Asynchronous motor with spiral sheet armature. Improvement of the functional characteristics of the asynchronous motors

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 (with its different magnetic variants) are analysed in 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 it is combined with different constructive and mechanical characteristics of the related elements: changing inertias, constructive materials, and the geometrical shapes and disposition of the sheets. These variants of motors have been first tested using computer aided tools (Matlab-Simulink) and afterwards by means of laboratory tests. In particular three stators (1000, 1500, and 3000 rpm) having the same constructive parameters, have been tested with the following rotors: solid armature, solid armature with diamagnetic rings, winding armature, diamagnetic hollow armature, resistant armature, and simple and double squirrel cage armature. All these results have been compared to those obtained with the four variants of spiral sheet armature, presented in 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 the motors, without any negative consequence on the torque.