Methods for the measurement and monitoring of electric running rune symmetries in induction machines with cage runners

摘要

1. Arrangement for the metrological detection and monitoring of electrical asymmetries of a rotor rotating in a stator of an induction motor, particularly of asymmetries caused by rod or ring breaks in induction motors with cage rotors, by means of a measuring coil which consists of one or a plurality of turns and which is arranged in the bore surface, facing the air gap, of the stator laminated pack, characterised in that the width (W) of the measuring coil is dimensioned in the circumferential direction of the bore surface such that the main field of the motor, the upper fields of the turns and the tooth saturation fields do not induce any voltage in the coil, while the additional air gap fields produced by electrical rotor asymmetries produce a maximum voltage.