Tests with a self-stable superconducting magnetic bearing

This study presents the development and experimental validation of a Passive Superconducting Magnetic Bearing (PSMB) designed to achieve Technological Readiness Level 5 (TRL 5). Unlike traditional Active Magnetic Bearings (AMB) that rely on sensors, electronics, and a continuous power supply, the proposed PSMB system exploits the stable levitation forces produced by field-cooled (FC) high-temperature superconductors in combination with permanent magnets (Halbach-configured NdFeB array), thereby offering a simpler, fail-safe alternative. Finite Element Analysis (FEA) was conducted to simulate the system's magnetic field distribution and to optimize key design parameters, including the vertical cooling offset of YBCO superconductors and the levitation and guiding force values. These simulations demonstrated that stable rotor support can be achieved without the need for auxiliary components. Experimental validation involved integrating two PSMBs into a high-speed electric motor, which successfully operated up to 7000 rpm under both no-load and load conditions, thereby eliminating the need for traditional touchdown and thrust bearings. Results confirmed excellent lateral stiffness and effective levitation, although precise rotor centralization remains a challenge. Additionally, implementing a compact cryogenic system is necessary for future industrial applications. Overall, the findings highlight PSMBs as a viable and promising alternative to PSMBs, with the potential to simplify system architecture and improve reliability in high-speed rotating machinery.