Study On Technology Of Asynchronous Motor Condition Monitoring And Fault Diagnosis

With higher performance to price and good adaption, asynchronous motor has been used widely in power system and industrial production as main power equipment. The operation status of asynchronous motor has a direct effect on the normal running of industrial production. Once serious fault occurs to motor, not only will it destroy motor itself, but also will lead the whole industrial production to break. The common fault of asynchronous motor can be classified as stator fault, rotor fault as well as bearing fault mainly. As the insulation system of stator winding is the weakest part of motor, probability of the fault occurring to stator winding is very high in proportion, which is a serious threat to the safe operation of the motor.Therefore, it is significant to develop a device used to record and locate the fault of asynchronous motor's major stator winding to avoid the occurrence of serious accidents, search the fault reason and take measures to maintain the fault.The device is composed of upper computer and lower computer. It can not only detect three-phase voltage and current as well as zero-sequence current continuous and save the result detected into a high-capacity flash memory,but read the time data of time chip and use it as time reference for detecting data. The data in the memory of lower computer can be transmitted to upper computer through RS232. The upper computer save the data received from the lower computer in the form of files. On one side, upper computer software can display the data upper transmitted in the form of curve, on the other side, the software can also use recorded data to process fault diagnose and analysis and draw a conclusion including fault type, fault position, the time fault appeared and so on. In this paper more detail description about the hardware as well as software design of the device will be given.Through theoretical deduction,this paper obtains the fault character of rotor barbreak,end collar crack which are very common for squirrel asynchronous motor,which is proved out by simulation.This simulation is carried out by building simulation equation when the motor is in the state of fault.Besides,this paper studies on the extraction method for fault characteristic signal and analyzes the problems which arised when adopting FFT to process spectrum analysis and analyze the simulation data.At last this papter presents an improved method and draws some useful conclusions.