Squirrel Cage Rotor Design and Manufacturing for High-Speed Applications

Abstract

A high-speed squirrel-cage induction machine requires totally different design compared to the traditional squirrel cage industrial motor because of mechanical limitations caused by the high speed. This results in a more complicated rotor construction, expensive material selection and sets higher standards to the manufacturing precision. The objective of this paper is to demonstrate the design aspects, material selection, and manufacturing of a squirrel cage rotor for high-speed applications. In this paper, the rotor dimensioning approach based on equations and data analysis is presented. Rotor material selection and construction topology influence on the electrical machine design are discussed. The results are illustrated with the design of a 6 kW, 120 000 rpm induction machine for a turbo-circulator. The rotor parameters' influence on the electromagnetic performance of the designed machine is demonstrated. Mechanical stresses for different topologies are studied with Finite Element Method (FEM) analysis. Several manufacturing methods to produce a high precision rotor are described and compared. Presented rotor design approach, which enables high electromagnetic performance and robust construction is verified by testing of a prototype.