So far we have assumed that currents are essentially confined in one-dimensional paths. Nonetheless, in many cases we find metallic pieces of electrical equipment moving in magnetic fields or located in changing magnetic fields. As a result, induced currents will circulate throughout the volume of the metal, with flow patterns resembling swirling eddies in a river.
Eddy currents induce drag forces on moving objects, and also waste heat.
Applications:
- Heating: eddy currents are used to heat materials in completely sealed containers for processes in which it is essential to avoid the slightest contamination of the materials.
- Metal detectors: metal detectors used at security checkpoints operate by detecting eddy currents induced in metallic objects.
- Magnetic breaks: the moving conductor experiences a drag force from the magnet that opposes its motion, proportional to its velocity. The kinetic energy of the moving object is dissipated as heat generated by the current flowing through the electrical resistance of the conductor.
https://youtu.be/sENgdSF8ppA - Eddy currents opposes movement https://youtu.be/8i2OVqWo9s0 - eddy currents + resistance implies heating
Dielectrics