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By Lenz's law, an eddy current creates a magnetic field that opposes the change in the magnetic field that created it, and thus eddy currents react back on the source of the magnetic field. For example, a nearby conductive surface will exert a drag force on a moving magnet that opposes its motion, due to eddy currents induced in the surface by ...
When a magnetic field moves through a conductor the movement induces an eddy current in the conductor. The flow of electrons in the conductor immediately creates an opposing magnetic field which results in damping of the magnet and produces heat inside the conductor similar to heat buildup inside of a power cord during use.
[1] [2] Damping is an influence within or upon an oscillatory system that has the effect of reducing or preventing its oscillation. [3] Examples of damping include viscous damping in a fluid (see viscous drag), surface friction, radiation, [1] resistance in electronic oscillators, and absorption and scattering of light in optical oscillators.
Electrodynamic suspension (EDS) is a form of magnetic levitation in which there are conductors which are exposed to time-varying magnetic fields. This induces eddy currents in the conductors that creates a repulsive magnetic field which holds the two objects apart. These time-varying magnetic fields can be caused by relative motion between two ...
The magnetic field (B, green lines) of one wire induces circular eddy currents (E) in the other wire. The eddy current flows in the opposite direction to the main current on the adjacent side of the wire (1) reducing it, but flows in the same direction as the main current on the far side of the wire (2) , increasing it.
Eddy currents flow in closed loops in planes perpendicular to the magnetic field. They have useful applications in eddy current brakes and induction heating systems. However eddy currents induced in the metal magnetic cores of transformers and AC motors and generators are undesirable since they dissipate energy (called core losses) as heat in ...
In metals the damping forces described by the constant λ are in many cases dominated by the eddy currents. One important difference between phonons and magnons lies in their dispersion relations. The dispersion relation for phonons is to first order linear in wavevector k, namely ώ = ck, where ω is frequency, and c is the velocity of sound.
Relative motion of the conductor and the magnet induces eddy currents in the conductor, which produce a force or torque that opposes or resists relative motion, or tries to "couple" the objects. The same drag-like force is used in eddy current braking and magnetic damping.