Calculation of magnetizing inductance and magnetizing current of squirrel cage induction motor

This paper describes a technique for calculating the magnetizing inductance and the magnetizing current of an induction motor with closed slots as a function of slip, using the magnetic energy and the magnetic co-energy. This method is based on the use of finite element method (FEM) analysis. And to calculate the magnetizing current from the phase difference between the stator and the rotor magnetomotive force (MMF), the two-dimensional (2-D) static FEM is also applied after the three-dimensional (3-D) nonlinear time-stepping FEM analysis. As a result, we can obtain the magnetizing inductance and the magnetizing current as a function of slip. The magnetizing inductance calculated from this method agrees well with the measurement result at the rated point of the motor. The method may be used for the calculation of the magnetizing inductance and the magnetizing current variation curves. It enables the motor characteristics to evaluate accurately in its design process.