Effects of impregnating materials on thermal and electrical stabilities of the hts racetrack pancake coils without turn-to-turn insulation

Hyun Jin Shin, Kwang Lok Kim, Yoon Hyuck Choi, Oh Jun Kwon, Seungyong Hahn, Yukikazu Iwasa, Haigun G. Lee

Research output: Contribution to journalArticle

44 Citations (Scopus)


A high temperature superconducting (HTS) coil without turn-to-turn insulation is proposed for the field coil of a wind turbine. In the case of the field coil, epoxy impregnation is generally necessary to protect the coil from mechanical disturbances by time-varying magnetic fields and rotational vibrations to provide high mechanical integrity. This study examined the thermal and electrical stabilities of non-insulated GdBCO racetrack pancake coils impregnated with CTD-521, Stycast 2850 FT, and paraffin through cool down, over-current, and repetitive cooling tests. Among the three epoxy impregnated coils, the Stycast 2850 FT-impregnated coil exhibited the best thermal and electrical stabilities during over-current testing. In repetitive cooling conditions, the CTD-521-impregnated coil exhibited less degradation of its superconducting property due to the well-matching of the thermal contraction between the GdBCO racetrack pancake coil and the epoxy.

Original languageEnglish
Article number7700404
JournalIEEE Transactions on Applied Superconductivity
Issue number3
Publication statusPublished - 2013 Feb 8



  • CTD-521
  • Coil impregnation
  • GdBCO racetrack coil
  • Stycast 2850 FT
  • paraffin

ASJC Scopus subject areas

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

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