The ability of high-temperature superconductors to levitate in a magnetic field can be harnessed to create passively stable friction free rotating bearings. This is typically achieved using pieces of solid or “bulk” superconducting material. However, bulk superconductors come with size and quality limitations. In this work, we explored substituting the bulk by a series of non-insulated coils of REBCO superconducting wire. Measurements of the levitation force and stiffness properties were measured at cryogenic temperatures between 28 K and 77 K, on coils of various sizes and turn count. Excellent agreement was obtained between experimental data and H-formulation finite-element simulations employing a rotated anisotropic resistivity. This work successfully lays the groundwork for future research to fully realise the potential of no-insulation coils in superconducting bearings.

This work was funded by the New Zealand Ministry of Business, Innovation and Employment (MBIE) Advanced Energy technology Platform (AETP) program “High power electric motors for large scale transport” contract number RTVU2004.

Keywords: Magnetic levitation bearings, No-insulation coils