US2528694A - Circuit breaker control system and apparatus - Google Patents

Description

Nov. 7, 1950 A. c. KELLE CIRCUIT BREAKER CONTROL SYSTEM AND APPARATUS Fz'led July 21, 1944 J 5 A Qav ,d -I f il s Q 4 ||.,..l| 4 4 a ||l|||f|j w 4 o www Y w A A i 0 Till 9 4 2 f 1 7 a n 6 a a o 7 7% O I. 4 a 6 o E 5 4,. 8 9 YW |11 e 4 o 6 J a o o Q O n/v 5 O 7 6 5 5 a A M Nov. 7, 1950 A. c. KELLE CIRCUIT BREAKER CONTROL SYSTEM AND APPARATUS 3 Sheets-Sheet 2 Filed July 21, 1944 @um @ma mfc/wa@ Nov. 7, 1950 A. c. KELLE CIRCUIT BREAKER CONTROL SYSTEM AND APPARATUS Filed July 21, 1944 3 Sheets-Sheet 3 Patented Nov. 7, 1950 CIRCUIT BREAK-ER CONTROL SYSTEM AND APPARATUS Arthur C. Kelle, Stoughton, Mass., assignor to Allis-Chahners Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Application July'21, 1944, Serial No.1545,929

., 6 Claims.

This invention relates in general to a pneumatic control system and particularly to an improved control system and parts thereof suitable for operating a gas blast circuit breaker.

As lpneumatically operated gas blast circuit breakers have been utilized to interrupt increasingly greater currents, the size of the contacts and operating elements of such circuit breakers has increased. This increase in size involves the use of a greater Volume of air for operating the circuit breaker and for extinguishing the arc. In prior art circuit breakers, the time necessary to operate a solenoid valve for initiating a circuit breaker operation has become a bottleneck in reducing the circuit breaker operating time to the desired minimum. This disadvantage has become greater as the sizes of such solenoid valves have increased.

It is therefore an object of the present invention to provide an improved operating system and apparatus for a gas blast circuit breaker that will provide circuit breaker opening and closing operations in a minimum of time.

It is also an object of the present invention to provide an improved operating system and apparatus for a gas blast circuit breaker that will provide for very rapid operation of the circuit breaker and which will also prevent undesired operation of the circuit breaker.

It is also an object of the present invention to ,provide an improved pneumatic control system Aand apparatus for a circuit breaker, in which there is a provision for manual operation and in which manual operation is prevented'if the operating pressure is below a predetermined minimum.

Objects and advantages other than those above set forth will be apparent from the following description when read in connection with the accompanying drawing, in which:

Fig. 1 is a diagrammatic representation of a gas blast circuit breaker and an operating system and apparatus therefor embodyingrthe present invention; Y

lFig. 2 is an enlarged front view (with some parts removed to more clearly show the structure) of the solenoid valve and low pressure lockout structure shown in Fig. 1;

Fig. 3 is a top view of thestructure shown in Fig. 2;

Fig. 4 is a section view taken on the lineIV---IV Fig. '7 isa partial end view similar to Fig. 6 showing the .parts in diilerent positions.

In `the drawing, .an electric circuit (not shown) connected to conductors 35 and 3| is shown as controlled Vby a circuit breaker of the gas blast type. The conductors 30 and 3l extend through studs .9 to contact blocks 40 which have thereon fixed contacts 3 shown as bridged by a conducting movable :mainor bridging contact 4.

In parallel with the bridging'contacts 3, 4 are arcingvcontacts l, 8 and disconnect contacts 5, '6 connected in series. A reservoir containing gas suitable forarc extinguishing is shown at Il), and .for vpurposes of .illustration the gas therein will be considered to be air maintained under pressure of the order of 100 to 500 pounds per square inch. In general, the flow of air is from the `tank l0 through a blast valve l l and a manifold `45 -through the .arcing contact chamber 26. Air travel continues from the arcing contact chamber `25 through the .Xed varcing .contact l into a Agas .cooling device or muiiier l2 and through an exhaust pipe .t3 to atmosphere.

Separate fluid motors 42, 5l, 52 and 53 are utilized to operate the arcing Contact, disconnect contact, the bridging contact and the blast valve, respectively. .Motor 5| is provided with a piston 20 `having a rod 2l movable therewith and connected through linkage including a cam member 22 .to the movable disconnect Contact 5. Motor 52 has a piston vH5 having a rod .l'l `connected through linkage to the movable bridging member 4. The cam member I8, operably connected to the rod Il, cooperates with cam 22 to prevent `opening of the disconnect contact 5 unless the bridging Contact 4 is in open position. Also., a .camming action of cam 1.8 closes .the disconnect .contact 5, if open, upon movement of the bridging contact 4 to closedposition.

In .the circuit breaker as shown in the drawing, the -contacts are :allshown inthe closed position and current flow is from conductor Y3i) through contacts .3, 4 to conductor v3|. Operation :of solenoid valve I4 initiates the opening operation of the circuit breaker. Air .under pressure from tank l0 is supplied through pipe l5, through the opening bridging contact 4. This movement of rod I'I upward rotates the cam I8 in a counterclockwise direction as viewed in the drawing and clears the path of movementl of the cam 22.

Upon movement of the piston I6 upward a predetermined distance, slide valve 12, connected to move with rod Il, closes off pipe 84 from supply pipe i6 and opens pipe 'i6 to pipe 46. With pipe 46 supplied with air under pressure, the blast valve motor 53 is operated. Air is supplied under piston 44 and, as outlet port 48 is covered by slide valve |09, the piston 44 is moved upward, thereby opening blast valve Il. Movement of piston 44 at the top of the stroke is arrested and the shock absorbed by resilient material 98.

Opening of the blast valve I l admits air to manifold 45 and thereby to the arcing Contact chamber 26 and to the cylinder containing arcing contact operating piston, 42. Movement of the piston 42 upward separates'the arcing contacts 'I and 8 drawing an arc therebetween. The air under pressure in chamber 26 blasts the arc through orilice contact i and extinguishes it. An auxiliary electrode 86 may be provided and connected to a resistance (not shown) which may be wound on the cooling chamber I2, which resistance is connected to contact block 48 by conductor 43. The electrode 86 is connected in the circuit by movement of the arc through contact l. The arc gases are cooled in the muffler I2 and exhausted through pipe I3 to atmosphere.

vWhen air is supplied to the manifold 45 by opening of the main blast valve II, pressure air is supplied through pipe 'I8 to the chamber 58 of fluid motor 5I. In order to assure a proper sequence of operation of arcing contact 8 and disconnecting contact 5, a needle valve 'I9 in the line 'I8 is provided for adjustment of the air ilow therein. As pressure builds up in chamber 58, the Valve 69 is opened admitting air under pressure to the bottom of piston 20. Movement of piston 28 and piston rod 2I upward rotates the cam member 22 in a clockwise direction about its pivot .1. 81, thereby opening the movable disconnect con- This releases mitting arcing contact 8 to reclose under bias of a spring (not shown). Rapid reclosing of blast valve Il and arcing contact 8 is very necessary from the standpoints of time of circuit breaker reclosing and of air conservation.

Fluid motors 5I, 52 and 53 are designed to permit a fast reclosing of the circuit breaker. Motor A5I is provided with valve 28 providing for release of pressure underneath piston 20 at or near the end of the upward stroke. An operating member on rod 2l operates poppet valve 54 permitting pressure in the chamber 58 to leak off to atmosphere. The difference of pressures under the piston 20 and in chamber 58 forces the valve 28 downward against theV pressure of its Vbiasing spring, thereby opening the space underneath the piston 20 to atmosphere and immediately relieving the pressure therein.

In the motor 52 a similar action takes place, poppet valve 64 is operated by operating member 65 movable with the piston rody I'I. Operation of v valve 64 lowers the pressure in chamber 68 thereby 4 operating valve 88 to permit a rapid release of pressure under piston I6. Motors 5I and 52 are therefore ready for immediate reversal.

An improvement in the solenoid valves I4 and I5 is of peculiar benet in the rapid reclosing of the blast valve l I and the reclosing of the circuit breaker. The valves I4 and I5 are similar structures and therefore the description of one of these valves will also describe the other. The manifold I9 is supplied with air under pressure from the reservoir I6 by a pipe l5. Air pressure from the header I9 is prevented from flowing into the pipe 16 by a piston operated valve 23. The valve 23 is biased to the closed position shown in Fig. 4 by a spring 32 and in this position the resilient material 25, set into the valve 23, is pressed against the valve seat. An opening 24 is provided in the valve piston 23 permitting air under pressure from the manifold I9 to normally be supplied, at a predetermined relatively slow rate, to the bottom of the piston 23. This air under pressure aids in maintaining a tight closure ofthe valve 23.

A small lightweight pilot valve 34 is provided in the bottom of the valve cylinder and is biased to the closed position shown in Fig. 4 by a spring 33. This valve has a iluted stem 29 which permits the air underneath the piston to beK exhausted to atmosphere when the pilot valve 34 is raised from its seat by attraction of armature 36 when the coil 35 is energized. The pilot valve 34 being light in weight can be quickly moved with little energy, independently of the size and weight of valve v23.

Upon energization of the coil 35, the armature 36 isattracted to open the Valve 34, thereby providing a drop in pressure underneath the piston 23. As there is full air pressure on the outer annu# lar top surface of the piston 23, the valve is quickly opened. The area of the valve opening of the valve-34 is several times the area of the opening24, so that the flow of air through the valve 34 is rapid relative to the ilow of air through opening 24.

It is desirable to provide manual operation of the solenoid valves I4 and I5 such as will function independently of the electric circuit. As more 'clearly shown in Figs. 3 and 6, the push buttons 3'I are provided with actuating stems 39 and are biased by springs 38 to the non-operative position shown in Fig. 6. When one of the push buttons V3'I is moved against the bias of its spring 38, the stem 39 moves a crank member 49 about its pivot 99 in a clockwise direction as viewed in Fig. 6. The crank member 49 pivotally supports an actuating member 6I by means of a cotter key'98. Movement of the actuating member 6I is guided by the members 91 and 62 so that upon movement of the crank member 49 in a clockwise direction, the member 6I is raised, thereby raising the armature 36 of the electromagnet.

A reduced pressure lockout device is provided whereby manual operation of the armature 36 to operate valve 34 is prevented, independently of whether or not the push button 3l is operated, upon a predetermined pressure drop in the mani- `fold I9. A bellows 'I3 is supported in a chamber Jadjacent the manifold I9. The bottom of the bellows is supported by the chamber in pressure `tight relation. The upper `end of the bellows is connected mechanically to an actuating rod "I4 so Ythat airpressure being supplied from the'manifold I9 through the opening 96 tends to collapse the bellows 'I3npushing downwardly on the rodv14.

A long narrow U-shaped bracket BVI is pivotally supported at 93 on the housing for the bellows '13. The rod '|-4 is pivotally connected `to the bracket 8l by a pin 94 so that pressure from the bellows is transmitted through rod 14 tending to provide movement of the bracket-8| about its pivot 93 in a clockwise direction as viewed in Fig. 5. The long narrow U-shaped bracket 8| has welded thereto a short wide bracket 9|, the closed ends of the U-shaped brackets being welded together back to back as more clearly shown in .Fig 3. The arms of the bracket 9| each have a lift rod 63 pivotally attached thereto by a pin 92 having a set screw therein. The lift rod 63 is guided for vertical movement by a bent wire guide |00 and at its upper end is bent to form an eye V83 providing a guide through which the stem 39 of the push button 31 extends.

A spring 82 is connected between a pin 89 in the U-shaped bracket 8| and an adjustably threaded member 95 supported by thevalve housing. The spring 82 provides the bias against which the air pressure on the bellows 13 is balanced.

When the pressure in the manifold |9 drops below a predetermined value, the bellows 13 will extend by reason of the pull of the spring 82 on the rod 14. Extension of the bellows 13 will raise the rod T4 thereby moving the bracket 8| about its pivot 93 in a counterclockwise direction as viewed in Fig. 5. Movement of the bracket 8| moves the bracket 9|, which is movable therewith, thereby lifting the rod 63 to the position shown in Fig. il. In this position the eye 83 raises the stem 39 to a position above the crank member 49, whereby operation of the push button 3`| can not rotate the crank member 49.

The control above effected has a great advantage in providing for manual operation entirely independent of the electrical control and in providing vagainst operation of the circuit breaker by such manual control unless air pressure of at least a desired minimum value is available in the manifold I9. This permits manual control of the circuit breaker in the event the electrical control does not function, but prevents part operation if insulicient air pressure is available. The conventional electrical control of coils 35, With low pressure lockout of the electrical system, may also be utilized in conjunction with the manual control above described, to operate the circuit breaker.

Due to the improved fluid motors, the improved blast and solenoid valves `and to the rapid interruption of the circuit, the opening operation can be completed in a few cycles. Upon completion of the opening operation, the circuit breaker is ready for reclosing which may be eected by energization of the solenoid valve |5. With solenoid valve |4 closed, pressure air from the pipe 15 is rapidly supplied through solenoid Valve I5 and pipe 'Il to chambers 59 and 69 of motors 5| and 52. The operation of valve |5 is similar to the above described operation of valve i4. With downward movement of pistons and I B the bridging contacts 4, 5 and the disconnect contacts 5, 6 are reclosed, with the limitation provided by cams i8 and 22 that the bridging contacts 3, 4 must be reclosed subsequent to closure of disconnect contacts 5, 6. If movement of contacts 3, 4 tends to be faster than movement of contacts 5, 6, movement of cam I8 in a clockwise direction forces cam 22 to close contact 5. This prevents arcing at the bridging contacts 3, 4 and provides for closing of the circiut at the disconnect contacts 5, 6 especially designed for closing against heavy currents.

Upon movementof pistons 20 and |6 downward, operating members V5'| and 61 operate poppet valves 56 and 65 to provide release of pressure above the pistons 20 and |6 in a manner similar to the pressure release aiTorded by valves .54 a-nd 64. Movement of piston rod l1 downward moves slide valve '|2 to the position shown in the drawing and the blast valve having been closed, the circuit breaker is immediately `ready for a subseqent opening operation. Considerable saving in reclosing time is effected by the simul, taneous energization of motors 5| and 52 for clos.- ing and by insuring of the proper closing sequence by the abutting cam members I8 and 22. The interlock afforded by cams 8 and 22 involves no loss of time.

Although the various elements of the circuit breaker system have been described as operating in conjunction with each other, the improvements disclosed have utility other than with all of the elements shown and described. For example, the fluid motors 5| and 52 may be utilized for any purpose where quick reversal of a uid motor is desirable. While the disclosed arrangement` of bridging contacts 3, 4 is desirable for circuit breakers of high current rating, these contacts may be omitted in the lower current ratings.

The improvements utilized in effecting a quick reclosure of the blast valve l although shown as initiated by movement of the disconnect contact 5, may as well be effected by an isolating movement of the arcing contacts 8 in cases vwhere no separate disconnect is utilized. The

present disclosure of an interrupting operation utilizing an auxiliary electrode 86 and associated resistor is by way of illustration, for in the lower current ratings, these elements may be omitted. The rapidly acting pneumatic operating system and apparatus above described may be utilized with circuit breakers having no gas blast across the arcing contacts.

For simplicity and clarity of disclosure, a single pole circuit breaker has been described and shown, although usually a multipole circuit breaker is operated. ln such cases, the manifold l5 extends to the interrupting chambers of the additional poles, and the linkages operated by motors 5| and 52 operate shafts for additionally operating the disconnect and bridging contacts of the other poles.

The improved solenoid valves i!! and l5 permit the use of the escape valve 34 that has only light weight moving parts. The valve 34 needs only a small movement to provide its pressure escape function. This permits the use of a short stroke electromagnet having light weight moving parts and provides for extremely rapid operation of the valve 23.

Although a single embodiment has been illustrated and described, it will be apparent to those skilled in the art that various changes and modications may be made therein without departing from the spirit or 'the invention or from the scope oi the appended claims.

It is claimed and desired to secure by Letters Patent:

l. In combination, a circuit breaker provided with xed and movable contacts cooperable to make and break an electric circuit, a source of gas under pressure, means comprising a valve for controlling the supply of gas under pressure from said source to operate said movable contact to open position, means responsive to said electric circuit for operating said valve, means for manually operating said valve independently of said electric circuit, and means operably responsive to a predetermined minimum gas pressure at said source for preventing operation` of said valve by said manually operable means.

2. In combination, a circuit breaker provided with cooperating iixed and movable contacts, a source of gas under pressure, means comprising a pneumatically operated main valve for supplying gas under pressure from said source to operate said movable contact to open position, an electrically operable auxiliary valve for controlling the supply of gas under pressure from said source to operate said main valve, means for manually operating said auxiliary valve independently of the electrical operation thereof, and means operably responsive to a predetermined minimum gas pressure at said source for preventing operation of said auxiliary valve by said manually operable means.

3. In combination, a circuit breaker provided with cooperating iixed and movable contacts, a source of gas under pressure, means comprising a valve for controllingf the supply o gas under pressure from said source to operate said movable contact to open position, said valve comprising a piston normally subjected to pressure gas from said source on both sides of said piston to maintain said valve closed, means comprising an electromagnet and armature for relieving the pressure on one side of said piston to rapidly open said valve, means independent of said electromagnet for manually operating said pressure relieving means, and means responsive to a predetermined minimum gas pressure at said source for preventing operation oi manually operable pressure relieving means.

4. In combination, a circuitl breaker provided with cooperating xed and movable contacts, a source of gas under pressure, motor means connected With said movable contact, said motor means energizable by said gas under pressure to force said movable contact to an open position, a first valve means comprising a cylinder and piston controliing the supply of gas under pressure from said source to said motor means for the operation thereof, said piston normally subjected on both sides to gas under pressure from said source, a second valve means for exhausting to atmosphere the pressure in said cylinder on one side of said piston, and a common spring for biasing said rst and second valve means in valve closing directions, said spring cooperating With said gas under pressure from said source maintaining said iirst and second valve means closed, and means for opening said second valve means for relieving the pressure on said one side of said piston to rapidly open said first valve means.

5. In combination, a circuit breaker provided with cooperating nxed and movable contacts, a source of gas under pressure, motor means connected with said movable contact, said motor means energizable by said gas under pressure to force said movable contact to an open position, a rst valve means comprising a cylinder and piston controlling the supply of gas under pressure from said source to said motor means for the operation thereof, said piston normally subjected on both sides to gas under pressure from said source, a second valve means for exhausting to atmosphere the pressure in said cylinder on one side of said piston, and a spring having one end thereof seated against said iirst Valve means and the other end thereof seated against said second valve means for biasing each of said valve means in valve closing directions, said spring cooperating with said gas under pressure from said source maintaining said first and second valve means closed, and means for opening said second valve means for relieving the pressure on said one side of said piston to rapidly open said rst valve means.

6. In combination, a circuit breaker provided With cooperating iixed and movable contacts, a source of gas under pressure, motor means connected with said movable Contact, said motor means energizable by said gas under pressure to force said movable contact to an open position,-

f' a rst valve means comprising a cylinder and.

valve closing directions, said springs and said gas under pressure from said source maintaining said first and second valve means closed, and means for opening said second valve means for relieving the pressure on one side of said piston to rapidly open said rst valve means.

ARTHUR C. KELLE.

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

UNITED STATES PATENTS Number Name Date 926,389 Collin June 29, 1909 1,201,426 Anderson Oct. 17, 1916 2,238,567 Prince Apr. 15, 1941 2,292,096 Thumim et al. Aug. 4, 1942 2,310,130 Thumim et al. Feb. 2, 1943 2,310,755 Thumim Feb. 9, 1943 2,329,001 Robinson Sept. 7, 1943 2,349,650 Cumming et al May 23, 1944 2,381,307 Peek et al. Aug. 7, 1945 2,390,333 Scott Dec. 4, 1945 2,401,008 Ludwig et al. May 28, 1946I 2,408,199 Cumming et al. Sept. 24, 1946 2,426,243 Scott Aug. 26, 1947

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