The Comparative Performance of Single-Sided Linear Induction Motors with Squirrel-Cage, Solid-Steel and Aluminum-Capped Reaction Rails

There is a wealth of information in the literature and in technical reports on the performance of single-sided linear induction motors (SLIM's) with aluminum-capped steel reaction rails. Several analytical approaches and extensive experimental data are available. Comparatively little attention has been devoted to other reaction rail options, i.e. the solid-steel and squirrel-cage configurations. These alternative rails could offer significant improvements in capital and/or operating costs of the propulsion system for specific transportation applications. At Queen's University we have conducted test programs to evaluate the performance of a SLIM with squirrel-cage, solid-steel and aluminum-capped reaction rails, using the same primary. A selection of the test results are presented to illustrate the comparative performance characteristics. It is shown that the aluminum-capped rail offers the highest thrust and the lowest normal force, and is the most efficient drive at low speed. However, end effects cause a deterioration in performance at higher speeds. Solid steel provides the cheapest rail, shows much less end effect and exhibits good plugging performance. However, as a drive, it is less efficient and exhibits lower thrust and appreciably higher normal force than the aluminum-capped rail. The squirrel-cage rail exhibits an intermediate performance and is the most expensive rail option. The suitability of the three rail alternatives for various applications will be discussed.