Magnetic particle clutches and brakes
How Magnetic Particle Clutches & Brakes Work
The MAGNECLUTCH is remarkably simple in construction and operation. The two moving parts - inner rotating member "A" and outer rotating member "B" - do not touch. They are cantilevered on bearings. The space between the inner and outer rotating members, "C", is filled with an extremely fine, dry magnetic powder. There is a second gap "D" between the outer rotating member and the stator frame. A stationary 90 volt DC coil "E" is built into the stator frame around this area. Current passing through the coil creates a magnetic field, causing the powder to form a link between the inner and outer rotating members and thereby transmit torque. Transmitted torque varies directly with the magnetic field strength through changes in current. The clutch has no slip rings, friction plates, or other friction bearing surfaces. Magnetic particle clutch characteristics do not change with years of usage.
When the magnetic particle clutch applies torque to a load, it starts without jerking. The load accelerates evenly, with no variations in acceleration rate. There is no bucking, grab, or shock - not even a tremor from the clutch. A friction clutch, however, uses two plates of metal or other material. When engaged, these two friction plates slip (rub against each other) until they reach locked-in running speed. With two surfaces rubbing at different speeds, precise control is difficult. The load doesn't accelerate evenly, because the plates tend to grab and release intermittently. This is known as the "stick-slip" phenomenon. As a result, the friction clutch can accelerate in jerks. The MAGNECLUTCH provides complete control because magnetic particle action makes torque output directly proportional to coil current, independent of slip speed. The MAGNECLUTCH makes equipment more controlled and stable, longer lasting, and easier to maintain.
The MAGNEBRAKE operates on the same principle as the MAGNECLUTCH except one of the rotating members is held stationary resulting in braking torque instead of transmitted torque. In base mounted MAGNEBRAKES, the inner rotating member is permanently fixed, thereby establishing the braking characteristic. In shaft mounted MAGNEBRAKES the outer housing is permanently secured to the frame of the machine using the housing through bolts and a torque arm or custom bracket to prevent the brake from rotating. Current passing through the coil creates a magnetic force leading to braking torque. The MAGNEBRAKE can slip continously within it's operating specifications without wear and loss of holding torque.
