Polyphase Induction Machine with a Slitted Ferromagnetic Rotor: I - Experimental Investigations and a Novel Slipmeter

In this and its companion paper, the performance of the polyphase induction motor with slitted ferromagnetic rotor is presented. Experimental studies covered the influence of physical dimensions of slits and their number on the rotor performance, effects of inserting a conducting, nonmagnetic material like copper in the slits, and the performance of these rotors terminated with and without copper end rings. The conclusions drawn are amply supported by the results of a careful measurement of flux penetration at different depths beneath the rotor surface. In addition, a slipmeter, an unique device with a high sensitivity at low slip regions, used for a quick and direct measurement of slip, is described. The authors believe it is likely to find extensive application in induction machine test ng.