GB331088A - Improvements in or relating to electrical transformers - Google Patents

Abstract

331,088. Koch & Sterzel Akt.-Ges. Dec. 15, 1928, [Convention date]. Transformers.-A transformer, more particularly an instrument transformer, is arranged within an insulating casing suspended at one point only so as to constitute a suspension insulator link. The casing 11, Figs. 1 and 5, has a cemented cover 13, or a cover secured by a fastening device 15, and contains the transformer and an insulating liquid. The transformer may be secured to the cover 13 by brackets 16 on which are held the pressure-plates 17 of the core. These plates are circular, as shown in Fig. 6, and have rounded edges; they act as screens and ensure good field distribution. In a modified form of construction the transformer rests on lugs 20 on the casing. Ribs 26 are provided round the casing. A bolt 23 in the lower opening of the casing carries the clip 24 to support the high-tension conductor 25. A suspension bolt 27 is secured to the cover, and is electrically connected to the high-tension main 25 through the cover 13, the brackets 16 and the high-tension winding 19. The secondary winding 18 is connected to metal cylinders 31, 32 in the bolt 33 and these connections lead to a voltmeter, or to a relay, or to the transformer system in the insulating casing 36 above. In a modification, the transformer insulator link is suspended from the high-tension line wire and the lower end of the high-tension winding is earthed. A number of such links may be used as shown in Fig. 14. The line wire 73 is strained to its support 75 by the insulator straining-chain 74, and passes into the switch-house through condenser leading-in tubes 77. A transformer suspension-chain I, II, III is connected between the point of attachment 78 and the line 73. Similar arrangements may also be used where the line is suspended from poles. Current transformers may be housed in the suspension insulator links, the primary current winding being wound round a tubular transverse aperture in the insulator while the secondary winding is wound on a core in the tubular aperture. A current transformer 55 of this type and a voltage transformer 56 may be included in one insulator link as shown in Fig. 8. The insulator casing is substantially funnel-shaped and may consist of two parts 57, 58 as shown in the lefthand side of the Figure, or may be made as one unit only as shown in the right-hand side of the Figure. The ends of the secondary windings are carired through the hollow suspension bolt 63. The connection terminals 70, 71 for the hightension lines 51, 52 are of spherical shape and contain a bridging resistance 72. The insulator may be filled with pure or graphitized quartz sand.