Patent ID: 7940506
Filing Date: 2011-05-10
Classification: H02H

Abstract:
1. An automated AC line filter which is activated when a lagging inductive current is detected at a load, the automated line filter comprising: an AC line filter; a current sensor adapted for electrical communication with an AC power line to the load for sensing the lagging inductive current at the load; comparison circuitry operably disposed to receive a voltage signal and an output of the current sensor, the comparison circuitry for sensing and detecting lagging current for inductive loads wherein the circuitry produces an error signal for a period that corresponds to a difference in phase between a voltage and the lagging inductive current; circuitry operably disposed adjust a voltage signal magnitude that corresponds to the lagging inductive current and that is output from the current sensor so that peak values of the voltage signal and the output of the current sensor are approximately equal to improve accuracy of the error signal; a switch mechanism in electrical communication with said current sensor and said AC line filter, said switch for providing electrical continuity between said AC line filter and the AC power line to the load upon a predetermined sensed lagging inductive current at said current sensor; and wherein the automated AC line filter is configured to: