Patent ID: 7656138

Claim:
An apparatus for regulating electrical voltage in multiphase power mains, the apparatus comprising: a control transformer having for each phase of the power mains a primary winding having a pair of ends, and a control winding having first and third end taps and a second tap connected centrally between the first and third taps and connected to one of the ends of the primary winding, the control winding being dimensioned such that winding lengths between the first and second taps and between the second and third taps are each equal to X % of a winding length of the primary winding, X being a whole number; first, second, and third circuit elements having respective inputs connected respectively to the first, second, and third taps, the circuit elements also having respective outputs; a reactor winding having ends connected to the outputs of the first and second circuit elements, the output of the third circuit element being electrically connected to the output of the first circuit element; a further circuit element connected across the reactor winding; and an output connected to a center of the reactor winding.