Investigation of Thrust and Efficiency in Single-sided Linear Traction Motors with Discontinuous Reaction Rail Using Space Harmonic Technique

Owing to the indispensable railroad switch and auxiliary apparatus, the reaction rail, i.e. secondary plate, is discontinuously placed along steel rails. This paper investigates the influence of the discontinuity on the propulsive force and efficiency in the motor by a quasi-three-dimensional space harmonic technique. First, possible cases of the SLIM working with discontinuous secondary are presented. Second, an analytical model, which takes skin effects, secondary constructions and end effects into account, is proposed. Third, the distributions of the air-gap flux density and eddy current in the reaction rail along longitudinal and transverse direction considering the discontinuous reaction rail are presented. Then, the thrust and efficiency are analytically calculated under the typical slip-frequencies. Finally, the calculation results are verified, and the good correlation is obtained.