GB479069A - Improvements in electric switches having arc preventing or limiting arrangements - Google Patents

Abstract

479,069. Liquid - break switches. GENERAL ELECTRIC CO., Ltd., and THOMPSON, W. G. Aug. 5, 1936, No. 21544. [Class 38 (v)] In a switch in which on separation of the contacts a current flow is established through a path of electrically - conductive liquid, the circuit is finally interrupted by mechanically dispersing the liquid. In the construction shown the hollow movable contact 1 is carried by a piston 4 movable in a cylinder 5. To open the switch, water or other conductive liquid under pressure is admitted from a tank 9 to the lower side of the piston through a pipe 7 ; the piston is forced upwards, carrying the contact 1 away from the fixed contact 2, and at the same time a jet of liquid is forced from the upper-part of the cylinder 5 through the contact 1 on to the contact 2. As the movable contact 1 approaches its upper position, a rod 6 nearly closes the aperture at the end of the contact, and causes the dispersion of the liquid in the form of a spray. The switch is closed by admitting liquid under pressure from a tank 9 to the upper side of the piston through a pipe 8. In a modification, upper and lower fixed contacts are connected by a hollow movable electrode, the lower contact being mounted on insulating means above a collecting vessel. The electrode is formed at its upper end with a piston which slides in a cylinder connected with a liquid reservoir at some height above the switch. A pump is provided for delivering liquid from. the vessel to the reservoir. Adjacent the upper fixed contact is a diffuser nozzle connected to a source of air under pressure. To open the switch, a valve is opened to allow water to flow from the reservoir through the electrode, and simultaneously the latter is drawn upwards. When the electrode leaves the lower contact, the circuit is maintained through the liquid until the latter is dispersed by admitting compressed air to the diffuser nozzle. The Provisional Specification describes another arrangement in which an iris diaphragm gradually reduces the cross-sectional area of the liquid column until the flow of liquid is interrupted.