US1959183A - Electrical switching apparatus - Google Patents

Description

flay 15,1934.

w. UEBERMUTH 1,959,183. ELECTRICAL SWITCHING APPARATUS Filed Sept. 2 19:0

His ATTor-ne gu Patented May 15, 1934 UNITED, STATES 1,959,183 ELECTRICAL SWITCHING APPARATUS Werner Uebermuth, Oberschoneweide, Germany,

assignor to General Electric Company, a corporation of New York Application September 2, 1930, Serial No. 479,162

In Germany October 31, 1929 '4 Claims. (Cl. 200-148) My invention'relates toelectrical switching apparatus and more particularly to high tension switching apparatus of the type utilizing a fluid under pressure for extinguishing arcing during interruption of the circuit In the interruption of polyphase currents and also-oi single-phase currents at high voltages, compressed gas or air-blast switches have been used comprising several individual switch units.

In this arrangement the points of current interruption of the individual switches are arranged insuch a mannerthat the exhaust gases evolved during the switching operation may flow away freely toward the other switch units. These gases are highly heated and as is wellknown, greatly decrease the dielectric strength of the surrounding air. Y Consequently, measures must be taken so that the switch gases from individual poles of the switch do not come into contact with one another to cause flashovers or interphase short circuits.

In accordance with the present invention, this problem is solved by arranging the individual switch poles obliquely in relation to one another,

the points of current interruption being remote- 1y located with respect to each other at the free or outer ends of the arms ot'the angle formed by the switch poles. In this arrangement, the switch gases radiate from the individual poles indiverging directions and rapidly dissipate in the atmosphere so that there is little occasion for the gases to break down the-dielectric strength of the air beween poles. Also, the points of highest potential are remotely positioned with respect to each other as c mpared with poles arranged in parallel relation for example.

In th operation of switchgear of the air-blast type it is also important that a swich comprising several individual switch units be actuated during 40 interruption so thatthe moving contacts open simultaneously with great accuracy. If a special mechanism were provided for each point of interruption, a relatively complicated switching apparatus would result in order to establish with 46 certainty simultaneously opening at the individual points of interruption. If, on the other hand, when using a common operating member, the movable contacts of the interruption points are connected by a transverse or bridging arrange- 50 ment, mechanical jamming or binding may occur during the switching operation as a result of elastic deformations of the entire construction. These mechanical diiliculties are avoided in the oblique arrangement oi" the individual switches 1 above referred to in accordance with a further aspect of the present invention, by the use of a common centrally located driving or operating member with which the movable contacts are pivotally connected through guide rods. A further advantage of this arrangement is that the conduction and distribution of the pressure gases for extinguishing the arcs can be effected from a common gear or mechanism casing. Also, for giiiding the compressed air, as well as for carrying out of the switching operation and also for extinguishing the arcs, but one'individual pressure gas valve is required for the source of pressure and insulated pressure gas pipes to the points of interruption are rendered unnecessary. In order to avoid transmission of a severe thrust to the piston in its limited position, the pressure gas serving to eiiect the opening movement is suitably throttled during the travel of the piston so that the driving force on the piston becomes smaller with the increase in stroke. The oblique arrangement of the individual poles has been shown to be advantageous when they are connested in series, as must be the case for high voltages. 'In this case, only fixed connecting lines are between the stationary contacts, so that the flow of curren need not take place through a movable current bridging member.

Referring to the drawing the single figure thereof is an elevational sectional view of a compressed gas circuit breaker embodying my invention.

By way of example, my invention is represented in a pressure gas switch of the air-blast type comprising concentric contact surfaces, between which a gas may be directed at high pressure for extinguishing the arc, there being two interrupt-- ing points per phase connected in series. The outer stationary contacts are represented at 1 and 2 to which the incoming and outgoing lines 3 and 4 are connected. The movable contacts 5 and 6 are adapted to slide in and be guided by the resilient and flexible contacts 7 and 8'which are provided with suitable springs and guide pieces. The guiding contacts 7 and 8 are electrically connected as by the stationary conductor 9 for completing the series connection. between the contacts 1 and 2. l i

Between the contacts 1 and'7, and 2 and 8 are disposed tubular. or cylindrical insulating members 10 and 11 forming longitudinal passages through which gas may be directed across the contacts during separation thereof, which are so designed that when the switch is opened the insulating structure is able towithstand the compressive and other stresses set up therein. The

thereof are each moved in a straight line in the passages in the corresponding insulating tubes 12 and 13 by means of insulating rods 14 and 15 which are connected respectively to the cross head members 16 and 17 guided within the extensions 18 and 19. The connecting rods 20 and 21 for the cross head members are pivotally secured to a hollow piston rod 22 comprising a driving member which is guided by the stationary hollow rod 23 provided with the lateral openings or ports 24.

In operating the switch compressed air or other suitable gas is admitted from a suitable source of pressure (not shown) through the opening 25 in the casing 26 and acts on the piston 27 so as to force it downwardly. The gas is directed to the working face of the piston through the ports 24,

the hollow piston rod 22 and the opening 28.-

That part of the cylinder 29 located at the opposite or exhaust side of the piston 2'7 is of course simultaneously evacuated during the opening stroke. During the downward stroke it will he :noted that the piston rod 22 in the manner of-a slide valve shuts off successively the ports 24 in the tube 23 so that the air supply to the operating piston is throttled and gradually ceases. Accordingly, the force acting on the piston at the end of the stroke is small and insuflicient to set up severe stresses in the mechanism due to impact at the limiting position" of the piston.

Simultaneous with the operation of the piston 27, the compressed air is directed into the longitudinal passages from the casing 26 and iiows past the cross head members 16 and 17 which do not appreciably obstruct the flow of gas through the passages in the extensions 18 and 19, and the insulation cylinders 12, 10 and 13, 11 to the points of interruption 1 and 2, so that the air blast across the contacts takes place at the moment of high speed separation. Upon separation of the coactving contactsi, 5 and 2, 6 the consequent arcing between these contacts is effectively extinguished by the blast of air directed longitudinally of the movable contacts so as to pass across the arcing surfaces of the contacts. The heated air or other extinguishing gas is accordingly exhausted from the individual switch units at high velocity and due to the diverging directions of the, air blasts, the gases are effectively dissipated without danger of flashover between the units.

The switching-in or closing movement is efthe interconnectingcross head and connecting rod mechanism.

It shall be understood that my inventionv is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention. I

What I claim as new and desire to secure by Letters Patent of the United States, is: a

1. A circuit breaker unit of the gas blast type wherein a 'singlesource of gas pressure is utilized to efiect opening of the circuit and interruption of arcing including a plurality of stationary and movable contactsand structure forming longitudinal passages through which gas under pressure may be directed to interrupt arcing between the coacting' contact surfaces, said movable contacts adapted to move during opening of the breaker in a direction substantially parallel with movable contacts 5 and 6 during the opening the flow of gas through said passages, operating means for the movablecontacts guided for movement within said passages, an operating piston effecting simultaneous opening of said movable contacts, and slide valve means connected to said piston controlling communication between a source of pressure and said operating piston in accordance with circuit opening movement, said source of. pressure likewise being in communication with said passages for conourrentlycausing flow of gas at high velocity across the separating contact surfaces.

2. In a circuit breaker of the gas 'blast type wherein a single source of gas pressure is utilized to effect opening of the circuit and. interruption of arcing comprising a'plurality of stationary and. movable contacts and structure, forming longitudinal passages through which gas under pressure is directed to flow across the contact surfaces during separation thereof, operating means forthe movable contacts comprising a cross head member operatively connected to each of said movable contacts and guided for movement within the corresponding passage, a piston connected to said cross heads for causing simultaneous opening'of the movable contacts, means including a plurality of ports adapted to communicate with a source of pressure for directing gas under pres-- sure to said piston to cause switch opening movement thereof, and means related to said piston for successively closing said Ports during the switch opening movement whereby the gas acting on said piston is graduallythrottled.

3. In a circuit breaker of the gas blast type wherein a single source of gas pressure is utilized to effect opening of the circuit and interruption of arcing comprising a plurality of poles, each pole having a stationary and movable contact and a tubular insulating member forming a passage for directing a gas under pressure across the contact surfaces of the contacts during separation thereof, said contact surfaces being disposed at the exhaust ends of said insulating members, operating means connected to each of said movable contacts, an operating piston having a hollow piston rod causing simultaneous opening of the contacts, means including ports-adapted to be in communication with a source of pressure for directing gas through said hollow piston rod to the piston to cause switch opening movement thereof, 125 said hollow piston rod being adapted to successively close said ports and throttle thegas acting on the piston during its opening stroke, and a casing in communication with said source of pressure for concurrently directing a flow of gas at high i velocity through said tubular members and across the separating contact surfaces to extinguis arcing therebetween.

4. A circuit breaker unit of the gas blast type wherein a single source of gas pressure is utilized to effect opening of the circuit and interruption of arcing comprising a pair of relatively movable contacts including a stationary nozzle-like .contact and a coacting rod contact, a' hollow insulating casing on which said stationary contact isfi mounted, said casing forming a passage through which gas isdirected at high velocity through said stationary contact and across the coacting contact surfaces to extinguish arcing, a piston operatively connected to said rod contact, said 14 piston being in communication with a source of WERNER UEBERMUTH.

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