Eddy currents are loops of electrical current induced within conductors, circulating like eddies in a stream, by a changing magnetic field. These currents flow in closed loops within the conductor and in planes perpendicular to the magnetic field. Eddy currents can be generated when a conductor moves through a magnetic field, or when the magnetic field around a stationary conductor changes.
A key application of eddy currents is in non-destructive testing (NDT). This method uses electromagnetism to detect surface and subsurface flaws in conductive materials, such as cracks, corrosion, and variations in material thickness. Eddy current testing is employed across various industries, including aerospace, transportation, and manufacturing, to assess material integrity without causing damage. They are also utilized for electromagnetic braking in trains and rollercoasters, induction heating, metal detection, and even in vending machines to detect counterfeit coins. However, eddy currents can also lead to energy loss in devices like transformers and electric motors, necessitating design modifications to minimize these effects.
