A control system for controlling the application of electrical power to a load

摘要

A lighting load can be turned on/off manually from one or more remote switching stations as well as from a master switch controller station, with ON/OFF control signals produced at the remote switching stations being transmitted to the master controller circuit on the traveler conductor of a conventional single phase AC power distribution system. The main controller has an internal dual mode DC power supply which is referenced to load potential. The dual mode power supply derives operating power from the voltage across the gate controlled power switch which corresponds with essentially hot potential when the power switch is off. The voltage drop across the power switch is boosted by a step-up transformer when the power switch is on. Remote turn-on and turn-off signals are derived independently from the hot power conductor and ground safety power conductor, respectively. Remote turn-on and turn-off of the master power switch is accomplished without interfering with automatic turn-off operation of the controller.