Kiertovirtansa

Kiertovirtansa is a Finnish term that translates to "circulation current" or "eddy current" in English. It refers to a type of electrical current induced within a conductor when it is exposed to 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 (voltage), and consequently, a current if the circuit is closed.

In conductive materials like metals, eddy currents flow in closed loops within the conductor itself. These circulating currents are typically localized and can dissipate energy as heat due to the electrical resistance of the material, a process known as Joule heating. The magnitude and direction of the eddy currents depend on the strength and rate of change of the magnetic field, as well as the electrical conductivity and geometry of the conductor.

Eddy currents have both beneficial and detrimental applications. In induction heating, they are intentionally generated to rapidly heat conductive materials for processes like metal hardening or melting. Conversely, in transformers and other electrical machinery, unwanted eddy currents can lead to significant energy losses and overheating, necessitating design considerations to minimize their formation, often through the use of laminated cores. The study of kiertovirtansa is fundamental to understanding electromagnetic induction and its practical implications in electrical engineering.