If you need to hold a load, you need a brake. The question is which type of brake and why? The first thing you need to decide is whether you want the brake to be applied when there is no power, or when power is applied. In most cases you want to hold the load when power is off, but there are applications like gates and turnstiles, where the brake must disengage in the case of a power failure. Power-to-energise brakes are also used in process control often in conjunction with a clutch to give a stop-start action. However these applications are increasingly being solved with servos or steppers, removing the need for brakes altogether.
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