Patents Assigned to National Industri A/S
  • Patent number: 4507636
    Abstract: The present invention relates to a structure of neutral point of multiphase transformers for large secondary currents. Such multiple phase transformers, usually three phase transformers, are used for example for the operations of arc furnaces, and the secondary current of the transformer may amount to several thousand ampere. The neutral point is made as a plate (24) of material with good electric conductivity and is located within the transformer tank (27). Between the neutral point plate (24) and the tank wall (27) there is located a plate (25) of a material with good conductivity and serving as a screen for reducing losses in the tank wall (screen plate). The transformer is star connected on the secondary side. Each phase of the secondary winding consists of several windings connected in parallel, and the tappings are passed as parallel conductors onto the neutral point plate (24).
    Type: Grant
    Filed: February 23, 1984
    Date of Patent: March 26, 1985
    Assignee: National Industri A/S
    Inventors: Odd J. Eilertsen, Ottar H. Svensen