How is heating caused by eddy currents in transformers overcome?
Laminating the core reduces the heat loss. The core is made out of strips of metal, separated by lacquer or other insulator, so the area of the eddy currents is reduced. Consequently, the flux and therefore the Faraday emf are smaller, so smaller eddy currents flow. You may notice transformers buzzing at 100 Hz (near G at the bottom of the bass clef) as the laminations all become electromagnets 100 times per second. Eddy current heating is never completely overcome, and transformers are usually at least a little warm. (In Sydney, cockroaches like to live on or near transformers because they are warm.) How does the principle of induction apply to cooktops in electric ranges? Some electric ranges have a coil of wire instead of a hot plate. This carries AC and produces a strongly varying magnetic field. When a conducting saucepan is placed upon it, eddy currents are induced in the metal in the base of the saucepan. These produce heat via ohmic losses (and hysteresis in magnetisation). One
