Three-phase Asynchronous motor with spiral sheet rotor - Material effects and analysis

The study of the magnetic characteristics and constructive shapes of conductive materials, allows a better use of Its electrical characteristics, reducing the maintenance and extending the life of the electrical machines. The improvements obtained on the torque with low currents using rotor with spiral sheets are analysed on this paper. To have a complete study, several rotors and stators have been built to verify the electromagnetic variations on the three-phase asynchronous motors where they combine different constructive and mechanical characteristics of the related elements: changing Inertias, constructive materials, and the geometrical shapes and disposition of the sheets. These different types of motors have been first tested in the laboratory, then, are simulated using computer aided tools (Matlab-Simulink). In particular four stators (1000rpm, 1500rpm, 1500rpm-type A, and 3000 rpm) having the same constructive parameters, have been tested with the following rotors: solid rotor, solid rotor with diamagnetic rings, drag cup, and simple and double squirrel cage rotor. All these results have been compared to those obtained with the seven variants of spiral sheet rotor, presented on this paper, It has been demonstrated that it is possible to considerably reduce the starting currents, and therefore reducing the maintenance and extending the life of motors, without any negative consequence on the starting torque.