A novel solid-rotor induction motor with skewed slits in radial and axial directions and its performance analysis using finite element method

Due to its simple construction and excellent mechanical/thermal stress withstanding capability, induction motor with solid-rotor structure is widely used in many high-speed, high pressure application fields. In this paper, a novel solid-rotor induction motor with skewed slits in both radial and axial directions is presented. The performance of the proposed solid rotor is simulated using time stepping finite element method (FEM). Because of the existence of the axial slits, the magnetic flux in the slit-rotor motor can penetrate, relative to those without slits, deeper into the rotor. Analysis shows that its torque is about 3.46 times of that of the motor with no rotor slits. By skewing the rotor slits in the radial direction in the novel motor being proposed, the torque is further increased by about 37.7% when compared with that of the motor with its rotor slits not skewed along the radial direction. Although more torque ripples are generated in rotors with skewed slits in the radial direction, it is shown that the torque ripples can be easily reduced by skewing of the slits along the axial direction.