Cryogenic cables

S. H. Minnich and G. R. Fox, Comparative Costs of Cryogenic Cables, paper presented at IEEE Winter Power Meeting, New York, January 25-30,1970. 

The matrix can be taken away by HN03 except at the ends of the wire, to allow easy soldering. Below IK, the electrical contact can be done also by squeezing the wires to be connected inside a thin A1 tube (see, for example, Section 12.4). For low-level signals, shielded twisted pairs or cryogenic coaxial cables are used. When thousands of wires are necessary, as in large experiments, Kapton strips with deposited conductors [3] or woven wires [4] are used. 

Fig. 16.3. Left Schematic picture of the damping system of MimiGRAIL. The suspension consists of seven stages, the upper four made of CuAl followed by three copper masses. The upper CuAl mass is suspended from the top flange of the cryostat by stainless steel cables hanging from helical springs. Mass number 5, the first copper mass, will be cooled by the dilution refrigerator. Right Picture of the four CuAl masses hanging from the top flange (courtesy of Leiden Cryogenics).

Ethylene Tetrafluoroethylene Copolymer - Thermoplastic comprised of an alternating copolymer of ethylene and tetrafluoroethylene. Has high impact resistance and good abrasion resistance, chemical resistance, weatherability, and electrical properties approaching those of fully fluori-nated polymers. Retains mechanical properties from cryogenic temperatures to 356°F. Can be molded, extruded, and powder-coated. Used in tubing, cable and wire products, valves, pump parts, wraps, and tower packing in aerospace and chemical equipment applications. Also called ETFE. 

The development of foam-insulated cryogenic containment piping was undertaken to achieve lower costs and to improve reliability. It was estimated that the foam thermal insulation would increase the low-temperature refrigeration load caused by heat transfer from the surrounding soil by an additional 49.7 kW/km (80 kW/mi) for a 3500-MVA cable system. This increase can be partially offset by... 

PROPERTIES OF PLASTIC TAPES FOR CRYOGENIC POWER CABLE INSULATION... 

The most severe problems facing the designer of cryogenic dielectric insulation are those of obtaining satisfactory mechanical properties over a wide temperature range. The dielectric must be able to withstand the variety of forces present during construction, installation, and over the normal life of the cable. 

Properties of Plastic Tapes for Cryogenic Power Cable Insulation (Invited)... 

Fluoroplastics have been used as wire coatings in military and aerospace applications since their discovery. They have also found their way into wire and cable applications that required extreme performance based on thermal extremes (cryogenic and high temperature applications), chemical resistance, etc., but the major market expansion in fluoroplastic use in the wire and cable industry occurred in North America when the National Electric Code (NEC) allowed polymers with low smoke-generation and flame-spread to be installed in building plenums without metal conduits. 

An example of high-current transmission lines is shown in Figs. 3.62 and 3.63, the warm dielectric cable and cryogenic dielectric cable fabricated by American Superconductor Corporation. 

FIGURE 3.63 High-current transmission line, cryogenic dielectric cable, from American Super-conductor Corp ... 

Usually in strain measurements we are faced with relatively low signals in the 25-50-mV range. This can cause problems, since strain measurements in cryogenic systems are always remote, and extraneous signals can be induced in the cabling and connectors. 

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