What is an electromagnetic hysteresis brake or clutch? What are its advantages and disadvantages?
Hysteresis brakes and clutches rely purely on magnetic action working through an air gap to develop torque. They have an extremely wide torque range. Hysteresis brakes and clutches are generally similar in construction to such magnetic particle devices, except that the magnetic particles are eliminated and magnetic forcesrather than frictional forcesprovide the clutching medium. Since torque is produced without physical contact of parts, hysteresis devices are not subject to wear. This feature makes them distinctly superior to mechanical-friction brakes and clutches in life expectancy, servicing requirements and consistency of performance. Since their working members have no physical contact they do not depend on mechanical friction. Therefore, hysteresis units are absolutely and constantly smooth at any slip ratio. Torque is reasonably independent of slip speed and is also directly proportional to coil current, making response time extremely quick. Hysteresis brakes and clutches are a
