Turn-to-Turn Contact Resistance Measurement of No-Insulation REBCO Pancake Coil at DC Current Operation

So Noguchi, Takahiro Tatsuta, Daisuke Nishikawa, Hiroshi Ueda, Seokbeom Kim

Research output: Contribution to journalArticlepeer-review

Abstract

No-insulation (NI) (RE)Ba2Cu3Oy (REBCO) magnets are very promising for practical applications to generate high magnetic field. The NI winding technique provides high thermal stability so that quench protection is unnecessary. However, the turn-to-turn contact resistance (sometimes called characteristic resistance) is an important factor to characterize the thermal stability and charging delay of NI REBCO pancake magnets. Although the conventional sudden-discharging method is widely used to measure the turn-to-turn contact resistance, it is not applicable to various conditions; e.g., the change of DC operating current and temperature. Therefore, we have previously proposed a turn-to-turn contact resistance measurement method using a low-frequency AC (LFAC) current. In this paper, we measured the contact resistance for different DC operating currents or change of DC current to confirm the validity of LFAC method. In addition, by heating a test coil, the contact resistances were also measured during the change of DC operating current. Since the electromagnetic stress is small enough not to change the contact condition, the change in contact resistance is negligible. The measured contact resistance was unchanged, so we could conclude that the LFAC method is effective in measurement of the contact resistance when DC operating current was applied.

Original languageEnglish
Article number8976078
JournalIEEE Transactions on Applied Superconductivity
Volume30
Issue number4
DOIs
Publication statusPublished - Jun 2020

Keywords

  • No-insulation winding technique
  • REBCO pancake coil
  • turn-to-turn contact resistance measurement

ASJC Scopus subject areas

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

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