Research And Development Of Insulation Life Prediction System For Low-voltage Motors

With the rapid development of China’s industrial modernizat ion in recent years,low-voltage motors have compete a vital role within the pillar industries of the economic system,like power,energy,machinery and petrochemical.As low-voltage motors are subject to complex working environment,their insulation performance deteriorates and even motor accidents occur,resulting in huge economic losses.Therefore,So as to scale back the economic losses caused by insulation failure of motors,it’s necessary to predict their insulation life.In this thesis,a two-parameter Weibull distribution model is developed to predict the insulation lifetime of low-voltage motors,and a complete system for predicting the insulation life of low-voltage motors is developed.The main research contents are as follows.Firstly,the insulation material,insulation structure and insulation distance of the stator insulation system of low-voltage motors are introduced,and the thermal and mechanical stresses are identified as the main aging stresses in the operation of low-voltage motors by analyzing and comparing four kinds of insulation aging stresses,and the parameters that need to be collected in the life prediction system are determined.Secondly,within the study of the life prediction method,the i mportance of insulation resistance and also the testing principle are explained;the two-parameter Weibull distribution model is introduced,and the least-squares estimation is selected after comparing five parameter estimation methods;a temperature-mechanical dual stress accelerated life test is designed and implemented,and the two parameters are estimated using the life data,and the correlation test and goodness-of-fit test prove that the insulation life of low-voltage motors obeys the two-parameter Weibull distribution;the model is used as the life prediction model for reliability analysis and average life modeling,and the reliability function and life prediction curve are plotted.Finally,the software and hardware solutions are designed to meet the system requirements.The hardware selection,circuit design and software programming of each function module in the embedded system of the lower computer are carried out,and realize the functions of parameter acquisition,insulation resistance detection,life prediction,data communication and display;the human-computer interaction interface of the upper computer is designed to realize the functions of paremeter display;the overall functions of the system are tested and verified from three aspects:lower computer,upper and lower serial communication and upper computer.The results show that the hardware circuit is highly reliable,the parametric error is small,the software program is reasonable,with good readability and portability,and the system is well coordinated among all levels,which can realize the prediction of insulation life of low-voltage motors and meet the requirements of the system.