Evaluation of fixed and moving primary linear induction motor systems

Linear induction motors being proposed for high-speed ground transportation may have their primaries carried on board the vehicle or embedded in the guideway. This paper evaluates various aspects, such as power requirements, power switching and controls, utilization factor, efficiency and cost, etc., for these two alternatives and provides the basic format on which relative merits of various systems can be readily evaluated. The analysis shows that, in the fixed primary system, it is economically impractical to energize sections of the roadbed substantially longer than the vehicle. Even when the primaries in the roadbed are energized in sections of minimum length, the cost of the linear induction motor and additional switching and power network for the fixed primary system is an order of magnitude higher than that for the moving primary system.