Christina H Chen, Hui Meng, and Min Fan

Presented on Aug 2018 at 2018 International Conference on Rare Earth Permanent Magnets and Advanced Magnetic Materials and Their Applications (REPM 2018)

At: Beijing, China

The magnetic force of magnetic components can be determined by using the Maxwell magnetic force equation F = B^2 A/(2μ0), with A is the cross-section area and B is the flux density. However, in many practical cases it is difficult to determine the B, and the accuracy is usually unsatisfactory. This paper reports a simple equation F = Br^2 (aA^2 +bA), where remanence Br is a known value of a magnet, and A is the magnet’s polar area. The factors a & b are function of magnet’s thickness t. The equation is developed based on the large database generated by using 3D computer simulation for the rare earth magnets (rings /cylinders /rectangular blocks) interacting with steel plates, and the equation is effective to all the magnets with high load lines. The effect of load line on the magnetic force is tremendous. For the magnets with low load lines, the magnetic force vs the area cannot develop satisfactory equation as the force values are in a large range for a single area. This paper also reports the details, including simulation set up, data analyses, equation development, and the effect of load line. Based on the database a Force Calculator App has been established for all the rare earth magnets with the gaps to steel are from 0.01 to 15 mm.