Eddy current brake for air driven centrifuge

摘要

An improved apparatus and method for braking the rotation of a centrifuge rotor is disclosed comprising magnet means operable in a first condition wherein substantially no eddy currents are induced in a rotating rotor made of electrically conductive material by the magnetic flux of the magnet means and a second condition wherein eddy currents are induced into the rotating rotor sufficiently to slow the rotor. In one embodiment, magnet means is movable from a first position wherein substantially no eddy currents are induced in an electrically conductive portion of the rotating rotor by the magnetic flux to a second position wherein eddy currents are induced into the rotating rotor in a quantity sufficient to slow the rotor. In an alternate embodiment, the magnet means is an electromagnet connected to an interruptible source of power so that, when power is applied, eddy currents are developed in the rotor sufficient to brake the rotation thereof, and, when power is disconnected, the braking eddy current force is immediately discontinued.