Abstract: An improved saturable reactance transformer having a main core and a pair of adjacent auxiliary cores is disclosed. The auxiliary cores carry DC control windings which regulate the reactance of the main core which carries the secondary, or output windings of the transformer. The primary winding is wound around all three cores, with the amplitude of the control voltage applied to the control windings regulating the output of the secondary windings. To prevent high voltage stresses in the transformer, each control winding is split into two or more windings, with the two windings being wound concentrically on their common core to reduce the voltage induced by the alternating current in the primary windings. In addition, the windings on the two auxiliary cores are cross-connected in pairs to equalize the reactance of each pair, thereby balancing the induced voltages.