When large pieces of conductors are placed in changing magnetic flux, small circulating currents are induced in them. These currents are called eddy currents because they swirl around in the conductor like eddies in water. This effect was discovered by physicist Foucault (1819-1868).
Magnetic flux linked with the plate keeps on changing as the plate moves into and out of the magnetic field. The eddy currents are induces in the plate due to flux change. Directions of eddy currents are opposite when the plate swings into the region between the poles and when it swings out of the region. See figure 11.
These currents are due to the motion of the free charges that are caused to move by the changing magnetic field.
Eddy currents are usually undesirable since they cause the conductor to heat up if they are excessive and dissipate electrical energy in the form of heat. Eddy currents are minimized by using laminated strips of metal, separated by insulating layers like lacquer. This prevents eddy currents from travelling across the laminations. The plane of the laminations is kept parallel to the magnetic field, so that they cut across the eddy current paths.
Advantages of eddy currents :
CBSE Electromagnetic Induction ( With Hint / Solution)
Class XII (By Mr. Ashis Kumar Satapathy)
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