Evaluation Criterion for Determining Turn-to-Turn Contact Electrical Resistance Satisfying High Thermal Stability and Shortening Charging Delay in NI-REBCO Coils for MRIs

• Published in: IEEE transactions on applied superconductivity Vol. 31; no. 5; pp. 1 - 5
• Main Authors: Yoshihara, Yuka, Hamanaka, Mai, Tsuyoshi, Kyoka, Kitamura, Mayu, Nemoto, Ui, Noguchi, So, Ishiyama, Atsushi
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.08.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Charging; Coils; Contacts; Criteria; Defect; Delay; Electric contacts; Electrical resistance; Heat generation; Immune system; Insulation; no-insulation; REBCO coil; Stability analysis; Stability criteria; Temperature distribution; Thermal resistance; Thermal stability; turn-to-turn contact electrical resistance
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2021.3067239

We have been developing a no-insulation (NI) coil technology to achieve high thermal stability and high current density. NI coils can continue to operate even if a part of the coils degrades; however, a charging delay occurs in the coils. Moreover, the turn-to-turn contact electrical resistance of the NI coils must be increased to shorten the charging delay; however, a large turn-to-turn contact electrical resistance reduces thermal stability. In this study, using turn-to-turn contact electrical resistance and I OP / I C ratios as parameters, we analyze thermal stability and consider the possibility that NI coils can continue to operate even if they have local defects. Furthermore, to establish an evaluation criterion for determining turn-to-turn contact electrical resistance that can shorten charging delay and ensure high thermal stability, we analyze and evaluate the relationship between turn-to-turn contact electrical resistance and thermal stability, focusing on three types of heat generation.