| As a power device,asynchronous motor is widely used in industrial fields such as power transmission,transportation and servo control.Therefore,it is an indispensable device in production and life.Its operation reliability is inseparable from the smooth progress of production activities.With the domestic motor output and demand rising year by year,the demand for convenient and efficient motor fault detection is also increasing year by year.In order to find the slight insulation fault of asynchronous motor in time,this paper designs an on-line detection system for stator inter-turn short circuit fault,which is composed of hardware circuit and software system.It is applicable to the detection of minor insulation fault of single-phase and three-phase asynchronous motors in operation.It has a certain early warning function to prevent minor faults from developing into large motor faults in the working process.The main research contents of this paper include the following parts:(1)The motor fault diagnosis technology is classified and summarized.According to the advantages and disadvantages of various fault diagnosis techniques,the working principle of asynchronous motor and the mechanism of motor failure,the fault detection method considering the real-time and accuracy is selected to complete the design of fault detection system.(2)The hardware circuit of the system is designed to complete the preliminary signal processing and data acquisition of the motor current signal.The hardware system adopts PCIe-6320 data acquisition card to collect signals,which ensures the accuracy of data acquisition and can realize multi-channel synchronous acquisition.(3)The system operation interface is designed by LabVIEW,and the functions of data acquisition,empirical mode decomposition,Hilbert envelope demodulation and fault judgement are compiled.The system uses software to design a closed loop tracking data acquisition algorithm to realize the whole period sampling of signals.The endpoint effect and the dense mode mixing problem of empirical mode decomposition are improved by using the mirror continuation method and the signal amplitude zoom method.(4)The detection system is used to detect a single-phase asynchronous motor.Comparative experiments are carried out for motors under different working conditions.The detection system can accurately reflect the severity of motor interturn short circuit fault,and the detection results of faulty motors under different loads are still accurate.The time spent in fault detection can be controlled within 12 s,with good real-time performance. |
