The Influence of Secondary Solid Ferromagnetic Plate Thickness on the Performance of Single-Sided Linear Induction Motors

ABSTRACT Two common configurations of the single-sided linear induction motor (SLIM) use a reaction rail consisting of (i) an aluminum cap over a solid steel core, and (ii) a simple solid steel strip. The influence of the thickness of the solid steel component on the electromechanical performance of the SLIM is analysed. An equivalent circuit of the SLIM, with speed and frequency dependent parameters, is used. The magnetizing and secondary impedances are evaluated from the solution of the two-dimensional field distribution in the machine. The performance of the SLIM is dependent on the ratio of secondary/ magnetizing current, which depends on steel thickness through changes in the magnetic permeability, saturation factor, and propagation constant of the electromagnetic wave in the steel. The analysis is validated by comparison with test results on two SLIMs, and is used to evaluate the effects of varying steel thickness under constant voltage and constant current excitation.