Method for rotor construction for alternating induction motor

Abstract

A method of fabricating rotors for induction motors. In a first aspect, arcuately spaced apart rotor bars pass through channels the magnetic core of the motor. The rotors are formed of an elongate portion having a constant cross section parallel to the magnetic core laminations and include two portions protruding beyond the end laminations at opposite ends of the magnetic core. The protruding portions are, at one end, a head much like the head of a 'T', and at the other end, a straight continuation of the elongate portion. The rotor bars are formed to fit closely with one another in an interleaving arrangement. The protruding portions form an end ring assembly which is subjected to a consolidation process. In this way, for a rotor having N rotor bars, there will only be N braze joints in each end ring. In a second aspect, the 'T' shape of the rotor bars may be added after straight rotor bars have been installed in the rotor bar channels in the magnetic core with their end portions extending beyond the rotor bar channels as by inserting small pieces of copper which mate to the shape of the sides of the straight rotor bars between each pair of rotor bars so as to form the end ring. In a third aspect, high-speed operation is facilitated by the addition of a shrink-fit containment ring on each end ring.