Uses of Eddy Currents

(1)    In aperiodic galvanometers, the coil is wound on a mental frame. When oscillating between the pole pieces of the magnet, the eddy currents induced in the frame damp these oscillations. Hence the coil comes to rest quickly.

(2)    If a rotating magnetic field is applied to a lightly mounted mental disc, the eddy currents set up in the disc make the disc rotate in a direction which tends to prevent the change in flux. This is the principle of the induction mirror.

(3)    The induction furnace used eddy currents to produce heat in metallic objects. In recent years induction heating has been used in industry to heat metals. The specimen is placed in a magnetic field of frequency about a few mega hertz. This process has also been used to prepare some of the alloys by melting the constituents in vacuum.

(4)    Eddy currents can be used to produce a braking effect in moving vehicles. A metallic drum is attached to the axle of the moving train. When a magnetic field is suddenly applied to the rotating drum, eddy currents are produced. This tends to oppose the rotation drum and leads to a braking effect.