GB354020A - Improvements in and relating to electrothermally operated electric vacuum switches - Google Patents

Abstract

354,020. Thermal switches. SCHERBIUS & RITTER KOMMANDIT-GES., 40, Konigstrasse, Wannsee, Berlin. July 1, 1930, No. 19989. Convention date, July 1, 1929. [Class 38 (v).] Cases.-Wires or strips arranged in parallel mechanically (so that their pulling forces are added together) and in series electrically are arranged within a vessel which is evacuated or filled with inert gas and serve to operate contacts also located in the vessel. In the construction shown in Fig. 1, the wire is wound round two insulating rollers 8 each of which may be divided into a series of small rollers. The lower roller is secured to the contact member 1 which carries the contact 2 and the upper one is mounted for slight upward and downward movement in a frame 12 moving on a fixed pin 29. The companion contact 5 is carried by a spring arm 4 which bears upon the frame 12 and keeps the wire taut. The wire becomes heated when a current flows in it and expands so that the spring arm 4 is able to rise and withdraw its contact 5. When the circuit is broken the wire contacts and circuit is made again so that the device serves as a continuous interrupter. In a modified construction, the wire is wound in zig-zag form concentrically round two contacts which under the action of a spring separate when the wire expands due to the current carried by it. A tubular insulating arcbarrier may be arranged between the wires and the contacts. In another form, Fig. 3, the wires 19 are arranged in diamond form with the spring arms carrying the contacts 27, 28 serving to keep the wires taut. Alternatively the wire structure may act on a lever which, when the wires contract, raise the movable contact from the fixed contact.