The electromagnetic powder brake consists of three basic components: a coil, a stator and a rotor.
When electric current is supplied to the brake, the magnetic field inside the coil starts to vary in proportion to the size of the current. The variations in the magnetic field alter the viscosity of the special powder positioned between the rotor and the stator.
When an electrical current is applied to the coil, the particles are aligned along the magnetic field force lines, create a dragging bond between the rotor and the stator and generate thereby the braking effect. When the current is disconnected, the powder is pushed against the stator by the centrifugal force, thus releasing
the rotor so that it can rotate.