US2418739A - Circuit breaker operating system - Google Patents

Description

Zseaq 6m mmB. w 2 thC nT .t w m a r chcm a w x w m A b a b C. THUMlM ETAL CIRCUIT BREAKER OPERATING SYSTEM Filed Nov. 29, 1940 April 8, 1947.

I.. Q 4 8 l 9 a w n: w. x 3 m o I M 9 P 7 H 0 2 9. w yfl a W w m T u 0 w 2. rFi imm E P. 7 h .wvv an u w il Patented Apr. 8, 1947 CIRCUIT BREAKER OPERATING SYSTEM Carl Thumim, Yeadon, and Alexander C. Boisseau, Lansdowne, Pa., assignors to General Electric Company, a corporation of New York Application November 29, 1940, Serial No. 367,789

20 Claims.

Ourinvention relates to circuit breaker operating systems and more particularly to a system for effecting high-speed operation of -a circuit breaker controlling large amounts of electrical energy.

In order to eliminate the fire hazard, circuit breakers have been satisfactorily designed which do not utilize oil or other inflammable liquid for arc-extinguishing purposes but instead employ a blast of fluid, such as air or other gas, to extinguish the arc formed both when the circuit is broken between the relatively movable contacts of the circuit breaker and also during the closing operation of the circuit breaker to prevent the formation of any are at this time. However, the value of any circuit breaker, whether or not it be of the fluid-blast type, lies in its ability to interrupt a circuit at the proper time and in the proper manner. Without a satisfactory operating and control system for such a circuit breaker, its value is largely lost for, if the control of the circuit breaker in the manner intended is not obtained, many undesirable conditions may result. Numerous control systems have been designed for satisfactorily controlling circuit breakers of the fluid-blast type. Our invention is specifically concerned with providing an operating or control system for a gas-blast circuit breaker which controls larger amounts of electrical energy than were heretofore thought possible, such as in the neighborhood of a million and a half kva or more. When such circuit breakers are used on high-voltage systems, because of the necessity of providing sufllcient electrical clearance between phases, it is customary to design them as single-pole units and to use a plurality of these units for a polyphase circuit breaker. It becomes necessary, therefore, to operate and interlock these units so/that they will act as a single circuit breaker.

Accordingly, it is an object of our invention to provide a new and improved operating system for controlling a fluid-blast circuit breaker of the type designed for controlling very large amounts of electrical energy which is rugged in construction, simple in design, and provides satisfactory operation in every respect.

It is another object of our invention to provide a new and improved operating and control system for a poly-phase fluid-blast circuit breaker in which a plurality of single-pole units are arranged to operate as a single circuit breaker.

Further objects and advantages of our invention will become apparent as the following description proceeds and the features of novelty which characterize our invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of our invention, reference may be had to the accompanying drawing in which Fig. 1 is apartly diagrammatic layout of an operating system for a fluid-operated gas-blast circuit breaker embodying our invention, and Fig. 2 is an elevational view par tially in section of an interrupting head forming a part of the polyphase circuit breaker schematically illustrated in Fig. 1.

Referring now to the drawing, we have illustrated our invention as applied to a polyphase circuit breaker generally indicated at H] com-- prising a plurality of single-pole units. Each of the single-pole units comprises a pair of substantially identical interrupting heads Ii and i2, the structural features of which are somewhat schematically illustrated in Fig. 2. These structural features of the interrupting heads as shown in Fig. 2 form no part of our invention but are disclosed and claimed in a copending application Serial No. 376,215, filed January 2'7, 1941, on behalf of William K. Rankin, and assigned to the same assignee as the present application.

For the sake of clearness, the similar parts of the interrupting units Ii and i2 are designated by the same reference numerals except that the subscripts a, b, and c are applied thereto depending upon which pole of the polyphase circuit breaker in is under consideration. Referring more particularly to Fig. 2, each of the interrupting units it or i2 includes a pair of relatively movable contacts i 3 and E4, the former being a retractable pin-type contact while the latter is a stationary contact. Preferably, retractable pintype contact I3 is suitably connected to a fluid motor which We have illustrated as comprising a piston I 5 mounted for reciprocal movement in a cylinder I6. Suitable biasing means, such as spring i'l, may be provided for constantly urging retractable pin-type contact i3 to the closed position to engage stationary contact M. The contact structure of the interrupting heads I i and i2 described thus far is in many respects similar to that disclosed and claimed in United States Letters Patent 2,084,885, granted June 26, 1937, upon an application of Josef Biermanns and assigned to the same assignee as the present application.

Each of the interrupting heads I l and i 2 is provided with terminals l8 and 19, respectively, the former being electrically connected to retractable pin-type contact l3 while the latter is connected to stationary contact [4. The terminals I8 are connected to the power circuit 20 which circuit breaker I is designed to control. The terminals I9 of the interrupting heads II and I2 are arranged to extend outwardly from the interrupting heads in the form of a stationary contact to cooperate with isolating contacts which are described in detail hereinafter. We have illustrated each of the interrupting heads II and I2 as suitably enclosed in an insulating supporting column 2I. The different supporting columns for polyphase circuit breaker I 0 are sulficiently separated to provide the necessary electrical clearance. As shown in Fig. 2, the interrupting units may also be provided with a suitable hood 22 for weatherprotecting purposes since such high-voltage circuit breakers are usually used in outdoor installations.

Separation of contacts I3 and I4 is obtained by introducing fluid under pressure into conduit 23, which causes the fluid motor to operate. Specifically, this fluid under pressure forces piston I5 to move upwardly in cylinder I6 against the bias of spring means IT. This fluid also flows past the are drawn between the relatively movable contacts I3 and I4 so that this are is subjected to the quenching effect of a high-pressure atmosphere and, consequently, is rapidly interrupted by the resulting fluid blast. As soon as the fluid under pressure in conduit 23 is cut off from its source of supply, spring means I! forces retractable pin-type contact I3 to reengage with stationary contact I4 to reclose the circuit at these interrupting contacts.

In order to complete the circuit-interrupting operation of circuit breakers utilizing retractable pin-type contacts, it is necessary to provide isolating contacts in series with the interrupting contacts which will isolate the circuit subsequent to the operation of the interrupting contacts, but before they reclose, by providing a sufllcient electrical clearance to prevent any restriking of the arc. Accordingly, in Fig 1 we have illustrated a disconnecting arm 24 as associated with each pair of interrupting heads I I and I2 or, in other words, with each of the poles of polyhase circuit breaker Ill. Disconnecting arms 24 preferably support an isolating contact 25 at either end thereof which is adapted to engage with the terminals IQ of interrupting units II and I2, respectively, thereby providing an arrangement in which a plurality of interrupting contacts and a plurality of isolating contacts are connected in series relationship.

Although each pair of relatively movable interrupting contacts I3 and I4 of circuit breaker I0 is individually operable in response to the fluid pressure from conduits 23 supplied to the respective interrupting heads II and I2, it would be desirable to operate circuit breaker I 0 as a single unit. Accordingly, we have inter-connected the disconnecting arms 24 so that all the isolating contacts 25 are operated simultaneously as a single unit. Each of the disconnecting arms 24, which are pivotally supported at 26, is provided with a crank 21, and these cranks are interconnected by an operating arm 28. The force for operating isolating contacts 25 may be applied through a suitable connecting rod 29, which is illustrated as connected to operating arm 24b through a crank 30.

As will be understood by those skilled in the art, it is desirable that contacts 25 be held in either of their extreme positions so that vibration will not cause undesirable movement thereof. Accordingly, we have provided locking means 3| and 32 for holding the isolating contacts 25 in the closed or open positions, respectively. Locking means 3| is adapted to engage the end of crank 30 to hold the isolating contacts in the closed position when the circuit breaker I0 is closed and locking means 32 is arranged to engage crank 21b to hold the isolating contacts 25 in the open position when the circuit breaker III is open. Preferably, connecting rod 29 is connected to operate isolating contacts 25 through a lost-, motion connection 33 to enable cams 34 and 35 provided on connecting rod 29 to cause release of locking means 3| and 32, respectively, to permit the isolating contacts 25 to open or close depending upon the direction of movement of connecting rod 29.

In order to supply fluid under pressure to conduits 23 to operate interrupting contacts I3 and I4 and to provide a blast of fluid, such as air, for arc-extinguishing purposes at the various interrupting heads, we provide a source of fluid under pressure which, in Fig. 1, is illustrated as three separate fluid reservoirs 36a, 36b, and 360 associated with the respective poles of circuit breaker Ill and interconnected for free and rapid interchange of air, as shown at 31. It will, of course, be understood by those skilled in the art that, instead of three reservoirs as illustrated, a single large reservoir could be provided. These reservoirs 36 are supplied with fluid under pressure, such as air, from suitable compressor means, not shown.

As will be understood by those skilled in the art, it is necessary to provide a suitable control valve for controlling the fluid blast at the respective interrupting heads. To reduce the distance that this fluid blast must travel, to provide equal distribution of the fluid, and to keep the control or blast valve down to a reasonable size, we have provided an arrangement in which an individual blast valve is provided for each single-pole unit of circuit breaker l0. These are illustrated as 33a, 38b, and 380 in the drawing. In order that circuit breaker I0 operates as a unit, however, it is necessary that blast valves 38a, 38b, and 380 be operated simultaneously and, to this end, we have provided a pilot valve 39 arranged to permit the introduction of fluid from reservoir 360 into the respective blast valves 38a, 38b, and 38c to cause opening thereof, which will be described in greater detail hereinafter.

The blast. valves 3842, 38b, and 380 are very similar to the blast valve disclosed and claimed in a copending application of Carl Thurnim, Serial No. 343,002, filed June 28, 1940, and assigned to the same assignee as the present application. Since these blast valves 38 are identical, only one of them, namely 380, has been shown in section to illustrate the streamlined path for fluid, leading from the source of pressure to the respective manifolds 40 which are connected to the conduits 23 associated with the interrupting heads II and I2 controlled by this blast valve. This streamlined path is arranged to be closed by a valve member 4| 0 which is connected to a piston 42c reciprocatingly mounted in a cylinder 430 formed integrally with the body of blast valve 380. Suitable spring means 440 tend to bias valve member 4| 0 to the closed position. To open blast valve 380, pilot valve 39 is operated to allow fluid, such as air under pressure, to enter the cylinder 43c below piston 42c through conduit 450. This fluid under pressure, by virtue of the larger area of piston 420 relative to the area of valve member He, forces valve member He away from its seat to provide a path between source 36c and interrupting heads He and Ho respectively. Fluid, such as air or gas, in the space above piston 420 is vented through port 46c so that high-speed operation of the blast valve may be obtained. When pilot valve 39 is closed, the space in cylinders 43a, 43b, and 430 below the respective pistons 42a, 42b, and 420 is vented to atmosphere through port 41 in pilot valve 39 and the air under pressure above pistons 42a, 42b, and 420 is effective through ports 46a, 46b, and 460 respectively to force the respective valve members 41a, Nb, and Ale to their closed positions. By this arrangement, both opening and closing of the blast valves 38a, 38b, and 380 are rapid and positive due to the action of pressure on both sides of the respective pistons 42a, 42b, and 420.

Any suitable means for operating the isolating contacts 25 may be provided. In Fig. 1 we have illustrated fluid motor 48 for this purpose which comprises a cylinder 49 and a double-acting piston 50 suitably connected to operate isolating contacts 25 through connecting rod 29 referred to above. In order to reciprocate piston 50 of fluid motor 48 and, consequently, to move isolating contacts 25 in response to fluid pressure, we have shown reservoir 36b connected by means of a conduit 51 to a manifold 52 from which fluid under pressure may be led to either end of cylinder 49 in accordance with the operation of either a circuit-breaker opening valve 53 or a circuit-breaker closing valve 54. Opening valve 53 is normally held in the position indicated in Fig. 1, closing the lower end of manifold 52 against the fluid pressure from conduit by means of a relatively heavy spring 55 acting on a lever 56 associated with the opening valve 53. Valve 53 is arranged to be operated by fluid means, which will be described hereinafter, which exerts a downward tripping force on the end of lever 56 to open isolating contacts 25 of circuit breaker H]. In its open position, opening valve 53 is adapted to close an escape port 51 in manifold 52 so as to vent the lower end of cylinder 49 to atmosphere when the circuit breaker Ill is being closed.

Similarly, closing valve 54 is normally held in the position indicated in Fig. 1, closing the, upper end of manifold 52 against the fluid pressure from conduit 5| by means of a relatively heavy spring 56. Closing valve 54 is arranged to be opened by a closing solenoid 59. In its open position, closing valve 54 is adapted to close an escape port 60 through which fluid from the upper end of cylinder 49 may escape to atmosphere when the isolating contacts 25 of circuit breaker are operated to the open position.

It will be understood by those skilled in the art that a suitable dumping valve will be pro vided between manifold 52 and cylinder 49 in order to provide trip-free operation for circuit breaker Hi. In order to simplify the drawing, this dumping valve has not been illustrated since it forms no part of our present invention but is clearly disclosed and claimed in a copending application of Carl Thumim, Serial No. 356,469, filed September 12, 1940, and assigned to the same assignee as the present application.

It has been discovered in connection with circult breakers of the fluid-blast type that a blast of fluid for arc-extinguishing purposes should be provided either simultaneously with the operation of the circuit breaker or prior thereto. The construction of the interrupting contacts i3 and I4 of circuit breaker l0 described thus far is such as inherently to require a blast of fluid under pressure for arc-extinguishing purposes simultaneously with the opening movement of the interrupting or arcing contacts. It is also ential that the isolating contacts do not operate until a blast of fluid under pressure is assured at the interrupting contacts of all of the interrupting heads II and 12 of circuit breaker I0. To accomplish this, each of the blast valves 38a, 38b, and 380 is provided with a small valve 6|, only valve 6|c being shown in the drawing. Valve tile is opened after valve member Me of blast valve 380 is partially open so that fluid under pressure may enter conduit 62 controlled thereby. Valve 6lc permits fluid under pressure to enter conduit 62 and cause opening of circuit-breaker opening valve 53 under certain conditions as will be described in greater detail hereinafter.

Valve He thus serves to prevent the isolating contacts 25 of circuit breaker ID from opening until blast valve 38c has been opened to allow fluid to enter the interrupting heads I la and 120. Since the disconnecting contacts 25 are operated simultaneously for all of the interrupting heads II and [2, it is necessary that all three of the air-blast valves 38a, 38b, and 380 be opened before the opening movement of the isolating contacts 25 is initiated. To accomplish this, we have provided a pneumatic tripping means and interlock, generally indicated at 63. Pneumatic tripping means 63 is illustrated as including three cylinders 64, 65, and 66 within which are reciprocatingly mounted pistons 61, 68, and 69 respectively. Piston 61 is operatively connected to a tripping plunger 10 which engages with the end of lever 56 so that downward movement of piston 61 causes opening valve 53 to operate so that isolating contacts 25 are opened bymeans of fluid motor 48 since fluid under pressure from conduit 62 is arranged to operate piston 61 and tripping plunger I0. A suitable spring means H is provided to bias tripping rod 10 to the upward r" nontripping position. However, to prevent trip ping plunger 10 from being operated until blast valves 38a. 38b, as'well as 380 have operated, cylinders 65 and 66 are connected by means of conduits 12 and 13, respectively, with blast valves 38a and 381), respectively, the fluid in conduits I2 and 13 being controlled by valves Bid and Gib, not shown in the drawings but substantially identical with He described above. Furthermore, pistons 68 and 69 are connected respectively to blocking plungers 14 and 15. Spring means 16 and I1 bias pistons 68 and 69 to the upward position shown. Air from conduit 62 cannot operate tripping plunger 10 when blocking plungers 14 and 15 are in their upper position shown in Fig. 1 since these plungers'block the passage 18 in pneumatic tripping means 63 leading from conduit 62 to cylinder 64. Each of the plungers l4 and I5 is provided with a portion of reduced cross section 19 and 80, respectively, which, when plungers l4 and 15 are moved downwardly, come into alignment with the passage 78 of pneumatic tripping means 63 so that fluid under pressure from conduit 62 causes tripping plunger 10 to be operated. By this arrangement, tripping plunger 10 can not be moved downwardly until all three of the valves 6ia, Bib, and Ho have been opened, which insures that fluid under pressure exists at all of the interrupting heads H and I2 of circuit breaker in. Any leakage past plungers l4 and "I5 I is vented to atmosphere through keyway 8 I, which cylinders 64, 65, and 66 are designed with a minimum volume in order to reduce the volume to be filled by the operating fluid and, onsequently, to get more rapid action of the tripping plunger 18.

In certain cases it is necessary to prevent the operation of isolating contacts 25 even though the air- blast valves 88a, 88b, and 880 have been opened, such as during the closing of circuit breaker I8 when fluid under pressure is desired at the interrupting contacts both to operate the interrupting contacts and to minimize arcing so that the circuit may be closed thereby rather than by the isolatin contacts, or when circuit breaker I8 is operated as a reclosing breaker, that is, when the circuit is interrupted by interrupting contacts I3 and I4, without any operation of the isolating contacts 25, so that immediate reclosure of the circuit is obtained. Isolating contacts 25 may be prevented from opening by merely blocking one of the blocking plungers 14 or 15. In Fig. 1, we have shown an interference rod 83 connected to solenoid 84 so that, when the latter is energized, interference rod 83 moves into the path of blocking plunger 14, thereby preventing fluid from reaching cylinder 84 to operate tripping rod 18. Interference rod 83, is held in the normally retracted position by spring means 85. Although interference rod 83 has been shown as electrically operated, it will be understood by those skilled in the art that it might equally well be operated pneumatically. Furthermore, interference rod 83 instead of interfering with plunger 14 might have been provided to interfere with plunger 15, the same result being accomplished in either case.

Although manual control of circuit breaker I8 is usually desired at a control panel which may be somewhat remote from the circuit breaker, itself, particularly in this case where the circuit breaker is designed for outdoor installation, it is also desirable to provide emergency manual control means at the circuit breaker, itself, and, to this end, we have provided closing pull handle 88 and emergency tripping handle 81. Closing of circuit breaker I8 may be obtained through operation of circuit-breaker closing pull handle 88, which opens circuit-breaker closing valve 54 and simultaneously therewith moves interference rod 83 into the path of blocking plunger 14. Manual opening of circuit breaker I8, on the other hand, may be initiated by moving emergency trip handle 81 in a clockwise direction. This handle is shown connected to lever 88a, which forms one portion of a bifurcated lever 88, the other portion comprising member 88b. Member 88b is connected by means of rod 88 to pilot valve 38 so that such movement of emergency trip handle 81 causes opening of pilot valve 38, thereby initiating the opening movement of circuit breaker I0. A suitable spring means 88, normally biases member 88b of bifurcated lever 88 to the upward position, thus also biasing pilot valve 38to the closed position.

In order that a blast of fluid may be provided adjacent the interrupting contacts I3 and I 4 during a circuit-closing operation or, in other words, so that closing of the circuit is accomplished at interrupting contact" I3 and I4, which are separated just prior to the closing of isolating contacts 25, we have provided a suitable cam 8I on connecting rod 29 which is arranged to engage roller 82 operatively connected to pivotally mounted lever 83. This lever 83 is connected by rod 84 to the end of member 88b of bifurcated lever 88 by means of a slotted connection 85. Downward movement of connecting rod 28 will cause lever 84 to be moved downwardly to open 8 .7 pilot valve 88 and, consequently, blsst valves 88a, 88b, and 88c, so that interrupting contacts I8 and I4 are separated just prior to the closing of isolating contacts 25 and the circuit is finally closed 5 at interrupting contacts I8 and I4 which are surrounded by a blast of arc-quenching fluid under pressure to prevent striking of the arc. A suitable spring 88 is provided to bias lever 84 to the upward position under normal conditions when cam 8I does not force it downwardly.

Although we have provided means for securing a blast of fluid adjacent interrupting contacts I8 and I4 during the circuit-closing operation, it will be understood by those skilled in the art that this closing blast may under certain conditions be omitted and clodng may be accomplished by isolating contacts 25 alone, particularly where these contacts travel at high speed and the striking of a destructive arc is very unlikely.

In order to control the operation of circuit breaker I8 and particularly to control the operation of pilot valve 88, closing solenoid 58, and interference rod solenoid 84, we provide an electric control circuit including a source of control potential 81. This source is connected to closing solenoid 58 through contacts 88 of pressure responsive device 88, manually operable closing switch I88, closing solenoid cutofl switch "I, solenoid 58, and cutoff switch I82, to the other side of control potential 81. Cutoflf switch I82, is arranged to be closed when the isolating contacts 25 of circuit breaker I8 are open, and opened when the isolating contacts 25 of circuit breaker I8 are closed. Operation of contacts I82 is acmeeting rod 28. This cam cooperates with a roller I84 operatively connected to a switch arm I85 adapted to bridge contacts I82 when the isolating contacts of circuit breaker I8 are moved to their own position.

In order to seal in closing solenoid 58 in the event that manually operable closing switch I88 is released prior to the completion of the closing operation, we have provided seal in contacts I88 paralleling closing switch I88. These seal in contacts I88 are closed when solenoid 58 moves upwardly to open closing valve 54.

Manual opening of circuit breaker I8 is normally obtained by moving manually operable opening switch I81 to the closed position. This connects tripping solenoid I 88 across control potential source 81 so as to move portion 88a of bifurcated lever 88 upwardly against the bias of spring means I88 to open pilot valve 38. The circuit for energizing tripping solenoid I88 may be traced from one side of control potential 81 through manually operable opening switch I81, contacts II8 of pressure responsive device 88, the winding of tripping solenoid I88, and contacts 0 I I I of an auxiliary or 11" switch to the other side of control potential 81. a switch contacts III are adapted to be closed by switch arm I85 when the circuit breaker I8 is closed and opened when the isolating contacts 25 of circuit breaker I8 are opened. In order to seal in tripping solenoid I88 in the event that manually operable opening switch I81 is released prior to the completion of the circuit breaker opening operation, we have provided seal-in contacts II2, operated by tripping solenoid I88, which are connected in a circult paralleling manually operable opening switch I81. This circuit also includes the contacts H3 or a reclosing limit switch to prevent seal-in con tacts II2 from becoming effective when circuit breaker I8 is operated as a reclosing circuit complished by virtue of cam I88 mounted on con-.

breaker. These contacts I I3 are opened when interference rod solenoid 84 is energized and closed when the latter is deenergized. It will be understood by those skilled in the art that in the event the pressure of the fluid in reservoirs 36a, 36b or 360 falls below a predetermined value pressure responsive device 99 will open contacts 98 and I I to render the circuit breaker control circuit ineffective.

Automatic tripping of circuit breaker I0 in response to an abnormal electrical condition on power circuit 20 is obtained by means, of contactor Ill which controls a circuit paralleling manually operable opening switch I01. Contactor II is operated by means of solenoid II energized from a current transformer II8 associated with the power circuit 20. An abnormal condition on power circuit 20 would cause contactor I to close and initiate tripping of circuit breaker I0 in the same manner as would the closing of manually operable opening switch I0I.

As has been described above, when a fluid blast is des red at each of the interrupting heads II and I2 during the circuit-closing operation, it is necessary to prevent the operationof the pneu- -matic-tripping means generally indicated at 53.

This is accomplished by energizing solenoid 84 for operating interference rod 83. As may be observed from Fig. 1, interference rod solenoid 84 is energized from source of potential 91 through contacts III which are closed by means of coopcratin switch member II8 during the closing stroke of the isolating contacts 25 of circuit breaker I0. Switch member H8 is illustrated as supported by pivotally mounted lever 93 and is operated when cam 9| associated with operating rod 29 opens pilot valve 39 during the closing stroke of circuit breaker I0. By this arrangement, plunger I4 i blocked by interference rod 83, tripping plunger is prevented from opening valve 53 and the circuit is closed at interrupting contacts I3 and I4 which opened and surrounded by a blast of arc-extinguishing fluid justprior to the closing of isolating contacts 25. It will, of course, be understood by those skilled in the art that, in the event a blast of fluid during the closing operation of circuit breaker I0 is not desired, it will be unnecessary to energize interference rod solenoid 84 during the closing stroke of circuit breaker I0.

A circuit breaker having serially connected interrupting and isolating contacts in'which the interrupting contacts are fluid operated and normally biased to the closed position is inherently adapted to operate as a reclosing circuit breaker and, accordingly, we have provided a control circult by means of which circuit breaker I0 may be operated as a reclosing breaker. It will be understood by those skilled in the art that reclosing operation of circuit breaker I0 may be obtained by preventing the isolating contacts 25 from operating, whereupon the interrupting contacts will interrupt the circuit and then immediately reclose. To prevent isolating contacts 25 from operating under such a condition, interference rod solenoid 84 is energized across control potential source 91 through contacts II9 of timedelay contactor I20, reclosing switch I2I, reclosing selector switch I22, and contactor II of the automatic tripping means for circuit breaker I0. The reclosing selector switch I22 is manually closed when it is desired to operate circuit breaker I0 as a reclosing circuit breaker. Reclosing switch I2I, on the other hand, is schematically illustrated as a snap acting switch, which is l0 moved to the closed position when manually operable closing switch I is moved to the closed position and is moved to the open position when manually operable opening switch II" is moved to the closed position. By this arrangement reclosing switch I2I will remain in the closed position alter once having been closed during the closing of manually operable closing switch I00 even though manually operable closing switch I00 is released so long as manually operable opening switch I0! is not closed.

Time-delay contactor I20 is provided to prevent immediate reclosing of circuit break er I0 when it is closed upon a short circuit. Consequently, whenever manually operable closing switch I00 is closed and thereafter seal-in con,- tacts I06 are closed upon operation of closing solenoid 59, time-delay contactor I20 is opened instantaneously since its winding I23 is energized whenever manually operable closing switch I 00 or seal-in contacts I06 are closed. The contacts II 9 thereupon are opened and do not close for a predetermined time by virtue of the time-delay means associated with time-delay contactor I20. This interrupts the reclosing control circuit 50 that immediate reclosing of circuit breaker I0,

which is closed on a short-circuit condition will not occur.

The operation of our new and improved circult-breaker control and operating system will be understood by those skilled in the art in view of the detailed description included above. However, a brief discussion will be included at this point to summarize the operating characteristics of circuit breaker I0. With the circuit breaker in the closed position shown in Fig. 1, opening thereof may be initiated In three separate ways, as follows: An abnormal current condition on polyphase power circuit 20 would cause contactor II4 to close, energizingtripping solenoid I08, which would open pilot valve 39. The closing or manually operable opening switch I01 would accomplish the same result. Also, pilot valve 39 could be opened by moving emergency tripping handle 81. in the clockwise direction. The opening of pilot valve 39 would allow fluid under pressure to be introduced in the respective cylinders 43 of blast valves 38 to move pistons 42 upwardly against the bias of springs 44 to open valve members 4| and, consequently, allow fluid under pressure from the sources 36 to be introduced into the various interrupting heads II and I2. As soon as valve members 4| have opened a predetermined amount, small valves 6| are opened to allow fluid under pressure to enter pneumatic tripping means 63 through conduits 62, I2, and I3. Iffluid under pressure exists at all the blast valves, then blocking plungers I4 and I5 are moved downwardly to open passage I8 so that fluid under pressure from conduit 62 may enter cylinder 64 to move tripping plunger I0 downwardly to cause operation of opening valve 53. It will, of course, be understood by those skilled in the art that the fluid under pressure entering interrupting heads II and I2 causes separation of the contacts I3 and I4 and the are drawn therebetween is rapidly quenched by virtue of the blast of fluid surrounding the same. When opening valve 53 is operated, fluid from manifold 52 enters the lower end of cylinder 49 of fluid motor 48 and. causes piston 50 to move upwardly pulling connecting rod 29 along with it. By virtue of the lost-motion connection 33 between connecting rod 29 and crank 30, cam 34 is allowed to cause release of locking means 33 so that all of the isolating contacts 25 are opened. After a predetermined opening movement of isolating contacts 25, cam I03 causes switch arm I05 to open a switch contacts III, thereby deenergizing tripping solenoid I08 if the pping operation is initiated electrically. During the opening Operation of circuit breaker I0, cam ill will cause pivotally mounted lever 93 to move downwardly, pulling lever 94 along with it and causing contacts III to be closed, energizing interference rod solenoid 84. However, since pilot valve 39 is already open, the movement of rod 94 will have no effect and since blocking plunger I4 has been moved downwardly, interference rod 83 can have no effect even though solenoid 84 is energized. When the opening operation is initiated electrically, a complete opening of the circuit breaker is insured even though manually operable opening switch I! is released since tripping solenoid I08 closes its own seal-in contacts II2.

With circuit breaker III in the open position, closing thereof may be initiated in two ways. Normal closing will be obtained by moving manually operable closing switch I00 to the closed position, which will cause energization of closing solenoid 59 through limit switch contacts I02 which are closed when the isolating contacts of circuit breaker I0 are in the open position. The energization of solenoid 59 will open closing valve 54 and cause piston 50 and connecting rod 29 to move downwardly. The initial downward movement of connecting rod 29 by virtue of lost-motion connection 23 and cam 35 will cause release of locking means 32, holding the isolating contacts 25 in the open position. At a predetermined point in the closing stroke of the isolating contacts of circuit breaker I0, cam 9I will cause pilot valve 39 to be opened and, simultaneously, will cause the bridging of contacts II'I, whereupon interference rod solenoid 84 is energized to prevent blocking plunger I4 from moving downwardly. The opening of pilot valve 39 will cause operation of blast valves 38 as described above during an opening operation of circuit breaker I0 so that fluid under pressure is supplied to all of the interrupting heads II and I2 causing separation of the interrupting contacts I3 and I4 just prior to the closing of the isolating contacts 25 so that the 'attained its fully closed position, witch arm I05 opens opening solenoid cutoff switch contacts I02, whereupon closing valve 54 moves to the closed position under the bias of spring means 58. The closing operation of circuit breaker I0 might also be initiated by manually operating pull handle 86, which would open closing valve 54 and move interference rod 83 so as to block the blocking plunger I4, after which the closing cycle described above will follow.

Circuit breaker I0 may be operated as a reclosing" circuit breaker by closing manually cp erable reclosing selector switch I22. If the closing operation of the circuit breaker is thereafter initiated by closing manually operable closing switch I00, reclosing switch I2I will also be moved to the closed position, and by virtue of the snap action arrangement disclosed, will remain in the closed position even though manually operable closing switch I00 is released. Thereafter, if an abnormal current condition should cause opening of circuit breaker I0, interference solenoid I94 would be energized through a circuit including reclosing switch IM and reclosing selector switch I02 so that isolating contacts 25 could not be operated and only interrupting contacts II and I4 would function. As soon as the abnormal current condition were removed and contactor II4 reopened, spring means I1 associated with the various interrupting heads would cause the interrupting contacts to reclose the circuit. The reclosing switch IOI would be opened in the event that manually operable opening switch I" were moved to the closed position.

While we have shown and described particular embodiments of our invention, it will, or course. be obvious to those skilled in the art that changes and modifications may be made without departing therefrom and we, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of our invention.

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

1. In combination, a. polyphase power circuit, a polyphase electric circuit breaker for controlling said circuit comprising cooperating interrupting contacts and cooperating isolating contacts serially connected with said interrupting contacts in each phase of said circuit breaker, said interrupting contacts for each phase of said polyphase electric circuit breaker being operable independently of the interrupting contacts for the other phases of said electric circuit breaker, means for controlling the isolating contacts for all of the phases as a unit for gang operation, means for opening said interrupting contacts, means for opening said isolating contacts subsequent to the openin of said interrupting contacts, and means for preventing the opening of said isolating contacts until all of said interruptin contact have opened.

2. In combination, a polyphase power circuit. a polyphase electric circuit breaker for controlling said circuit comprising cooperating interrupting contacts and cooperating isolating contacts serially connected with said arcing contacts in each phase of said circuit breaker, said interrupting contacts for each phase of said polyphase electric circuit breaker being operable independently of the interrupting contacts for the other phases of said electric circuit breaker, means for controllin the isolating contacts for all of the phases as a unit for gang operation, means for opening said interrupting contacts. a source of fluid under pressure, means including a fluid motor for operating said isolating contacts subsequent to the operation of said interrupting contacts, and means for preventing the operation of said isolating contacts until all of said interrupting contacts have opened.

3. In combination, a polyphase power circuit. a polyphase electric circuit breaker for controlling said circuit comprising cooperating interrupting contacts and cooperatin isolating contacts serially connected with said interrupting contacts in each phase of said circuit breaker, the isolating contacts for all of the phases bei arranged for gang operation, said interrupting contacts for each phase of said polyphas electric circuit breaker being operable independently of the interrupting contacts for the other phases, means continuously tending to maintain said interrupting contacts closed, means for opening said interrupting contacts against the action of the first said means, a source of fluid under pressure, a fluid motor for operatin said isolating contacts subsequent to the operation of said interrupting contacts, and meansfor preventing the operation of said isolating contacts until all of said interrupting contacts have operated.

4. In combination, a polyphase power circuit, a polyphase electric circuit breaker for controlling said circuit comprising cooperating interrupting contacts and cooperating isolating contacts serially connected with said interrupting contacts in each phase of said circuit breaker, the isolating contacts for all of the phasesbeing arranged for gang operation, said interrupting contacts for each phase of said polyphas electric circuit breaker being operable independently of the interrupting contacts for the other phases,

means continuously tending to maintain said interrupting contacts closed, a source of fluid under pressure, means connected to said source for producing a blast of fluid adjacent all of said interrupting contacts for arc-extinguishing purposes and for simultaneously opening said interrupting contacts against the action of said last-mentioned means, a fluid motor for operating said isolating contacts subsequent to the operation of said interrupting contacts, and means for preventing the operation of said isolating contacts until a blast of fluid under pressure exists adjacent all of said interrupting contacts.

5. In a multipole fluid-blast circuit breaker, a pair of cooperating interrupting contacts for each pole of said circuit breaker, a pair of cooperating isolating contacts for each pole of said circuit breaker arranged in series relationship with the respective interrupting contacts, means including a valve for each pole of said circuit breaker for controlling the flow of a blast Of fluid under pressure adjacent said interrupting contacts for arc-extinguishing purposes, means for opening said isolating contacts, and pneumatic means for controlling said last-mentioned means comprising a plurality of movable members each responsive to the operation of a different one of said valves to permit the opening of said isolating contacts only when a blast of fluid exists adjacent the interrupting contacts of all of said poles.

6. In a multipole fluid-blast circuit breaker, a pair of cooperating interrupting contacts for each pole of said circuit breaker, a pair of cooperating isolating contacts for each pole of said circuit breaker arranged in series relationship with simultaneously opening the isolating contacts for all of the poles of ,said circuit breaker, and pneumatic means for controlling said last-mentioned means comprising a plurality of pistons each arranged to be moved by fluid under pressure in response to the operation of a different one of said valves to permit the opening of said isolating contacts only when all of said valves have operated.

7. In a multipole circuit breaker having serially connected interrupting and isolating contacts in each pole thereof, means for operating said interrupting contacts, means for subsequently opening said isolating contacts, means for controlling said last-mentioned means comprising a tripping plunger operable when certain operating conditions exist with respect to one of said poles of said circuit breaker, and a plurality of additional plungers, one for each of the other poles of said circuit breaker for rendering said tripping plunger inefiectlve unless similar operating conditions exist with respect to all of said other poles of said circuit breaker.

8. In a multipole fluid-blast circuit breaker including a plurality of relatively movable interrupting contacts for each pole thereof, means for producing a blast of fluid for arc-extinguishing purposes adjacent all of the interrupting contacts of said circuit breaker, a pair of isolating contacts for each pole of said circuit breaker connected in series relationship with the respective interrupting contacts, means for operating said isolating contacts after the circuit has been ins terrupted at said interrupting contacts, a pneumatic means for controlling said last-mentioned means comprising a plurality of plungers, one for each pole of said circuit breaker, said plungers being so interlocked with respect to said firstmentioned means as to be inoperative to control said means for operating said isolating contacts unless a blast of fluid under pressure exists adjacent all of said interrupting contacts.

9. In a multipole circuit breaker having serially connected, interrupting and isolating contacts at each 'pole thereof, means including a fluid motor for each pair of interrupting contacts, a source of fluid under pressure arranged to be connected to said fluid motors to open said interrupting contacts, means for subsequently opening said isolating contacts, means for controlling said last-mentioned means comprising a tripping plunger operable in response to a predetermined condition of the interrupting contacts of one pole of said circuit breaker, a plurality of additional plungers, one for each of the other poles of said circuit breaker for rendering said tripping plunger ineffective unless the same predetermined condition exists with respect to the interrupting contacts of the other poles of said circuit breaker, and means for interfering with the operation of one of said plungers to prevent the operation of said tripping plunger under certain operating conditions of said circuit breaker.

10. In combination, a polyphase power circuit, a polyphase electric circuit breaker for controlling said circuit comprising cooperating interrupting contacts and cooperating isolating contacts serially connected with said interrupting contacts in each phase of said circuit breaker, the isolating contacts for all of the phases being arranged for gang operation, means continuously tending to maintain said interrupting contacts closed, a source of fluid under pressure, means connected to said source for producing a blast of fluid adjacent all of said interrupting contacts for arc-extinguishing purposes and for simultaneously opening said interrupting contacts against the action of the said last-mentioned means, means including a fluid motor for operating said isolating contacts subsequent to the operation of said interrupting contacts, mbanvfor controlling said fluid motor to open said isolating contacts only when a. blast of fluid under pressure exists adjace'nt all of said interrupting contacts, and means for rendering said last-mentioned means ineffective during a closing operation of said circuit breaker.

11. In combination, a polyphase power circuit, a polyphase electric circuit breaker for controlling said circuit comprising cooperating interrupting contacts and cooperating isolating contacts serially connected with said interrupting contacts in each phase of said circuit breaker, means for controlling the isolating contacts for all of the phases as a unit for gang operation, means continuously tending to maintain said interrupting contacts closed, a source oi fluid under pressure, means connected to said source for producing a blast of fluid adjacent all of said interrupting contacts for arc-extinguishing purposes and for simultaneously opening said interrupting contacts against the action of the said last-mentioned means, means including a fluid motor for operating said isolating contacts subsequent to the operation of said interrupting contacts, means for controlling said fluid motor to open said isolating contacts only when a blast of fluid under pressure exists adjacent all of said interrupting contacts, and means for rendering said last-mentioned means inefl'ective to prevent opening of said isolating contacts when said circuit breaker is operated as an automatic reclosing circuit breaker.

12. In a multipole fluid-blast circuit breaker having serially connected interrupting and isolating contacts in ach pole thereof, a source of fluid under pressure, means associated with said source including a separate blast valve for each pole of said circuit breaker, each of said blast valves being arranged to control the flow of a blast of fluid adjacent the interrupting contacts of one pole of said circuit breaker for arc-extinguishing purposes and for simultaneously separating the interrupting contacts of said one pole, means for subsequently opening all of said isolating contacts simultaneously, each of said blast valves comprising a piston-operated valve member, and a single control valve for simultaneously admitting fluid under pressure from said source to operate said piston-operated valve member of all of said blast valves to cause opening thereof and consequently opening of said multipole circuit breaker.

13. In a multipole fluid-blast circuit breaker having serially connected interrupting and isolating contacts in each pole thereof, a source fluid under pressure, means associated with said source including a separate blut valve for each pole of said circuit breaker, each of said blast valves being arranged to control the flow of a blast of fluid adjacent the interrupting contacts of one pole of said circuit breaker for arc-extinguishing purposes and for simultaneously separating the interrupting contacts 01' said one pole, means for subsequently opening all of said isolating contacts simultaneously, each of said blast valves comprising a piston-operated 'valve member, a single control valve for simultaneously admitting fluid under pressure from said source to operate said piston-operated valve members of all of said blast valves to cause opening thereof and, consequently, opening of said multipole circuit breaker, and means for controlling said last-mentioned means to prevent operation thereof until the blast valves for all of said poles have opened a predetermined amount.

14. A gas blast multipole circuit breaker comprising a plurality of separate circuit interrupting units each having a pair of separate contacts, operating means for simultaneously operating all of said pairs oi contacts, a source of gas under pressure for supplying a blast of gas to each of said units to extinguish the arcs formed on separation of said contacts, a separate blast valve associated with each of said units for controlling the flow of blast gas from said source to said unit, and a gas pressure operating system for said blast valves, said operating system having a single master control valve for simultaneously controlling operation of said plurality of blast valves.

15. A multipole compressed air circuit breaker comprising a plurality of separate circuit interrupting units each having a pair of separable contacts, operating means for simultaneously operating said contacts, a, source of compressed air, air conduits connecting said units to said source of compressed air for conducting blasts of compressed air from said source to said contacts to extinguish arcs formed upon separation of said contacts, a separate air blast valve for each unit for controlling the flow of blast air to said unit, a compressed air operating system for said blast valves including a single master control valve for controlling the operation of said blast valves, and an electromagnet for controlling said master valve.

16. A multipole compressed air circuit breaker comprising a plurality of separate circuit interrupting units, each having a pair of separable contacts, operating means for said contacts, a source of compressed air, blast air conduits connecting said units to said source oi compressed air for conducting blasts of compressed air from said source to said contacts to extinguish arcs formed upon separation of said contacts, a separate air blast valve for each unit for controlling the flow of blast air to said unit, compressed air operating means for said blast valve comprising a master relay valve for simultaneously controlling the operation of said plurality of blast valves, and an electromagnetic means for controlling said relay valve.

17. An electric circuit breaker comprising an arcing chamber, a pair 01' cooperating arcing contacts arranged in said chamber, a pair of cooperating disconnecting contacts serially connected with said arcing contacts, means for closing said disconnecting contacts, means responsive to closing movement of said disconnecting contacts for fllling said chamber with are extinguishing fluid under pressure and for opening said arcing contacts, and means responsive to substantial completion of the closing movement of said disconnecting contacts for releasing the fluid contained within said chamber and for reclosing said arcing contacts.

18. An electric circuit breaker comprising an arcing chamber, a pair 01' cooperating arcing contacts arranged in said chamber, a pair of cooperating disconnecting contacts serially connected with said arcing contacts, means for closing said disconnecting contacts, means responsive to closing movement of said disconnecting contacts for opening said arcing contacts and for directing a blast of arc extinguishing fluid between said contacts and through said chamber, and means responsive to substantial completion of the closing movement of said disconnecting contacts for reclosing said arcing contacts and interrupting said fluid blast.

19. An electric circuit breaker comprising a pair of cooperating arcing contacts, a pair of cooperating disconnecting contacts serially connected with said arcing contacts, means for opening said arcing contacts, means for closing said disconnecting contacts, means for reclosing said arcing contacts, and means for causing sequential operation of the first, second and third said means in the order recited.

20. The method of effecting a normal circuit closing operation of a circuit breaker comprising arcing contacts serially connected with disconnecting contacts in the circuit comprising the steps of opening the arcing contacts, closing the disconnecting contacts, and reciosing the arcing contacts to complete the circuit.

CARL THUMIM. ALEXANDER C. BOISSEAU.

REFERENCES CITED The following references are of record in the file of this patent:

Number 18 UNITED STATES PATENTS Name Date Dryer Jan. 29. 1924 Uhde June 22, 1937 Milliken Aug. 10, 1937 Thoumen Sept. 3, 1940 Schiesser May 6, 1941 Freeman Jan. 5, 1897 Nero Sept. 14, 1926 Riley June 17, 1930

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