Abstract

The following specification discloses an electrical power controller that has been specifically directed toward the control of lighting. The invention is directed toward reducing electrical energy consumption of high intensity discharge (HID) lamps and fluorescent lamps. The controller is connected at its input to a power line to light a bank of lamps or other electrical energy consuming devices. The output of the controller to the lamps can effectively be optimized at a substantially lower level, providing a high degree of lighting while effectuating a substantial energy saving. The output is controlled by a variable autotransformer having a drive motor that is in turn controlled by an amplifier comparator circuit. A bidirectional ramp generator provides increases and decreases of voltage in a manner to maintain the lights in their optimum operating condition. A timing circuit provides a timing function to allow for sufficient high voltage to light the HID lights over a prescribed period of time for the lights, after which it allows the system and controller to go to a low set point, which is sufficient to maintain the lamps in their lit condition. In the eventuality a load change occurs on the lighting bank, such as an increased series of lights being lit, a wattmeter output is fed back to a power change detector. This resets the controller for purposes of providing an increased amount of voltage sufficient to light the extra bank of lights while at the same time preventing the existing lights from being extinguished.