Force on a Coil Moving over a Conducting Surface Including Edge and Channel Effects

Abstract

The lift force FL and the drag force FD on small conducting coils placed near a large rotating conducting cylinder have been measured as functions of velocity, height, and coil geometry. These data are compared with exact calculations based upon Fourier transforms for coils moving over infinitely wide flat plates. By placing the coil near the edge of the cylinder, the effect of the edge on FL and FD and the transverse force FT were studied. A channel was then cut in the cylinder, and the properties of a U-shaped guideway were examined. Both the edge effects and channel effects were compared with approximate calculations. Agreement was generally good, substantiating a variety of predictions for the large magnets proposed for the suspension of high-speed ground vehicles.