| Project/Area Number |
12450113
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
電力工学・電気機器工学
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| Research Institution | Kagoshima University |
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Principal Investigator |
SUMIYOSHI Fumio Kagoshima Univ., Faculty of Eng., Professor, 工学部, 教授 (20136526)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAGOE Akifumi Kagoshima Univ., Faculty of Eng., Research Associate, 工学部, 助手 (40315396)
KAWABATA Shuma Kagoshima Univ., Faculty of Eng., Associate professor, 工学部, 助教授 (00244260)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥12,900,000 (Direct Cost: ¥12,900,000)
Fiscal Year 2001: ¥6,100,000 (Direct Cost: ¥6,100,000)
Fiscal Year 2000: ¥6,800,000 (Direct Cost: ¥6,800,000)
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| Keywords | high temperature superconductor / tape / conductor / loss / current distribution / electromagnetic property / pinning / power application / 高温超伝導導体 |
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| Research Abstract |
Realization of superconducting power machines cooled with liquid nitrogen has been concerned. However, a large amount of ac losses produced in high temperature superconducting (HTS) tapes and degradation of critical currents of the tapes due to the face-on orientated magnetic field applied in to the tapes have been serious barrier to the realization. The former comes from the electromagnetic phenomena that whole filaments act as a thick mono-filament, and transport currents locally flow in the outer filament. The latter is the characteristic property of the Bi-2223 tape that is the most hopeful candidate as a real tape for power applications.
Theoretical analyses were carried out on the relation between current distributions and ac losses in Bi-2223 tapes, and an adequate method to reduce the loss was discussed. Because the previous loss-measuring method is not adequate with purpose of this study, a new system to measure losses of the tape under the real application conditions, i.e., simultaneous sweep of transport currents and external transverse magnetic fields, was developed. We call this system the 'Poynting vector method.' The validity and usefulness of it were successfully demonstrated for the short and straight Bi-2223 tape. Then it was improved to be able to measure losses of the single-layered, solenoidal coil wound with HTS tapes. The ac loss produced in the double pan-cake type coil wound with Bi-2223 tapes was also measured in detail in liquid nitrogen. As the result, the electromagnetic properties of the HTS tapes were clarified for the wide range of frequencies of the real condition applied to the tape. Moreover, a new coil winding method to get excellent performances was studied theoretically and experimentally, and showed this is useful for realization of the superconducting power machines cooled with liquid nitrogen.
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