Means for controlling lumen output in power consumption of phosphor

Abstract

A device and a method for reducing power consumption and correspondingly reducing lumen output of a phosphor excitable lamp, such as a fluorescent lamp, connected to a source of power for operation of the same, without any appreciable loss of operating efficiency. A load limiting arrangement, often referred to as a load limiting control device, and which generally includes a capacitive element is electrically connectable to one terminal of the phosphor excitable lamp. This device, when connected, is effectively electrically interposed between the lamp and the source of power in a series connection. The capacitive element is selected with a capacitive value so that the lumen output is reduced but with substantially uniform lumen output at the reduced level and the power consumption is reduced without substantially changing the voltage to the lamp and without any appreciable effects on the efficiency of operation of the lamp or the source of power. Further, when using the device and method, a circuit path is not created directly between the conductive terminal of the socket and the end terminal of the lamp, but rather through the capacitive element to thereby reduce the power consumption and lumen output. In addition the load limiting arrangement may adopt the form of a capacitive-inductive circuit arrangement. In a preferred embodiment, the device is constructed so that conductive pins on the device is inserted in the pin receptacles of the fixture and pin receptacles on the device are offset to receive the pins on the lamp.