GB218918A - Improvements in and relating to electric transformers - Google Patents

Abstract

218,918. British Thomson-Houston Co., Ltd., (General Electric Co.). Dec. 7, 1923. Transformers.-Losses due to magnetic leakage are reduced by providing auxiliary laminated magnetic shields in the path of the leakage magnetic flux. In a single-phase core type trans. former with interleaved coils 2, 3, Fig. 1, the magnetic shields 4 are mounted on the faces of the outside laminations of the core 1, and prevent leakage flux from entering the core across the laminations. In a modification, Fig. 3, the shield comprises a series of stepped laminations 5 parallel to the laminations of the core. A three-phase transformer with concentric cylindrical windings 8, 9, Fig. 6, is provided with laminated magnetic shields 11 between the ends of the windings and the core clamps; the shields providing low reluctance paths for the leakage flux between the ends of the winding spaces. In a single-phase shell type transformer, Fig. 7, laminated shields 12 are provided at each end of the cylindrical space between the windings on each side of the core to receive the leakage flux, these shields being curved in against the inner faces of the core jokes.