Loss and Air-gap Force Analysis of Cage Induction Motors With Non-skewed Asymmetrical Rotor Bars Based on FEM

Non-skewed asymmetrical rotors bars can be used to eliminate the slot harmonic fields and the resulting noise and vibration in cage induction motors. However, it is difficult to determine the spatial distribution of the asymmetrical rotor bars and the slot combinations, which can affect the loss and the air gap force significantly. With a 5.5 kW, 4-pole induction motor as an example, this paper studies the influence of the above factors on the loss and the air gap force by time-stepping finite element method, and the experiments are performed to validate the calculations.