The present improvement essentially integrates a DC link inductance within an interphase power transformer (IPT). The integration is achieved by creating auxiliary magnetic paths for leakage inductance inside the IPT core. The magnetic path can be created, for example, by incorporating extra portions of magnetic material commonly referred to hereinafter as shunts. The IPT flux shared between windings does not cross these shunts. Therefore, this magnetic path increases the self-inductance of the IPT but does not contribute to the mutual inductance between windings. This extra magnetic path allows for leakage inductance of a much higher quantity than that achievable with a conventional IPT.

The present improvement essentially integrates a DC link inductance within an interphase power transformer (IPT). The integration is achieved by creating auxiliary magnetic paths for leakage inductance inside the IPT core. The magnetic path can be created, for example, by incorporating extra portions of magnetic material commonly referred to hereinafter as shunts. The IPT flux shared between windings does not cross these shunts. Therefore, this magnetic path increases the self-inductance of the IPT but does not contribute to the mutual inductance between windings. This extra magnetic path allows for leakage inductance of a much higher quantity than that achievable with a conventional IPT.

Building automation systems, energy meters, and associated methods. A method includes receiving a plurality of voltage inputs and a plurality of current inputs from a multiphase power source. The method includes selecting a first voltage input from the plurality of voltage inputs. The method includes performing a signed power factor computation between respective pairs of the first voltage input and each of the plurality of current inputs. The method includes identifying a pair with a greatest positive power factor value. The method includes designating the identified pair with the greatest positive power factor value as an associated phase pair.

A transformer assembly is provided that includes a housing, transformer oil disposed within the housing, a plurality of coils of electrically conductive wire, and aliphatic polyamide insulation material operable to insulate the coils disposed within the oil. The plurality of electrically conductive coils is disposed in the housing and in contact with the transformer oil. The aliphatic polyamide insulation material includes stabilizing compounds and nano-fillers. The stabilizing compounds provide thermal and chemical stability for the insulation material.

This new type of transformer comprises a ferromagnetic drum-type core characterized in that the drum core has a plurality of holes or windows parallel to the drum longitudinal shaft to place the windings being the windows arranged close to the periphery of the drum symmetrically distributed at 360° of the circumference, each winding being parallel to the longitudinal shaft of the drum and each one of the windings crossing said longitudinal shaft. The core comprises two main components: a central body and an air gap filling system. The central body is formed by a plurality of silicon steel sheets, stacked one over the other, each of them has slots or spaces on its periphery thereof to place the windings and with an air gap filling system. Said filling system can be: wedge-shaped sheets, set of sheets extending parallel to the shaft of the core or a metal sheet wound around the central body.

This new type of transformer comprises a ferromagnetic drum-type core characterized in that the drum core has a plurality of holes or windows parallel to the drum longitudinal shaft to place the windings being the windows arranged close to the periphery of the drum symmetrically distributed at 360° of the circumference, each winding being parallel to the longitudinal shaft of the drum and each one of the windings crossing said longitudinal shaft. The core comprises two main components: a central body and an air gap filling system. The central body is formed by a plurality of silicon steel sheets, stacked one over the other, each of them has slots or spaces on its periphery thereof to place the windings and with an air gap filling system. Said filling system can be: wedge-shaped sheets, set of sheets extending parallel to the shaft of the core or a metal sheet wound around the central body.

In a stacked core (1, 21) for a stationary induction apparatus according to an embodiment, joint surfaces where yoke portions (2, 3, 12, 22, 23) and leg portions (4, 5, 6, 11, 24, 25, 26) are joined have protrusions (8, 13) formed from a plurality of magnetic members (7), and recesses (9, 14) formed from a plurality of magnetic members alternately, and the yoke portions and the leg portions are configured to be butted in such a form that the protrusions and the recesses mesh with each other, sheet-like magnetic insulators (10, 15) are each disposed in a butt-joint portion between the protrusions and the recesses in such a form as to bend in a bellows shape along a butt line, and an air gap is provided, and in a relationship between the number of the stacked magnetic members forming each of the protrusions and the number of the stacked magnetic members forming each of the recesses, the number of the stacked magnetic members forming each of the protrusions is made smaller than the number of the stacked magnetic members forming each of the recesses corresponding to a thickness of the magnetic insulator.

A three-phase transformer including a transformer housing, a shell-form five-limb transformer core wherein main limbs include two outer main limbs and a middle main limb, three coil arrangements including two outer coil arrangements each arranged around a respective one of the outer main limbs, and a middle coil arrangement arranged around the middle main limb. The outer coil arrangements have an inter-coil insulation configured to electrically insulate the coil arrangements from the transformer housing and from the respective other ones of the coil arrangements, and wherein no inter-coil insulation is provided to the middle coil arrangement.

Asymmetric AC to DC autotransformer for turboelectric propulsion, and associated systems and methods are described herein. In one embodiment, an asymmetric AC to DC autotransformer includes: a first coil, a second coil and a third coil of a delta winding Each coil is energized at its corresponding input phase. A first plurality of correction windings coupled to the first coil, a second plurality of correction windings coupled to the second coil, and a third plurality of correction windings coupled to the third coil. A bridge rectifier having a plurality of rectifiers is coupled to respective individual correction windings. Phases of the individual correction windings are asymmetric such that individual phase voltages are controlled relative to the opposite input phase. Voltages are unbalanced relative to neutral.

The invention relates to a self-induction transformer which includes: At least two magnetic circuits (4 and 5) in connection, and at least three electrical windings (1, 2 and 3): The primary (1) which surrounds the free part of the first magnetic circuit. The secondary (2) which surrounds the linking part of the two magnetic circuits. The tertiary (3) which surrounds the free part of the second magnetic circuit