Experimental and theoretical study of high-speed single-sided linear induction motors

An advanced experimental study of single-sided linear induction motors is presented. Experiments were carried out using a rotary-type test facility of practical scale; the input power is 150 kVA and the maximum velocity is 300km/h. Attention was concentrated on electromagnetic forces. There are three forces: the thrust, the vertical force, and the lateral force, the latter two forces of which possibly disturb the levitation and guidance control of a vehicle. The effect of lamination of the backing iron in a secondary, the influence of a pole pitch, and the influence of asymmetric positioning of a stator were examined. The lamination of the backing iron increased the thrust, especially for low-speed operation. However, the lamination was not so effective for high-speed operation where the end effect was considerable. It is found that the end effect and the magnetic saturation of the secondary play an essential role in a high-speed singlesided LIM. The experimental results were found to agree practically well with the theoretical calculations obtained using a 2-dimensional or a 3-dimensional theory.