GB519113A - Improvements in electrical switches and circuit breakers of the gas blast type - Google Patents

Abstract

519,113. Gas-blast switches. WHITEHEAD, G. E., and WHITEHEAD SWITCHGEAR & INVENTIONS, Ltd. July 15, 1938, No. 21104. [Class 38 (v)] A gas-blast switch comprises a relatively fixed, and a linearly-movable, contact enclosed in a common container, the movable contact being directly coupled to a diaphragm working with piston-fit in the container and having one or more apertures so disposed relatively to the contacts that, on operation of the movable contact to open circuit, the gas-movement caused by displacement of the diaphragm is concentrated past the contacts substantially in the line of contact-movement, so as to quench the arc. In Fig. 1, the fixed contact structures 3 are' each located in a porcelain or other refractory insulating cylinder and provided with an exhaust opening 10. A further porcelain member 13 of disc shape serves as blast-producing piston with the tank 1 as the cylinder, the piston being operated by the lift rod 11 and provided with a throw-off spring 12. The piston is apertured to receive tubes 16, which carry the hollow movable contacts 15 and are secured to opposite ends of the bridge-member 17. The closed position is shown at the left-hand side of the Fig. and the other side shows the opening movement. In closing the breaker, the gas stream is :n the opposite direction to that shown by the arrows. Relief valves (not shown) may be mounted on the lift rod to adjust the pressure beneath the piston. In a three-phase switch, the tank is cylindrical and the contact-groups spaced equally around the periphery, the three bridges 17 being parallel to one another and located in a common piston. In Fig. 3, each fixed laminated-sleeve contact 24 is mounted at the mouth of an explosion pot 28 in the form of a cylinder carried by a terminal rod, the arcing contact 23 being located in an opening 29 in the wall of the pot. The movable arcing and main contacts 25, 26 are carried on bridge 27, which is secured to a piston-like porcelain block 32 slidable on a central rod 31 and formed with a cavity for each break. Specifications 392,926 and 409,085 are referred to.