[Trade Journal]
Publication: Elektrotechnische Zeitschrift
Berlin, Germany
vol. 21, no. 15, p. 293-294, col. 2,1
High-voltage insulator "Delta - Bell".
The porcelain factory Hermsdorf-Klosterlausnitz. has launched a high voltage insulator under the name "Delta-Bell", of which Fig. Page 13 As can be seen, there are four jacket surfaces between the stem and the bundrille, which have different angles of inclination.
The holes are not deep and allow the penetration of air and light, which prevents insects from nesting in the hollows and reduces the insulating nature. The three mantle tiles inserted between the outer mantle and the stem have the consequence that rainwater does not, in the case of the insulators, when it runs down from the outer mantle surface, electrostatic effects are attracted to the stem; rather, the rainwater is repelled from the other mantle surfaces electrostatically charged in damp weather, which have the same potential as the outside, so that the drops fall down in arcs roach outside; This avoids or reduces the losses otherwise caused by edge discharges during rainy weather. The Delta bells, which are produced in four different versions — 6000, 12,000, 25,000 and 50,000 V — have, according to the measurements made, a strength of about 1400 kg under horizontal tensile stress of the drill and a strength of about 1400 kg under vertical tensile stress and vertical compressive stress on the crown groove of around 1800 kg. The insulators are separated against edge discharges with 5 to 7 times the safety of the insulators, since in heavy rain visible edge discharges in the smallest type only at 40,000 V, in the second at about 70000 V and the third at 120,000 V. At of the largest type, which is listed in Fig. 14 is shown, - and in which the second outermost shell surface is formed twice, the corresponding value has been estimated at about 200 000 V. Insulators of these constructions have been years in a number of installations with operating voltages of 10,000 to 20,000 V.
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| Fig. 13. |
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| Fig. 14. |
