Eddy current losses in finite length conducting cylinders

This paper introduces normalized graphs for the active and reactive powers absorbed by a finite length magnetic or nonmagnetic cylinder placed in an axial uniform time-harmonic magnetic field. Boundary element analysis is used to treat the integral equations relating the azimuthal current density and the tangential magnetic field at the surface of the cylinder. The values of the powers are normalized w.r.t, the corresponding values in the high frequency limit when impedance boundary condition prevails. An equivalent radius is defined for the finite length cylinder. This is a function of the length to diameter ratio and the power demagnetizing factor. The latter is introduced for magnetic cylinders to account for the nonuniformity of the magnetic field in the low frequency limit. Through this normalization a very compact representation of the active and reactive powers for a very wide range of length to diameter ratio, frequency and permeability is achieved.