Irregular AC losses with long time constants in large cable-in-conduit conductors

T. Hamajima, Y. Kakusho, K. Hoashi, M. Tsuda, N. Harada, H. Yamada, K. Takahata, T. Satow

研究成果: Conference article査読

7 被引用数 (Scopus)

抄録

A large superconducting coil wound with Cable-in-Conduit (CIC) conductor causes both irregular AC losses that cannot be estimated from short conductor sample test results, and regular AC losses that are proportional to cable twisting pitch squared. We proposed a mechanism forming loops that generated the irregular losses. The CIC conductor is composed of several stages of sub-cables. If one strand on the surface of a sub-cable contacts another strand on the surface of the adjacent sub-cable, the two strands must encounter each other again at the LCM (Least Common Multiplier) distance of all staged cable pitches, and thereby a long loop is formed. We orderly labeled all strands in CIC conductors for the SMES and the LHD. It was found that strands in a triplet were widely displaced from their original positions on one cross section, but contacted each other tightly on the other cross section. This fact suggests that the loop with the large displaced strand links irregularly with external field so that the loops cause the irregular AC losses. Moreover, it indicates that a contacting length of the large displaced strands can be quite long, giving rise to a low contact resistance for the loop, and leading to the long time constants. It is believed that the widely displaced strand are inherent in a CIC conductor. It was demonstrated that the strand surface coated with CuNi was effective to suppress the irregular AC losses.

本文言語English
ページ(範囲)2384-2387
ページ数4
ジャーナルIEEE Transactions on Applied Superconductivity
13
2 II
DOI
出版ステータスPublished - 2003 6
外部発表はい
イベント2002 Applied Superconductivity Conference - Houston, TX, United States
継続期間: 2002 8 42002 8 9

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学
  • 電子工学および電気工学

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