Abstract: An apparatus especially adapted for use in AC power systems of the type having a device for reducing power consumption by reducing load voltage, the apparatus having a sensor for detecting an increase in load current and for controlling a responsive increase in load voltage to compensate for the added load causing the increase in current. The apparatus can be used in three-phase AC systems for controlling each phase independently and can be made sufficiently sensitive to operate in a 28,000 Watt fluorescent light load while responding to as little as 400 Watt load additions to assure quick and efficient ignition of newly turned-on lights. A digital memory device, in the form of a state machine in the preferred embodiment, is used to control operation and timing for one to three phases while permitting low line voltage override and periodic timing override operation.

Abstract: An apparatus for reducing the voltage applied to a load in an AC system utilizes an autotransformer and a relay or equivalent switching device between the common winding and the series winding. In each of the AC lines, the common winding and relay are connected between the load and the AC common while the series winding is connected between the input and the output. The relay is normally open to pass substantially full input voltage to the load, but when closed the relay permits current flow in the common winding to reduce voltage to the load. The relay or equivalent switching is therefore not in the direct flow of load current and can be of lower current rating and smaller size and cost as compared to prior art voltage reduction systems.