Magnetic levitation using a stack of high temperature superconducting tape annuli
Publication Date
2017-02-01Journal Title
Superconductor Science and Technology
ISSN
0953-2048
Publisher
Institute of Physics
Volume
30
Issue
2
Number
024007
Language
English
Type
Article
This Version
VoR
Metadata
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Patel, A., Hahn, S., Voccio, J., Baskys, A., Hopkins, S., & Glowacki, B. (2017). Magnetic levitation using a stack of high temperature superconducting tape annuli. Superconductor Science and Technology, 30 (2. 024007)https://doi.org/10.1088/1361-6668/30/2/024007
Abstract
Stacks of large width superconducting tape can carry persistent currents over similar length scales to bulk superconductors, therefore giving them potential for trapped field magnets and magnetic levitation. 46 mm wide high temperature superconducting tape has previously been cut into square annuli to create a 3.5 T persistent mode magnet. The same tape pieces were used here to form a composite bulk hollow cylinder with an inner bore of 26 mm. Magnetic levitation was achieved by field cooling with a pair of rare-earth magnets. This paper reports the axial levitation force properties of the stack of annuli, showing that the same axial forces expected for a uniform bulk cylinder of infinite $\textit{J c}$ can be generated at 20 K. Levitation forces up to 550 N were measured between the rare-earth magnets and stack. Finite element modelling in COMSOL Multiphysics using the H-formulation was also performed including a full critical state model for induced currents, with temperature and field dependent properties as well as the influence of the ferromagnetic substrate which enhances the force. Spark erosion was used for the first time to machine the stack of tapes proving that large stacks can be easily machined to high geometric tolerance. The stack geometry tested is a possible candidate for a rotary superconducting bearing.
Keywords
high temperature superconductor, critical state modelling, HTS tape, superconducting levitation, magnetic bearings, coated conductor
Sponsorship
The authors would like to acknowledge the financial support of SKF S2M, the magnetic bearing division of SKF, the Isaac Newton Trust, Cambridge and EPSRC.
Funder references
EPSRC (EP/P000738/1)
Embargo Lift Date
2100-01-01
Identifiers
External DOI: https://doi.org/10.1088/1361-6668/30/2/024007
This record's URL: https://www.repository.cam.ac.uk/handle/1810/261969
Rights
Attribution 4.0 International, Attribution 4.0 International, Attribution 4.0 International