What are the useful applications of eddy current?

1.   Eddy currents are used for braking; since there is no contact with a brake shoe or drum, there is no mechanical wear. However, an eddy current brake cannot provide a "holding" torque and so may be used in combination with mechanical brakes.

2.  Repulsive effects and levitation

In a varying magnetic field the induced currents exhibit diamagnetic-like repulsion effects. A conductive object will experience a repulsion force. This can lift objects against gravity.

3. 

3. Attractive effects

In some geometries the overall force of eddy currents can be attractive, for example, where the flux lines are past90 degrees to a surface, the induced currents in a nearby conductor cause a force that pushes a conductor towards an electromagnet.

4.  Identification of metals

In coin operated vending machines, eddy currents are used to detect counterfeit coins, or slugs. 

5. Vibration and position sensing[edit]

Eddy currents are used in certain types of proximity sensors to observe the vibration and position of rotating shafts within their bearings. A Ferraris acceleration sensor, also called a Ferraris sensor, is a contactless sensor that uses eddy currents to measure relative acceleration.

6. Structural testing

Eddy current techniques are commonly used for the nondestructive examination (NDE) and condition monitoring of a large variety of metallic structures, including heat exchanger tubes, aircraft fuselage, and aircraft structural components.

7. Coating Thickness Measurements

8. Sheet Resistance Measurement