IN HIGH PERMEABILITY MATERIALS

Eddy currents flowing in thin skin depths are of great importance in some electrical machine parts, such as transformer tank walls and turbine generator rotors. The skin depth of the eddy currents is usually very small compared with the overall dimensions of the device, so that it is curl$ (gradTxn).n (3) uneconomic to model this type of problem by means of the usual 3D volume elements. It is shown here how surface elements can be used. Some experimental results are compared with simulations from the MEGA program (4) package.