Subharmonic resonance of a rotor supported by a high-Tc superconductor

Tatsuya Suda, Shintaro Kobayashi, Toshihiko Sugiura

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


This paper investigates subharmonic resonance, one of typical nonlinear phenomena, appearing in a high-Tc superconducting bearing system. In such low-damping systems having noncontact support by magnetic force, complex dynamical behaviors can be caused by nonlinearity of the magnetic force. In this study, the magnetic rotor, supported by a high-Tc superconducting bulk, is bound to a D.C. motor with a universal joint. According to the equation of motion, caused by the quadratic term of the levitation force, subharmonic resonanceofthe rotor can occur when therotor rotates, not at its critical speed, but at twice its critical speed. This analytical prediction was confirmed by our numerical and experimental results. Additionally, our study also found occurrence of internal resonance induced by this subharmonic resonance. These findings beyond linear regimes can be important for the design of high-Tc superconducting levitation systems.

Original languageEnglish
Article number5678597
Pages (from-to)1493-1496
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Issue number3 PART 2
Publication statusPublished - 2011 Jun


  • Coupled vibration
  • Nonlinear dynamics
  • Steadystate resonance
  • Subharmonic resonance
  • Superconducting levitation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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