Abstract: A symmetrical ac power system provides a balanced ac output, whose maximum voltage with respect to a reference ground potential is one-half the ac output voltage, and which is derived from a single phase ac source through the use of an isolation transformer having a center-tapped secondary winding. The center tap is connected to the output power load circuit as a ground reference potential with respect to the symmetrical ac output so as to constitute the reference ground potential for the power supply and load. Since symmetrical ac power is applied to the load by the system, reactive load currents, other power artifacts, EMI and RFI emissions and other interference and noise components ordinarily resulting from the application of conventional ac power to the load are reduced or eliminated by appearing as equal inversely phased signal elements which cancel one another. In order to maximize the performance of the symmetrical power system, the isolation transformer has a bifilar-wound secondary winding.

Abstract: The present invention discloses a method for providing balanced power to a single-phase ac load from a three-phase ac power source. The method includes imposing an isolation power transformer between the ac power source and the load wherein the isolation transformer has a three-phase primary winding and a six-phase "wye" connected secondary winding, at least one of the three legs of the secondary having a center tap and being connected to the load such that the center tap provides a reference potential for the load and the reactive load currents are equal and inversely-phased with respect to the reference potential.