Abstract: An electrical transformer is disclosed. The electrical transformer comprises a central axis, a first modular section, and a second modular section. The first modular section is positioned about the central axis and comprises a first support, a first winding of a conductive element, and a first insulating material. The first winding of a conductive element is located about the first support. The first insulating material covers a portion of the first modular section. The second modular section is axially aligned with the first modular section and electrically connected to the first modular section. The second modular section comprises a second support, a second winding of a conductive element, and a second insulating material. The second winding of a conductive element is located about the second support. The second insulating material covers a portion of the second modular section.

Abstract: A method and apparatus for detecting a partial discharge in a voltage transformer, the transformer having a first voltage winding and a second voltage winding. A grounded electrostatic shield being operably attached to the transformer, preferably between the windings. A radio frequency current transformer is operably connected to the electrostatic shield wherein the partial discharge occurring within the voltage transformer is detected.

Abstract: A protected transformer system and method are disclosed. The protected transformer system uses positive temperature coefficient resistive devices. The system can comprise a transformer and a positive temperature coefficient device. The transformer has a primary and a secondary winding. The secondary winding has a housing, a first terminal, a second terminal, and an insulated covering. The positive temperature coefficient device is connected to the first terminal of the secondary winding. The positive temperature coefficient device mounted in the housing. The positive temperature coefficient device has a first and second side. The first side of the positive temperature coefficient device is mounted between 0.2 mm 0.4 mm from the secondary winding. The second side of the positive temperature coefficient device is mounted between 1 mm and 5 mm from the secondary winding. The insulated covering is between the first side of the positive temperature coefficient device and the secondary winding.

Abstract: A method and apparatus for detecting a partial discharge in a voltage transformer, the transformer having a first voltage winding and a second voltage winding. A grounded electrostatic shield being operably attached to the transformer, preferably between the windings. A radio frequency current transformer is operably connected to the electrostatic shield wherein the partial discharge occurring within the voltage transformer is detected.

Abstract: A transformer including a core having first and second portions, and first and second primary winding sections. The first primary winding section includes a plurality of winding layers (L1−Ln) about the first portion of the core, and the second primary winding section includes a plurality of winding layers (L1−Ln) about the second portion of the core. Corresponding winding layers of the first and second winding sections are separated by a distance (D1−Dn). The distance (D1−Dn) between the corresponding layers of first and second primary winding sections increases as the number of winding layers (L1−Ln) increases.

Abstract: The present invention relates to a transformer having a conductive element spiraling along the length of an insulated wire of the coil. When formed into plurality of adjacent turns, the conductive element couples one of the plurality of turns with another of the plurality of turns. The conductive element increases the series capacitance of the transformer circuit. A resistive element may also spiral along the length of the insulated wire to couple one of the plurality of turns with another of the plurality of turns. The resistive element not only increases the series capacitance of the transformer, but also increases the series conductance of the transformer circuit. The increase in the series resistance increases the dampening of the switching resonance.

Abstract: The present invention relates to a transformer comprising a coil having an insulated wire formed into a plurality of turns defining a layer and a resistive element wrapped around the outer surface of the layer. The resistive element couples one of the plurality of turns with another of the plurality of turns. The resistive element not only increases the series capacitance of the transformer, but also increases the series conductance of the transformer circuit. The increase in the series resistance increases the dampening of the switching resonance.

Abstract: This invention relates to a cooling system for a transformer. A winding defining a coil, including a duct having an open top and bottom, is sealed to a sleeve, thus forming a closed circulatory path. A fluid is retained and circulated within the circulatory path.

Abstract: A hybrid transformer core assembly having a first leg having a first end and a second end, a second leg having a first end and a second end, and opposing first and second yokes coupling the first and second legs to the first and second yokes to create a closed core. The first leg and second legs are made of a plurality of packets of laminations having a high grain orientation, and the first and second yokes are made of a plurality of packets of laminations having a lower grain orientation than the material of the first and second legs. Alternating laminations of the first and second legs are staggered to alternately extend beyond adjacent laminations of the respective leg at first and second ends thereof. A portion of the laminations of the first and second legs which extend beyond adjacent laminations of the first and second legs, respectively, overlaps portions of alternating laminations of the yokes and couples with notches of alternating laminations of the yokes.

Abstract: A transformer assembly comprises a tank body enclosing a transformer and a cooling liquid. A cooling collar is fixedly attached to the outer surface of the tank body. The cooling collar is formed separately from the tank body in a corrugated shape so as to be elastically expandably mounted onto the tank body. The collar is attached to the tank body by a thermally conductive epoxy. The corrugations of the collar define cooling fins for dissipating heat from the tank body. The cooling collar can be of one-piece or multi-piece construction, the latter comprising a plurality of collar segments hooked together in end-to-end fashion.

Abstract: A gapped low voltage bushing (10) comprising a controlled spark gap (1), a metallic arc strap (18), a resistive material (46) and a metallic tank ground pad. Surges entering the transformer on any of the secondary bushings of sufficient magnitude to induce gap sparkover, result in a shunting of otherwise damaging currents safely outside the transformer.

Abstract: A dry type, air cooled transformer having a mitered magnetic core and a compression bonded coil. In the disclosed embodiment, the magnetic core is of the mitered, stacked lamination type. The coil on each of the core legs is generally rectangular in shape and comprises a plurality of layers of wound conductor with the conductor layers in the end portions of the coil being spaced apart to form a plurality of air ducts for the passage of cooling air therethrough. The conductor layers in each of the side portions of the coil are compressed and then bonded together in their compressed state by means of a heat cured adhesive coated on opposite sides of the sheets of insulation between adjacent layers. This compression bonding of the coil sides squares up the inner and outer surfaces of the coil so as to improve the coil and core space factors thereby allowing a smaller core.

Abstract: A dry type, air cooled transformer having a mitered magnetic core and a compression bonded coil. In the disclosed embodiment, the magnetic core comprises a plurality of stacked lamination layers wherein each layer comprises a plurality of grain-oriented laminations wherein the ends of most of the laminations are mitered thereby resulting in joints between the leg and yoke pieces oriented at an angle to the favored magnetic directions of the adjoining laminations. The coil on each of the core legs is generally rectangular in shape and comprises a plurality of layers of wound conductor with the conductor layers in the end portions of the coil being spaced apart to form a plurality of air ducts for the passage of cooling air therethrough. The conductor layers in each of the side portions of the coil are compressed and then bonded together in their compressed state by means of a heat cured adhesive coated on opposite sides of the sheets of insulation between adjacent layers.