| Title |
A Joining Method between HTS Double Pancake Coils |
| Authors |
손명환(Sohn, Myung-Hwan) ; 심기덕(Sim, Ki-Deok) ; 김석호(Kim, Seok-Ho) ; 김해종(Kim, Hae-Jong) ; 배준한(Bae, Joon-Han) ; 이언용(Lee, Eon-Young) ; 민치현(Min, Chi-Hyun) ; 성기철(Seong, Ki-Chul) |
| Keywords |
parallel joint ; joining method ; superconducting coil ; joint resistance ; Joule heat |
| Abstract |
High temperature superconductor (HTS) winding coil is one of the key component in superconducting device fabrication. Double-pancake style coils are widely used for such application. High resistance between pancake coils greatly affects the machine design, operating condition and thus the stability. In order to reduce such resistance, experimentalists are looking for efficient and damage free coil connecting methods. In this respect, here we proposed parallel joining method to connect the coils. This is to do crossly joining with HTS tapes on two parallel HTS tapes. Joint samples between two parallel HTS tapes were prepared by using HTS tapes and current-voltage (I-V) characteristic curves were investigated at liquid nitrogen temperature i.e., 77.3 K. A 20 cm length joint connected between two parallel HTS tapes shows 32.5n{Ω}, for currents up to 250 A. A small HTS magnet, having two double pancake sub-coils connected together through new parallel joint method was fabricated and their current-voltage (I-V) characteristic curve was investigated. At 77.3K, critical current(Ic) of 97 A and resistance of 55n{Ω} for currents upto 130 A were measured. At operating current 86 A lower than Ic, Joule heats generated in whole magnet and at joint region between sub-coils were 226 mW and 0.4 mW, respectively. Low Joule heat generation suggests that this joining method may be used to fabricate HTS magnet or windings. |