Progress of superconducting bearing technologies for flywheel energy storage systems

N. Koshizuka, F. Ishikawa, H. Nasu, M. Murakami, K. Matsunaga, S. Saito, O. Saito, Y. Nakamura, H. Yamamoto, R. Takahata, Y. Itoh, H. Ikezawa, M. Tomita

Research output: Contribution to journalConference articlepeer-review

55 Citations (Scopus)


We report present status of NEDO project on "Superconducting bearing technologies for flywheel energy storage systems". We fabricated a superconducting magnetic bearing module consisting of a stator of resin impregnated YBaCuO bulks and a rotor of NdFeB permanent magnet circuits. We obtained levitation force density of 8 N/cm2 at 81 K and rotation loss per levitation force of 3 mW/N at 77 K. We confirmed that both pre-loading and excess cooling methods are effective for suppressing gradual fall of rotor due to flux creep. We designed a 10 kWh class flywheel energy storage test system and investigated feasibility of active magnetic bearings for controlling rotation axis vibration under high speed rotation of the flywheel.

Original languageEnglish
Pages (from-to)444-450
Number of pages7
JournalPhysica C: Superconductivity and its applications
Publication statusPublished - 2003 Apr 15
Externally publishedYes
EventICMC 2002 - Xi an, China
Duration: 2002 Jun 162002 Jun 20


  • Active magnetic bearing
  • Flywheel energy storage system
  • Levitation force
  • Rotation loss
  • Superconducting magnetic bearing

ASJC Scopus subject areas

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


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