US Patent 8436602 Voltage compensation circuit

A voltage compensation circuit is disclosed for proving an elevated output AC voltage upon an under voltage input AC voltage condition. The voltage compensation circuit comprises an autotransformer having a first and a second autotransformer winding. A first position of a switch connects the first autotransformer winding to the input AC voltage for providing an elevated output AC voltage at the second autotransformer winding. The second position of the switch shorting the first autotransformer winding for providing a non-elevated output AC voltage.