of natural frequency and critical speed of rotor-bearing system were carried by the application of SAMCEF Field, and the influence of different bearing stiffness on the natural frequency was analyzed. At the same time, through harmonic response analysis and transient response analysis, the displacement and acceleration response of the rotor system under different frequencies and changing time were also obtained, and the vibration reponse of the rotor system in the different bearing clearance was also studied, which laid the foundation of the analysis of the rotor dynamic balance and the bearing vibration.