Surface impedance models for corners and slots

The penetration of flux into metallic parts is limited by the skin effect at power frequencies and so, when analyzing eddy-current fields, such metallic parts may be excluded from the region of solution at a great saving in computing effort, by replacing the metal by a surface impedance. However, at corners, in slots and under saturated conditions, the model breaks down, as penetration increases. In this paper, we provide means for continued use of the these mode is under these conditions. The significance of this to memory requirements is all the more important because eddy current solutions involve 2 variables per node, so that as parts are eliminated from solution regions, matrix storage requirements, go down even faster.