Патент USA US2110672код для вставки
7 March 8, 1938. I 2,110,672 o. MAYR ELECTRIC CIRCUIT INTERRUPTER Filed March 6, 1957 ' lnventor' Ott Q Magr', by 1/ 6:1] H S Attorney Patented Mar. 8, 1938 2,110,672 UNITED STATES PATENT OFFICE 2,110,672 ELECTRIC CIRCUIT INTERRUPTER Otto MayrIBerlin-Karlshorst, Germany, assignor to General Electric Company, a corporation of New York Application March 6, 1937, Serial No. 129,422 In Germany March 23, 1936 ' 4' Claims. - (c1. zoo-149) This invention relates to electric circuit inter the following description referring to the accom rupters, more particularly to the expulsion type panying drawing, and the features of novelty wherein automatic generation of an arc-extin~ guishing gas takes place in accordance with the which characterize my invention will be pointed out with particularity in the claims annexed to 5 circuit opening operation. In the operation of electric switches or cir cuit breakers of the gas-expulsion type, for ex and forming a part of this‘ speci?cation. Referring to the drawing the single ?gure thereof is an elevational'view, partly in section, ample, wherein an arc-extinguishing gas is re— 7 of an electric circuit interrupter of the gas-ex leased from the walls of the arc chamber under '10 in?uence of the arc heat, there is often'encoun tered di?iculty’ in interrupting both large and small currents with equal facility. “Phat is, since the amount of extinguishing gas generated de pends, among other things, on the intensity of 15 the arc current, the‘size of the arc chamber is generally a compromise between the optimum for low current and high current interruptions. If the capacity of the arc chamber is selected so that an effective gas expulsion takes place at low ‘cur 20 rents for interrupting the arc, the pressure gener ated during the interruption of a high current are may be so great as to burst the chamber casing. Converselyyif the capacity of the arc chamber is increased so as to provide for the 25 larger amount of gas generated during interrup tion of a high current- arc, the expulsion effect at low currents may be so- weak that the arc is not interrupted. ' i The principal object of myinvention is the 30 provision of .an improved circuit interrupter of the aforesaid type which is e?icient and positive pulsion ‘type embodying the present invention. The circuit interrupter shown by way of ex ample is an expulsion type switch in the open circuit position. ‘ The switch or circuit breaker comprises essentially an extinguishing tube I or an equivalent structure forming an, arc-inter rupting chamber I’ centrally of the tube. The 15 tube I, or the walls of the arc chamber, is com posed of a gas-yielding material such as, for ex ample, ?ber or hard rubber so that an arc-inter rupting gas is generated within the arc chamber when the chamber walls are subjected to therarc. M 0 The closed end of the arc chamber I’ is located adjacent the ?xed contact structure 2, which is shown as of the segmental type, suitably mount ed within a stationary terminal housing 3. The coacting movable contact comprises a rod 4 mov able through the open or gas exhaust end of the arc chamber into engagement with the ?xed contact 2. The tube I is suitably secured. to the ?xed housing 3 in any suitable manner, such as by screw-threaded engagement. The closed end of the arc chamber I’ is de- in operation throughout its entire rated range ' ?ned by a movable wall portion 5 which is oper of interrupting capacity, and simple and durable in construction. 35 ' . In accordance with my invention in a simple form thereof an arc-extinguishing chamber is provided with a wall portion which is movable in response‘to predetermined pressure within the arc chamber for automatically regulating the - 40 pressure of the arc-extinguishing gas during in terruption of currents throughout the rated range of the interrupter. In a preferred arrangement the movable wall portion is formed as a piston normally biased by a‘ spring or the equivalent 4-5 thereof so as to de?ne a minimum arc-chamber volume. Predetermined arc pressure generated within the chamber is effective to move the pis ton against the biasing force so as to enlarge the arc chamber and thereby reduce bursting pres 50 sures during interruption of high current arcs. I 55 able within a chamber 6 in the terminal housing 3 and suitably biased by a spring ‘I into engage ment with the ?xed contact structure 2. In this position the movable wall portion, which in the present instance is formed as a piston, de?nes an arc chamber of minimum volume for the inter ruption of light or medium currents. That is, during the interruption of small or medium cur 40 rents the piston 5 remains in the position shown and the are drawn between the contacts 2 and 4 acts on the inner walls of the chamber I’ to release the arc-extinguishing gas. When the rod contact 4 leaves the lower exhaustMend of the chamber a gas blast takes place which inter rupts the are. i ‘ .1 When comparatively large currents are to be interrupted, the chamber 6 serves as a compres sion chamber and the_gas pressure generated In the normal position of therpiston, the restricted ' within the arc chamber I’ forces the piston 5 volume of the .arc chamber is such that small or upwardly against the bias of spring I to enlarge medium currents are effectively interrupted by the volume of the arc chamber, thereby reducing the gas pressure generated. therein. the bursting pressure. A vent 8 can also be pro .My invention will be more fully 'set forth in vided in the compression chamber 6, and if de 2 $23,110,672 sired, may be formed as an adjustable throttle the aforesaid arc ‘chamber in response to prede opening. termined gas pressure generated within said arc This-permits a certain degree of ad- . justment in regulating the pressures to be re lieved in accordance with the circuit-interrupt ing requirements of the switch. ' » A further advantage of’ the movable chamber wall as arranged in accordance with the present invention is that the energy stored in the spring ll during the initial circuit opening movement is returned. in the form or“ an augmented gas blast when the movable switch rod ll clears the exhaust end of the arc chamber l’. The piston, therefore, in returning to its-original position serves to aid chamber upon separation of said contact struc ture, and means forming an expansion chamber within which said piston-like member operates, said member being biased to return gas under pressure to said are chamber for aiding interrup tion during the latter part of the circuit-opening operation. - 3. An electric circuit interrupter of the gas expulsion type comprising a ?xed and a movable rod contact, an insulating cylinder forming an arc chamber through which said rod contact is movable for coacting with the other contact, said final interruption of the arc. . It should be understood that my invention is chamber having walls composed of a material 15 not limited to speci?c details of construction and adapted to emit an arc-extinguishing gas when arrangement thereof herein illustrated, and that subjected to the arc formed upon separation of changes and modi?cations may occur to one said contacts, said contacts arranged to sepa skilled in the'art without departing from the rate at one end of said chamber, means forming an expansion chamber at said one end of said 20 spirit of my invention; chamber, and a piston forming a con?ning wall ‘ What I claim as new and desire to secure by portion of said are chamber operable in the afore Letters Patent" of the United States, is: said expansion chamber normally biased so as 1. An electric circuit interrupter of the gas expulsion type comprising means for opening the to restrict the volume of said chamber, said piston 25 circuit, insulating structure de?ning a chamber being movable into said expansion chamber to 25 having an exhaust opening within which an arc is formed upon opening of the circuit, said chamber having wall portions composed of a , material adapted to emit an arc-extinguishing 30 gas when subjected to said are, means forming a pressure resisting movable wall portion of said chamber, said wall portion being movable in a direction to increase the volume of said chamber ~ substantially independently of the exhaust there 35 from in response to predetermined gas pressure generated within said chamber, and means coact increase the volume of said arc chamber in re sponse to predetermined gas pressure generated during separation or said contacts, and operable to return gas under pressure to said arc chamber for aiding interruption when the arc pressure has 30 decreased a predetermined amount. a. An electric circuit interrupter of the gas expulsion type comprising a ?xed contact and a‘ coacting movable rod contact, an‘insulating tube having a sleeve-like ?t with respect to said rod 35 contact through which said contact is operable ing with said movable wall portion forming an to engage said ?xed contact at one end of said expansion chamber, from which gas is returned ' biased so as to restrict the volume of said cham tube, said tube forming an arc chamber having walls composed of a material adapted to emit an arc-extinguishing gas when subjected to the are 40 formed upon separation of said contacts, means substantially closing the end of said tube adjacent said ?xed contact, a piston member disposed within said closing means adjacent said end of said tube, said piston being normally biased so as 45 to restrict the volume of said are chamber, said piston being movable ‘in opposition to said bias to ber, said chamber also having wall portions com increase the volume of said arc chamber in re to said are chamber by said wall portion during 40 the latter part of the circuit-opening operation. 2. An electric, circuit interrupter of the gas expulsion type comprising relatively movable con tact structure, an insulating cylinder forming an arc chamber co-operating with said contact struc ture, a .i piston-like member forming a con?n ing wall portion of said are chamber normally posed of a material adapted to emit an arc 50 extinguishing gas when subjected to the arc, said member being movable in a direction to enlarge sponse to predetermined gas pressure generated within said chamber. OTTO MAYR.