Current Controlled Hysteresis Brakes for stable control tension

Overview of Hysteresis Brake
Standard Hysteresis Brakes produce torque strictly through a magnetic air gap without the use of magnetic particles or friction components. This method of braking provides far superior operating characteristics (smoother torque, longer life, superior repeatability, high degree of controllability, and less maintenance and down time) which make them the preferred choice for precise tension control during the processing of nearly any material, web or strand.

Structure of Hysteresis Brake
The hysteresis effect in magnetism is applied to torque control by the use of two basic components-a reticulated pole structure and a specialty steel rotor/shaft assembly-fastened together but not in physical contact. Until the field coil is energized, the drag cup and shaft can spin freely on its bearings. When a magnetizing force from either a field coil or magnet is applied to the pole structure, the air gap becomes a flux field. The rotor is magnetically restrained, providing a braking action between the pole structure and rotor.