GB356693A - Improvements in or relating to high potential transformers - Google Patents

Abstract

356,693. Transformers. KOCH & STERZEL AKT.-GES., 40, Zwickauerstrasse, Dresden, Germany. April 8, 1930, No. 11208. Convention date, April 30, 1929. [Class 38 (ii).] In a voltage transformer for use on high tension circuits, the high tension winding 12, Fig. 3, is arranged on an insulating spool 11 and the connection to the high tension line is brought out through the flange of the spool from the inner layer of the winding so that the potential of the layers decreases from the inside to the outside of the winding. The inside and outside surfaces of the spool are separately metallized to form condenser elements which are connected respectively to the high potential and earthed ends of the winding. The leading-out insulator 17 may be formed integrally with the flange of the spool and may serve as housing for a replaceable fuse 27, Fig. 8. In this form the spool body is formed with an extension 26 enclosing the upper yoke 24 of the core. Other forms of spool body are described in which the leading-out insulator is located concentrically. In another form, Fig. 7 (not shown), the spool carrying the windings is immersed in an oil tank and a separate oil-filled leading-out insulator is provided on the cover of the tank. The high tension winding is surrounded by a metal jacket 19 which is electrically interrupted by insulating material introduced between the folds of the seam. The jacket may be secured to a base 30, or a fixing flange may be secured to the upper part of the jacket. Alternatively, a cover provided with suspension means may be secured tothe jacket, the lower part of the spool body being formed as a suspension insulator for the high tension line. Fig. 16 shows a modified arrangement of the high tension winding in which the centre point is at earth potential, and the two parts on opposite sides thereof are arranged on opposite sides of a centre rib formed on the spool body. A plurality of winding units of the type shown in Fig. 3 may be mounted on a common iron core for use on polyphase systems. Cascadeconnected arrangements are also described, Fig. 20 being one example in which the winding in the upper unit is arranged in accordance with the invention, whilst the winding in the lower unit has its innermost layer at earth potential. The metal jackets surrounding the two winding units are connected so as to form overcoupling windings. In other cascade systems, Figs. 17 and 19 (not shown), the units are designed as suspension elements in a chain insulator for the high tension line.