Abstract
Modern uses of rotating shafts depend upon bearing speeds and temperatures that exceed normal operating parameters. In order to accommodate these excessive parameters, magnetic bearings have replaced ball or thrust bearings. However, eddy currents cause a loss of power and instability in magnetic bearings. The eddy current magnitude is responsible for the power loss, while the phase lag between the magnetic field and the input or control current causes the instability. This study incorporated finite element studies of magnetic thrust bearings using static bench testing procedures to investigate configurations that promote eddy current reduction. Several rotor/stator configurations, including solid metal, laminated washers, tapewound lam-inates. and solid wedge pieces are used to determine the smallest phase lag configuration. Finite element analysis will compare a solid configuration bench test with an axisymmetric finite element model and illustrate the fringing effect that occurs with magnetic bearings. A fringe factor accounting for the effect caused by extending the rotor past the stator is developed using finite element analysis.
DeWeese, Randall Thomas (1996). A comparison of eddy current effects in a single sided magnetic thrust bearing. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1996 -THESIS -D49.