hysteresihäviöt

Hysteresihäviöt, in physics and engineering, refers to energy loss that occurs in ferromagnetic materials when they are subjected to a cyclic magnetization process. This phenomenon is a direct consequence of magnetic hysteresis. When a magnetic field is applied to a ferromagnetic material, the magnetic domains within the material align themselves with the field. As the field is increased and then decreased, the domains do not retrace their original paths perfectly. This lagging or "hysteresis" in the magnetization response leads to irreversible changes in the domain structure. These irreversible changes require energy to overcome the internal friction and domain wall movement resistance, and this energy is dissipated as heat, thus constituting the hysteresis loss. The amount of hysteresis loss is proportional to the area enclosed by the hysteresis loop, which is a graphical representation of the relationship between the magnetic field strength and the magnetic flux density of the material. Materials with narrow hysteresis loops exhibit lower hysteresis losses and are preferred for applications where energy efficiency is crucial, such as in transformers and electric motors. Conversely, materials with wide hysteresis loops have higher losses and are used in applications like permanent magnets, where the energy loss is less of a concern than the ability to retain magnetism. Understanding and minimizing hysteresis losses are important for improving the efficiency and performance of many electrical and magnetic devices.