Description: Eddy currents are electric currents induced in conductors by a changing magnetic field. This phenomenon is based on Faraday’s law of electromagnetic induction, which states that a change in magnetic flux through a closed circuit induces an electric current in it. Eddy currents are important in various technological applications, as they can be both useful and detrimental. On one hand, they can be harnessed in devices such as electromagnetic brakes and in induction heating for cooktops. On the other hand, they can cause energy losses in transformers and electric motors, resulting in reduced efficiency. To mitigate these unwanted effects, materials with high resistivity are used, or components are designed with specific shapes that limit the circulation of these currents. In the context of various technologies, eddy currents can be used to enhance the efficiency of control systems and for the development of advanced sensors that detect changes in the environment through variations in magnetic fields.
History: The phenomenon of eddy currents was discovered by French physicist Léon Foucault in 1851. Foucault observed that moving a magnet near a conductor induced currents in it, leading to a greater understanding of electromagnetic induction. Over the years, this discovery has been fundamental to the development of electrical and electromagnetic technologies, influencing the creation of transformers, electric motors, and induction devices.
Uses: Eddy currents are used in various applications, such as in electromagnetic brakes, where currents are generated in a metal disc to create a braking force. They are also employed in induction heating for cooktops, where the currents heat the container directly. Additionally, they are used in metal detection devices and in induction welding techniques.
Examples: A practical example of eddy currents is their use in high-speed train brakes, where they are employed to decelerate the train without physical contact. Another example is induction welding, which uses these currents to heat and join metal pieces efficiently.
