Abb Technology Ag

Abb Inc.

Tri D Vu

Arthur Lanni

Joseph Oravsky

Varagur Ramanan

Vladimir Segal

A preferred embodiment of a transformer includes a core, and a primary and a secondary winding positioned on the core so that the primary and secondary windings are inductively coupled when the primary winding is energized. The transformer also includes a sensor for measuring an operating parameter of the transformer, an audible signaling device, and an actuator for activating the audible signaling device when the operating parameter reaches a predetermined value.

Fault-annuciating system for a transformer

A presently-preferred process for bending a workpiece includes placing a first portion of the workpiece on a substantially flat surface so that a second portion of the workpiece overhangs an edge of the substantially flat surface, and securing the first portion of the workpiece on the substantially flat surface by clamping the workpiece between the substantially flat surface and a substantially v-shaped end portion of a male die. The presently-preferred process also includes causing the second portion of the workpiece to pivot around a tip of the substantially v-shaped end portion by rotating a bending die around the tip while the bending die contacts the second portion of the workpiece.

Process for bending a workpiece

There is disclosed a method of making transformer core laminates with bent corners from magnetic strip material having a predetermined thickness and power loss in the manufacture of a low-stress polyhedral core for a power transformer. The method includes mechanically bending corners in each laminate about predetermined bending lines while limiting the zone in each corner where the laminate is subject to plastic deformation to <5 times laminate thickness so that the specific power loss in the transformer core will equal that of the magnetic strip material except within the distance from the bending lines, where the power loss is higher due to plastic deformation of the magnetic strip material.

Method of manufacturing magnetic cores for power transformers

A reduced-cost core for an electrical-power transformer comprises at least a first magnetic loop and a second magnetic loop. The first and the second magnetic loops are positioned substantially side by side to form a winding leg for a phase winding. The first magnetic loop includes a first plurality of laminae each having a first thickness, and the second magnetic loop includes a second plurality of laminae each having a second thickness, where the second thickness is less than the first thickness.

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Tri D Vu