US2389942A

US2389942A - Circuit breaker operating system

Info

Publication number: US2389942A
Application number: US317564A
Authority: US
Inventors: Thumim Carl; Edward J Frank; Alexander C Boisseau
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1940-02-06
Filing date: 1940-02-06
Publication date: 1945-11-27
Anticipated expiration: 1962-11-27
Also published as: US2292096A

Description

NOV. 27, 1945. c, THUM|M` Er AL 2,389,942

CIRCUIT BREAKER OPERATING SYSTEM Filed Feb. 6, 1940 2 Sheets sheet 1 l 3 is 44 '.f.. Png. l.

Inventors: Carl Thumm,

Edward J. Frank,

' Al Xander C. Bossea Nov. 27, 1945. 1 c. THUMIM ETAL CIRCUIT BREAKER OPERATING SYSTEM Feb. 6, 2 Shee,ts sheet 2 inventors: Garfi Thurnim, Edward J. Frank, Alexander` C, Boisseau Patented Nov. 27, 1945 rCIRCUIT BREAKER OPERATING SYSTEM Carl Thumim and Edward J. Frank, Yeadon, and

Alexander C. Boisseau, Lansdowne, Pa., assignors to General Electric Company, a corporation of New York Application February 6, 1940, Serial No.l 317,564

26 Claims.

Our invention relates to circult+breaker operating systems and more particularly to a combined pneumatic and electrical system for effecting high-speed operation of a circuit breaker.

In order to eliminate the fire hazard, circuit breakers have been designed which do not utilize oil or other inflammable liquid for arc-extinguishing purposes but instead/employ a blast of 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 arc at this time. Apart from numerous operating and structural advantages of gas-blast circuit breakers for many applications, the problem of providing a suitable control or operating system furnishes considerable difficulty.

The value of any circuit breaker lies in its ability to interrupt the circuit at the proper time and in the proper manner and, without a proper provide a, new and improved operating system for a circuit breaker overcoming the disadvam tages above noted and wherein rapid, positive, and eilicient high-speed interruption may be obtained combined with reliability, economy, and

y low rst cost.

operating system for such circuit breaker, its

value is largely lost since the value of the operating system lies in its ability to effect control of the circuit breaker in the manner intended. if such control is not obtained in the manner desired, many undesirable conditions may result.

It is necessary to obtain opening of the circuit breaker in as short a time as possible after the condition which initiates the opening movement occurs and this is no less true of gas-blast cir'- cuit breakers than oi any other type. in order to produce the gas-blast, a valve must be operated releasing the iluid under pressure at the proper instant. To operate such a valve directly against the uid pressure would require considerable force and, in addition, would tend to slow down th'e operating cycle of the circuit breaker. Balanced pressure valves have been proposed for this purpose, wherein a pilot valve requiring relatively little force to operate, unbalances the pressure on a piston-operated valve so. that the fluid pressure forces the blast valve open. The balanced pressure valves of the prior art did not operate with the speed desired for high-speed circuit breaker operation and gas-blast circuit breaker operating systems employing balanced pressure valves were not as satisfactory as might It is another object of our invention to provide an operating system for an electric circuit breaker of the gas-blast type in which higher speed ci operation may be obtained than was heretofore possible.

It is a further object of our invention to provide a new and improved operating system for an electric circuit breaker of the gas-blast type wherein a blast of liuid for arc-extinguishing purposes is insured prior to the initiation oi any opening movement oi said circuit breaker.

A further object of our invention is to provide a huid-operated gasblast circuit breaker in which trip-free operation is provided at any time during the operating cycle of the circuit breaker.

Still another object of our invention is to pro vide an operating system for a fluid-operated gas-blast circuit breaker wherein energy-storage means charged during the circuit-closing operation are provided to increase the speed with which the circuit breaker may be opened.

Stili another object of our invention is to prooperating system of the circuit breaker,

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

For a better understanding of our invention, reference may be had to the accompanying drawings in which Fig. 1 is a partly diagrammatic layout of an operating system for a fluid-operated gas-blast circuit breaker embodying our invention, Fig. 2 is a cross-sectional view of the blast valve shown schematically in Fig. 1, and Fig. 3 is a .sectional view of the blast Valve taken on line 3 3 of Fig. 2.

Referring now to the drawings, we have illustrated our invention as applied to a fluid-operated circuit breaker I0 of the cross gas-blast type comprising a, stationary contact I I and a movable contact I2 arranged to be operated so as to draw an arc in an arc chute I3. The fixed Contact Il is connected to the line terminal I4 while the movable contact I2 is connected to the line terminal I5. The xed contact II is provided with spring pressedcontact ngers I Ia and longer arcing contact lingers I' while movable contact I2 is provided with an arcing tip I2' so that, when the contacts separate, an arc therebetween occurs between arcing tips and I2'. Immediately after separation of the contacts, one terminal of the are ls transferred by an air or gas-blast through conduit I5 from contact lingers to the contact II which is provided with a tip of arc-resistant metal. The air or gas blast from conduit I6 upon opening of the breaker drives the arc into the arc chute i3 against the edges of a plurality of partitions i1 in the arc chute, which partitions are transverse to the arc gap and the ends of which extend close to the path a of movement of the arcing tip l2' of the movable contact l2. The circuit breaker itl, illustrated by way of example in order to describe the openating system better, is not our invention but is f described and claimed in the joint application of connection 2| arranged to operate a tripping means 22 for releasing latch 23 which holds the circuit breaker lill in the closed position. For high-speed opening of circuit breaker II), it is desirable to release some form of energy-storage means to aid the iluid pressure in the opening` operation. Latch 23 is provided in order to hold energy-,storage means 24 comprising a spring in A the charged condition. This 4energy-storage means or spring 24 is charged or compressed by iluid pressure during the closing movement of closing one end of manifold 32 against the uid pressure from conduit 3| by means of a. relatively circuit breaker I0 and latch 23 cooperating with member 25 restrains the circuit breaker and energy-storage means 24 in the closedand charged positions respectivelyY until upward movement of piston I9 causes member 26 of lost-motion connection 2| to engage with tripping means 22 whereby latch 23 is` released.

In'order to operate piston I9 and, consequently, also movable contact I2 in response to fluid pressure, we provide a reserve huid-pressure tank 21 which is connected to a fluid-pressure supply system through a nonreturn valve, not shown, so as to trap sullicient fluid which, for example, may rbe air, at a suitable pressure to permit at least one operating cycle independent of the main -fluid-pressure supply. Therefore, if the main uid air supply should fail for any reason, one

operating cycle of circuit breaker I0 may still be' obtained by virtue of the air or other lluid trapped in reserve tank 21. Reserve tank 21 is matically at 23 as comprising a Sylphon bellows breaker closing valve 34. Opening valve 33 isV normally held in the position indicated il! F15. 1,-

provided with a pressure switch, indicated sche- 29 connected to the reserve tank 21 and operaheavy spring 35 acting on lever 36 associated with opening valve 33. Valve 33 is arranged to be operated by openingsolenoid 31, which also operates its own seal-in switch 38; Opening valve 33 in its open position is adapted to close escape port 33 through which fluid below piston I3 may escape during the closing operation of the circuit breaker I0.

Similarly, closing valve 34 is normally held in the position indicated in Fig. l, closing the other end of manifold 32 against the uid Vpressure from conduit 3| by means of a relatively heavy spring 40 acting on lever 4| associated with closing valve 34. Lever 4|, howevencomprises two parts 4ta and 4|b, both mounted on a fixed pivot 4|', and. hence, dilers from lever 36 associated with .opening valve 33 in a manner which will be described in greater detail hereinafter. Closing valve 34 is arranged to be operated by closing solenoid 32 which also operates its own seal-in switch 43. Closing valve 34 in its open position is adapted to close escape port 44 through which fluid above piston I9 may escape during the open ing operation of circuit breaker I0.

Trip-free operation of circuit'l breaker lI0 is obtained by virtue of the fact that lever 4I associated with closing valve 34 and closing solenoid 42 is constructed of two parts 4Ia and 4|b which are heldtogether as a single lever by means of latch 45 pivotally mounted on member 4|b and adapted to engage with an extension on member 4|a. A relatively light spring 46is provided to bias member 4|b in such a direction that latch 45 may engage the extension on member 4Ia.

I3. If, however, during the closing operation of the circuit breaker, opening solenoid 31 should be energized through any cause, such, for exam ple, as an4 abnormal current condition in the power circuits |4 and |5, opening valve 33 will 'be operated. In order to obtainrapid closing of closing valve 34 under such conditions and, hence, trip-free operation of the circuit breaker, rod 41 associated with opening lever 36 is provided which will engage a projection 43 on latch 45, thereby releasing lever 4|a and allowing spring 4|! to close valve 34 rapidly even though closing solenoid 42 is still energized and holding lever 4| b downwardly against the tension of relatively light spring 46. v

It is evident that the reversal of the direction ko1' piston I9 during the trip-free closing stroke canbe greatly expedited if the back pressure on the closing or upper end of piston I9 is reduced instantaneously to a practicable minimum. Accordingly, weprovlde between the openings in cylinder I8 and the respective opening and closing valves 33 and 34 a dumping valve 43 which is arranged to provide a very large opening to atmosphere for the upper end of cylinder I3 during the opening operation o! circuit breaker I3. '1111s dumping valve 49 comprises a. relatively large valve member 53 operatively connected to a piston 5| of the same or larger diameter. reclpzocable in a cylinder 52 and normally biased by means of Prins 53 to hold dumping valve member 50 in the closed position. Operatively connected with piston 5| is a second valve member 54 associated with escape port 55 which is normally open when dumping valve member 50 is closed so as to allow air or lluid from the lower end of cylinder I8 to escape to atmosphere in the same manner as port 39 and, in addition thereto, during the closing movement of circuit breaker l0. During the closing stroke of circuit breaker I0, the back pressure in the lower end of cylinder I8 without escape port 55 might build up suilicientlyhigh to lift dumping valve member 50 from its` seat with the resultant slowing up of the closing movement, since port 39 may not be sufficiently large under certain conditions to prevent this undesirable condition. When closing valve 34 is opened, the pressures operating on piston 5l and valve member 50 are substantially equal or the resultant force tends to hold valve member 58 closed, which force is supplemented by that of spring member 53. On the other hand, when opening valve 33 is operated, fluid pressure from manifold 32 operating against the relatively large surface of piston 5l overcomes the force of spring 53 and moves the entire valve assembly upwardly so as to open dumping valve member 50 and valve member 54 closes the escape port 55. By this arrangement, the upper end of cylinder it has the pressure therein instantaneously reduced so that rapid opening operation of circuit breaker l may be obtained.

The cross gas blast for arc-extinguishing purposes in arc chute i3 is also obtained from reserve fluid-pressure tank 21 through blast valve 5 and conduit i6. Blast valve S of the balanced pressure type, shown in detail in Figs. 2 and 3, is illustrated as mounted directly below reserve pressure tanl; 21 and comprises a streamlined valve member 51 which allows duid pressure from tank 2l to pass through annular passageway 58 to conduit i8 leading to arc chute i3. Conduit it is illuse trated in Fig. 2 as mounted at an angle with respect to blast valve 55 in order to provide additional space for illustrating the details of the control mechanism therefor. Valve member 5l cooperates with a replaceable valve seat which is mounted in a casing 59 enclosing cylinder 6i within which piston Bil operatively connected to valve member 5l reciprocates. Piston te is preferably exibly connected with valve member 51 for the purpose of self-alignment and is iJfovided with a valve guide 62 reciprocating in a sleevelike member da. A spring member Bil is placed between sleeve member t3 and 'valve inember 5l normally to tend to hold alve ber in the closed position. Cylinder iii. sleevelike member and spring member Et are supported centrally by radial ribs t5 across annular air passage 58.

The upper end of cylinder di is closed by a plate 86 to which is fastened a metallic striking plate S1. Between the metallic striking plate B1 and plate 66 is a exible buffer disk Se to cushion the opening of blast valve 5B. The space 69 in cylinder 5l between piston 68 and striking plate 61 is maintained at the absolute minimum determined only by the space required for opening valve 51 as willbe set forth in greater detail hereinafter. A small passage is provided in piston 50 to interconnect the cylinder 6l on either side of piston 8U and, hence, to balance the pressures operating on the upper and lower surfaces under steady-state conditions. The area of piston 68 7's relatively large compared to the area of valve member 51 so that a considerably lower pressure operating on piston 60 may overcome a higher pressure operating on valve member 51.

In order to open blast valvev56, a pilot valve 1I of relatively large diameter is opened, rapidly releasing the pressure on the upper side of pis- `ton 69, whereby an unbalance of the pressure on piston is obtained and the fluid pressure operating against the under side of piston 60 is sufcient to overcome the forces holding valve meinber 51 closed, which comprise the fluid pressure acting on the back of valve member 51 and spring means 64. Thereupon valve member 51 is forced open rapidly and piston 60 contacts with striking plate 61 whereupon check valve 12 closing port 13 in piston 69 is opened by virtue of the extension 14 thereon which engages with striking plate 61. The upper surface of piston is recessed at 15 so that fluid pressure either through small passage 10 or port 13 within which check valve 12 operates is distributed over the entire upper surface of piston 60.

The time of opening of valve 51 is dependent upon the rate of pressure drop in space 69 which, in turn, is a function of the volume of space 59 and the area of pilot valve 1i. In the balanced pressure valves of the prior art, the volume of space 69 was necessarily large to accommodate the biasing spring which was contained in this space. By eliminating spring 6d from space GS, it has been possible to greatly decrease the volume of space 99 determined only by the clearance necessary for valve member 5l. Furthermore, the area of pilot valve 1i has been made as large as practicable and this combination has enabled us to obtain an operating speed much higher than was possible heretofore.

'Check valve 'l2 is provided so that pressure in space 69 may be built up rapidly when pilot valve 'la is closed so that valve member 5? is snapped shut in a minimum period of time. The extension M on check valve 12 is sufiiciently long so that check valve 12 is maintained in the open position for a reasonable length of time to prevent fluttering of the valve member 5l.

It will be understood by those skilled in the art that operation of pilot valve 1i requires considerably less operating force than would be required to open blast valve 51 directly. The pilot valve il and operating mechanism 16 therefor are mounted as a complete constructional unit in U-shaped frame members 11 and 18 which are bolted at 'i8 and 88 respectively to casing 59. Pilot valve 1l is held in the closed position by means of spring mechanism 8l supported by U- shaped member 18 and including adjustable means S by which the closing force on pilot valve il may be adjusted to just overcome the normal fluid pressure in space 69 tending to open the pilot valve 1l. Movement of pilot valve 1l against the force of spring mechanism 8| is effected through a pair of levers 831 pivotally mounted at 84 to U-shaped member 11 and interconnected by block 85 provided with an opening 86 through which-rod 8 1 for operating pilot valve 1l is connected. This opening 86 in block 85 is enlarged at either end thereof so as to prevent any binding action between rod 81 and block 85 during the pivotal movement of levers 83. Pivotal movement of levers 83 is obtained either by the leftward pull of armature 88 of opening air blast solenoid 89 or by the leftward thrust of armature 90 of closing air blast solenoid 9|. Pivotally mounted levers 83 are connected in clevislike fashion to armature 88 at 92 while an extension 93 provided with a roller 94 is connected to amature 90 of closing air blast solenoid 9| so that movement of armature 90 may be transmitted through roller 94 and armature 88 to pivotally mounted members 83 for operating pilot valve 1l. l Solenoids 89 and 9| are .coaxially mounted and connected to one another by means of U-shaped plates 95. The entire apparatus including solenoids 89 and 9i is supported from casing 59 as a unitary structure by member 96.

Pivotally mounted levers 83 are provided with a roller 91 which tends to hold a switch 98 in the open position whenever pilot valve 1i is closed. The contacts of switch 98, however, are biased to the closed position by spring means 39 so that, whenever the opening air blast solenoid 83 is energized, switch 98 is closed after which opening operation of the circuit breaker i is initiated. ly this'arrangement, switch 98 insures that the opening air blast for circuit breaker su is provided before opening of the circuit breaker may take place. f

Certain features-of our invention disclosed in this application relating to blast valve 56 per se are described and claimed in a copending application, Serial No. 345,810, led' July i6, 1940, vghich application is a division of this applicat on.

In order to control the operation of opening `valve 33, closing valve 34, and blast valve 56, we

provide an electrical control system including a source of direct-current potential 100. This source of control potential is connected to closing solenoid 42 through pressure switch 30, con-- tacts 30a, close button IOI, and mechanically operated cut-ofi' switch |02 which'is arranged to be closed by' cam member |03 when circuit breaker l0 is open and which opens at the end of the closing stroke of circuit breaker I0. Switch |02- for mechanically cutting ofi solenoid closing coil 42 is provided with a holding coil |04 for preventing pumping of the circuit breaker I0 in the event that it is closed upon an abnormal current condition and the operator fails to release close button I0 I. At a predetermined point in the closing stroke of circuit breaker` |0, switch |05 which is open in both the closed and open positions of the-circuit breaker is closed by virtue of cam member |08 mounted Von connecting rod 20 whereby closing air blast solenoid 9| is energized for producing a blast of arc-extinguishing iluid in arc chute I3 by virtue of the movement of armature 90 which operates pilot valve I I4 and, hence, also valve member 51 of blast valve 58. Mechanically operated switch |05 forcontrolling the closing air blast is closed before contacts II and I2 meet and opens after the contacts have engaged. As has been mentioned before, clos-i ing solenoid 42 is provided with a, seal-in switch 43 so that the operator may release close but" ton IOI prior to the completion of the closing operation. .v

Tripping operation of the circuit breakermay `tective relay |08, manually operable open button |01, or pressure relay 28 through the energization-of opening air blast solenoid'89 through mechanically cutoi switch 'I I0. This switch H0 opens during the opening stroke of the circuit breaker I0 by virtue of cam III attached to connecting rod 20 and cuts off the opening air blast at the proper moment after the arc drawn has been extinguished. As soon as opening air blast solenoid 89 is energized, switch 98 is closed and opening solenoid 31 is energized through mechanical cut-oir switch H2 which is closed at the be'- ginning of the closing stroke by virtue oi. cam H33 mounted on connecting rod 20. and opens at the end of the opening stroke of circuit breaker iii. As'was mentioned above, opening solenoid 31 is provided with a seat-in switch it to insure completion of the tripping operation even though open button iol?, protective relay ii or pressure responsive relay 2t bridging contacts Stb are immediately opened.

An auxiliary switch M3 is provided in series with signal means H4 which, for example, may comprise a green light to indicate that the circuit breaker is in the, open position. Switch H3 is closed when circuit breaker I0 is open and is opened mechanically by means of cam I I5 on connecting rod 20 when circuit breaker ID is in the closed position. A signal means IIB which, for example, may comprise a red light is provided and is energized through opening air blast-solenoid 89 and mechanically operated cut-olif switch IID for opening air blast solenoid 89 when the circuit breaker Il) is in a closed position. It will be understood by those skilled in the art that theresistance of signal means H6 is such as to allow only a very small currentto flow through this circuit which is insufficient to cause solenoid 89 to pull armature 88 to the left and. hence, initiate tripping of circuit breaker I0. A signal means I I1 is also provided in series with relay switch 30 and contacts 30a to indicate the condition of the fluid pressure in reserve tank`21. If, for any' reason, the pressure in reserve tank 21 should fall below a predetermined amount, Sylphon bellows 29 will contract opening contacts 30a so that closing of the circuit breaker if it is in the open position is prevented. Furthermore, closing of contacts 30h will energize the opening air blast coil 89 and initiate tripping operation of the circuit breaker in the event that it is' in the closed position.

Although we have described our invention as applied to a single-pole circuit breaker, it will be understood by those skilled in the art that it may equally wellbe applied to a multiple circuit breaker in `which case blast valve 56 would be conbe initiated in one of three ways, either by manual operation of "open button |01, by automatic closure of protective relay I08`which is energized fromcurrent transformer' YIll!) associated with power line I5 whenever an abnormal current condition occurs therein, or by the bridging of contacts 30h of pressure relay switch 30 in the event the pressure in 1reserve tank 21 falls below a predetermined minimum. All three of these tripping means are connected in parallel with one another but, in any event, opening solenoid 31 cannot be energized until switch 98 has been closed which is accomplished by the operation of pronected to a suitable manifold' todistribute the iluid pressure to the different arc chutes of the multipole circuit breaker and connecting rod 20 would be adapted to operate a plurality vof poles instead of only a single one.

The operation of our invention will be described with reference to Fig. 1 when the circuit breaker I 0 is in the closed position as indicated. Tripping operation of the circuit breaker may be initiated in one of three ways; namely, if the operator manually depresses "open button |01, if an ab-l normal current condition occurs in power line I5 causing energization-of protective relay |08, or if the pressure in reserve pressure tank 21 decreases sumciently so that pressure relay 28 causes switch 30 to bridge contacts 30h. If either ofv these three situations occur, opening blast solenoid 89 is energized from control circuit 'I 00 through mechanical cut-oil switch I I0, thus pulling armature 88 thereof to the left and opening pilot valve 1I as is eviwill allow the pressure in space 88 to decrease rapidly so that the pressure balance on piston 50 is disturbed and valve 51 is opened, allowing a blast of fluid from tank 21 to pass through conduit I6 into arc chute I3. This fluid blast occurs before the initiation of the opening operation of circuit breaker I0. As soon as opening blast solenoid 89 is energized and armature 88 is pulled to the left, switch 98 is closed, allowing opening valve solenoid 31 to be energized both to close its seal-in switch 38 and to open opening valve 33 while closing escape port 39. This allows iluid under pressure from tank 21 and manifold 32 to enter the lower end of cylinder I8. Furthermore, this fluid pressure moves' piston 5I of dumping valve 49 upwardly to close escape port 55 and provide a very large opening to atmosphere at the upper end of cylinder I8 so that high-speed opening of circuit breaker I may take place. The initial upward movement of piston I8 by virtue of lost-motion connection 2| causes member 26 to engage tripping means 22, whereby latch 23 is re leased from member 25 and energy-storage means 24 is released to aid the fluid-pressure means in high-speed opening of circuit breaker I0. As the circuit breaker I0 reaches a predetermined position in the opening stroke, a cut-off switch I I0 is opened, thereby deenergizing opening air blast solenoid 89 whereby pilot valve 1| is closed by spring means 8| and check valve 12 allows fluid pressure to enter space 69 and cause valve member,51 to snap to the closed position. Further movement in the opening direction of connecting rod 20 causes cut-off switch ||2 to open the energization circuit of solenoid 31, whereby opening valve 33 is forced shut by relatively heavy spring 35. Auxiliary switch I|3 is allowed to close and energize signal means I I4 for indicating that the circuit breaker is in the open position.

vTo close the circuit breaker when it is in the open position, close button I0| is operated and, if 'the pressure in tank 21 is sufficiently high so that pressure relay 28 allows switch 30 to bridge contacts 30a, closing solenoid 42 is energized through mechanically operated cut-oil switch |02, which is in the closed position when circuit breaker I0 is open. The energization of closing solenoid '42 causes seal-in switch43 to close and, furthermore, causes opening of closing -valve 34 and closing of escape port 44 against the force of relatively heavy spring 40. This allows iluid un- Y der pressure from manifold 32 to enter the upper end of cylinder I8. Since the area of piston 5I is at least as large as that of valve member 50 of dumping valve 49, valve member 50 is maintained in the closed position by the force of spring 53 and piston I9 is forced downwardly,

charging energy-storage means 24 and moving circuit breaker I0 to thevclosed position. Fluid underneath piston I9 is allowed to exit to atmosphere through escape ports 39 and 55. At a predetermined point prior to the meeting of con tact tips II' and I2', cut-off switch |05 for clos'- ing air blast solenoid 9| is closed, whereby armature 90 is moved to the left opening pilot valve 1I and operating blast valve 56 in the manner described above to produce a blast of gas or air transverse of contacts |I and I2 prior to the closing thereof. After contacts II and I2 have engaged one another, cut-oil' switch |05 is opened, deenergizing closing air blast solenoid 9| and. hence, allowing spring means 8| to close pilot valve 1I, whereby blast valve 56 is closed cutspring 40 forces closing valve 34 to close manifold 32. At the same time, latchA 23 engages with member 25 and tripping means 22 is reset to maintain energy-storage means 24 in a charged condition and, furthermore, hold circuit breaker I0 in the closed position. Auxiliary switchv I3 is opened, deenergizing signal means I|4 and signal means I I6 is energized through opening air blast solenoid 89 and cut-oft switch |I0 therefor which has been closed as the 'circuit breaker reaches the closed position.

The trip-free operation of the circuit breaker will be understood by those skilled in the ait in view of the detailed description given above and Will only be briefly mentioned hereinafter.

If. during the closing operation of the circuit4 breaker described in the preceding paragraph,.

protective relai,r |08 should initiate a tripping operation which it may do as soon as mechanical cut-oft switch ||0 is closed, the tripping operation described above will be initiated and energization of opening solenoid 31 will occur, whereby lever 36 causes rod 41 to engage projection 48 of latch 45 allowing member 4Iz to pivot and close closing valve 34 by virtue of relatively heavy spring 40 even though solenoid 42 is still energized. Hence, trip-free operation is obtained and rapid opening of circuit breaker I0 is accomplished.

It will be apparent to those skilled in the art that our invention is not limited tothe particular construction shown but that changes and modifications may be made Without departing from the spirit and scope of our invention and we aim in the appended claims to cover all such changes and modifications.

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

l. In an operating system for an electric cir,- cuit breaker comprising a plurality of relatively movable contacts, a source of fluid under pressure, means operable by said fluid under pres- `sure for producing relative movement between tion of said circuit breaker in the event that said circuit breaker is closed on an abnormal current condition.

2. In an operating system for an electric circuit breaker comprising a plurality of relatively movablecontacts, a fluid motor for producing relative movement between said contacts, a source of fluid under pressure for operating said motor, a first valve for connecting said source s of fluid with sind` uuid motor for dosing said circuit breaker, a second valve for connecting said source of fluid with said fluid motor for opening said circuit breaker, said valves being so constructed and arranged as to control exhaust ports associated with said fluid motor, solenoid means for operating each of said valves, and means associated with said first valve and operable by means associated with said second valve for causing trip-free operation of said circuit breakereven though said solenoid means asso-f ciated withl said first valve is energized to connect said fluid source with said fluid motor to close said circuit breaker.

3. In an operating system for an electric circuit breaker comprising a plurality of relatively movable contacts, a fluid motor for producing relative movement between said contacts, a source of fluid under pressure for operating said motor, a valve for connecting said source of fluid with said fluid motor for closing said circuit breaker, said valve being so constructed and arranged as to control an exhaust port associated with said fluid motor. means for operating said valve to close said circuit breaker, means for causing opening movement of said circuit breaker, and

means associated with said valve for causingA trip-free operation of said circuit breaker in the event that said circuit breaker is closed upon an abnormal current condition.

4. In an operating system for an electric circuit breaker comprising a plurality of relatively vmovable contacts, a fluid motor for producing relative movement between said contacts, a source of fluid under pressure for operating said motor, a, first valve for connecting said source of fluid with said uid motor for closing said circuit breaker, a second valve for connecting said source of fluid with said fluid motor for opening said circuit breaker, solenoid means for operating each of said valves, a lever interconnecting said valves with its associated operating solenoid, spring means tending to hold said valves in the closed position so as to disconnect said source of fluid from said fiuid motor, said lever associated with said first valve being biiurcated and provided with a latching means to hold it as a unitary structure when said associated solenoid is energized to open said rst valve, and means associated with said second valve operating on said bifurcated lever for causing said first valve to close even though its associated solenoid is still energized, whereby trip-free operation ci the circuit breaker may be obtained.

5. In an operating system for an electric cir-v cuit breakercomprising a plurality of relatively y movable contacts, a fluid motor for producing re1- ative movement between said contacts, a source of uid under pressure for operating said motor, valve means for selectively interconnecting said source of fluid andsaid motor for producing relative movement between said contacts, energystorage means-arranged lto be charged during the closing stroke of said circuit breaker, restraining means for holding said circuit breaker in the closed position and said energy-storage means in g the charged condition,`a lost-motion connection between said uid motor and one of said relatively movable contacts including a tripping means for releasing said energy-storage means when said uid motor is operated to open said circuit breaker, whereby high-speed opening of said circuit breaker is obtained.

6. In an operating system for an electric circuit breaker comprising a plurality of relatively movable contacts, a. uid motor for producing relative movement between said contacts, a source of fluid under pressure for operating said motor,

means for interconnecting said source of fluid and said motor for closing said circuit breaker, energy-storage means for opening said circuit breaker so constructed and arranged as to be y charged during the closing. stroke of said circuit breaker, means for restraining said energy-storg age means in the charged condition when said circuit breaker is in the closed position, tripping means for releasing said energy-storage means to open said circuit breaker whereby high-speed opening of said circuit breaker is obtained, means for producing ablast of fluid for arc-extinguishing purposes during the opening operation of said circuit breaker, and means for preventing the release of said energy-storage means until said last-mentioned means is operative to produce said arc extinguishing fluid blast.

7. In an operating system for an electric circuit breaker comprising a plurality of relatively movable contacts, a iiuid-motor for producing relative movement between said contacts, a source of uid under pressure for operating-said motor,

solenoid operated valve means for connecting said source of uid with said fluid motor for opening said circuit breaker, means including a blast valve for producing a blast of iiuid adjacent'said contacts for arc-extinguishing purposes, means for operating said blast valve to produce a blast of fluid adjacent said contacts upon initiation of the opening operationof said circuit breaker, `and means dependent upon the operation of said blast valve for causing operation of said solenoid-operated valve to connect said source of uid with said fluid motor to open said circuit breaker.

A8. In an operating system for an electric circuit breaker comprising a plurality of relatively movable contacts associated with a chamber, a iluid motor for producing relative movement between said contacts, a source of liuid under pressure. valve means for selectively interconnecting said source of fluid and said motor4 for opening or closing said circuit breaker, means including a blast valve for'interconnecting said source of iluid and said chamber so that said contacts may be surrounded with a blast of said iiuid under pressure for arc-extinguishing purposes, means for operating said blast valve prior to the initiation of the opening movement of said circuit breaker, and means for operating said blast valve to produce a blast of fluid at said contacts at a. predetermined point in the closing stroke of said circuit breaker.v

9. In an operating system for an electric circuit breaker comprising a plurality of relatively movable contacts, a fluid motor for producing relative movement between said contacts, a source of uid under pressure for operating said motor, valve means for selectively interconnecting said source of fluid and said motor for opening or closing said circuit breaker, means including a blast valve associated with said source for producing a blast of fluid adjacent said contacts for arc-extinguishing purposes, said blast valve comprising a piston having the pressure on either side thereof balanced when said blast valve is in I the closed position, and solenoid-operated means including a pilot valve for unbalancing the pressure on said piston to cause opening movement of said valve to produce a fluid blast adjacent 'said contacts, means for operating said blast valve for producing relative movement betweenI said contacts, a source or iiuid under pressure valve means associated with said source for producing a blast of duid adjacent said contacts during both opening and closing movements of said relatively movable contacts, and means for oper- .ating said valve means for a period of time during the circuit-interrupting operation of said circuit breaker which is independent of the period of time that said valve-means is operated during the circuit-closing operation.

11. In an operating system for an electric circuit breaker of the fluid-blast type comprising a plurality of relatively movable contacts, means for producing relative movement between said contacts, a Source of fluid under' pressure, valve means associated with said source for producing a blast of fluid adjacent said contacts during both opening and closing movements of said relatively movable contacts, means for opening said valve means for a period of time during the circuit-v interrupting operation .of said circuit breaker which is independent of the period of time that said valve means is' open during the circuit-closing operation, and means for initiating the operation of said first-mentionedA means only after the operation of said valve means.

` 12. In an operating system for an electric circuit breaker of the fluid-blast type comprising a plurality of relatively movable contacts, means for producing relative movement between said contacts, a source of iiuid under pressure, means including a valve associated with said source for producing a blast of fluid adjacent said contacts means including a blast valve associated with said source for producing a blast of fluid adjacent said contacts for arc-extinguishing purposes during the opening movement of said circuit breaker, and fluid-operated means for initiating the opening movement of said circuit breaker only after a predetermined opening movement of said blast valve.

16. In an operating system for an electric circuit breaker comprising a plurality of relatively movable contacts, means for producing relative movement between said contacts, a source of fluid under pressure, means including a valve associated with said source for producing a blastbf fluid adjacent said contacts for arc-extinguishing purposes during both opening and closing movements of said circuit breaker, means for opening said valve in response to an abnormal current condition on the power circuit associated with said circuit breaker prior to any opening movement of said circuit breaker, fluid-operated for arc-extinguishing purposes during both opening and closing movements of said circuit breaker, means for initiating the opening of said valve prior to the opening movement of said circuit breaker, and means responsive to the opening movement of said circuit breaker for determinin the closing instant 0f said valve.

13. In an operating system for an electric circuit breaker comprising a plurality of relatively movable contacts, means` for producing relative movement between said contacts, a source of fluid under pressure, means including a valvel associated with said source for producing a blast of fluid adjacent said contacts for arc-extinguishing purposes during both opening and closing movements of said circuit breaker, means' for opening said valve in response to an abnormal current condition on the power circuit associated with said circuit breaker prior to any opening movement of said circuit breaker, and means for f maintaining said valve in the open position until a predetermined separation of said relatively movable contacts has occurred.

14. In an operating system for an-electric circuit breaker of the fluid-blast type comprising a plurality of relatively movable contacts, means for producingfrelative movement between said contacts, a, source of fluid under pressure, means including a valve associated with said source for producing a blastof fluid adjacent said contacts for arc-extinguishing purposes during both opening and closing movements of said circuit breaker,

means for initiating the opening of said valve prior to' the opening movement of said circuit breaker, cam means responsive to the opening movement of said circuit breaker fondetermining the closing instant of said valve, and independent cam means for'controlling the operation of said valve during the closing operation of said circuit breaker. v

15. In an operating system for an electric circuit breaker comprising a plurality of relatively movable contacts, means for producing relative movements between said contacts to open said cirmeans for initiating the opening of said circuit breaker after a predetermined opening movement of said valve, and means for maintaining said valve in the open position until a predetermined separation of said relatively movable contacts has occurred.

17. In an operating system for an electric circuit breaker of the luid-blast type comprising a plurality of relatively movable contacts, means for producing relative movement between said contacts, a source of fluid under pressure, means including a valve associated with said source for producing a blast of fluid adjacent said contacts for arc-extinguishing purposes during both opening and closing movements of said circuit breaker, a. plurality of means for operating said valve prior to any opening movement of said circuit breaker, fluid-operated means for initiating the opening movement of said circuit breaker only after a predetermined opening of said valve has occurred, and means responsive to the opening movement of said circuit breaker for determining the closing instant of said valve.

18. In an operating system for an electric circuit breaker comprising a plurality of relatively movable contacts, means for producing relative movement between said contacts, means for holding said contacts in current-conducting engagement when said circuit breaker is in the closed position, iuid-operated means for releasing said last-mentioned means so that said rst-mentioned means may cause opening movement of said circuit breaker, a source of fluid under pressure, means associated with said source for producing a blast of uid adjacent said contacts for arc-extinguishing purposes during the opening movement of said circuit breaker, and means for operating said uid-operated means only after mined position, and means interposed between said motive means and one of said relatively movable contacts lincluding a tripping means for rendering said restraining means ineffective in response to initial operation of said motive means to permit relative movement between said contacts to occur. cuit breaker, a source of fluid under pressure. 20. In an operating system for an electric said motive means and one of said relatively movable contacts including a tripping means for ren- -dering said restraining means ineective when said motive means is operated to produce relative movement between said contacts.

21. In a gas blast circuit breaker, separable contacts for establishing an arc, a source of gas under pressure, means for directing a blast of gas from said source against the arc to extinguish the arc, operating means actuated by gas under pressure from said source for moving said contacts to .closed position, means for positively mechanically holding said contacts in the closed position, and said holding means being operated mechanically by the pressure of said source for releasing said contact means to move to open position with the pressure from said source for releasing the holding means appliedv prior to the application of force to the moving contact tending to move it in opening direction.

22. In a circuit interrupter, 'separable contacts for establishing an arc, a source or gas under pressure, operating means actuated by gas under pressure from said source for moving said contacts to closed position, mechanical means for rigidly holding said contacts in the closed position, and means operated by gas pressure applied thereto from said source prior dto the application of force to said contacts tending to separate them for mechanically releasing said holding means and permitting movement of `the contacts to open position.

23. In a circuit interrupter, separable contacts for establishing an arc, a source of gas under pressure, operating means including a piston actuated by gas under pressure from -said source for moving said contacts to closed position when pressure is applied to one side of said piston and for moving said contacts toopen position when pressure is applied to the other side of said piston, mechanical means operable automatically upon said contacts reaching closed position for rigidly holding said contacts in the closed vposition against any force applied to the contacts tending to move them to open position, and means operated by the gas pressure admitted from said source to the opening side of the piston for automatically mechanically releasing said holding means and permitting movement of the contacts to open position by the gas pressure admitted to the opening side of the piston, and said means acting to begin the release of theholding means prior to the applica.. tion of force to the contacts tending to move them in the opening direction.

24. In a circuit interrupter of the iiuid blast type, separable contact structure for establishing an arc, iiuid pressure actuated means for operating said contact structure, operating valve means controlling the supply of iiuid under pressure to said operating means, blast valve means for controlling the supply of arc extinguishing fluid to said contacts, and means dependent upon the position of said blast valve means for controlling the operativeness of said operating valve means controlling the supply of uid to said operating means.

25. In a circuit interrupter of the fluid blast type, separable contact structure for establishing an arc, operating means for moving said Contact structure to open and closed positions, said operating means including a iiuid actuated piston, an opening valve for controlling the supply of iluid to one side of said piston for opening said contact structure, a closing valve for controlling the supply of fluid to the other'side of said piston to close said contact structure, a blast valve for controlling the supply of an extinguishing fluid to said contact structure, and means interlocking saidopening valve and said blast valve for maintaining said opening valve closed until said blast valve is moved toward its open position.`

26. In a circuit interrupter, separable contact structure, operating means for moving said contact structure to open and closed positions, said operating means including iiuid actuated piston means, opening valve means for controlling the supply of fluid to one side of said piston means for opening said contact structure, closing valve means for controlling the supply of uid to the other side of said piston means for closing said contact structure, and means responsive to the actuation of said opening valve means to the open position for holding said closing valve means in y the closed position.

. CARL THUMIM.

vEDWARD J. FRANK.

ALEXANDER C. BOISSEAU.