Abstract: An improved core-form transformer is disclosed. The core-form transformer includes a c-wrapped ribbon conductor with opposing wide sides and opposing thin sides. The c-wrapped ribbon conductor is wound around a core to form a plurality of coil sections. Adhesive is applied directly to one of the wide sides of the ribbon conductor to form a strong mechanical coupling within the coil sections. A novel transposing fold of the ribbon conductor is employed to create coil transpositions. The core-form transformer of the invention reduces circulating current losses while utilizing only a small number of transposing folds, generally adjacent to a first coil section, a last coil section, and an intermediate coil section.

Abstract: A disk wound transformer winding employing at least two external electrostatic shields extending axially along the outside of the disk winding for grading the impulse voltage within the winding. The inner external shield closest to the winding is connected to the line terminal and the outer external shield is connected to ground. A substantially linear voltage gradient under impulse conditions is attained by the combination of a disk winding arrangement and a specifically tailored assembly of external shields extending along the outside of the winding.

Abstract: An electrostatic shielding arrangement for improving the initial distribution of voltage which in turn reduces the insulation stresses on disc-wound coils resulting from the application of impulse or steep wave-front voltages to such coils. Floating electrostatic shields are placed near or internal of the innermost or the innermost and outermost turns only of a disc coil section. Shields are connected together in pairs, with no more than one shield connection being made between adjacent coil sections.