Three coils, each having several serial windings, have selected windings connected in a delta. Input AC power is applied through outrigger windings at the delta apices. At least two strategically located, direct tap, natural output points are provided at each side of the delta. For 6-phase output, only the six natural output points are required. For 9-phase output, an additional central output terminal connects to each side of the delta through a stub winding. The 6-phase or 9-phase output is passed to a rectifier circuit.