Abstract: A wide range voltage regulator circuit exhibiting minimum circuit impedance at maximum output voltage employs a pair of regulating windings in series having their movable contact controlled by a plurality of normally open and normally closed limit switches. The extreme stationary contacts within the first regulating winding are connected with the movable contacts within the second regulating winding to provide a wide range of voltage regulation with negligible impedance at the maximum voltage position.

Abstract: A voltage regulator to provide a wide range of regulation, especially useful with process control. The regulator is provided with an extra bushing connected to the exciting winding of the regulator. By this means two or more regulators may be connected with their exciting windings in parallel and their series windings in series to provide a desired wide range of regulation. The invention also encompasses a selector switch so that the regulator operating at the top of the regulating range may be interchanged with one or more other regulators to alternate the tap-changing duty among the various regulators. Automatic operation of the regulators is disclosed.