Investigation of Magnetic Fields and Forces Arising in Open-Circuit-Type Magnetic Bearings

The concept of magnetic bearings consists of using magnetic forces to maintain controlled separation between bearing surfaces. The closed-circuit-type magnetic bearings have been analyzed and reported in literature. In this paper, the development of a theory together with experimental verification for predicting both normal and transverse forces in open-circuit-type magnetic bearings in a quasi-static environment is described. For purposes of analysis, the magnetic bearing system was mathematically modelled by current densities and forces were calculated by using Ampere's law. Very good agreement between the theory and experimental data was observed. Also, experiments were performed to validate the previously developed theory for closed-circuit-type bearings employing high-permeability materials for the case when permanent magnets were used as a battery to energize the magnetic circuit. Presented at the 41st Annual Meeting in Toronto, Ontario, Canada May 12-15, 1986