01-10-2017, 01:17 PM
25-10-2017, 11:17 AM
Eddy current s (also called Foucault currents) are loops of electric current induced inside the conductors by a changing magnetic field in the conductor, due to Faraday's induction law. Foucault currents flow in closed loops within conductors, in planes perpendicular to the magnetic field. They may be induced within near stationary conductors by a time-varying magnetic field created by an electromagnet or AC transformer, for example, or by relative motion between a magnet and a nearby conductor. The magnitude of the current in a given loop is proportional to the magnetic field strength, loop area and flux rate, and inversely proportional to the resistivity of the material.
According to Lenz's law, a parasitic current creates a magnetic field that opposes a change in the magnetic field that created it, and therefore the parasitic currents react again at the source of the magnetic field. For example, a nearby conductive surface will exert a pulling force on a moving magnet opposing its movement, due to parasitic currents induced at the surface by the moving magnetic field. This effect is used on eddy current brakes used to quickly stop rotary power tools when they are turned off. The current flowing through the conductor resistance also dissipates energy as heat in the material. Therefore, Foucault currents are a cause of energy loss in alternating current (AC) inductors, transformers, electric motors and generators, and other AC machines, which require special construction such as laminated magnetic cores or ferrite cores for minimize them. Foucault currents are also used to heat objects in induction heating furnaces and equipment, and to detect cracks and defects in metal parts using eddy current test instruments.
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28-01-2018, 05:23 PM
Full information about eddy currents is required for the project and its working also...pls work on it