Two and three dimensional models of an electromagnetic velocity sensor

The authors present a method for the analysis and the optimization of reluctance-type electromagnetic velocity sensors using 2-D and 3-D finite-element CAD (computer-aided-design) packages. The computations are checked against experimental measurements. The key feature of the method is the model chosen to take into account a nonlinear permanent magnet in an open circuit in which the reluctance variation is small compared to the total reluctance. It is found that because of the small size of the sensor, the analysis must be three-dimensional.<>