eddyströmsförlust

Eddyströmsförlust, also known as eddy current loss, is a phenomenon that occurs in conductive materials when they are subjected to a changing magnetic field. This phenomenon leads to the generation of circulating currents within the material itself, known as eddy currents. These currents are induced by the principle of electromagnetic induction, as described by Faraday's law.

The eddy currents flow through the conductive material, encountering electrical resistance. This resistance causes the kinetic energy of the charge carriers to be converted into thermal energy, resulting in heat. Consequently, eddy current loss represents a form of energy dissipation, where electrical energy is converted into heat within the conductor.

The magnitude of eddy current loss is influenced by several factors. These include the resistivity of the material, the frequency of the changing magnetic field, the strength of the magnetic field, and the geometry of the conductor, particularly its thickness. Materials with lower resistivity will experience greater eddy current losses, as they offer less resistance to the induced currents. Higher frequencies and stronger magnetic fields also tend to increase the induced voltage and thus the eddy currents, leading to more significant losses.

Eddy current losses are undesirable in many electrical devices, such as transformers and electric motors, where they reduce efficiency and can lead to overheating. To mitigate these losses, conductive materials in such applications are often laminated. Lamination involves dividing the conductive core into thin sheets that are electrically insulated from each other by a thin layer of oxide or varnish. This increases the overall resistance path for the eddy currents, significantly reducing their magnitude and the associated energy loss.