Patent ID: 8582262

Claim:
A method for reducing inrush current to an electrical load in response to detection of a disturbance occurring in an input AC power supply coupled to the electrical load, comprising: applying an input voltage to the electrical load; monitoring the current drawn by the load; recording peak values of the current drawn by the load; continuously monitoring the voltage of the input AC power supply to detect a voltage sag to a predetermined level below rated voltage for short periods of time of one half cycle or more indicating a disturbance in the input AC power supply that would cause an inrush current to the electrical load upon ending of the disturbance; in response to detection of the voltage sag, recording a peak current limit reference (I max ) corresponding to a maximum peak current value thus far recorded; detecting when the current level exceeds the peak current limit reference (I max ) as indicating the disturbance occurring in the input AC power supply; and adding an impedance to the electrical load in response to detecting the disturbance, wherein an inrush current to the electrical load is limited as the input voltage returns to a normal operating level voltage.