The Polyphase Commutator Regulator for Speed Control

This paper presents an explanation of the theory and explains the characteristics of an a-c adjustable-speed drive obtained by using a polyphase commutator regulator mechanically coupled to the shaft of a wound-rotor induction motor and electrically connected to its slip rings. The theoretical loci of the system current vectors with respect to the voltage vectors of the induction motor are developed in terms of the constants of the machines and the applied voltage. A method of determining the characteristics of the drive from no-load tests or from design data is presented. The characteristics predicted on these bases are in excellent agreement with those obtained experimentally.