Eddy or Focault currents are the currents induced in the body of a conductor when the magnetic flux linked with the conductor changes.
Since i = \(\frac{e}{R}\)
But e = \(-\frac{d\phi}{dt}\)
∴ i = \(-\frac{d\phi\ /dt}{R}\)
The direction of eddy currents is given by Lenz’s law or Fleming's left hand rule. Eddy currents are reduced by taking laminated sheets of metal instead of single plate.
Applications
1. Induction motor or a.c. motor.
A rotating magnetic field due to alternating current produces strong eddy current in a rotor which starts rotating in the direction of rotating magnetic field.
2. Induction furnace makes use of heating effect of electric currents. The substance to be melted (say to form alloys) is placed in a high frequency magnetic field. The strong eddy currents developed in the substance produces so much heat that it melts. Such an arrangement is called induction furnace.
