Many household items and objects encountered in daily life operate in magnetic fields that occur as the result of electricity moving through metal conductors. Electromagnets differ from the simple, permanent magnets you might see displayed on a refrigerator door; in contrast, electromagnets, also known as temporary magnets, can be switched on or off. Electromagnets can be found in small devices such as doorbells to large machines that pick up and release cargo.
An electromagnetic device acquires its power from the magnetic fields that form when electrons travel in an electric current through a metal conductor. Objects powered by electromagnets are considered superconductive, or resistant. They range from small objects that use a single wire for conduction to large, superconducting machines found in medical and institutional settings.
Ordinary objects powered by electromagnets include telephones, toasters, televisions and door locks. Some automobile parts, including brakes and clutches, use electromagnets to operate. Electromagnets also provide power to electric motors and generators, stereo speakers and circuit breakers.
Mark Bird, director of Magnet Science and Technology at the Magnet Lab in Tallahassee, Florida, describes resistive electromagnetic devices as magnets that use regular electricity, multiple metal coils and insulators to generate high magnetic fields. According to Dr. Eric Palm, D.C. field director at the Magnetic Lab, scientists all over the world use these high-powered electromagnets as research instruments to conduct their experiments.
According to Iain Dixon, a research associate at the Magnet Lab, an extremely cold temperature (-425 degrees Fahrenheit) provides an unobstructed passage for electrons as the electrical current moves through conductive material in electromagnets known as superconductors. This type of electromagnetic device includes magnetic resonance imaging (MRI) machines and machines designed for the study of nuclear magnetic resonance (NMR).
Dan Norrgran, marketing manager for Heavy Industries at Eriez Heavy Industries Group, explains the function of suspended magnetic separators, which are superconducting electromagnets used in industrial settings. These electromagnetic machines attract and extract metal parts from coal, rock and other materials as they move down conveyor belts.