Calorimetric Measurements of the Effect of Nickel and Stabrite Coatings and Resistive Cores on AC Loss in Accelerator Cables under Fixed Pressure

Sumption, M. D.; Scanlan, R.M.; Nijhuis, Arend; Kate, Herman H.J. ten; Collings, E. W.

doi:10.1007/978-1-4757-9059-7_169

Cited by 11 publications

(18 citation statements)

References 12 publications

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“…The strand type is different but this probably has no considerable influence on the time constant of the cable. Low coupling loss for bare strands, has been noticed before in Rutherford cables and it is probably caused by a thin oxide layer on the strand surface [6].…”

Section: Variation In Chromium Coating Thicknessmentioning

confidence: 54%

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Parametric study on coupling loss in subsize ITER Nb/sub 3/Sn cabled specimen

et al. 1996

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The cable in conduit conductors for the various ITER coils are required to function under pulse conditions and fields up to 13 T. A parametric study, restricted to a limited variation of the reference cable lay out, is carried out to clarify the quantitative impact of various cable parameters on the coupling loss and to find realistic values for the coupling loss time constants to be used in ac loss computations. The investigations cover ac coupling loss measurements on jacketed sub-and full size conductors with variations in type of cabling, twist pitch, void fraction, and thickness of the chromium coating. The results are summarised and conclusions regarding the ITER cable design are presented. Scaling laws for coupling loss versus void fraction and number of cabling stages are presented.

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Section: Variation In Chromium Coating Thicknessmentioning

confidence: 54%

“…Other plating conditions of coating strands with Cr layers may lead to different results. Variations in contact resistance up to a factor 6 are found for the same spoon size, using Ni coatings of different vendors [6]. For Cr this will be investigated in the near future.…”

Section: Variation In Chromium Coating Thicknessmentioning

confidence: 90%

Parametric study on coupling loss in subsize ITER Nb/sub 3/Sn cabled specimen

et al. 1996

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“…The results of previous measurements of AC loss in Rutherford cables and of direct interstrand contact resistances, indicate that the magnitudes and characteristics of coupling currents that inevitably become established in accelerator dipole magnets [8,9,23] depend primarily on the surface condition of the strand. To ensure adequate current sharing, the strand surface should be metallic, not insulating.…”

Section: Concluding Discussionmentioning

confidence: 94%

“…Expressed in terms of "AC loss" the results of this and earlier work [8,9] show that the insertion of metallic or insulating cores suppresses the generation of the primary FO coupling currents. Furthermore the residual coupling loss is rendered insensitive to the application of "cold" uniaxial stress, to which standard stabrite-coated cables are particularly susceptibility.…”

Section: Importance Of the Corementioning

confidence: 93%

“…For this reason, the insertion of a core drastically suppresses the total loss. Sytnikov's expressions for AC loss [7] which we have made use of in previous publications [8,9], and find convenient for our present purposes, are given below. The conditions necessary to generate this long-range coupling current that encompasses the entire length of cable sample and has a long decay time have been investigated by Verweij [15,16] to which the acronym BICC is due.…”

Section: B Classification Of Interstrand Coupling Currentsmentioning

confidence: 99%

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Suppression and control of coupling currents in stabrite-coated Rutherford cable with cores of various materials and thicknesses

Collings

Sumption²,

Kim³

et al. 1997

IEEE Trans. Appl. Supercond.

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Calorimetric and magnetic measurements of AC loss have been performed on stabrite-coated Rutherford cable conforming to the Large Hadron Collider (LHC) innerwinding (28 strand) specification, with the applied field directed either perpendicular to the broad face (the face-on, FO, orientation) or parallel to it (edge-on, EO). It was found that the insertion of a thin metallic or insulating core into the cable suppressed the FO AC loss under typical conditions by a factor of 10 and rendered it practically insensitive to the application of cold uniaxial stress (of up to about 78 MPa). The FO loss having been suppressed, it could also be controlled (i.e. finely adjusted) by changing the level of internal compaction (by varying core thickness at fixed overall thickness) or external compaction (by changing the overall thickness of the cable). Of course the EO loss was much less sensitive to the presence of a core, the use of which therefore enabled the FO and EO losses to be independently adjusted.

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