JPS56161619A - Oil-immersed transformer - Google Patents

Abstract

PURPOSE:To contrive to improve the strength of the outside case for subject transformer by a method wherein U-shape members are mounted on the surface of the outer circumference of the flanges located at the coupled sections of the upper and the lower outside cases and a high density energy welding is performed on the flanges and the U-shape members. CONSTITUTION:At the coupled sections of the upper outside case 1 and the lower outside case 2, the flanges 3c and 3d having the same width the installed and the members 7 having a U-shape section are mounted on the entire or part of the surface of the outer circumference of the flanges 3c and 3d. Then, a sealed weld section 8 is formed penetrating the intercontacting surface of the flanges 3c and 3d and the contacting surface of the flanges 3c, 3d and the member 7 by performing the high density energy welding. At this time, as the high density energy welding has low heat generation, no damage by burning is given to the coated film on the inner surface of the outside cases when weld lines are formed at the sections adjacent to the inner section of the transformer outside cases. In the oil-immersed transformer constituted as above, the moment to be used for weld section 8 can be reduced remarkably even when the force separating the flanges to each other is generated by the increased internal pressure.