Torque and suspension force in a bearingless switched reluctance motor

Masatsugu Takemoto, Akira Chiba, Hirofumi Akagi, Tadashi Fukao

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Bearingless switched reluctance motors, which can control rotor radial positions with magnetic force, have been proposed. The bearingless switched reluctance motors are characterized by integration of switched reluctance motors and magnetic bearings. These motors have two kinds of stator windings composed of motor main windings and suspension windings in the same stator in order to produce suspension force that can realize rotor shaft suspension without mechanical contacts or lubrication. For successful stable operation, accurate theoretical formulas of instantaneous torque and suspension force are necessary to a rotational speed controller and a rotor radial position controller. This paper derives the theoretical formulas of the instantaneous torque and the suspension force from an assumption of simple permeance distribution. This derivation process makes an assumption that fringing fluxes are distributed on elliptical lines. It is shown with experimental results that the derived theoretical formulas are very accurate in terms of practical application.

Original languageEnglish
Pages (from-to)72-82
Number of pages11
JournalElectrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi)
Issue number2
Publication statusPublished - Nov 15 2006
Externally publishedYes


  • Bearingless motor
  • Magnetic suspension
  • Permeance method
  • Switched-reluctance motor

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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