Design and performance of low-thermal-resistance, high-electrical-isolation heat intercept connections

• Published in: Cryogenics (Guildford) 1995-11, Vol.35 (11), p.829-832
• Main Authors: Niemann, R.C., Gonczy, J.D., Phelan, P.E., Nicol, T.H.
• Format: Article
• Language: English
• Subjects: Applied sciences; composite; Electric connection. Cables. Wiring; Electrical engineering. Electrical power engineering; Exact sciences and technology; heat intercept; thermal interference fit; Various equipment and components
• ISSN: 0011-2275; 1879-2235
• DOI: 10.1016/0011-2275(95)90926-7

Electrical conductors often require the removal of heat produced by normal operation. The heat can be removed by mechanical connection of the conductor to a refrigeration source. Such connections require both effective heat removal (low thermal resistance) and effective electrical isolation (high electrical resistance and high dielectric strength). Fabrication of these connections should be straightforward, and performance must be reliable and independent of operating temperature. The connection method described here involves clamping (by thermal interference fit) an electrically insulating cylinder between an outer metallic ring and an inner metallic disc. Material candidates for insulating cylinders include composites, e.g. epoxy/fibreglass, and ceramics, e.g. alumina. Design factors, including geometry, materials and thermal contact resistance are discussed. The design, construction experience and performance measurements of a heat intercept connection in a high-temperature superconducting lead assembly is presented.