Hysteresihäviöitä

Hysteresihäviöitä, known in English as hysteresis loss, refers to energy dissipated as heat in a ferromagnetic material when subjected to a cycle of alternating magnetization. This occurs because the magnetic domains within the material do not perfectly align and realign with the external magnetic field instantaneously. As the magnetic field strength is increased, domains align, and when the field is decreased, some domains retain their alignment or realign in a direction slightly different from the previous state. This lagging effect is called hysteresis.

The energy loss associated with hysteresis is proportional to the area enclosed by the hysteresis loop, which is a graph plotting the magnetic flux density (B) against the magnetic field strength (H). Materials with narrow hysteresis loops, like soft magnetic materials, experience lower hysteresis losses and are preferred for applications involving alternating magnetic fields, such as transformers and inductors. Conversely, materials with wide hysteresis loops, like hard magnetic materials, exhibit higher hysteresis losses but retain their magnetism more strongly, making them suitable for permanent magnets.

Hysteresis loss is an important consideration in the design of electrical devices to minimize energy waste and prevent overheating. Factors influencing hysteresis loss include the material's composition, crystal structure, and the frequency of the alternating magnetic field. Reducing this loss is crucial for improving the efficiency and performance of various electromagnetic components.