Rotary dynamoelectric machine having high-resistance rotor

Abstract

A rotary dynamoelectric machine having a generally annular polyphase stator with a predetermined number of wound poles and an induction rotor. The rotor has a cylindrical laminated ferromagnetic core positioned within the stator for rotation about a central axis thereof when the stator is energized by an a.c. power source. The rotor is of squirrel-cage construction having a plurality of electrically conductive bars each extending the length of the core adjacent the cylindrical surface thereof. Conductive end rings at the ends of the rotor are electrically connected to the ends of the bars at the respective ends of the core. The end rings have a plurality of radial slots therethrough thereby forming a plurality of spaced arcuate ring segments whereby the rotor has a relatively high resistance, e.g., at least three times that of such a squirrel-cage rotor with unsegmented end rings. The stator windings may be interconnected with a source of single-phase a.c. power source to permit the machine to be used as a self-starting rotary phase converter for supplying three-phase power to a load or they may be connected to a single or polyphase a.c. power source to provide a motor having low inrush current and high starting torque.

Dependencies are inferred from the claim text.