A New Squirrel Cage Rotor Structure to Improve the Dynamic Performance of the Single Phase Induction Motor

Audible noise radiated by electrical machines is gaining more and more importance in the design process of electrical machines. The radial electromagnetic forces in induction motors play an important role in the production of audible noise and vibrations. The magnetic flux pulsations at the iron surfaces produce these radial forces which act on the stator and rotor structures. A squirrel-cage induction motor produces electromagnetic vibration and noise caused by interaction between many harmonic fluxes in the air gap. In this paper, a new structure of the squirrel cage rotor to improve the distribution of the air gap magnetic flux and reduce the electromagnetic forces and, consequently, the electromagnetic noise in a single-phase induction motor will be introduced. For this purpose, in the proposed design the rotor bars are located on the rotor according to a sinusoidal form. The results show that this structure of the rotor improves the dynamic behavior and many parameters such as electromagnetic forces, harmonic distortion of magnetic flux, and torque ripple.