Analytical calculation of equivalent circuit parameters accounting for deep bar effect in multiple-cage squirrel cage rotor

This paper deals with deep bar effect in squirrel cage rotors. Induction machines using this type of rotor are widespread. Some cages enhance the deep bar effect to improve the starting performances. In cited references, the analytical calculation of the equivalent circuit parameters has only been investigated for single-cage and double-cage rotors. In this paper, an analytical model is developed for the general case of n-cage rotor. The expressions of the equivalent circuit parameters are given and then applied to a double-cage slot. The results are compared to a finite element analysis for several slot dimensions. The limits of the model are shown for specific slot dimensions and conductor shapes. This paper shows that under typical dimensions the model provides good accuracy with the simulations on a wide range of frequencies.