Core Losses

When ferromagnetic materials are subjected to magnetic fluxes, which vary with respect to time, such materials experience energy losses which show up in the form of heat. No such losses occur in the magnetic circuits of devices in which the magnetic flux is constant. However, the cores of transformers, iron-core choke coils, and the armature of d-c and a-c machines carry alternating fluxes that give rise to core losses or iron losses. The core losses consist of hysteresis and eddy-current losses.