GB341499A - Improvements relating to electric switches - Google Patents

Abstract

341,499. High - tension switches. RUPPEL, S., 8, Palmengartenstrasse, Frankfort-on-Main, Germany. Sept. 14, 1929, No. 27983. [Class 38 (v).] In switches employing a blast of gas under pressure to extinguish the arc, gas at different pressures are used, the pressure being increased or decreased when the movable contact has travelled a predetermined distance. In the construction shown in Fig. 1, the hollow contact-member 9 serving to bridge the fixed contacts 4, 6 slides in a guide-tube 18 provided with ports. To open the switch, low pressure is supplied through the valve 23 to the upper end of the piston 11 carried by the contact-carrying member. At the same time, the low-pressure supply is admitted to the container 1 and to the insulating chamber carrying the fixed contacts and so through the ports 15 in the movable contact to the neighbourhood of the arc. The valve 23 is interlinked with the high-pressure valve 24 so as to operate the second valve when the opening movement has commenced and admit high pressure, by way of the chamber 19 and port 16, to the interior of the contact-carrying member and so through the ports 14 to the outside of the contactcarrying member. When the contacts further separate, the supply is admitted through the ports 12, 13 of a deflector to the interior. In a modification (Fig. 2 not shown), in which two breaks per phase are employed, the high-pressure chamber leads through a two-way passage to the exterior of the upper ends of the two movable contacts. The high-pressure supply may be generated in the hollow movable contact itself which may enclose a fixed piston. As the contact moves downwards, air is compressed within it and at the moment of break ports at the upper of the contact are opened releasing the compressed air. The high pressure may be generated by the low-pressure gas operating a large piston in the switch cylinder and actuating a smaller piston in the same or in a separate cylinder to compress the gas which is released at break. A separate source of highpressure gas may be employed for the high-pressure supply, and this source may be controlled in accordance with the voltage or current of the circuit.