Abstract: A regulated three phase power supply with a wye connected, isolated neutral transformer having a full wave three phase bridge connected between the phase windings and the common point. A clipper transistor is connected across the bridge so that each phase current flows through the transistor. A drive circuit for the clipper transistor is isolated from ground. Reducing the drive to the clipper transistor increases its impedance and clips the voltage wave across the transformer primary. An output circuit is connected with the transformer. A three phase feedbck circuit is connected from either the output circuit or the wye connected circuit to the clipper transistor and is responsive to the instantaneous phase voltages to increase the transistor impedance, clipping the input voltage, when the sensed condition is excessive.Current regulation is provided by increasing the drive to the transistor as the current through it increases.