| Co-Investigator(Kenkyū-buntansha) |
ITSUMI J. Sojo University, Faculty of Engineering, Professor, 工学部, 教授 (50134896)
FUKAI S. Saga University, Faculty of Science and Engineering, Associate Professor, 理工学部, 助教授 (30189906)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2004: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2003: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
Superconducting magnets have been studied to extend the new technology region. At present, low T_c superconductive wire (LTSW) has almost reached the level of practical use. In contrast, high T_c superconductive wire (HTSW) is more advantageous than LTSW, because it is possible to use liquid nitrogen in the cooling. The HTSW of long-length multi filaments has recently been manufactured, and a shift from LTSW to HTSW is expected in the future. A grasp of AC loss for the superconducting magnet is very important, since the AC loss is essentially generated in the superconducting wire.
In this research, the phase difference measurement, which is related to the evaluation of the AC loss of the superconducting magnet, was carried out. The methods of three types were proposed to measure the phase difference of the superconducting magnet and the measurement of the phase difference was performed.
First, the superconducting magnet of a double pancake coil was constructed using HTSW with Bi-2223 multi filaments. Next, an exciting test of the magnet using the AC power supply was performed. As a result, it was confirmed that the phase difference between the voltage and the current of the magnet almost approximated 90°. Finally, the phase difference of the superconducting magnet was measured using the electronic circuits of three types. Especially, the measuring result of the electronic circuit using op-amps agrees with the result by a lock-in amplifier comparatively well, and thus it is considered that the electronic circuit is practical.
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