3D to 2D transformation solution of transient eddy current electromagnetic fields in an actuator

A 3-D to 2-D transformation finite-element technique for solving the transient eddy current problem in an electromagnetic actuator is presented. The solution uses only one component in a two-dimensional field instead of three in three dimensions. The approach has been applied to an electromagnetic actuator design problem. The accuracy achieved using the transformation finite-element method (FEM) is acceptable compared with the static 3-D methods and the measured results of tests performed on an electromagnetic actuator. The proposed method results in considerable economy in computation. The results are informative on the sensitivity of electromagnetic actuators to nonsinusoidal currents, which is important for current tripping where significant harmonics are present