What loss occurs when an AC current is continuously changing in a magnetic core?

Hysteresis loss occurs in magnetic materials when they are subjected to a cyclic magnetic field. This loss results from the lag between the change in magnetizing force and the change in magnetization of the material. As an alternating current (AC) flows through a coil wound around a magnetic core, the magnetic domain structures within the core material attempt to align with the changing magnetic field. However, due to the inherent properties of the material, there is resistance to this alignment and re-alignment, causing energy to be dissipated as heat.

The magnitude of hysteresis loss is influenced by the material properties, particularly the coercivity and the frequency of the AC current. Higher frequencies result in more rapid changes in the magnetic field, leading to increased hysteresis losses. Understanding this concept is essential when designing transformers, inductors, or other devices that rely on magnetic cores to ensure efficiency and minimize energy losses. Other forms of loss, such as copper loss, primarily relate to resistive heating in the conductors due to current flow, whereas eddy loss is associated with induced currents within the core material itself that oppose the original magnetic field and may also convert energy into heat, but they are distinct phenomena from hysteresis loss.