Calculation of short circuit impedance and leakage impedance in transformer windings

A method for calculating short-circuit and leakage impedances in transformer windings is described. The method is based on a formula which is derived from an exact solution of Maxwell's equations for coils on ferromagnetic cores. The calculation is based on winding geometry and on the core magnetic permeability and effective electrical resistivity. Eddy-current losses in the core and windings are included. The model takes account of the frequency-dependent nature of short circuit and leakage impedances in transformers. Results are presented for a ferrite pot core of the type used in switching mode power supplies.<
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