The FEB line of disc brakes from Carlyle Johnson Machine Co., Bolton, Conn. (, generates the most holding torque in the smallest package, according to the company. Its engineers, backed by 100 years of experience in power transmission, also devised a set of wave springs that quickly separate the discs when the brake is disengaged, regardless of the brake's orientation. This eliminates parasitic drag, which can shorten brake life. And flux paths were designed to minimize flux leakage between the armature and discs.

The brakes apply holding torque (15 to 550 lb-ft) when electrical power is removed from the brake coil, either intentionally or in a power failure. When the coil loses power, compression springs release and clamp several composite friction discs between the armature and stationary end plate, creating a constant holding force. This sends braking torque to the hub and shaft through the discs. Applying power releases the brake by generating a magnetic field that pulls the armature against the coil springs and away from the discs. Typical applications include medical diagnostic equipment, part-handling machinery, brakes for servodrives and robots, and emergency brakes for power-generation equipment.