A bearingless coaxial magnetic gearbox

Research output: Contribution to journalArticle

4 Citations (Scopus)


Recently, magnetic gearboxes (MGBs) are serious contenders to their conventional mechanical counterparts in terms of reduced maintenance requirements, improved reliability, tolerance to mechanical inaccuracies, and inherent overload protection. MGBs are preferably employed in high speed applications and compact harsh environments subjected to severe shock and vibration. A high gear ratio MGB is also a suitable candidate for single stage high-speed transmission applications such as helicopter power transmissions. In this paper, the conventional planetary magnetic gearbox is equipped with a three-phase winding to provide additional magnetic levitation capabilities besides torque transmission, thus creating a bearingless MGB configuration. This was achieved by adding a three-phase winding in the space between the ferromagnetic pieces. The current in this additional winding is controlled to provide decoupled axial forces irrespective of the transmitted mechanical power. This feature is important to reduce the mechanical losses especially for high-speed rotors and can be a viable method for vibration suppression.

Original languageEnglish
Pages (from-to)573-582
Number of pages10
JournalAlexandria Engineering Journal
Issue number3
Publication statusPublished - 2014



  • Bearingless machines
  • Finite elements
  • Gearbox
  • Magnetic planetary gear
  • Permanent magnets
  • Speed reduction ratio

ASJC Scopus subject areas

  • Engineering(all)

Cite this