Measurements of the self-field a.c. losses in PbBi2223 tapes with different core/sheath configurations

Abstract

Measurements have been made of the a.c. self-field losses in PbBi2223 tapes with different core/sheath configurations. Three different tapes have been measured, two monocore tapes with core thicknesses of 25 µm and 80 µm and a multifilamentary tape of overall thickness 200 µm. The a.c. losses have been obtained by measurement of the loss electric field E l at a sufficient distance (three times the tape half-width) from the tape axis. Measurements of the spatial dependence of the loss and inductive electric fields E l (x ) and E i (x ) have also been made. The results indicate that the 'thin' monocore tape can be adequately described by the thin-rectangle geometry whilst the behaviour of the 'thick' monocore tape lies in between those of the thin rectangle and thin ellipse. The behaviour of the multifilamentary tape follows closely that of a monocore ellipse tape indicating that there is a strong interaction between the filaments.

Estimation of Apparent AC Transport Losses for Cylindrical Conductors Composed of Superconductor Tapes

“…F OR MEASURING the AC transport self-field losses in high temperature superconductor (HTS) tapes or cable conductors composed of them by the standard AC four terminal method, the apparent loss values are determined by the products of transport current and resistive electric field (which is in-phase component with transport current) detected from the voltage taps [1]- [3]. In the case of a tape sample in an isolated state, it is well known that the electric field distributions around the sample are strongly influenced by the anisotropic geometry of superconductor and nonlinear magnetic flux penetration [1]- [3].…”

“…In the case of a tape sample in an isolated state, it is well known that the electric field distributions around the sample are strongly influenced by the anisotropic geometry of superconductor and nonlinear magnetic flux penetration [1]- [3]. On the other hand, in the cylindrically assembled conductors composed of HTS tapes, it is expected that the electric field distributions near the conductors in AC cycle are influenced not only by the tape geometry but also by the tape arrangements therein.…”

Untitled

“…Since most applications imply alternating currents and fields, the reduction of the ac losses is an important task. For this reason, much research has been aimed at further development of these materials, with special attention to lowering the ac losses [3][4][5][6]. High ac losses are partially caused by the very low resistivity of the Ag sheath, resulting in important induced currents flowing through the Ag matrix.…”