GB165117A - Improvements in or relating to electric oil switches - Google Patents

Abstract

165,117. Victoria Falls & Transvaal Power Co., Ltd., and Price, B. Sept. 9, 1919. Oil switches; switches, quick-break.-In an oilbreak switch in which the are is driven out in an explosion chamber enclosing the fixed contact the oil pressure in the explosion chamber is increased to augment the pressure of the quenching jet by means which restrict the passage of the oil from the explosion chamber to the container. In the form shown in Fig. 3, the conical orifice c through which the movable contact j passes into and out of the explosion chamber containing the fixed contact l is provided with two hinged flaps g which are pushed aside when the contact enters the chamber, as shown, but when the contact passes through the orifice the rush of oil shuts the flaps and closes the orifice except for a small opening formed by cut-away parts g in the meeting edges of the flap. Through this restricted opening the oil is forced at an increased pressure to quench the arc. In the form shown in Fig. 4 when the contact is withdrawn the orifice is closed except for small passages s bv a ball which rolls into a seating r in the upper end of the orifice which is so shaped as to produce in conjunction with the movable contact a suction effect on the oil and increase its velocitv. In the form shown in Fig. 8, the movable contact member is hollow and provided with a transverse passage t of restricted area.; during the downwards movement of the contact member the passage t is closed by the parallel walls of the orifice whereby pressure is stored in the explosion chamber this pressure serving to ferce the oil with great pressure into the arc and through the tubular contact when the passage t is carried below the orifice. In the construction shown in Fig. 9 the movable contact is arranged to move, when released, under the action of a spring and accelerated by the explosion, independently of the operating gear. The movable contact is secured to a sleeve in the spindle u and is acted upon by a coiled spring tending to bring it to the off position; it is connected to the terminal 3 by rubbing brush contacts 1 secured to a projection 2 of the terminal. The contact member at the part where it passes into the explosion chamber is shaped concentric with its axis of movement. The switch is brought to the closed position and held there by raising the hinged catch 7a on the end of the pivoted link 8 through link 10 and bevel gearing 12 operated by an external hand wheel; the catch 7<a> drives the switch-gear through the projection 6. To trip the switch a bell-crank lever is operated through links 17, 19 to push aside the catch 7a. The rebound of the contact member is taken up by a spring dashpot buffer 24.