Thrust actuator with passive restoration force for wide gap magnetic bearings

Abstract

Active thrust magnetic bearings provide an axial force to balance the moving parts of machines. However, most devices produce null or unbalancing passive forces. Furthermore, reported designs usually feature very small axial and radial gaps. This paper presents a thrust actuator for wide axial gaps that produces both passive and active restoring axial forces. It features a long biconical rotor and a stator housing a single winding and two permanent magnets. Simulations are done using finite-element-analysis (FEA) and compared to magnetic circuit analysis and experimental results from a prototype with a diameter of 48 mm and 20 mm axial displacement.

Dynamic performance of three-DoF conical magnetic bearing in Vernier gimballing MSFW

“…Moreover, the rotor shaft in the turbo-compressor was quite long, and the moment of inertia was small, so the coupling effect was weak. A long conical rotor was supported by a single EM winding and a PM ring [35], and a wide axial gap was achieved with the active force of EM windings and the passive restoring force of the PM ring.…”