Simulation of a Turn-to-Turn Short Circuit in an Induction-Motor Rotor Winding

The article is devoted to the calculation and modeling of asynchronous motors with interturn short circuit in the rotor circuit. A brief description of analytical and numerical methods for calculating such modes is presented. The incompatibility of the analytical methods for calculating asymmetrical modes with the problems of considering nonlinear processes in electric machines is noted. The choice in favor of a three-phase natural coordinate system is justified in relation to the specific task of calculating an asymmetric running mode in combination with consideration of the nonlinear properties of the magnetic-core steel. The modified mathematical model of an asynchronous motor in a three-phase natural coordinate system for calculating currents and electromagnetic torque at an interturn short circuit in the rotor-winding phase is presented. This model is a modified classical model. The results of the numerical simulation of this running mode are presented. An analysis of the distinct features of the selected mode in comparison with the symmetrical running mode and of its influence on the behavior of electric motors during operation is carried out. An estimation is carried out of the minimum percentage of short-circuited turns, at which the electromagnetic torque of the motor in the area of failure is below the nominal load torque.