Analysis of a perpendicular-type eddy-current speed meter

The method of the noncontacting speed measurement of a moving conductive slab is to use the eddy current effect. The slab speed can be measured by the variation of the electromotive force of a detecting coil which is arranged in the neighbourhood of an exciting coil. In the paper, we propose an eddy-current speed meter which consists of one exciting coil and one detecting coil, perpendicular to each other. We carried out a theoretical analysis of this speed meter and confirmed validity of the theoretical formula by experiment. We also obtained some theoretical predictions by the calculation examples. Since this type of speed meter is of a simple structure, and capable of being miniaturised, it is very useful for the continuous manufacturing process, etc.