Altra brand Warner Electric magnetic particle clutches and brakes provide adjustable, smooth torque control for web tensioning while maintaining a clean, dust-free environment.
Magnetic particle clutches and brakes 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. The ability to engage across a wide range of input power makes the magnetic particle designs useful 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 helps eliminate this behavior, even down to single-digit RPMs.
Source: Packaging World - Packaging news, trends & innovations