By John Pieri, Thomson-Deltran Product Line Manager, Danaher Motion
Dynamic spring-set brakes come in two basic types. The first holds the load with power applied to the electric brake solenoid and the other type holds with the power disconnected. Power-on brakes secure the load when the specified voltage energizes the solenoid, but unfortunately lose their grip during an inadvertent power failure. Power-off brakes, on the other hand are safe by default. Either intentional or inadvertent power loss engages the brake to hold the load by virtue of a mechanical spring. In addition, the latter brake is the safest and the most preferred type to use in machines where the load moves vertically.