A Model of Magnetic Reluctance of Cylindrical Solid Iron Cores

A model of magnetic reluctance is considered in the frequency domain for cylindrical solid iron-cores when magnetic flux normally enters and leaves on the circumferential surface. To have an analytical model, we take a iron core that is sufficiently high to spread the magnetic flux over the circumferential surface and not out over the upper and lower ends. First, a three-dimensional distribution of the magnetic field is solved with Laplace transform. Then, the magnetomotive force between the two pole faces is obtained by a mean value along flux paths on the surface to describe the magnetic reluctance. The model given by Bessel functions is approximated in a simple form. The numerical result is compared with an experimental result to check the applicability of the model to actual cores.