Segmental-rotor linear reluctance motors with large airgaps

Abstract

A semi-analytical theory for segmental-rotor linear reluctance motors is developed and confirmed by experiment. Approximate expressions for the airgap field components are obtained in closed form, with two coefficients which may be determined by numerical solution of the field equations; values of these coefficients are given for a range of segment shapes and airgap lengths. Expressions are derived for the normal and tractive forces, power factor and efficiency; a goodness factor is defined, and the effects of scale on machine performance are considered.