Momentary voltage sags are responsible for billions of dollars per year in lost revenues in the manufacturing and process industries. The Coil-Lock protects ac relay, contactor and solenoid hold-in-devices by keeping motors and other critical process control elements engaged during those annoying momentary voltage sags or dips. Literally, any device that is controlled by energizing an ac coil, when powered through a Coil-Lock unit will remain latched through these power disturbances. ... more about Coil-Locks