The Effect of Ladder-Bar Shape Variation for A Ladder-Secondary Double-Sided Linear Induction Motor (LSDSLIM) Design to Cogging Force and Useful Thrust Performances

Abstract

This paper describes an investigation on the variation of the magnetic circuit of LSDSLIM (Ladder Secondary Double-Sided Linear Induction Motors) for the ladder-bar shape effects of cogging action and useful thrust. The comparisons are based on the Maxwell Stress method and FE method. The background of this investigation is related to that there are conflicts between the air gap length and cogging force and useful thrust for the Linear induction motor design with ladder secondary. Therefore, as the first stage of the design, the objectives are to investigate the minimum cogging forces and maximum useful thrust for the ladder shape effect. The methodology of investigation is based on the variation of the tooth width and the slot width of stationary part for the variation of the shape of ladder-bars. The tooth width and the slot width of moving part remain constant. The two laddershaped which are investigated include trapezoidal ladder bar and rectangular ladder bar. In each shape, the variation of the ratio between the tooth width and the slot width of ladder bar is conducted, and the maximum magnitude of the cogging action and magnitude maximum of useful thrust are investigated. The goodness of this procedure is the ratio between cogging action to useful thrust. This investigation shows that the trapezoidLadder Bars can decrease the magnitude of the Cogging Action in linear induction motor until 2.5% compared to the rectangular ladder-bars, and the thrust does not decrease in significant value.