A linearlized model considering the effect of eddy currents is shown to be useful for the analysis of the dynamics of active magnetic thrust-bearings, in which electromagnet cores are composed of solid steel. The dynamics of a magnetic control-force is modeled by the first-order time-lag system with unknown parameters : a gain and a time constant. The parameters are estimated from experimental results : the static relation between coil current and magnetic control-force, and the frequency response of the magnetic flux for input to a power amplifier. The effect of eddy currents on the dynamics is confirmed by the frequncy response of the flux for coil current. Model simulations with estimated paramneters are compared with experiments in frequncy response and impulse response. The results show the effectiveness of the linearlized model.
