Analysis of transient state of the squirrel cage induction motor by using magnetic equivalent circuit method

Finite element method is very flexible for new shapes and provides to us flux distribution, magnetomotive force, eddy currents, and torques. However, finite element method needs to long calculation time in order to desired accuracy. Magnetic equivalent circuit method takes the computation time less than finite element method. Therefore, finite element method mainly use to confirm the completed design and magnetic equivalent circuit method is convenient of complicated analysis of the transient state of the induction motor. Magnetic equivalent circuit method is restriction on only one direction of magnetic flux. In this paper, the construction elements (that is, stator iron, rotor iron, yoke, air gap etc.) of the squirrel cage induction motor was represented by flux tube. And, air gap magnetomotive force was calculated by magnetic equivalent circuit method. Starting transient torque and phase current of the squirrel cage induction motor was verified by the theoretical calculation and the experiment.