US2645697A

US2645697A - Electric circuit breaker

Info

Publication number: US2645697A
Application number: US202100A
Authority: US
Inventors: John W Beatty
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1949-12-21
Filing date: 1950-12-21
Publication date: 1953-07-14
Anticipated expiration: 1970-07-14

Description

J. W. BEATTY ELECTRIC CIRCUIT BREAKER July 14, 1953 Filed Dec. 21, 1950 N m u w m Inventor: John W. Beattg,

Patented July 14, 1953 ATENT OFFICE ELECTRIC ,cmcmr assaults John W. Beatty, Lansdowne', Pa), assignor to General Electric Company, a corporation of New York Application December 21, 1950, Serial No. 202,100

1 This invention relates toelectric' circuit'break ers and more particularly to a circuit breaker of the gas blast type having biased-closed interrupting contacts'arranged in series with isolating contacts and wherein resistance means is connected in parallel with'the interrupting contactsl In circuit breakers of this type a blast of gas is used to extinguish the are drawn between the interrupting contacts after separation thereof and resistance'ineans connected across the interrupting contacts is for the purpose of limiting the recovery voltage peaks tending to cause a restrike of the are between the interrupting contacts. interrupting contacts allows current to bypass the interrupting contacts after the arc is extinguished at these contacts, it is necessary to interrupt this current at the isolating contacts. In high voltage breakers such interruption may prove difficult, if not impossible, unless specialprovision for interrupting the arc at the isolating contacts is made.

A principal object of this invention is to provide an improved means for interrupting the resistor current at the isolating contactsand for establishing an isolating gap in a gas blast breaker having resistor means in shunt with its main interrupting contacts, and to arrange the isolating gap means in such a way that the entire assembly is protected from the Weather by a common enclosing 'housingand so that the entire assembly is compact and requires a minimum of space.

According to the invention a gas blast circuit breaker is provided having a conducting structure formed of atleast two relatively movable parts, each of which forms a portion of a series circuit through the breaker. A first contact structure is normally biased into engagement with one of the parts of the conducting structure and a second contact structure is normally biased into engagement with another of the parts of the conducting structure. Both of these contact structures are separable from the conducting structure by a blast ofgas which also acts to extinguish the arcs drawn between the contact structures and the conducting structure. After extinguishment of the arcs, one of the parts of the conducting structure is moved relative to its associated contact structure so as to establish an isolating gap for the breaker and a resistor is ordinarily connected between the other part of the conducting structure and its associated contact structure.

' As already stated, the resistor is in shunt with Since the resistance in parallel with. the

8 Claims} (01. 20c 14s) one of the contact structures and a part of the conducting structure which together comprise the interrupting contacts of the breaker.

Acomparable arrangement, wherein a pair of seriesarcs are drawn in an interrupting circuit witha resistor in shunt'across one of them, is dis closed and claimed in U. S. Patent 2,222,719 to D. C. Prince; while another comparable arrangement is disclosed in the co-pendin application Serial No. 201,961, Roxburgh et al.; both of these being assigned to the assignee of this present application.

The-invention will be better understood with reference to the accompanying drawing in which the single figure thereof is a side sectional view of a gas biast circuit breaker einbodyingthe principles of the invention.

Referring to the drawing, the numeral 1 is used to designate an insulating support for a portion .of the breaker while the numerals 2 and 3 designate base plate members forming a support for another portion of the breaker. It will be understood that suitable insulating means not shown would be disposed underneath the plate 2 to form a. support therefor which also mightconstitute a structure for housing an appropriate operating mechanism, source of gas or air pressure, and other associated components. Secured to the base plate 3 by means of suitable bolts :2 is a structurally strong'insulating cylinder 5 on which is mounted the metallic assembly 6 which assembly is secured to cylinder 5 by means of bolts and their associated clamping means. Disposed on the assembly 6 is an upper insulating cylinder member 53 secured to assembly 5 by means of bolts 9 and their associated clamping means. Mounted .on the cylinder 3 vis the contact assembly iii which assembly is secured to cylinder 8 by means of bolts l i and their'associated clamping means. Exhaust chamber i2 is disposed on the assembly The horizontal insulating cylinder 53, which may be similar or identical to cylinder 8, is connected to the central assembly 6 by means of bolts P 15, an insulating sleeve [8 is disposed within the tion 22 of the assembly structure I5, the contact fingers 2| being biased into good conducting engagement with the tubular conducting structure 23 by suitable spring means 24. Contact structure l5 is provided with an exhaust opening 25 and with an apertured spider member 26, which constitutes an arcing electrode, through which exhaust of gases to the exhaust chamber I! may be efiected. Thus the finger arrangement comprising the radially arranged fingers 2| is similar to that disclosed and claimed in U. S. Patent 2,427,195 to Cox et al.; while the electrode member 26 may conform to that described and claimed in U. S. Patent 2,391,759 to Wilcox, both of these being assigned to the assignee of the present application.

Suitable mufiler means 21 may be disposed within the exhaust chamber I! for cooling purposes thereby preventing the flaming or incandescent products of arcing from escaping to atmosphere. Ports 28 are provided in the assembly IE to assist the finger contacts 2| holding in the open position against the structure l5 during the application of the blast as explained in the aforesaid Cox et al. patent. Contact assembly l0, hereafter called the secondary interrupting contacts is similar in construction to contact assembly l5; or, as in some applications, it is convenient to make it identical thereto. Thus, the various parts of secondary contact assembly II] have been assigned designating numerals corresponding to the numerals assigned to the parts of the main interrupting contact assembly l5. In view of the description of assembly l5 above, it is believed that another detailed description of the parts of secondary interrupting contact H! is not necessary.

The contact fingers 2| of the secondary interrupting contact II) are biased into engagement with the tubular conducting structure 29 which, according to one aspect of the invention is movable, i. e. conducting tubular member 29 is arranged to be drawn downwardly by means of the insulating operating rod 30 after interruption of the breaker circuit is accomplished by the extinguishing gas blast applied to the secondary interrupting units I and the main interrupting unit l5. It may be observed here that the conducting structure intermediate the main gas-blown contacts and the secondary contacts l0 comprises the fixed tubular conducting element 23, the associated movable tubular conducting member 29 which constitutes the so-called isolating blade or contact, with the fixed and movable

tubular elements

23 and 29 electrically interconnected through the agency of the metallic supporting and gas-dividing structure 6 which holds the several circuit breaker cylindrical components 5, 8 and I3 rigidly together.

Thus, electrical contact between assembly 6 and movable conducting isolator 29 is achieved through the agency of the sliding contact members 3| which are spring-biased into engagement and which are supported on the sub-structure 32 formed integrally with a flanged bolted cover member which as shown, may be readily removable as a subassembly from the assembly 5. Suitable openings 33 are provided in the lower end of movable conducting isolator 29 through which exhaust gases proceeding from arcing contacts I0 may escape from within the member 29 through the short radial conduits 34 cored into the support casting 6 and thence through the cooling muflier arrangement 35 to atmosphere. Similarly, are products from the main arcing contacts |5 can exhaust to atmosphere through the same mufiler in passing from the lefthand interior portion of the tubular conducting structure 23 via the space 36 of assembly 6 after flowing radially through the passages 31 from the interior of tubular structure 23.

It, therefore, will be apparent that the circuit through the interrupter comprises the terminal T1, main interrupting contacts l5, fixed tubular structure 23, assembly 6, sliding contact 3|, movable tubular isolator 29, secondary interrupting contacts l0 and terminal T2.

For the purpose of limiting the recovery voltage peaks tending to cause restrikes of the are drawn between the main interrupting contacts |5 and the cooperating fixed tubular structure 23, a schematically represented resistor R is provided and is connected as a shunt current path around the main interrupting contacts. Preferably such resistor comprises windings arranged in such a way that adjacent turns neutralize one another so as to render the device non-inductive.

When the interrupter performs an interrupting and isolating operation, a blast of are extinguishing fluid such as pressure gas, is directed through the openings 38 and 39 respectively of the base plates 2 and 3 and follows the course indicated by arrows 40 to impinge upon the contact fingers 2| of the main interrupting contacts IS. The force of this blast will cause the finger contacts 2| to move out of engagement with the fixed tubular structure 23 and the are drawn between the tube 23 and the fingers 2| is extinguished by pressure fluid which exhausts axially in opposite directions, i. e., through the opening 25, through the spider electrode 26 and the exhaust chamber I1; and also through the bore of fixed tube 23 following the path of the arrows 4| through the ports 31 and out through the muffler 35 as already described.

As determined by any convenient throttling of the flow passages, a predetermined portion of the pressure fluid supplied through openings 38 and 39 is directed upwardly along the course indicated by the arrows 42 to impinge upon the normally closed finger contacts 2| of the secondary interrupting contacts 10. These finger contacts also are separated from the movable tubular isolating contact 29 by the force of the blast which too exhaust axially in opposite directions from the region of arcing by flowing upwardly through the orifice 25 and the spider electrode 26, and the exhaust chamber |2 to atmosphere and. also by flowing downwardly in the direction of the arrows 43 through the ports 33, the radial passageways 34, mufiling chamber comprising the mesh means 35 to atmosphere.

As is well understood, extinction of the are drawn between the fingers 2| of the main interrupting contact l5 and the fixed tubular member 23 will place the resistor R in series with the contacts comprising the movable tubular member 29 and the fingers 2| of the secondary interrupting contact assembly I0. Thus these gas-blown secondary'contacts, in moving from the movable isolator contact, musteffectivelyinterrupt'the residual resistor current.

Immediately after the arcs at both of the series interrupting contacts have been extinguished, the operating rod 3|] is drawn downwardly for isolating by suitable operating mechanism not shown. Such sequential operation of gas-blown interrupting contacts and isolating contacts is well-known in the art and might assume various forms; that described in U. S. Patent 2,418,739 to Thumim et al., which is assigned to the assignee of the present application, being illustrative of one embodiment thereof. This downward movement of operating rod causes the movable isolating member 29 to move downwardly with respect to the now opened fingers 2! of secondary interrupting contact 10. In this way, the initial gap opened by the fingers 2| is extended to form a widening safe isolating gap within the weather protection afforded by the enclosing cylinder 8. The phantom-lined open position 44 of the isolator operating rod coupling 44 indicates the desirable extent of this safe gap. In'this position, the tip of the isolator tube 29 would be somewhat above the metallic structure 6.

During this isolating'movement, when a safe gap is assured, the blast of pressure fluid supplied through a blast valve from a source not shown through the openings 38 and 39 to the interrupter is shut off. When the fluid blast is cut off, the fingers 2| will then move back to the positions shown in the drawing due to the action of their biasing springs 25.

It will be observed that, after a' certain downward movement of operating rod 36 with isolator tube 29, the ports 33 disposed in the lower portion of tubular member 29 will have moved out of registry with the exhaust passages 34 and into the region of blast supply as indicated by the arrows 42. Accordingly, continued flow within isolating tube 29 will cease with the downward flow indicated by the arrows 43 being bucked by the upward flow indicated by the arrows 42. Thus, automatic cut-off of part of the blast is eflected anticipatory to the mechanical cut-off of the blast valve which is about to take place, and until this moment a scavenging stream will fiow only upwardly through the orifice 25. Such a reduction in the continued use of pressure fluid at the isolating contacts is advantageous because the magnitude of blast required to prevent the re-establishment of an are between the rapidly widening gap is much less than that required earlier to motivate the contact fingers 2! of assembly iii to their open position'and also to extinguish the arcs.

Conversely, for a closing operation, this arrangement automatically provides a diminished blast which is all that is needed for the closing operation when the blast is for the purpose of limiting prestriking of an arc across the gap as the contacts approach one another.

While I have shown and described a particular embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the invention in its broader aspects and I, therefore, intend in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

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

1. An electric circuit breaker comprising conducting structure constructed of at least two relatively movable parts, first contact means normally biased into engagement with one of said parts of said conducting structure, second contact means normally biased into engagement with another of said parts of said conducting structure, said conductingbeing located in a position which is intermediate said first and second contact means, means for supplying a blast of pressure fluid to said first and said second contact means to cause predetermined separation thereof from the associated parts of said con ducting structure, and means for moving one of said parts of said conducting structure relative to its associated contact means after movement of said contact means by said fluid blast to establish an isolating gap.

2. An electric circuit breaker comprising housing structure, conducting structure disposed in said housing structure and constructed of at least two relatively movable parts, first contact means normally biased into engagement with one of said parts of said conducting structure, second contact means normally biased into engagement with another of said parts of said conducting structure, said conducting structure being loeated in a position which is intermediate said first and second contact means, means for supplying a blast of pressure fluid to said first and said second contact means to cause predetermined separation thereof from their associated parts of said conducting structure, and means for subsequently moving one of said parts of said conducting structure relative to its associated contact means to establish an isolating gap after movement of said contact means by said fluid blast has established a predetermined arc extinguishing gap thereat.

3. An electric circuit breaker comprising housing structure, conducting structure disposed in said housing structure and constructed of at least two relatively movable parts, means for maintaining an electrical connection between said parts, first contact means normally biased into engagement with one of said parts of said conducting structure, second contact means normally biased into engagement with another of said parts of said conducting structure, said conducting structure being located in a position which is intermediate said first and second c0ntact means, means for supplying a blast of pres sure fluid to said first and said second contact means to cause predetermined separation thereof from their associated parts of said conducting structure, and means for subsequently moving one of said parts of said conducting structure relative to its associated contact means to establish an isolating gap after movement of said contact means by said fluid blast has resulted in the establishment of a predetermined are extinguishing gap thereat.

4. An electric circuit breaker comprising hollow conducting structure constructed of at least two relatively movable parts, means forming an electrical connection between said parts, first contact means normally biased into engagement with one of said parts of said conducting structure, second contact means normally biased into engagement with another of said parts of said conducting structure, said conducting structure being located in a position which is intermediate said first and second contact means, means for supplying a blast of pressure fluid substantially simultaneously to said first and said second contact structures to cause predetermined separation thereof from their associated parts of said conducting structure, and means for subsequently moving one of said parts of said conducting structure relative to its associated contact means to establish an isolating gap after movement of said contact means by said fluid blast has established a predetermined are extinguishing gap thereat.

5. An electric circuit breaker comprising housing structure, intermediate hollow conducting structure disposed within said housing structure and constructed of at least two relatively movable electrically connected parts, first contact means normally biased into engagement with one of said parts of said conducting structure and forming secondary interrupting and isolating contacts for the breaker, second contact means normally biased into engagement with another of said parts of said conducting structure and forming main interrupting contacts for the breaker, an exhaust opening in said housing structure adjacent said first and second contact means, means for supplying a blast of pressure fluid into said housing structure and to said first and said second contact means to cause predetermined separation thereof from their associated parts of said conducting structure, a portion of said blast being exhausted through said exhaust openings, and means for subsequently moving said one of said parts of said conducting structure relative to its associated contact means to establish an isolatin gap after movement of said contact means by said fluid blast has established a predetermined arc extinguishing gap thereat.

6. An electric circuit breaker comprising housing structure, intermediate hollow conducting structure disposed within said housing structure and constructed of at least two relatively movable electrically connected parts, first contact means normally biased into engagement with one of said parts of said conducting structure and forming secondary interrupting and isolating contacts for the breaker, second contact means normally biased into engagement with another of said parts of said conducting structure and forming main interrupting contacts for the breaker, an exhaust opening in said housing structure adjacent said first and second contact means, means for supplying a blast of pressure fluid into said housing structure and to said first and said second contact means to cause predetermined separation thereof from their associated parts of said conducting structure, a portion of said blast being exhausted through said exhaust openings, and a portion of said blast being exhausted through said hollow structure to atmosphere, means for moving said one of said parts of said conducting structure relative to its associated contact means to establish an isolating gap after movement of said contact means by said fluid blast has established an arcing gap, and resistance means in shunt with the main interrupting contacts of the breaker.

7. An electric circuit breaker comprising in termediate conducting structure constructed of at least two relatively movable parts, first contact means normally biased into engagement with one of said parts of said conducting structure, said first contact means and said one of said parts forming secondary interrupting and isolating contacts for the breaker, second contact means normally biased into engagement with another of said parts of said conducting structure, said second contact means and said another of said parts forming main interrupting contacts for the breaker, means for supplying a blast of pressure fluid to said first and said second contact means to cause predetermined separation thereof from the associated parts of said conducting structure to establish series arcing gaps thereat, means for subsequently moving one of said parts of said conducting structure relative to its associated interrupting contact means after movement of said contact means by said fluid blast to establish an isolating gap, and resistance means in shunt with said interrupting contacts.

8. An electric circuit breaker comprising a housing having two apertured extremities, hollow conducting structure supported within said housing the two ends thereof normally disposed adjacent said apertured extremities respectively, a first set of blast-responsive movable contacts for drawing an arc of predetermined gap length ad jacent one end of said hollow structure, a second set of blast-responsive movable contacts for drawing another are adjacent the other end of said hollow structure in series with said firstmentioned arc, means for supplying a blast of pressure gas to both sets of contacts for extinguishing the arcs drawn thereat, and means for extending the gap length at one of said sets of contacts for establishing thereat a subsequent isolating gap.

JOHN W. BEATTY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,445,529 Leeds July 20, 1948 2,454,586 Amer Nov. 23, 1948 2,531,617 Forwald -1 Nov. 28, 1950 2,588,933 Latour Mar. 11, 1952 FOREIGN PATENTS Number Country Date 619,243 Great Britain Mar. '7, 1949