SU1690015A1 - High-voltage air-break switch for electric heat-treatment installations - Google Patents

Abstract

The invention relates to electrical engineering, in particular to high-voltage air switches for electrothermal installations with frequent switching operations. The aim of the invention is to increase the operation stability, reliability and mechanical life of the switch with frequent switching. The arcing chamber 1 has a fixed contact 2, a movable copper contact nozzle 3, a lower current-carrying output 4, an upper current-carrying output 5 with current-collecting sliding Z-contacts 6, a contact spring 7, a gas outlet 8, a piston 9, a guide 10, steel sleeve 11, elastic cuff 12. In the end surface of sleeve 11 there is an annular protrusion 13 in contact with the end face of the contact nozzle 3 facing the sleeve 11, the width t of the annular protuberance (0.25-0.35) T of the lower ring base lk. 1 il. (Ls

Description

The invention relates to electrical engineering, in particular to high-voltage air switches for electrical installations with frequent switching operations.

The aim of the invention is to increase the operation stability, reliability and mechanical life of the switch during frequent switching operations.

The drawing shows an arc suppressor-switch chamber for electrothermal installations in the off position.

The arcing chamber 1 has a fixed contact 2, a movable copper contact nozzle 3, a lower current-carrying output 4, an upper current-carrying output 5 with current-collecting sliding Z-shaped contacts 6, a contact spring 7, a gas outlet 8, a piston 9, a guide 10, a steel sleeve 11, preventing the contact spring 7 from burning an electric arc, an elastic cuff 12, the ring base of which is fixed to the current-carrying terminal 5 in contact with the movable contact nozzle 3 by means of a lining, and centrally protruding above the ring base m has a part facing towards the spring loaded piston 9 a conical outer surface and a tapered hole inside for the passage of the movable contact 3. The front of the nozzle surface of the steel sleeve 11 has an annular projection 13, with soprikasayuschiys

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the end face of the sleeve 11 facing the surface of the copper contact nozzle 3, the width t of the annular protrusion being 0.25-0.35 of the width T of the lower annular base of the sleeve.

The operation of the switch when turned on is as follows.

After switching off the short-circuit current switch and the release of compressed air from the arcing chamber 1, the piston 9, the sleeve 11 and the movable contact nozzle 3 begin to move towards the fixed contact 2 under the action of the contact spring 7. The air outlet from the space and through the gaps between the contact nozzle 3 and sliding Z-shaped contacts 6 of the current lead 5 are prevented by the cuff 12, the upper end portion of which is pressed to the contact nozzle 3 by compressed air in the space a.

At the stage of movement of the movable contact nozzle 3, the activation of compressed air from the air through the leakage between the cylindrical surface of the piston 9 and the guide 10 between the end contact surfaces of the piston 9 and sleeve 11, between the upper end portion of the cuff 12 ( insufficient elasticity) and the contact nozzle 3, as well as between the end of the annular protrusion 13 of the sleeve 11 and the end facing the sleeve 11 surface of the contact nozzle 3.

After several switching on of the switch, the end surface of the contact nozzle 3 and the end of the annular protrusion 13 of the sleeve 11 are nailed to each other and as a result of the removal of the protruding parts approach each other, increasing the number of points and the contact area, which leads to certainty in the gap between these surfaces and, as a consequence of this, to the stability of the force-suppressing air buffer of the arcing chamber.

The lower the piston 9 falls, the greater the pressure in space a and the greater the decelerating force of the air buffer, which significantly reduces the speed of the movable contact nozzle 3 and consequently reduces its impact on the fixed contact 2, thereby increasing the mechanical life of the switch.

Studies have shown

that, when the ratio t (0.25-0.3) T is fulfilled, in the end surface of the copper contact nozzle 3, in the place of contact with the end face of the annular protrusion 13, the steel sleeve 11 forms an annular groove beyond

by minimizing contact points, which increases the contact area of these parts, as a result of which the stability of the switch, when the switch is turned on, increases, and its mechanical recovery increases.

Claims (1)

Claims of the Invention A high-voltage air switch for electrothermal installations, each arc chamber containing a piston mounted on one axis, contact springs, a bushing, a fixed contact and a movable contact nozzle, as well as an elastic cuff, the central part of which protrudes over an annular base has towards the movable piston, the conical outer surface and the conic bore inside for the passage of the movable contact, characterized in that, in order to increase the stability operation, reliability and mechanical life of the switch during frequent switching operations, an annular ledge is made in the front part of the surface of the sleeve that protects the contact spring from burning; an annular protrusion is made, the width t of which is 0.25-0.35 of the width T of the lower ring the base of this sleeve.