Improvements in and relating to liquid-break electric switches of the explosion chamber type

摘要

383,931. High-tension switches. INTERNATIONAL GENERAL ELECTRIC CO., Inc., 120, Broadway, New York, U.S.A. -(Assignees of Allgemeine Elektricitõts- Ges. ; 2, Friedrich Karl-Ufer, Berlin.) July 23, 1932, No. 20819. Convention date, July 23, 1931. [Class 38 (v).] In a liquid break switch of the explosion chamber type, in order to provide for an adequate generation of vapour pressure from the switching liquid even with the smallest currents the switch may be called on to interrupt, the period of time elapsing between the separation of the contacts and the final withdrawal of the movable contact from the explosion chamber is varied in accordance with the current to be interrupted. In the construction shown in Fig. 1, the " fixed " contact 6 with which the movable contact 5 co-operates forms part of the explosion chamber 1 which is filled with liquid, for example water, and is immersed in liquid in the container 7. The explosion chamber is carried on guide pins 2 and is maintained in the raised position by the springs 3. Electrical connection with the contact 6 is effected by the spirally wound metal strip 4. When breaking heavy currents, the differential action of the pressure developed in the explosion chamber, through the upper end of which the movable contact is passing depresses the chamber as a whole away from the movable contact so that the time taken for the movable contact to clear the chamber is reduced. With small currents, the pressures developed are inadequate to produce this movement and, in consequence, the duration of the arc is a maximum. In a modification, Fig. 2, the chamber is mounted to slide upon the fixed contact 2 mounted on the outer chamber and the movable contact has an enlarged portion 51 passing into the explosion chamber, the diameter of this enlarged portion being greater than that of the fixed contact on which the chamber slides so that the necessary differential action is ensured.