Research On The Vibration Of AC Motor Caused By Faults

Vibration is one of the expression styles of the running status of motor. And different running status' takes out different vibration styles. When the motor has fault, greater vibration will be taken out and it will influence the working quality and life of the device which drove by the motor. So it is very important to study the vibration of the AC motor.Modal Analysis Method (MAM) can use less motion equations or freedoms to reflect the vibration of a more complex structure system in a straight, simple and very accurate way. It has less working time of measuring, analyzing and calculating than other ways.In this paper, the method conjoint of Finite Element Method (FEM) and Experiment Modal Analysis (EMA) is used to study the whole vibration characteristic of asynchronous motor. It has a pierce to the ways of just studying some part of a motor or the motor in static status in the past. And it can study the vibration characteristics to estimate whether the motor has fault or not, when the motor is running. So it is more advantaged.The vibration of the motor running in no-load and rated-load is studied respectively. It is compared that it is hard to estimate whether the motor has fault when running in no-load status. And when the motor is running in rated-load status, it is much easier to distinguish. So in this paper, the motor running in rated-load will be mainly studied.By simulating and made the various faults to the motor, such as one-bar broken and two-bar broken of rotor, the vibration of the motor running in fault status and normal status is studied. The natural frequencies and their related mode shapes of the motor running in various status are gained. And by comparing and analyzing on them, a law is found. The fault component (1 ± 2s)f₁, is also found in the vibration signal when the motor has fault. And it becomes more obvious when the fault is heavier. It is useful to the fault diagnosis of the motor.