The brake slides onto a shaft and couples with a roll pin or integral clamp. A torque arm holds the brake body stationary. Torque is produced by magnetizing microscopic stainless-steel spheres. Strength of the magnetic field and hence, torque, scales with input current. Torque is independent of slip rpm.

Magnetic particle brakes are typically used where infinitely variable, smooth, slip torque is needed, such as for winding systems. Here, input current controls unwind tension. The brakes also provide a variable load for performance and life testing of stepper motors, gearmotors, and mechanical systems.

Hollow-shaft brakes come in sizes 0 to 15 to 220 lb-in. Larger solidshaft brakes and clutches handle torque to 300 lb-ft and dissipate up to 1,900 W.

Placid Industries Inc., 139 Mill Pond Dr, Lake Placid, NY 12946, 518 523-2422,