Coupling loss and contact resistance in cored stabrite cables-influences of compaction and variation of core width

AC loss due to coupling currents in a Rutherford cable can be modified by changing the interstrand contact resistance (ICS) by: adjusting the level of native oxidation of the strand, coating it, or by inserting a ribbon-like core into the cable itself. With regard to cored cables further effective-ICR adjustments can be achieved by changing: (i) the degree of compaction during manufacture; (ii) the thickness of the core at fixed overall thickness; and (iii) the width of the core. The authors report on the results of magnetic and calorimetric AC loss measurements on stainless-steel-cored stabrite cables which had been: (i) externally compacted by rolling to thicknesses of 0, 6, 9, and 11% below the standard thickness; (ii) internally compacted by being furnished with cores of thickness 1 mil (30 μm) and 2 mil (50 μm); and (iii) furnished with cores whose widths, w_core, were about 20%, 50%, 75% and 100% of the maximum possible width. The measurements were made in applied AC fields that were directed perpendicular (face-on) and parallel (edge-on), respectively to the broad cables faces