Modeling of Electrodynamic Bearings

A new model of electrodynamic bearings is presented in this paper. The model takes into account the R-L dynamics of the eddy currents on which this type of bearing is based, making it valid for both quasistatic and dynamic analyses. In the quasistatic case, the model is used to obtain the force generated by an off-centered shaft rotating at a fixed speed in a constant magnetic field. The model is then used to analyze the dynamic stability of a Jeffcott rotor supported by electrodynamic bearings. The essential role played by nonrotating damping in ensuring a stable operating range to the rotor is studied by means of root loci. Comparison with literature results is finally used to validate the model.