Development of a Cryogenic Helium-Neon Gas Mixture Cooling System for Use in a Gd-Bulk HTS Synchronous Motor

• Published in: IEEE transactions on applied superconductivity 2011-06, Vol.21 (3), p.2213-2216
• Main Authors: Felder, B, Miki, M, Zigang Deng, Tsuzuki, K, Shinohara, N, Izumi, M, Hayakawa, H
• Format: Article
• Language: English
• Subjects: Applied sciences; Closed-cycle thermosyphon; Cooling; Copper; cryogenics; Design. Technologies. Operation analysis. Testing; Electrical engineering. Electrical power engineering; Electrical machines; Electromagnets; Electronics; Exact sciences and technology; Heating; Helium; helium-neon mixture; High temperature superconductors; Integrated circuits; Magnetic heads; Miscellaneous; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Special rotating machines; superconducting rotating machines; Temperature sensors; Various equipment and components
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2010.2101573

Temperature Superconductors (HTS) applied to rotating machines require an efficient cooling system. It is necessary to increase the maximum trapped flux density in the bulk HTS magnets and decrease the overall cooling time. In this paper, we added a gaseous helium phase to a condensed-neon closed-cycle thermosyphon. The latent heat of neon-film cooling is combined with helium's high thermal conductivity. Different mixture proportions were evaluated in terms of resistance to variable heat loads. More helium decreased the temperature variation of the evaporator. The mixture was then used to cool down a 30 kW-grade gadolinium-bulk HTS synchronous motor. The eight bulk HTS conductors of the rotor were cooled to 40 K in less than six hours. The application of this thermosyphon is envisioned for larger rotating machines.