By far the major use of brakes on theatre machinery is to hold loads in place rather than to slow or stop moving loads. These holding brakes keep wagons in position and flown scenery up in the air when their winch motors are off. Two completely independent brakes are often used as part of a single failure proofing scheme in machines designed to run lifts or flying effects.
For stage use, spring-set power-release brakes are by far the most useful. Whenever power is removed from the brake, force from a compressed spring or springs acts to press friction pads against a rotating disk or drum. The friction developed creates the braking torque. The value of this torque is the main rating given to a brake, and is the rating ...