Faults Analysis Of Short-circuit In Stator Winding For Three-phase Induction Motor

The three-phase induction motor is the type of motor with the largest coverage and the most amount,which is used as a driving device.With its advantages in low price,simple structure,convenient use,easy manufacturing,high reliability and suitable for complex work environment,it has been widely used.The short circuit fault of stator winding is the serious failure of the induction motor,which can burn the motor and damage the load,causing great loss.Based on an 11 k W three-phase induction motor as an example,considering the motor under the condition of short circuit magnetic saturation,using field-circuit combined with the analysis method,the equivalent magnetic network and finite element method(FEM),the transient process of a phase and two phase short circuit fault of the stator winding is simulated and analyzed.First of all,based on the theory of electromagnetic field,motor learning knowledge,and the actual working characteristics of motor,showing the basic parameters of the motor,and lists the mathematical model of three-phase induction motor and the definite condition;According to the short circuit of the motor,the external circuit is set up,and the field circuit of the motor is set up to analyze the calculation model.Then,through the initial conditions are set up,the magnetic field and operating characteristics of the motor are solved by applying the method of combination analysis.Secondly,the magnetic field of the motor is divided into several flux tubes by equivalent magnetic network method,so that all the magnetic force lines cross the cross section vertically.When the motor works at the knee point of the magnetization curve in the saturation region,the main magnetic circuit and the leakage magnetic circuit are changed,and the leakage of the magnetic circuit is the most important.The current interaction between the electric reactance of the motor and the saturation of the magnetic field after short circuit fault.Showing the algorithm of dynamic reactance,as an example of one phase short circuit of stator winding in three-phase induction motor,to analyze the changing rule of the inductance and current.It can be used to adjust the dynamic reactance after saturation of the magnetic field.Finally,the transient characteristics of three-phase induction motor stator winding with one phase and two phase short circuit are solved by field circuit analysis combined with finite element software.The corrected dynamic reactance value is replaced by the corrected dynamic reactance value after the short circuit fault of the motor stator,so that more accurate motor short-circuit current and short circuit torque characteristics can be obtained.It provides an effective means for motor stator winding short circuit fault to make quick judgement and accurate location.