kiertovirtauksista

Kiertovirtaukset, known in English as circulating currents or eddy currents, are a phenomenon observed in conductive materials when they are exposed to a changing magnetic field. These induced currents flow in closed loops within the material, much like eddies in a fluid.

The principle behind their formation is Faraday's law of induction. When a conductor is subjected to a time-varying magnetic flux, an electromotive force (EMF) is generated. This EMF drives current within the conductor. Due to the conductive nature of the material, these currents tend to form localized, circular paths, hence the name "kiertovirtaukset."

The magnitude of the eddy currents depends on several factors, including the strength and rate of change of the magnetic field, the conductivity of the material, and the geometry of the conductive object. Higher conductivity and faster changing magnetic fields generally lead to stronger eddy currents.

While eddy currents can be undesirable in some applications, leading to energy loss through Joule heating and potential overheating of components, they also have valuable practical uses. In induction heating, eddy currents are deliberately generated to heat conductive materials rapidly. They are also employed in eddy current testing for non-destructive evaluation of materials, detecting surface cracks and flaws. Furthermore, eddy current brakes utilize their resistive effect to slow down moving objects without physical contact. Understanding and controlling kiertovirtaukset is crucial in electrical engineering and materials science.