Patent ID: 7375996
Filing Date: 2008-05-20
Classification: H01F,H02M

Abstract:
1. A T-shaped connected autotransformer for converting three-phase ac input voltages to nine phase shifted ac voltages comprising: a first serial winding connected between two phases; a second serial winding connected between a third phase and a center point of said first serial winding at or about a 90° angle to said first serial winding to form the T-shaped connection of said autotransformer; a neutral point on the second serial winding; a plurality of stub windings connected at predefined taps of said first and second serial windings and being magnetically coupled to corresponding serial winding; a plurality of nodes being provided on said serial and stub windings such that the voltage magnitude at each of the nodes is measured by a vector between the neutral point and the corresponding node, said serial and corresponding stub winding being sized and arranged to obtain a predetermined phase shift; thereby the nine phase shifted output voltages being derived from the outputs of selected stub windings connected to said first and second serial windings and the end points of said serial windings.