Experimental Investigation of an Eddy-Current Bearing

An AC-electromagnetic bearing based on eddy-current repulsion has been built and tested. The bearing was found to be inherently stable and able to provide support in five degrees of freedom, i.e. a short rotor was fully supported by a single bearing without any feedback control. However, with the current design configuration, the load carrying capacity and the stiffness and damping are lower than for the conventional DC-electromagnetic bearing and the power consumption is higher. Experimental confirmation of the inherent bearing stability and the support capabilities was reported in an earlier paper. The current paper reports on the experimental investigation of two additional capabilities, namely motoring and emergency shutdown without catcher bearings. In addition, quantitative experimental results are presented by which the goodness of each of the bearing capabilities can be judged. Based on these results, design modifications are proposed for improving the bearing capabilities.