An autotransformer for converting three-phase AC power to nine-phase AC power. The autotransformer includes three coils each having serial connected windings and non-serial connected windings. The combination of the serial and non-serial windings are interconnected to form a polygon for a total of six windings per phase, in an arrangement which reduces the power rating of an autotransformer suitable for 18-pulse AC to DC power converters. There are a plurality of direct outputs that are equal in magnitude and are out of phase with respect to the voltages at the input. The input is offset from the nine outputs to create the required phase magnitudes for DC power converters.

A container arrangement for power transformers that are constructed from individual components. The components are releaseably connected to one another in such a way that simple mounting/demounting and separate transportation is made possible. At least some of the components are arranged in containers, wherein each container contains a predetermined type of components in such a way that the components necessary for intended construction variants of the power transformers at the use location are contained in a corresponding selection of containers. This renders possible the correct and efficient mounting of power transformers.

A configuration for replacing a multi-phase transformer includes a plurality of single phase transformers each having a housing which is filled with an insulating fluid and in which a core with a high-voltage winding and a low-voltage winding is disposed. The configuration can be set up flexibly and also connected easily and conveniently to a supply network or consumer network by providing each housing with at least one cable connection and connecting each cable connection through a cable line to an outdoor connection which is air insulated, constructed for outdoor use and set up separately from the housing.

An electrical transformer includes a coil pack including windings, and spacers axially spacing turns of the windings from one another and being formed of a thermoplastic material. Sticks couple and position the spacers. The coil pack has high resistivity to creep and permits temperature rise without degradation of transformer insulation, providing for extended service life and unique methods of transformer system upgrade.

A coil device with a cooling structure includes: a coil unit that has a core structure having one or more leg parts and one or more coils wound around the one or more leg parts; and a flow-rectifying member having a flat plate portion covering a face of the one or more coils and flow-rectifying ribs inwardly protruding from an inner surface of the flat plate portion, the flow-rectifying ribs extending in a direction parallel to center axes of the one or more coils and being positioned to face side boundaries of the face of the one or more coils. The flat plate portion and the flow-rectifying ribs form a first air cooling channel at a substantially uniform gap outside of the one or more coils along the direction parallel to the center axes thereof, the first air cooling channel passing cooling air to air-cool the one or more coils.

A method and apparatus for forming a direct current power supply. An apparatus comprises a transformer and a rectifier. The transformer is figured to output a plurality of phase-shifted alternating currents in response to receiving a plurality of alternating currents. The plurality of alternating currents and the plurality of phase-shifted alternating currents form a plurality of input alternating currents that are offset relative to each other by one-twelfth of a cycle in phase. The rectifier is configured to form a direct current power supply having a common mode voltage reduced to zero within selected tolerances in response to receiving the plurality of input alternating currents.

A method and apparatus for forming a direct current power supply. An apparatus comprises a transformer and a rectifier. The transformer is figured to output a plurality of phase-shifted alternating currents in response to receiving a plurality of alternating currents. The plurality of alternating currents and the plurality of phase-shifted alternating currents form a plurality of input alternating currents that are offset relative to each other by one-twelfth of a cycle in phase. The rectifier is configured to form a direct current power supply having a common mode voltage reduced to zero within selected tolerances in response to receiving the plurality of input alternating currents.

In one aspect, a medium voltage power converter includes a plurality of slices each having: a transformer including a plurality of primary windings to couple to a utility source of input power and a plurality of secondary windings; and a plurality of power cubes coupled to the plurality of secondary windings, each of the plurality of power cubes comprising a low frequency front end stage, a DC link, and a high frequency silicon carbide (SiC) inverter stage to couple to a high frequency load or to a high speed machine.

A vector-magnetic-property-controlling material according to the present embodiment is subjected to a scratching process in two directions that intersect on the surface of a steel material. An iron core according to the present embodiment is configured from an oriented magnetic steel material which has been subjected to a scratching process in two directions that intersect on the surface thereof.

A vector-magnetic-property-controlling material according to the present embodiment is subjected to a scratching process in two directions that intersect on the surface of a steel material. An iron core according to the present embodiment is configured from an oriented magnetic steel material which has been subjected to a scratching process in two directions that intersect on the surface thereof.