Behavior of the Three-Phase Induction Motor With Spiral Sheet Rotor

Improvements in torque at low currents using a rotor with spiral sheets are analyzed. Several rotors and stators have been built combining different constructive and mechanical characteristics of the related elements: inertias, constructive materials, geometrical shapes of the sheets, and geometrical disposition of the sheets. These different types of motors have been simulated using computer-aided tools and then tested in the laboratory. Finally, four stators (1000, 1500, 1500-type A, and 3000 r/min), with the same constructive parameters, have been simulated and tested with the following rotors types: solid rotor, solid rotor with diamagnetic rings, drag cup, and simple and double squirrel cage rotor; the results have been compared to those obtained with the seven variants of the spiral sheet rotor presented in this paper.