Energy Flow in Transformers

The presence of a leakage magnetic field is necessary for the transfer of energy between the primary and the secondary. Relations are derived for the electromagnetic field and for the energy transfer in an infinitely long transformer of circular cross section. The necessary information to calculate the field and the energy flow for a shell type transformer of cylindrical symmetry, in which the placement of primary and secondary is arbitrary, is given. Results for specific placements of primary and secondary are analyzed, computed, and interpreted.