Superconducting magnetic bearing for a flywheel energy storage system using superconducting coils and bulk superconductors

K. Nagashima, H. Seino, Naomichi Sakai, Masato Murakami

Research output: Contribution to journalArticle

24 Citations (Scopus)


Stable levitation or suspension of a heavy object in mid-air can be realized using a combination of a permanent magnet and a bulk superconductor with high critical current density, in that the force density has reached 100 kN/m2. The superconducting flywheel system for energy storage is attractive due to a great reduction in the rotational loss of the bearings. So long as a permanent magnet is used as a magnetic source, however, the electromagnetic force (EMF) is essentially limited by its field strength. In order to overcome such a limitation, we employed a superconducting coil/magnet as a magnetic source and studied the EMF characteristics of bulk superconductors in high-magnetic fields. We also measured the EMF between a bulk superconductor and a specially designed superconducting coil having a high field gradient, and confirmed that the EMF reached 9450 N (force density: 2507 kN/m2).

Original languageEnglish
Pages (from-to)1244-1249
Number of pages6
JournalPhysica C: Superconductivity and its Applications
Issue number15-20
Publication statusPublished - 2009 Oct 15



  • Bulk superconductor
  • Energy storage
  • Flywheel
  • Magnetic bearing
  • Superconducting coil

ASJC Scopus subject areas

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

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