PERMANENT MAGNET THRUST BEARING: THEORETICAL AND EXPERIMENTAL RESULTS

Abstract

This paper presents the design and analysis of permanent magnet (PM) thrust bearing made up of three ring pairs for flve degrees of freedom of the inner rings (rotor rings). The arrangement pattern of rings in PM bearing is considered in two ways: conventional structure and Halbach structure. The simplifled three dimensional (3D) mathematical models employing Coulombian approach and vector method are used to design the bearing. MATLAB codes are written to evaluate the axial force, stifiness and moments in both the structures for flve degrees of freedom, thereby the efiect of axial, radial and angular displacements of the rotor on the aforementioned characteristics is addressed. The results of the mathematical model are validated by the results of 3D Finite Element Analysis (FEA) and experiments. It is observed that, the conventional structure seems to be more sensitive to the angular displacement, as the percentage decrease in force and stifiness is more with respect to angular displacement than the Halbach structure. The efiect of angular displacement of the rotor on the performance of bearing in both the structures is crucial.