Research On Diagnosis Method And Testing System Development For Rotor Fault Of Induction Motor

As important driving device,induction motor is widely used in industry and life for its simple structure,high reliability and maintenance convenience.However,failure of motor would result in expensive repairing costs and low producing efficiency,and endanger the safety of equipment and personnel.Health monitoring and fault detection of incipient weak fault based on health management technology are effective approach to ensure the reliability and safety of equipment.Rotor is the rotating part of motor,and broken rotor bar is a typical mechanical fault of motor which is of great harm.Fault detection methods based on vibration signal processing needs installing sensors and expensive testing equipment,the problems of vibration analysis methods such as uncertain fault mechanism,indirect signal transfer path and difficulty on detecting of incipient weak fault are still unsolved.Focus on fault detection of broken rotor bar,nonintrusive detection and diagnosis method based on motor current signature analysis is studied.The main contents include:1.The rotor composition and common causes of broken rotor bars of induction motor are studied,and the characteristic performance and the influence of the broken rotor bars fault on the stator current is analyzed from the perspective of electromagnetic.2.Based on the equivalent physical model,the dynamic model of induction motor is built,and then the rotor fault simulation model of the induction motor in the ABC coordinate system is established.The studies have shown that the simulation model can effectively simulate the broken rotor bars fault by changing the equivalent resistance of the rotor windings,and depicting the rotor broken bar fault of motor current effect and provides the basis for fault analysis.3.Combined with the characteristics of the motor current signal,the fault detection algorithms based on energy operator and principal component modulus of rotor broken bar are proposed,and validated by simulation model data and the measured motor operation data.the research results show that energy operator algorithm is computationally simple and suitable for DSP processor because less data is needed comparing with methods based on vibration signal,the principal component modulus considering the current sequence information adequately,and would not introducing cross terms cause spectral interference,and the two algorithms can realize the fault detection for the broken rotor bar of motor.4.Based on DSP technology,the hardware design of the broken rotor bars fault test system of induction motor is carried out,and the circuit modules such as signal acquisition and processing,analog digital conversion,operation control,human computer interaction and system power supply are developed,and then the archetypal detection system is established.