pyörrevirtahäviöitä

Pyörrevirtahäviöitä, known in English as eddy current losses, are a phenomenon occurring in conductive materials when they are subjected to a changing magnetic field. This process, described by Faraday's law of induction, induces circulating electrical currents within the material itself, known as eddy currents. These currents flow through the resistive body of the material, dissipating energy in the form of heat due to Joule heating.

The magnitude of eddy current losses depends on several factors. The rate of change of the magnetic field is crucial; a faster change induces stronger currents. The electrical conductivity of the material also plays a significant role, with more conductive materials experiencing higher losses. Furthermore, the resistivity of the material directly influences the amount of heat generated, as higher resistivity leads to greater energy dissipation. The geometry and size of the conductive object are also relevant, with larger cross-sectional areas generally leading to more substantial eddy currents.

Eddy current losses are an undesirable side effect in many electrical devices. In transformers and electric motors, they contribute to energy inefficiency and can lead to overheating. To mitigate these losses, conductive cores are often laminated. Lamination involves dividing the core into thin sheets that are insulated from each other. This increases the overall resistance of the path for eddy currents, effectively reducing their magnitude and the associated power loss. The insulation between laminations breaks the continuous path for the induced currents.