Thrust Performance Improvement of a Linear Induction Motor

  • Lee, Hyung-Woo ;
  • Park, Chan-Bae ;
  • Lee, Byung-Song
  • Received : 2010.05.14
  • Accepted : 2010.06.22
  • Published : 2011.01.01


The end effect of a linear induction motor (LIM) has been known for several decades, especially in high speed operation. The exit part of the primary is not dealt as extensively as the entry part because of its minor effect. However, the exit part is one of the keys to weaken the dolphin effect, which occurs in high speed operation. In this paper, the concept of the virtual primary core is introduced, and chamfering of the primary outlet teeth is proposed to minimize the longitudinal end effect at the exit zone. For this, LIM for the high-speed train is designed and analyzed by using finite element method. Results confirm that chamfering can improve thrust performance effectively.


End effect;Dolphin effect;LIM;Linear motor;Virtual primary core


  1. Hyung-Woo Lee, Ki-Chan Kim and Ju Lee, "Review of maglev train technologies," IEEE Trans. Magnetics, Vol. 42, No. 7, pp. 1917-1925, 2006.
  2. Hyung-Woo Lee, Sung Gu Lee, Chanbae Park and Hyun-June Park, "Characteristic Analysis of a Linear Induction Motor for a Lightweight Train according to Various Secondary Schemes," International Journal of Railway, Vol. 1, No. 1, pp. 6-11, 2008.
  3. Sakae Yamamura, "Theory of linear induction motors," University of Tokyo Press, 1978.
  4. I. Boldea and S. A. Nasar, "Linear motion electromagnetic devices," Taylor & Francis, 2001.
  5. Korea Railroad Research Institute, "Linear Electric Railway System," pp. 1-8, 2007.
  6. Japan Subway Association, "Linear Metro System," pp. 1-28, 2004.
  7. T. Hirasa, S. Ishikawa and T. Yamamuro, "Equivalent circuit of linear induction motors with end effect taken into account," Electrical Engineering in Japan, Vol. 100, No. 2, pp. 65-71, 1980.
  8. J. F. Gieras, G. E. Dawson and A. R. Eastham, "A new longitudinal end effect factor for linear induction motors," IEEE Trans. Energy Conversion, Vol. EC-2, No. 1, pp. 152-159, 1987.
  9. Y. Mori, S. Torii and D. Ebihara, "End effect analysis of LIM based on the wavelet transform technique," IEEE Trans. Magnetics, Vol. 35, No. 5, pp. 3739-3741, 1999.
  10. N. Fujii and T. Harada, "A new viewpoint of end effect of linear induction motor from secondary side in ladder type model," IEEE Trans. Magnetics, Vol. 35, No. 5, pp. 4040-4042, 1999.
  11. T. Higuchi, S. Nonaka and M. Ando, "On the design of high-efficiency linear induction motors for linear metro," Electrical Engineering in Japan, Vol. 137, No. 2, pp. 36-43, 2001.
  12. N. Fujii, T. Harada, Y. Sakamoto and T. Kayasuga, "A compensation method for the end effect of a linear induction motor," Electrical Engineering in Japan, Vol. 143, No. 3, pp. 58-67, 2003.
  13. N. Fujii, T. Kayasuga and T. Hoshi, "Simple end effect compensator for linear induction motor," IEEE Trans. Magnetics, Vol.38, No.5, pp.3270-3272, 2002.
  14. J. Jamali, "End effect in linear induction and rotating electrical machines," IEEE Trans. Energy conversion, Vol. 18, No. 3, pp. 440-447, 2003.
  15. A. H. Selcuk and H. Koeroem, "Investigation of end effects in linear induction motors by using the finiteelement method," IEEE Trans. Magnetics, Vol. 44, No. 7, pp. 1791-1795, 2008.
  16. R. C. Creppe, J. A. C. Ulson and J. F. Rodrigues, "Influence of design parameters on linear induction motor end effect," IEEE Trans. Energy conversion, Vol. 23, No. 2, pp. 358-362, 2008.
  17. H. Mosebach, "The effects of finite length and width in linear induction motors for both the short primary and the short secondary types," Ph.D dissertation (in German), Technical University of Braunschweig, Germany, 1972.
  18. H. Lee, C. Park, B. Lee and H. Park, "Exit End Effect Reduction of a Linear Induction Motor for the Deepunderground GTX," will be presented in ICEM, 2010.

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