Thrust/Input-power Ratios and Size of Annular Linear Induction Motor

Abstract

The characteristics by the changing scale of size in annular linear induction motors are not clear so far. In this paper, therefore, the thrust/input power ratios by the changing scale of pole pitch and radius of the annular linear induction motor are clarified theoretically and experimentally under the conditions of constant voltage source and of constant current source. The theoretical analysis is given by the electromagnetic field equations in analytical model and the circuit equation in equivalent circuit. In experiment, the thrust/input power ratios at slip 1.0 are given by changing length of size in three test prototypes.
The thrust/input power ratio in constant input voltage is inversely proportional to the length of pole pitch (one-dimensional change of size). In the two-dimensional change of size, it is little changed by the length of radius. In the three-dimensional change of size (pole pitch and radius), it shows almost the same as the characteristic of the one-dimensional change of size. In the case of constant input current, the thrust/input power ratios show the same tendency as the case of constant input voltage by influence of annular type structure.
As a result, the thrust/input power ratios depend nearly on the length of pole pitch.