Modeling of Linear Eddy Current Speed Sensors for Moving Nonmagnetic Bars Using a Novel Combined Finite Difference and Space Harmonic Method

This paper presents the modeling and analysis of eddy current speed sensors for linear speed measurement of rectangular nonmagnetic bars. A novel 3D computational method is developed to model eddy current speed sensors using combined finite difference and space harmonic methods. The modeling and analysis of the sensors are performed at constant and variable speeds. Detailed measurements of the eddy current speed sensors at two frequencies are performed. Two bars with a square-shaped cross-section and one bar with a rectangular cross-section are chosen for the measurements and modeling, and their materials are brass and aluminum. A comparison of the measurements and calculations shows adequate precision of the 3D computational model. The paper aims to present an efficient computational tool for 3D analysis of eddy current speed sensors with rectangular configurations.