Penetration of flux into saturating steel in the presence of transverse fields

Most studies of flux penetrating the end region of a machine, such as the stator core of a turbo-generator, have not taken into account the large core flux already present in the iron laminations. In the paper an experimental system is described in which the electric field within a stack of laminations is measured when flux penetrates from the surface in the presence of a large sinusoidal magnetic field at right-angles to the flux. The fundamental and third-harmonic components of electric field, computed using a two-dimensioanl model of the system, give good agreement with the experimental results. Analytical expressions for the electric field within the steel are obtained using a one-dimensional model assuming a step B/H characteristic, an assumption which is reasonable for the high field strengths present in a real machine. A comparison of the predictions of this theory are also made with the results from the experimental system.