Hysteresförluster

Hysteresförluster, or hysteresis loss, refers to the energy dissipated as heat within a ferromagnetic material when it is subjected to a cyclic magnetic field. This energy loss is a consequence of the material's magnetic hysteresis loop. When a ferromagnetic material is magnetized, its magnetic domains align with the external magnetic field. As the field is reversed, these domains resist this change in alignment, leading to a lag between the applied magnetic field and the resulting magnetization. This resistance to change requires energy to overcome, and this energy is converted into heat, which is the hysteresis loss.

The area enclosed by the hysteresis loop on a graph of magnetic flux density (B) versus magnetic field strength (H) is directly proportional to the hysteresis loss per unit volume per cycle. Materials with narrow hysteresis loops experience lower hysteresis losses, making them suitable for applications where energy efficiency is crucial, such as in transformers and electrical motors. Conversely, materials with wide hysteresis loops have higher hysteresis losses and are often used in applications requiring permanent magnets or damping. Factors influencing hysteresis loss include the material's composition, its microstructure, and the frequency of the applied magnetic field. Higher frequencies generally lead to increased hysteresis losses.