Peculiarities in electromagnetic behavior of MF NbTi composites for AC use

Abstract

The paper presents results obtained in the study of the current -voltage characteristics, critical and quenching currents a s well as of the AC transport current and magnetization losses in four series of fine filament NbTi composites prepared by Showa Electric Wire & Cable Co., Japan. Complementary measurements have been made also on a commercially available t y p e T AC superconducting wire produced by G E C Alsthom Company, France.The samples differ in filament diameter, matrix thickness between filaments and in the number and structure of filament bundles in the composite. I n two series of samples b a r r i e r type artificial pinning centers have been introduced to increase J, and decrease the normalized magnetization losses. The conclusions concerning the optimization of multifilamentary composites and cables for AC use a t low working magnetic field are briefly reviewed.

Quench currents of AC superconductor in supercritical helium

“…Factors which increase hic, such as low field and high frequency operation, tend to reduce the strand's dynamic stability [9]. This conclusion is qualitatively born out by the results for the Alsthom short sample (Fig.…”

The influence of magnetic field on current-voltage characteristics of fine-filament NbTi superconductors and the effect of a filament break

“…The effective diameters of the superconducting filaments in the wire cross-section are rather different (the maximal diameter is nearly twice the minimal one) as can be seen from SEM photographs of the fine-filament wires [12]. These photographs show that the filament diameters are equal in the filament clusters from which the 116 multifilamentary wire is assembled and change significantly from cluster to cluster.…”