Warner Electric (South Beloit, WI) offers their line of magnetic particle clutches and brakes as a solution for many web tensioning processes that require adjustable torque while maintaining a clean, dust-free environment. Magnetic particle clutches and brakes used for tension control or torque limiting are electro-magnetically actuated and consist of input and output members with a cavity between them. Within that cavity are very small magnetized metal particles. Because the particles are contained within the cavity, there are no wear particles as might exist in a friction design clutch or brake. In addition, the ability to engage across a wide range of input power makes the magnetic particle designs a good fit for tension control applications where a less than fully locked-up condition is an advantage. Frictional units can suffer from a stick-slip behavior when low engagement force and low speed are applied. In magnetic particle clutches and brakes, the ability of the particles to slip against each other eliminates this behavior, reducing RPMs.
ADVERTISEMENT