Abstract: System for controlling operation of a plurality of gaseous discharge lamps for selectively turning on or off one or more of the lamps and producing desired lumen output of the lamps as needed, to provide for conservation of electrical energy. In the system, each of the discharge lamps is connected to a separate variable impedance ballast device, a control circuit for varying the impedance of each ballast device, and a signal processing circuit connected to each control circuit for operating the same, and a signal transmitting device for transmitting information to each of the signal processing circuits, whereby the latter circuits selectively operate the respective control circuits in response to the information received from the signal transmitting device. In a preferred embodiment, the signal transmitting device is a remote transmitter such as a radio frequency signal device for remote control of the lighting system.

Abstract: Gaseous discharge lamp is connected to a current sensing transformer which generates a signal when the lamp is on to turn on a triac operating a relay for turning off an auxiliary incandescent lamp which automatically operates when the gaseous discharge lamp is extinguished. A time delay circuit including a temperature-sensitive resistor is connected to the triac for keeping the auxiliary lamp in operation until the gaseous discharge lamp reaches a suitable light level.

Abstract: Thermal switch assembly for photoelectric control device to switch loads such as street lighting luminaires on and off in response to ambient light levels. Housing having a portion integral with base of photocontrol unit and having a removable cap contains a bimetal relay assembly and positive temperature co-efficient resistor (PTCR) connected to a photocell for actuating the electrical contacts of the relay assembly.