An Approach for Enhancing the Performance of Rotary-Linear Induction Motor

While the commercial motor produces only one-dimensional (linear or rotary) motion, we propose a new type of tubular linear induction motor (TLIM) with two-dimensional motion in this paper. The proposed motor consists of plural short primary LIMs arranged on the same circumference and a common secondary. By applying independently energized ring-windings of double-layer to the primary, we can achieve both the reduction of coil-end region and the freedom of alternating current supply. The secondary conductor is capable of producing any one of rotary, linear, and helical motions by controlling the phase of supply currents in each primary winding. We first investigate the driving characteristics of the proposed motor by three-dimensional finite element analysis, in order to obtain the optimal feeding conditions to increase the subsidiary rotary-force. Then, we make the experimental machine based on the analysis results. In addition, we deduce an optimal arrangement of the primary slot currents enhancing the secondary thrust in the short primary LIM. Finally, we confirm the adequacy of analytical results by experimental ones.