Electromagnetic brake
Electromagnetic brakes have the same purpose as conventional brakes; to cause deceleration in a moving system. Conventional brakes operate by applying pressure to a material so that it comes in contact with a moving surface. Because of friction between then the two materials the momentum of the moving part to gradually be converted to heat and deceleration occurs. A consequence of conventional braking is that the materials that physically rub together also wear away and must be occasionally replaced.
The parts of an electromagnetic brake do not phyically touch each other. A typical electromagnetic brake is composed of a metal disc that is attached to a wheel and an electromagnet that that generates a field that intersects the disc. To cause deceleration a current is passed through the electromagnets causing the generation of a magnetic field. The movement of the the metalic disc through the magnetic field causes a current to be generated in the disc called an eddy current. The eddy current causes a magnetic field that opposes that of the electromagnet. As a result the disc will decelerate and some of the absorbed energy causes the disc to heat. Vehicles that employ regenerative braking are able to use the generated eddy current to recharge a battery or capacitor.
--216.113.128.194 21:18, 2 May 2005 (UTC)Joel Johnson