örvényáramok

örvényáramok, also known as eddy currents, are electrical currents induced within conductive materials by a changing magnetic field. This phenomenon is a direct consequence of Faraday's law of induction, which states that a changing magnetic flux through a circuit induces an electromotive force (EMF). In a bulk conductor, there are no predefined circuits, but rather the changing magnetic field induces circulating currents within the material itself.

These induced currents flow in closed loops and are called eddies, hence the name eddy currents. The magnitude of these currents depends on the strength of the magnetic field, the rate of change of the magnetic field, the conductivity of the material, and the geometry of the conductor. The resistance of the material causes these eddy currents to dissipate energy in the form of heat, a phenomenon known as Joule heating.

örvényáramok can be both beneficial and detrimental. In applications like induction heating and magnetic braking, eddy currents are intentionally generated and utilized for their heating or retarding effects. For instance, induction cooktops use eddy currents to directly heat cookware. In contrast, eddy currents can cause significant energy losses in electrical transformers and motors due to the heating of their iron cores. To minimize these losses, the cores of such devices are often constructed from thin laminations of highly permeable material, insulated from each other. This increases the electrical resistance of the paths for eddy currents, thereby reducing their magnitude and the associated energy dissipation.