The finite element solution of transient axisymmetrical nonlinear Eddy-current field problems

In this paper, the procedure that is available for computing transient nonlinear axisymmetrical eddy-current field problems with the finite element method under the condition of the source voltage, not the exciting current, to be given is described. The transient diffusion equation is discretized by Galorkin projective technique in space, and implicit forward differential scheme in time. The quasilinearization of the nonlinear equation is handled by the Newton-Raphson scheme. The transient values of exciting current are determined by the combination of computations of field and circuit at each discrete time step, and an iterative procedure is needed. In order to reduce the computing time, the accelerating convergence factor α is indroduced. The method is applied to the disc electromagnetic brakes. The combination of the finite element method with the Maxwell´s stress view is accepted for calculating the electromagnetic force. The computing values all coincide with the experimental results.