GB384007A - Improvements in or relating to electric switches with arc extinction by self-generated vapour - Google Patents

Abstract

384,007. High-tension switches. SIEMENS - SCHUCKERTWERKE AKT.- GES., Siemensstadt, Berlin. Sept. 15, 1931, No. 25889. Convention date, Sept. 18, 1930. [Class 38 (v).] In liquidbreak switches instead of the arc being drawn under the surface of a conducting or semiconducting liquid it is drawn in the neighbourhood of bodies steeped in liquid in which they are immersed so that the contacts themselves are not immersed. In the arrangement shown in Fig. 1, the arc 12 is drawn between the contacts 10, 11 and is controlled by a magnetic field due to the coil 13 so as to impinge upon a porous body 15 one end of which dips into the quenching liquid, which may be water. Sufficient vapour pressure is developed to ensure the deionization of the gases in the arc path..The arc is extinguished at the zero point of the A.C. cycle. In the construction of " expansion " , switch shown in Fig. 2, an inner are chamber is formed by substances permeated with capillaries such as a wick 23 dipping into the liquid 21. When the contact 30 is moved from the fixed contact 22 spring-pressed plates 24, 25 restrict the inner arc chamber to confine the arc more closely to the liquid-impregnated material. The arc is extinguished when the contact 30 leaves the container.. In a modification, Fig. 3 (not shown), the upper end of the chamber is closed by a spring-pressed cover which opens only when sufficient vapour pressure has been developed to ensure, on expansion, the complete deionization of the arc path.