Dependence of Self Field AC Losses in AC Multifilamentary Composites and Cables on External AC Magnetic Field
We measured AC losses of AC multifilamentary wires (NbTi and Nb3Sn) and a cable of (6+1) configuration due to transport currents in an AC external magnetic field at 50Hz. We also studied the stabilities of the NbTi and Nb3Sn wires and the cable. The Nb3Sn AC wire has thinner filamentary zone than the NbTi wire. It was shown by the experiment that the Nb3Sn wire had better stability against the magnetic instability and that AC quench currents of the Nb3Sn wire reached the critical current in DC back ground field, while the AC quench currents of the NbTi wire were far below the critical current due to the magnetic instability. The AC losses of the Nb3Sn wire due to the wire transport current are higher and less dependent on the direction of the external magnetic field than those of the NbTi wire. AC losses of a cable of (6+1) configuration made of the NbTi wire were higher than those estimated from the single wire. Those experimental results are discussed and is explained by estimating thickness of saturated zone in the wire where the filaments carry their critical current.
KeywordsSaturated Zone Transport Current Single Wire Magnetic Instability Wire Cross Section
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- 1.K. Miyashita, M. Toyama, S. Sakai, K. Kamata and H. Tanaka, “Development of Nb-Ti Superconducting Wires with Cu-Ni-Mn Matrix for AC Use,” Proc. of 1CFA Workshop on AC Superconductivity, KEK, Japan, 152(1992)Google Scholar
- 2.S. Fukui, O. Tsukamoto, N. Amemiya and I. Hlásnik, “Dependence of Self Field AC Losses in AC Multifilamentary Composites on Phase of External AC Magnetic Field,” presented at ASC ′94, Boston. U.S.A. (1994)Google Scholar
- 4.S. Le Naour, A. Lacaze, Y. Laumond, P. Estop and T. Verhage, “AC Current Distribution and Losses in Multifilamentary Superconductors Exposed to Longitudinal Magnetic Field.” presented at MT-14, Tampere, Finland (1995)Google Scholar
- 5.O. Tsukamoto, N. Amemiya and I. Hlásnik, “Current Degradation in Superconducting AC Coils — Causes and Stabilization,” Advances in Cryogenic Engineering, 4(A):598 (1994)Google Scholar