Measurement of a Conduction Cooled Nb3Sn Racetrack Coil

[摘要] Use of superconducting coils for wind turbines and electric aircraft is of interest because of the potential for high power density and weight reduction. Here we test a racetrack coil developed as a proof-of-concept for cryogen-free superconducting motors and generators. The coil was wound with 1209 m of 0.7-mm-diameter insulated tube-type Nb3Sn wire. The coil was epoxy-impregnated, instrumented, covered with numerous layers of aluminized mylar insulation, and inserted vertically into a dewar. The system was cooled to 4.2 K, and a few inches of liquid helium was allowed to collect at the bottom of the dewar but below the coil. The coil was cooled by conduction via copper cooling bars were attached to the coil but also were immersed in the liquid helium at their lower ends. Several current tests were performed on the coil, initially in voltage mode, and one run in current mode. The maximum coil Icat 4.2 K was 480 A, generating 3.06 T at the surface of the coil. The coil met the design targets with a noticeable margin.

[发布机构] Department of Materials Science and Engineering, Ohio State University, Columbus; OH; 43210, United States^1;Hyper Tech Research Incorporated, 539 Industrial Mile Road, Columbus; OH; 43228, United States^2

[关键词] Aluminized Mylar;Conduction cooled;Electric aircrafts;High power density;Proof of concept;Racetrack coils;Superconducting motors;Weight reduction