Surface heating by induction

THE generation of heat within the iron core of a power transformer is termed the core loss, which is one form of induction heating. It is customary to divide the core loss into hysteresis and eddy-current loss. The hysteresis loss is a characteristic property of ferromagnetic materials, whereas the eddy-current loss is an I²R loss due to current circulation in the material, resulting from electromotive forces induced by the varying induction. Replacing the iron of the core by a nonmagnetic metal will eliminate the hysteresis loss, but eddy currents will still be induced and heat generated. Hence, magnetic as well as nonmagnetic metals respond to induction heating.