US2394086A

US2394086A - Circuit interrupter

Info

Publication number: US2394086A
Application number: US431394A
Authority: US
Inventors: Leon R Ludwig; Benjamin P Baker; Andrew H Bakken
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1942-02-18
Filing date: 1942-02-18
Publication date: 1946-02-05
Anticipated expiration: 1963-02-05

Description

Feb. 5, 1946. L.. R. I UDwlG ET Al.

` CIRCUITA NTERRUPTER 5 sheets-sheet s' Filed Feb. 18, 1942 mvENToRs yVVTNESSESZ lean Elf/dwf' genjavmn /Barerand dreljgZ/z. @ijf/ ATTO EY Feb.5,1946. L. R. LUDWIG Em 2,394,086

C IRCUIT INTERRUPTER ATToR Y Patented Feb. 5, 1946 assauts cmcurr nrrnnanr'raa Leon R.

Baker, Turtle Edgewood, Pa., assign Ludwig,

11 Claims.

The invention relates to circuit interrupters and, more particularly, to circuit interrupters of the fluid blast fluid operated type for high voltage high power circuits.

In high voltage circuit breakers of the type re ierred to, it is necessary to provide an external disconnect` switch electrically connected in series with the current interrupting contacts to provide the extral insulation needed to effectively isolate the two parts o1 the connected circuit since the in terruptlng contacts arc not capable of withstand-1 ing high voltages in the open position after the iiuid blast is cut off.

It is important that the disconnect contacts should open only after the current flow has been completely interrupted by the current interrupting contacts, and it is also desirable that the current interrupting contacts close before the disconnect contacts on a closing operation in order to eliminate the necessity of providing fluid blast for the interrupting contacts during a closing operation.

Reliable sequencing ofthe operation of the current interrupting contacts and the disconnect contacts, coupled with the increasing demand for higher speed opening and reclosing operations presents, a diiiicult problem in the provision of a satisfactory circuit breaker.

An obiect of the inventionU is the provision oi a high voltage high power circuit interruptor o the iinid blast type having a set of current im terrupting contacts and a set of disconnect con-a tacts connected in series, and an improved compressed gas operating system capable of electing igh speed opening and closing of the two sets of contacts in a predetermined sequence.

Another object of the invention is the provision of a high voltage high power circuit interruptor vembodying an improved compressed gas operating system of simple construction for operating the current interrupting contacts and the disconnect contacts and correlating their motions to insure the proper sequence of operation.

other object of the invention is the provision f of a high voltage fluid blast type circuit interrupter comprising series connected current interf rupting contacts and disconnecting contacts, and `an improved compressed gas operating system for sequentially opening and closing both sets of confacts to always interrupt the circuit at the current interrupting contacts and close the circuit by the disconnect contacts.

Another object of the invention is the provision of a circuit interrupter having a set of current interrupting contacts and a set of disconnect con- Wllkinsburg, Creek, and Andrew H. Bakken,

Benjamin P.

y ors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application February 18, 1942, Serial No. 431,394

(Cl. ZOO-148) tacts connected in series each operated by a separate duid motor, the two motors being uid interlocked in a novel manner to provide the proper sequence of operation of the contacts, without the use of intermediate levers or other intermediate moving parts.

Another object of the invention is the provision of a fluid blast high voltage circuit interrupter having current interrupting contacts and disconnecting contacts, and an improved compressed air operating system for sequentially opening and sequentially closing the contacts and which is capable of eilecting rapid reversal of switching oper; ations.

Another object of the invention is the provision of a circuit interruptor embodying an improved compressed air operating mechanism capable of effecting high speed opening and closing of the interruptor and rapid reversal of switching operations.

Another object of the invention is the provision of a circuit interrupter embodying an improved compressed air operating means comprising an operating cylinder and double acting piston for opening and closing the interrupter, and means automatically operated by the ow of operating compressed air to one end of the cylinder for simultaneously establishing an exhaust connection to atmospherefor the opposite end of the cylinder so that the air in the cylinder ahead of the direction of movement of the piston will not retard the movement of the piston.

Another object of the invention is the provision of a circuit interrupter embodying an improved compressed air operating means comprising a cylinder and double acting piston for opening and closing the interruptor. and exhaust or dump valve means operated automatically in response to the flow of operating compressed air to either end y of the cylinder for dumping poslte end ofthe cylinder.

Another object of the invention is the provision of a high voltage circuit interruptor having series connected current interrupting contacts and disconnecting contacts. and a compressed air operating system for opening and closing the two sets of contacts in a predetermined sequence comprising a separate cylinder and double acting piston for each set of contacts. and dump valve means common to the two cylinders automatically operated by the flow of operating compressed air to dump the air from the portions of both cylinders ahead oi the direction of movement of the pistons.

Another object of the invention in accordance with a modication thereof is the provision of a the air from the opbeen cut ofi'.

Another object of the invention is the provision of an improved high voltage fluid blast circuit interrupter which is simple, reliable in operation and relatively inexpensive to manufacture.

The novel structural features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to structure and operation together with additional objects and advantages thereof will be best understood from the following detailed description of several embodiments thereof when read in conjunction with the accompanying drawings, in which:

Figure 1 is a side elevational view showing a high voltage circuit interrupter embodying the features of the invention;

Fig. 2 is an enlarged view, partly in section, showing the contact operating mechanism of the circuit interrupter.

Fig. 3 is a view, partly in section, of the arcing contact operating cylinder showing the dump valves and a portion of the pneumatic interlocking means, the view being taken at right angles to Fig. 2.

Fig. 4 is an enlarged fragmentary view, partly in section, showing the control valve assembly of the circuit interrupter.

Fig. 5 is a view, partly in section. of the control valve assembly shown in Fig. 4, as viewed at a right angle to Fig. 4.

Fig. 6 is an enlarged detail view, partly in section, of the opening valve mechanism of the circuit interrupter.

Fig. 'l is a diagrammatic view of the circuit interrupter and control circuits for controlling the operation thereof, and

Fig. 8 is detail view, partly in section, showing a modification of the invention.

Referring to the drawings, the reference numeral iI designates a framework which may be formed of structural steel or other suitable material. Rising from the left-hand side of the framework are a plurality of hollow supporting insulators I3` I5 and I 1, only the first two of which are shown in Fig. 1, and all three being indicated in Fig. 5. Supported upon the upper ends of the insulators I3, I 5, and |I is a casing I9 for housing operating mechanism more clearly shown in Fig. 2. The casing I9 supports a hollow insulator 2| which in turn supports a circuit interrupting element 23. A hollow insulator similar to insulator 2| extends upwardly from the circuit interrupting element 23 and has a metallic terminal cap 2'I secured to the upper end thereof.

A stationary contact member 29 extends downwardly from the terminal cap 2l through the hollow insulator 25, and the lower end of this contact member projects into the chamber of the circuit'interrupting element 23. A movable contact; member 3| cooperates with the stationary contact member 29 and extends downwardly through the interrupting element 23 and hollow insulator 2|. The lower end of the moving contact member 3| extends into the casing I9 and is rigidly connected to a corresponding piston of aso-ipse the operating means as shown in Fig. 2 and which will hereinafter be more fully described.

The contact members 29 and 3| form the arcing contacts which are openable to provide a current interrupting break in the circuit controlled by the circuit interrupter.

The circuit interrupter is also provided with n pair of disconnect contacts electrically connected in series with the contacts 29, 3|, and arranged to be operated in a predetermined scquence with the arcing contacts. The disconnect contacts comprise a relatively stationary disconnect contact member 33 mounted Within a terminal cap 35 of a hollow insulator 31, and :i cooperating movable disconnect contact member 39 supported on the casing I9. The stationary disconnect contact member 33 comprises an arm of conducting material plvotally mounted intermediate its ends by a pivot pin II on a bracket 43 secured to a plate within the terminal cap 35. The contact member 33 carries a cup-shaped finger contact assembly 45 at one end adapted to receive the free end of the movable disconnect contact member 39 in the closed position thereof. The finger contact assembly 45 is disposed in an opening formed by a sleet hood 45 provided on the terminal cap 35. Movement of the contact arm 33 about its pivot 4| is limited to a very small amount by stops (not shown). The contact arm is biased in a counterclockwise direction about its pivot 4I by a spring 5| which is compressed when the movable disconnect contact member 39 is in closed position. The tail portion 49 of the contact arm is connected by a flexible shunt conductor (not shown) to the terminal cap 35. The stationary disconnect contact assembly briefiy described above is fully disclosed and some features thereof claimed in the copending application of Raymond Leitzel et al., Serial No. 444,498, filed May 26, 1942, now Patent 2,356,069, issued August i5, 1944, which is assigned to the assignee of thc present invention.

The hollow insulator 31 having the terminal cap 35 is mounted on the right-hand end of the framework and this insulator serves as a housing for transformers and other suitable instruments for the control of the circuit interrupter.

The movable disconnect contact member 39 comprises a tubular hollow rod of conducting material and is mounted and guided in suitable bearings for straight line sliding movement in the direction of its longitudinal axis, the axis of movement being disposed at an angle to the axis of movement of the arcing contact member 3|. The contact member 39 is movable to a closed position in engagement with the stationary disconnect contact 33, and to the open position shown in Fig. 1 in which it provides an isolating break in the circuit capable of withstanding high voltages.

'I'he movable arcing contact member 3| is electrically connected to the movable disconnect contact member 39 through the agency of resilient connector contact means 53 (Fig. 2) which is slidably engaged by the contact member 3|, and by means of electrically connected conducting strips 55 and 51 which connect the contact means 53 to a similar connector contact means 59 in sliding engagement with the movable disconnect contact member 39. External circuit connections to the circuit interrupter are made to a terminal BI on the terminal cap 21 and to a terminal 63 on the terminal cap 35. Thus from the foregoing description it is apparent that when the circuit interrupter is in closed circuit position, the current flow proceeds from the terminal I, terminal cap 21, stationary arcing contact 29, movable arcing contact 3|, connector contact means 53, conducting strips 55 and 51, connector contact means 59, movable disconnect contact member 39, stationary disconnect contact 33 and terminal cap 3E to the terminal 63.

1i the movable arcing contact 3| is operated to the open circuit position while the circuit interrupter is carrying a load, an arc will be drawn by the movable arcin'g contact member. Extinction of the arc may be accomplished by any suitable type of arc extinguishing means but preferably by an arc extinguisher of the fluid blast type which, for example, may be of the form fully disclosed and claimed in the copending application of L. R. Ludwig and B. P. Baker, Serial No. 373,856, filed January 9, 1941, and assigned to the assignee of this application. Since the present application is not directed per se to the arc extinguishing structure, it is believed that the general designation of an arc extinguishing unit 95 which is supplied with a blast of arc extinguishing fluid, such as compressed air, will be sufflcient for the purpose at hand.

The movable arcing contact member 3| and the movable disconnect contact member 39 are operated in a predetermined sequence, to open and to closed position by a compressed air operating means which will be fully described hereinafter.

Fluid under pressure for extinguishing the arc l drawn by the arcing contact member 3|, and also for operating the contact members 3| and 39, is stored in a tank 61 mounted within the framework |I. Fluid, in this instance compressed air, is stored and maintained above a predetermined pressure in the tank 61. by a suitable motor driven compressor unit (not shown). Extending from the left-hand end of the tank 61 is an air conducting pipe or manifold G9 which has mounted thereon and in communication therewith, a blast valve mechanism indicated generally at 1|. The blast valve mechanism comprises a valve housing 13 which communicates with a short section of hollow pipe 15 and through the same with the passage through the hollow support insulator I3. The passage through the insulator I3 communi- Cates by way of a pipe 11 with the passage through the hollow insulator 2| which supports the circuit interrupting element 23. Thus vfluid under pressure from the tank G1 is conducted to the arc extinguishing structure 65 in the chamber of the circuit'interrupting element 23 by way of the manifold E9, blast valve 1I, pipe 15, hollow' insulator I3, pipe 11 and hollow insulator 2|.

The blast valve mechanism 1| is more clearly shown in Fig. 4. The blast valve housing 13 has a valve I9 therein which is operated to open and closed position by a rocker arm 8| carried by a shaft 83 journaled in the side of the valve housing 13. The rocker arm 8| is actuated by a piston 85 operated within a cylinder 81. A spring 89 disposed within the cylinder 81 normally biases the piston 85 downwardly and holds the valve closed.

The now of compressed air to the lower end of the cylinder 81 for causing opening of the blast valve is controlled by a pilot valve 9| which is normally biased closed and operated to open position by an electromagnet or solenoid 93. When the solenoid is energized, the pilot to open the blast valve 19 thereby permitting a blast of compressed air to .flow through the insulators I3 and 2| to the arc extinguisher 65.

When the solenoid 93 is deenergized the pilot valve closes, thereby causing the spring 89 to return the piston 85, and consequently the valve 19 to closed position shutting off the air blast.

The compressed air operating means for the contact members 3| and 39 comprises an oper- Iating cylinder 99 having a double acting piston |0| therein connected to the lower end of the movable arcing contact member 3|, and a second operating cylinder |03 having a double acting piston |05 therein connected to the inner end of the movable disconnect contact member 39. The cyllnders 99 and |03 are mounted in the housing I9, the cylinder 99 being secured at its lower end by bolts |01 to a casting |09 which is in turn bolted to the bottom |I| of the casing I9 and which forms the lower end closure of the cylinder. The lower portion of the contact rod 3| slidably extends, in a substantially fluid tight manner. through the offset portion of the blast air pipe 11 and through an opening in the upper head ol' the cylinder 99, the lower end of the contact rod 3| being connected to the piston IOI.

The body of the cylinder 99 has a laterally projecting portion ||3 (Fig. 3) adjacent the upper end thereof and formed integral therewith. The portion ||3 is provided with a passage H5 communicating with the interior of the upper end of the cylinder, and with a port in communication with the passage H5. A compressed air line or conduit ||1 is connected to the inlet port of the projection |I3 and this compressed air conduit communicates at its other end with the passage through the hollow insulator I1 and through a compressed air line or conduit I|9 (Fig. 5) to an opening valve means which controls the flow of compressed air for effecting an opening operation of the circuit interruptor. A similar projection |2| is formed integral with the body of the cylinder 99 adjacent the lower end thereof on the opposite side of the cylinder from the projection ||3. The projection I2| has an inlet passage |23 communicating with the interior of the lower end of the cylinder 99 and has an inlet port communicating with this passage. A compressed air line or conduit |25 (Fig. 2) is connected at one end to the inlet port oi the projection |2I and the other end of thecornpressed air line |25 is in communication through the passage of the lhollow insulator l5 and through the compressed air line |21 with a clos-A ing valve which controls the ow of compressed air for efecting a closing operation 0f the circuit interruptor.

The operating cylinder |03 for the movable disconnect contact member is mounted in the casing I9 and the upper portion of this cylinder extends outside of the casing I9 through an opening provided therefore man annular casting or support member |29 which is secured to a wall of the casing by a plurality of bolts |3I. The annular casting |29 forms a support for the cylinder |03. The lower end of the operating cylinder |03 yextends into a cylinder head |33 which closes the lower end of the cylinder, the cylinder head |33 being secured on the lower end of the cylinder by means of a plurality of elongated bolts |35 (only one being shown) which extend through a flange formed on the cylinder head and which thread into the annular support member |29. The upper end of the operating cylinder |03 extends into a cylinder head |31 which is securely clamped on the upper end of the cylinder by a plurality ot elongated bolts |39 (only one being shown) passing through a flange of the cylinder head |31 and threaded into the annular support member |29. A metal cover |4| is mounted on the cylinder head |31 and secured thereto by extensions of the bolts |39 which extend through a ange of the cover |4| and through the flange of the cylinder head |31. A closure cap |45 is tightly clamped over the upper end of the cylinder head |31 between the cylinder head and the cover 4| by means of the bolts |39. The tubular disconnect contact member 39 slidably extends into the cylinder 03 through bearing openings provided in the cover |4| and in the cylinder head |31. The cover |4| encloses the connector contact means 59 which resiliently and slidably engages the contact member 39. This contact means is electrically connected t the cap |45 and cylinder head |31 and the conducting strip 51, and the conducting strip 51 is electrically connected to the conducting strip 55 through the agency of a bolt (not shown), which clamps the ends of the strips 55 and 51 to the support member |29.

The lower cylinder head |33 is provided with passages |49 and |5| through which the compressed air for operating the disconnect contact 39 to closed position iiows into the lower end of the cylinder beneath the piston |05. The upper cylinder head |31 is also provided with passages |53 and |55 through which compressed air is admitted to the upper end of the cylinder above the piston |05 to operate the disconnect contact member 39 to open position. A sleet hood |51 encloses the exposed portion o! the cylinder assembly |03 and this sleet hood is secured by bolts (not shown) to the wall of the casing adjacent the support member |29.

Compressed air from th'e tank 61 is utilized to actuate the contact operating pistons 0| and |05. For this purpose, the manifold or pipe 69 is provided with two branches |59 and |6| (Fig. 5). The branch |59 leads to the opening valve mechanism generally indicated at I 63 whereas the branch |6| leads to the closing valve mechanism generally indicated at |65.

The compressed air from the opening valve mechanism |63 is conducting through the pipe ||9 to the passage through the supporting insulator I1 and through the compressed air line ||1 to the upper end of the operating cylinder 99 to eifect opening of the circuit interrupter. Compressed air for effecting closing operation of the circuit interruptor flows through the closing valve mechanism |65, pipe |21 and the passage through the hollowV insulator I5 and compressed air line |25 into the lower end of the operating cylinder 99.

It is important that the

disconnect contacts

33 and 39 should be open onlly after the arcing contacts 29, 3| have opened and the current iiow has been completely interrupted by the East-mentioned contacts; otherwise a long uncontrolled arc may be drawn by the movable disconnect contact member 39. 1t is also desirable that the disconnect contacts should close after the arcing contacts have closed during a closing operation of the circuit interrupter so as to eliminate the necessity of providing a blast oi' arc extinguishing iluid for the arcing contacts during closing of the interrupter. In accordance with the present invention, the proper sequence of operation of the arcing contacts in the disconnect contacts is accomplished by pneumatically interlocking the operating pistons for the two sets of contacts. For this purpose, the operating cylinder 99 of the disconnect contact member of the arcing contact member is provided with a projection |59 (Fig. 3) lformed integral with the cylinder adjacent the upper end thereof directly opposite the projection |I3. The projection |69 has an air passage 1| formed therein which communicates at one end with the interior of the cylinder at a point which is a predetermined distance below the upper end of the cylinder. The other end oi' the passage |1| communicates with a port provided in the projection |69 and this port is connected by a compressed air line or conduit |13 and a compressed air line or conduit |15 to the passages in the cylinder head |31 leading to the upper end of the disconnect contact operating cylinder i 03. The compressed air lines |13 and |15 communicate with one another through an air passage |11 formed in the annular support member |29. The point of entry of the passage |1| into the cylinder 99 is so located that it is uncovered by the operating piston after the piston has moved downwardly a. predetermined distance in an opening direction, the distance being such that the movable arcing contact member 3| will have reached its full open position bei'ore the flow of compressed air through the compressed air lines |13 and |15 starts to move the disconnect contact member 39 out of engagement with the stationary disconnect contact 33. This arrangement allows the movable arcing contact member 3| to overcome static friction and come up almost to full speed and slide out of engagement with its stationary contact 29 before compressed air is admitted to the upper end of the disconnect contact operating cylinder |03. This insures that interruption of the current flow will also be completed before the disconnect contacts separate.

The lower ends of the operating cylinders 55 and |03 are also pneumtaically interlocked to secure the proper sequence of operation of the arcing contacts and the disconnect contacts during a closing operation of the circuit interrupter. For this purpose the operating cylinder is provided with a projection |19 (Fig. 3) formed integral with the cylinder adjacent the lower end thereof, and this projection has a passage |3| therein which communicates at one end with the interior of the cylinder at a point a predetermined distance above the lower end oi.' the cylinder. The other end of the passage |9| communicates with a port formed in the projection |19 and this port is connected by a compressed air line or conduit |63 (Fig. 2) to the passage leading to the lower end of the disconnect contact operating cylinder |03. The point oi' entry of the passage |0| into the cylinder is located so that it is uncovered by the operating piston |0| after the piston is moved upwardly a predetermined distance in a closing direction, the location being such that the arcing contacts 29 and 3| will be completely closed before the compressed air closes the disconnecting contact member 39.

The pneumatic interlocking arrangement described above is much simpler and more reliable than mechanical or electrical interlocking arrangements for sequence operations.

In order to obtain a prompt and fast opening "mosphere through an exhaust port 205.

operation following immediately after a closing operation of the interrupter, and to obtain a quick and fact closing operation immediately after an opening operation of the interrupter, it is necessary that the air in front of the direction of the movement of both pistons be quickly exhausted to atmosphere so as not to retard the switching motion of'the pistons. In accordance with the present invention, this is accomplished by the provision of two dump valves one of which opens the lower end of each of the cylinders 99 and |03 to atmosphere and is operated by the flow of compressed air to the upper end of the cylinder 99, and the other of which opens the upper end of the two cylinders 99 and |03 to atmosphere immediately upon the flow of compressed air to the lower end of the operating cylinder 99.

Referring to Fig. 3, a dump valve |81 is mounted within the cylinder projection |19 in the air passage |8|. The dump valve |81 is connected by a rod |89 to a/,piston I9I vslidably mounted in a. cylinder |93 formed in the projection I3 which contains the inletl passage I for the opening air. The top of the piston I9| is in communication with the passage ||5 so that it is moved downwardly immediately upon the flow of compressed air into the upper end of the operating cylinder 99. This downward movement of the piston I9| by the opening air affects opening of the dump valve |01 thereby establishing communication between the passage |8I adjacent the lower end of the cylinder 99 and atmosphere through an atmosphere exhaust port |95. v Since the passage IBI is in communication with the lower end of the operating cylinder 99 and also the lower end of the operating cylinder |03, opening of the dump valve |81 opens the lower end of both cylinders to atmosphere through the exhaust port |95.

A similar dump valve |91 is mounted in the passage I1I of the 'projection |69 adjacent the upper end of the operating cylinder 99. The dump valve |91 is connected by a rod |99 to a piston 20| which is slidable in a cylinder 203 formed in the projection |2I of the operating cylinder containing the passage |23 for admitting closing air to the lower end of the operating cylinder 99. When compressed air is admitted to the lower end of the operating cylinder 99 through the passage |23 to effect a closing operation of the interrupter, the piston 20| is immediately moved upwardly by the flow of compressed air and thereby effects opening of the dumpvvalve |91 at the opening end of the operating cylinder 99. When the dump valve |91 is moved to open position it establishes communication between the passage I1I and outside at- Since the passage |1| is in communication with the upper ends of both operating cylinders 99 and |03, the opening of the dump valve |91 opens the upper ends of both cylinders to atmosphere through the exhaust port 205. The dump valves |81 and |91 are normally biased to closed position by compression springs 201. The compression spring 201 of the valve |81 encircles a portion of the rod |99 and is disposed betweenI a collar on the rod and the projection |19. Similarly, the compression spring 201 for the valve |91 encircles a portion of the rod |99 and is disposed between a collar on the rod and the projection |69.

The provision of the dump valves |81 and |91 and the operation thereof described above ensures low pressure ahead of the direction of moveno D ment of both pistons I0| and |05 and consequently high speed operation of the contact members regardless of when the interrupter has received an operating impulse thus providing for high speed opening and also for high speed reclosing of the contacts of the circuit interrupter.

Referring to Fig. 6, the opening valve mechanism |63 comprises a valve housing 209 having a valve 2|3 adjacent the lower end thereof. The valve 2I3 has a stem 2|5 encircled by a spring 2|1 for normally holding the valve closed. The

valve stem 2|5 is actuated to open position by a piston 2I9 operative within the housing 209, and the piston has an upper effective pressure reactive area greater than the'lower area of the piston so that when the upper side of the piston is subjected to compressed air from the pipe |59, the piston will be moved into engagement with the stem 2|5 to actuate the valve 2I3 to open position. Compressed air is admitted from the pipe |59 to the upper side of the piston 2I9 through passages 22| and 223. Control of the flow of compressed air through these passages is obtained by an electromagnetically operated pilot valve 225 which is biased closed and adapted to be opened by a solenoid 221. Upon opening of the main valve 2|3, compressed air is permitted to flow from the pipe |59 through a main port 229 into the pipe II9. The flow of compressed air then proceeds through the pipe I I9, hollow in- Sulator IT, and pipe I|1 to the upper side of the arcing contact operating piston IOI in the operating cylinder 99 so as to actuate the piston IOI to downwardly open circuit position andr cause operation of the arcing contact 3| to open position and to also open the

disconnect contacts

33, 39

after the opening of the arcing contacts. `When the pilot Valve 225 is closed, uponv deenergization of the solenoid 221, pressure is relieved on top of the piston 2|9 and the piston is moved to its upper or normal position by a spring 23|. The piston 2I9 has a sleeve 233 secured to the lower side thereof which serves to control a small bleeder passage 235 disposed in the housing 209. When the piston 2I9 is lin its uppermost position, the sleeve 233 uncovers the bleeder passage 235, thereby connecting the upper Side of the operating piston |0| to atmosphere. However, during the initial stages of movement of the piston 2I9 towards the valve stem 2|5, the bleeder passage 235 is closed by the sleeve 233.

The closing valve mechanism |55 is generally similar to the opening valve mechanism |63 and is more fully illustrated in Fig. 5. Referring to Fig. 5, this mechanism includes the valve housing 239 having a valve 24| operative adjacent the lower end thereof. The 'valve 24| has a stem 243 that is spring actuated to closedposition. The

valve stem 243, however, in this instance has an extension 245, the purpose of which will appear more fully hereinafter. Actuation of the valve 24| to open position is accomplished by the piston 241 operative within the valve housing 239 and slidableabout the extension 245.

Control of the flow of compressed air from the pipe I6I to the topof the piston 241 is obtained by an electromagnetically controlled pilot valve 249 which is biased closed, and which is operated to open position by a solenoid 25|. When the solenoid 25| is energized, the-pilot valve 249 opens to permit a flow of compressed air from the pipe to the upper side of the piston 241 which actuates the piston downwardly against the stem 243 so as to open the main valve 24 I. Compressed air will then flow from the pipe |6| through a port similar to port 229 of the opening valve. Compressed air then iiows through the pipe |21, hollow insulator I5 and pipe |25 to the lower side of the arcing contact operating piston IOI so as to actuate the movable arcng contact member 3| to the closed circuit position and to also close the disconnect contacts 33-39 after the closing of the arcing contacts. The piston .241 of the closing valve also controls a small bleeder passage 253 for the purpose of connecting the lower side of the operating piston |I to atmosphere at the end of a closing operation.

In order to prevent improper operation of the operating mechanism which may be caused by conflicting control impulses being impressed upon the

valve controlling solenoids

221 and 25|, an interlock is provided between the opening and closing valve mechanisms |03 and |55. For this purpose, the upper end of the closing valve housing 239 is provided with a cylinder 255 lnto which the extension 245 of the valve stem 243 extends. Operative within the cylinder 255 is a piston 251 normally urged to its lowermost position by a spring 259. The upper end of the extension 245 is provided with a stop such as a nut and washer arrangement 26| against which the interlock piston 251 may be moved. The lower end 0f the cylinder 255 communicates by means of a pipe 263 to the valve housing 209 oi the opening valve and with the port 220 of that housing. Thus when the valve 2I3 of the opening valve mechanism |63V is open, compressed air may ilow through the pipe 263 to the lower side of the interlock piston 251 so as to raise that piston against the stop 25|. The eiective iluid pressure area of the interlock piston 251 is made larger than the effective fluid pressure area of the piston 241 so that if the electromagnetlcally actuated pilot valve 249 is opened to admit compressed air to the top of the piston 241 tending to move the piston downwardly to open the valve 24|, the force exerted upon the valve in a downward direction will be less than the force exerted by the interlock piston 251 in the upper direction. Consequently, the closing valve 24| will remain closed, and the opening valve 2I3 of the opening valve mechanism |63 will function in its normal manner to complete the opening operation. It will thus be seen that an opening impulse will always take preference over a closing impulse by reason of the Iinterlocking arrangement between the opening and closing valves.

An auxiliary switch means 255 (Fig. 1) is mounted on the framework I| adjacent the insulator I3. The auxiliary switch means 255 may be of any conventional'construction embodying a plurality of sets of contacts forming a plurality of poles for control and indicating purposes. The operating lever of the auxiliary switch means 265 is connected by a

linkage system

261, 200 and 21| to a rotatable member or Vcrank arm 213 mounted on the lower cylinder head |33 of the disconnect contact operating cylinder |03. The rotatable member 213 is adapted to be partially rotated in opposite directions by the reciprocating movement of the disconnect operating piston |05, thereby operating the auxiliary switch means in accordance with the position of the movable disconnect contact member 30. The coupling means between the auxiliary switch means and the operating piston |05 is fully disclosed and claimed in the copending application of B. P. Baker and A. H. Bakken, Serial No. 431,395, led February 18, 1942, and issued November 21, 1944, as Patent No.

2,363,283, to the assignee of the present invention.

Referring now to Fig. 7, which diagrammatically shows the circuits for electrically controlling the circuit interrupter, 215 and 211 designate a pair of supply conductors connected to a source of electrical energy (not shown). The winding oi' the solenoid 25| which controls the admission of compressed air to the operating cylinders for closing the contact members of the circuit interrupter is connected in an energized circuit 210 extending from the supply conductor 215 through the winding of the solenoid 25| and front contacts 20| of a closing relay 203 to the supply conductor 211. The energizing winding o! the closing relay 203 is connected in an energizing circuit which extends from the supply conductor 211 through a conductor 205, back contacts 201 of a release relay 200, energizing winding of the closing relay 203, conductor 20|, conductor 293 and through a manual closing control switch 295 and conductor 201 to the supply conductor 215. A reclosing relay 200 has contacts 30| connected in shunt to the closing control switch 295, The reclosing relay 200 may be energized to automatically reclose the circuit mterrupter in a manner well known in the art.

'The energizing winding of the release relay 200 is connected in an energizing circuit which extends from the supply conductor 211 through a conductor 303, through an auxiliary switch 300 which is adapted to be closed when the disconnect contact member 39 ofthe circuit interrupter reaches closed position, through a conductor 301, energizing winding of the release relay 203, conductor 300, through front contacts 3II of the closing relay 203 and through a conductor 3|! to the supply conductor 215.

A stick circuit is provided for maintaining the closing relay 203 energized after a momentary operation of the manual closing control switch 295 or the contacts 30| of the recloslng relay. This stick circuit extends from the supply conductor 211 through the conductor 205, back contacts 201 of the relay 209, conductor 3|5, energizing winding of the closing relay 203, conductor 29| and front contacts 3II of the closing relay and through conductor 3 I 3 to the supply conductor 215.

A locking circuit is also provided for maintaining the release relay 200 energized after the disconnect contacts of the interrupter close and until the manual closing control switch 205 has been opened. This locking circuit for the release relay 209 extends from the supply conductor 211 through conductor 205, front contacts 3|1 of release relay 209, through the winding of the release relay 209. conductor 203, manual closing control switch 205 and conductor 201 to the supply conductor 215. The purpose of this locking circuit is to prevent pumping of the circuit interrupter in the event that the circuit interrupter fails to remain closed and the manual closing control switch 295 is held by the operator in closed position.

The winding of the solenoid 221 for controlling the opening valve |63 which controls the flow of compressed air to the cylinder 00 for effecting opening operation of the circuit interrupter, and the winding of the solenoid 93 which controls opening oi .the blast valve 1I are connected in parallel in an energizing circuit which extends from the supply conductor 215 through a conductor 32|, front contacts 323 of an opening relay 325, conductor 321, the energizing windthe'blast valve mechanism 1| ings o! the

solenoids

221 and 93 in parallel, conductor 329, through auxiliary contacts 33|'which are open when the disconnect contact member 39 is in open position, and throughconductor 303 to the supply conductor 211. The branch or portion of the circuit including the winding of the solenoid 93 has a .pair of auxiliary Icontacts 330 connected in series with the winding of sole-'- noid 93, and these auxiliary contacts open as soon as the disconnect contact member 39 starts its opening movement, thereby deenergizing the solenoid 93 so that the blast valve returns to closed position.

The energizing winding of the opening relay 325 is connected in an energizing circuit which extends from the supply conductor 215 through conductor 291, through the contacts 333 of a protective relay 335 through conductor 331, energizing winding of opening relay 325, conductor 339 through auxiliary contacts 34| which are closed when the disconnect contact member 39 is in closed position and which are opened when the disconnect contact member reaches full open position, and through conductor 303 to .the supply conductor 211.

A manual opening lcontrol switch 343 is connected in shunt to the contacts 333 of the protective `relay for the purpose of manually controlling opening of the circuit interrupter by energizing the opening relay over the circuit previously described.

A stick circuit is provided for maintaining the opening relay 325 energized after a momentary closing of the

contacts

333 or 343 and until the disconnect contact member 39 reaches full open position. This stick circuit extends from the conductor 215I through a portion of conductor 32|, front contacts 345 of .the opening relay 325,

energizing winding of the opening relay 325, cone ductor 339, auxiliary contacts 34|, and conductor 303 to the supply conductor 211'.

A circuit interrupter is adapted to be quickly automatically reclosed immediately following opening of the disconnect contact member 39 through the agency of the reclosing relay 299 providing the circuit of the reclosing relay is rendered operative by a manual control switch 35|. If quick automatic reclosing is not desired, the manual switch 35| may be opened thus rendering reclosing relay 299 inoperative.

The protective relay 335 maybe of the current overload type which is operative in response to an overload in the main circuit 353 controlled by the circuit interrupter. The operating coil of the protective relay 3351s adapted to be energized through the agency of a current transformer 355 associated with the main circuit conductor 353. j

' The operation of the circuit interrupter is as follows: Assuming the lcircuit interrupter to be in closed position as shown in Fig. '7, when a ypredetermined overload ror short circuitoccurs in the main circuit 353 controlled by the interrupter, `the protective relay 335 is immediately energized and closes `its contacts 333 to effect energlzation of the opening relay 325. The operationof the "opening relay 325 completes the ener- 'gizing circuit for the solenoid 221 of the 'opening valve'rv mechanism |63 and for the solenoid 93 of n Compressed air from'the tank 61 then ows through the opening 'valve |63, through passages previously described, into the upper end of the operating cyl- 'inder 99 lto effectl downward movement of the i piston thereby operating 4the movable arcing contact member 3| to open position.v At the same time, the Ilow of compressed air to the upper end of the operating cylinder 99 opens the dump valve |81 thereby connectingthe lower ends of the operating'cylinders 99and|03 to atmosphere. AsA soon as' the arcing contact operating piston 0| has moved a predetermined distance in an opening direction, it uncovers a port connected .to the pipe |13 to admit compressed air to the upper end of the disconnect operating cylinder |03 through the pipe |13. By the time the contact member 3| reaches full open position, the

D flow of compressed air into the operating cylinthe closing valve and admitting compressed air` ing valve |63 by deenergizing the solenoid 221 which controls this valve.

During the opening operation of the arcing contact member 3|, a blast of compressed air is directed to the arcing contacts in interrupting element 23 to quickly extinguish the arc drawn by these contacts.v This blast valve returns to closed position, however, as soon as the disconnect contact member 39 starts to open.

I The circuit interrupter is adapted to be quiskly automatically reclosed immediately* following an opening operation'thereof through the agency of the reclosing relay 299, energzation of which may be effected by auxiliary contacts (not shown) operated when the disconnect contact member 39 reaches open position. Closing of the reclosing relay contacts 30| completes an energizing circuit for the closing relay 203. When `the closing relay 283 is energized, "it completes its previously described vcircuit for energizing the winding 25| of the closing valve mechanism |65 thereby opening to the lower end of the operating cylinderv 99. The

flow of compressed'air to the lower end of the operating cylinder immediately effects opening of the dump valve |91 which opens the upper ends of the cylinders 99 and |03 to atmosphere. The compressed air admitted to the lower side of the piston |0| moves thispiston upwardly to effect movement of the arcing contact member 3| to closed position. After the operating piston 0| is moved upwardly a predeterminedvdistance, it4

uncovers the port which is connected by the pipe |83 to thelozrwei` end of the cylinder |03, thereby admittingcompressed air'to the lower end of the disconnect contact operating cylinder |03.- After the arcing contact member 3| has reached' closed position, the compressed air admitted to the lower side of the operating piston |05 effects movement vof the piston upwardly thereby moving the disconnect contactl member 39 toI closed position. As soon as the disconnect `contact member 39reaches closed position, the auxiliary contacts 305 close and'effect energizatiori of the release relay 289. Energization of the release relay 209 eiTects deenergization of the closingrelay' 283 by opening of thecontacts 281. The release relay 289 is then deenergized bythe opening of the conf tacts 3|| o1' the closing relay.' When the closing relay 283 drops out, the solenoid 25| is deenergized and the closing valve |65 returns to closed position.

It the fault condition which caused opening of the breaker has cleared by the time the disconnect contact member reaches closed position, the circuit interrupter will remain closed. However, if the fault condition is still present upon closing of the disconnect contacts, the protective relay 335 will again be energized and immediately effect opening operation in the manner previously described. A lockout device may be provided in the automatic reclosing circuit to limit the number of automatic reclosing operations to one or any other desired number in a manner well known in the art.

Since the main conductor circuit may be completed slightly before the disconnect contact member reaches the fully closed position, faultresponsive relay 335 may be energized prior to complete closing of the interrupter if a fault condition is present in the main circuit. Under such conditions, the opening relay eiiects opening of the valve mechanism i 63 and this will result in quick reversal of the switching operation from closing to opening due to the fact that the opening and closing valves are interlocked in the manner previously described, whereby an opening impulse will always take precedence over a closing impulse.

The pneumatic interlocking arrangement of the two operating cylinders insures the proper sequence of operation of the contact members 3i and 38 irrespective of the speed of operation oi the operating means, and the dump valve arrangement previously described provides for high speed opening and reclosing operations of the interrupter.

In accordance with a modification of the invention, the arcing contact member 3| may be automatically returned to closed position immediately after the supply of opening air is cut off. in order to remove potential across these contacts. For this purpose a spring 36| may be provided as indicated in Fig. 8 for biasing the movable arcing contact member 3l to closed position. The spring does not otherwise aiiect the operation oi' the system which is the same as that previously described. The flow of compressed air to the lower end of the operating cylinder 99 in this instance insures that the arcing contact member 3l will be moved to the fully closed position before the disconnect contacts are closed.

While the invention has been disclosed in ac cordance with the provisions of the patent statutes, it is to be understood that various changes in the structurey details and arrangement of parts thereof may be made without departing from some of the essential features of the invention It is desired, therefore, that the language of the appended claims be given the broadest reasonable interpretation permissible in the light of the prior` art.

We claim as our invention:

1. A circuit interrupter comprising a. pair of current interrupting contacts, a pair of disconnect contacts connected in series therewith, compressed gas operating means for opening said pairs of contacts in a predetermined sequence and for c losing said pairs of contacts in a predetermined sequence, said operating means comprising a double acting compressedl gas motor for opening and closing said current interrupting contacts, a separate double acting compressed gas motor for opening and closing said disconnect contacts, a

source of compressed gas for operating said motors, control valve means for controlling the flow of compressed gas to the motor of said current interrupting contacts to effect opening or closing of the circuit interrupter, and means pneumatically interlocking said motors to cause said disconnect contacts to be opened only after said current interrupting contacts have opened a predetermined distance during opening operation of the circuit interrupter and for causing said disconnect contacts to close after said current in terrupting contacts are completely closed during closing operation of the interrupter, said interlocking means comprising gas connections for admitting compressed gas to said disconnect contact motor arranged to be opened and 'closed by said current interrupting contact motor.

2. A circuit interrupter comprising a pair of current interrupting contacts, a pair of disconnect contacts connected in series therewith, compressed air operating means for opening said pairs of contacts in a predetermined sequence and for closing said contacts in a predetermined sequence, said operating means comprising a separate double acting compressed air motor for each pair of contacts for opening and closing the same. a source of compressed air for actuating said motors, control valve means for controlling the flow of compressed air to said motors for eiiecting opening and closing of the circuit interrupter, and means pneumatically interlocking said motors for causing said disconnect contacts to open only after said current interrupting contacts have opened a predetermined distance during opening operation of the circuit interrupter and for causing said pairs of contacts to be closed in a predetermined sequence during a closing operation of the interrupter, said pneumatic interlocking means comprising air passages connecting said motors and controlled by said current interrupting contact motor to admit compressed air to said disconnect contact motor.

3. A circuit interrupter comprising a pair oi current interrupting contacts, a pair of disconnecting contacts connected in series therewith, compressed gas operating means for opening and closing said contacts, said operating means including a separate cylinder and piston for each pair of contacts, a source of compressed gas for operating said contacts, opening valve means for controlling the ow of compressed gas to one end of the operating cylinder for said interrupting contacts for opening the contacts, closing valve means for controlling the flow of compressed gas to the other end of the operating cylinder o! said interrupting contacts for closing the contacts, and

means comprising gas passages connecting the' ends of the operating cylinder of said disconnecting contacts to predetermined points of said interrupting contact operating cylinder for pneumatically interlocking said contacts to cause said disconnecting contacts to open after said interrupting contacts have opened a predetermined distance during opening operation of the interrupter and to cause said disconnecting contacts to close after said interrupting contacts have closed during closing operation ot the interrupter.

4. A circuit interrupter comprising a pair of current interrupting contacts, a pair of disconnect contacts connected in series therewith, compressed air operating means for opening said pairs of contacts in a predetermined sequence and for closing said pairs of contacts in a. predetermined sequence, said operating means including a cylinder anddouble actdngpiston therein for opening and closing said current interrupting contacts. another cylinder and double acting piston therein for opening and closing said disconnect contacts. a source of compressed air for operating said pistons, opening valve means for controlling the iiow of compressed air to one end of the current interrupting contact operating cylinder to eiect opening operation of the circuit interrupter, means separate from said opening valve means operable to cause a blast of compressed air to extinguish the arc drawn between said current interrupting contacts during opening of said contacts, closing valve means for controlling the flow of compressed air to the opposite end of said current interrupting contact operating cylinder to etect'closing operation of the circuit interrupter, and means including a pair of air passages connecting the ends of said disconnect contact operating cylinder to predetermined points of said current interrupting contact operating cylinder for pneumatically :nterlocking said pistons to cause said disconnect contacts to be opened only after said current interrupting contacts have opened a predetermined distance during opening operations of the circuit interrupter and to cause said disconnect contacts to close after said circuit interrupting contacts during closing operation of the interrupter.

5. A vcircuit interrupter comprising a pair of current interrupting contacts, a pair of disconnect contacts connected in series therewith, compressed air operating means for opening saidpairs of contacts in a predetermined sequence and for closing said pairs of contacts, said operating means including a cylinder and double acting piston therein for opening and closing said current interrupting contacts, another cylinder and double acting piston therein for opening and closing said disconnect contacts, a source of compressed air for operating said pistons, opening valve means for controlling the flow of compressed air to the opening end of said current` interrupting contact operating cylinder to effect opening operation of the circuit interrupter, closing valve means for controlling the flow of compressed air to the closing end of said cylinders to eil'ect a closing operation of the circuit interrupter, means including an air passage connecting the opening end of the disconnect contact operating cylinder to a predetermined point of the current interrupting contact operating cylinder for causing said disconnect contacts to be opened only after said current interrupting contacts have opened a predetermined distance during opening operations of the circuit interrupter, and a single dump valve means operated by the ilow of compressed air to the opening end of said current interrupting contact operating cylinder for dumping air from the closing ends of both of said cylinders directly toatmosphere.

6. A circuit interrupter comprising a pair of current interrupting contacts, a pair of disconnecting contacts connected in series therewith, compressed air operating means for opening said pairs of contacts in a predetermined sequence and for closing said pairs of contacts, said operating means comprising a cylinder and double acting piston therein for opening and closing said current interrupting contacts, another cylinder and double acting piston therein for opening and closing said disconnect contacts, a source of compressed air for operating said pistons, opening valve means for controlling the flow of compresed air to the opening end ot said current interrupting contact operating cylinder to effect circuit opening operation of the circuit interrupter, closing valve means for controlling the flow of compressed air to the closing end of said current interrupting contact operating cylinder to eiect closing operation of the circuit interrupter, means including a pair of air lines connecting the ends of said disconnect contact operating cylinder to predetermined points of said current interrupting contact operating cylinder for causing said disconnect contacts to be opened only after said current interrupting contacts have opened a predetermined distance during an opening operation and for causing said disconnect contacts to close after said current interrupting contacts during a closing operation, dump valve means operated by the now of compressed air to the opening end of said current interrupting contact operating cylinder for simultaneously dumping air from the closing ends of said cylinders to atmosphere, and a single dump valve means operated by the flow of compressed air to the closing end of said current interrupting contact operating cylinder for simultaneously dumping air from the opening ends of both Aof said cylinders to atmosphere.

'7. A circuit interrupter comprising a pair of current interrupting contacts, a pair of disconnecting contacts connected in series therewith, compressed air operating means for opening said pairs of contacts in a predetermined sequence and for closing said pairs of contacts, said operating means comprising a cylinder and double acting piston therein for opening and closing said current interrupting contacts, another cylinder and double acting piston therein for opening and closing said disconnect contacts, a source of compressed air for operating said pistons, opening valve means for controlling the flow of compressed air to the opening end of said current interrupting contact operating cylinder to eilect opening operation o! the circuit interrupter, closing valve means for controlling the flow of compressed air to the closing ends of said cylinders to eiiect closing operation of the circuit interrupter, means including an air passage connecting the end of said disconnect contact operating cylinder to a predetermined point of said current interrupting contact operating cylinder for causing said disconnect contacts to be opened only after said current interrupting contacts have opened a predetermined distance during opening operation of the circuit interrupter, and a single dump valve means operated by the iiow of closing compressed air for causing the dumping of air from the opening ends of both of said cylinders to atmosphere.

8, A circuit interrupter comprising a pair of current interrupting contacts, a pair of discon- ,necting contacts connected in series therewith,y

compressed air operating means for opening said pairs of con'tacts in a Apredetermined sequence and for closing said pairs of contacts, said operating means comprising a cylinder and double acting piston therein for opening and closing said current interrupting contacts, another cylinder and double acting piston therein for opening and closing said disconnect contacts, a source of compressed air for operating said pistons, opening valve means for controlling the ow of compressed air to the opening end of said current interrupting contact operating cylinder to eilect opening operation of the circuit interrupter, closing valve means for controlling the now of compressed air to the closing ends of said cylinders to effect closing operation of the circuit interrupter, means including an air passage connecting the end of said disconnect contact operating cylinder to a predetermined point oi" said current interrupting contact operating cylinder for causing said disconnect contacts to be opened only after said current interrupting contacts have opened a predetermined distance during opening operation of the circuit interrupter, and a single dump valve means operated by the flow of closing compressed air for causing the dumping of air from the opening ends of both said cylinders to atmosphere, and a single dump valve means operated by the iiow of compressed air to the opening end of said circuit interrupting contact operating cylinder for dumping air from the closing ends of both of said cylinders to atmosphere.

9. A circuit interrupter comprising a pair of current interrupting contacts, a pair of disconnect contacts connected in series therewith, compressed air operating means for opening and closing said pairs of contacts, said operating means comprising a cylinder and piston therein for operating said current interrupting contacts, another cylinder and double acting piston therein for opening and closing said disconnect contacts, a source of compressed air for operating said pistons, opening valve means for controlling the flow of compressed air to one end of said current interrupting contact operating cylinder to effect opening operation of the circuit interrupter, closingvaive means for controlling the iiow of compressed air to one of said cylinders for effecting closing operation of the circuit interrupter, means including an air passage connecting the opening end of said disconnect contact operating cylinder to a predetermined point of said current interrupting contact operating cylinder for causing said disconnect contacts to be opened only after said current interrupting contacts have opened a predetermined distance during opening operation of the circuit interrupter, and spring means operable to effect reclosing of said current interrupting contacts after closing said current interrupting contacts, an-

other cylinder and double acting piston therein for opening and closing said disconnect contacts, a source of compressed gas for operating said pistons, opening valve means for controlling the .flow of compressed gas to one end of said arcing contact operating cylinder to effect opening operation of the circuit interrupter, closing valve means for controlling the flow of compressed gas to the opposite end of said arcing contact operating cylinder to eil'ect closing operation of the circuit interrupter, means including a pair of gas passages connecting the ends oi' said disconnect contact operating cylinder to predetermined points of said arcing contact operating cylinder for causing said disconnect contacts to be opened only after said arcing contacts have opened a predetermined distance during opening opera-A tion of the` circuit interrupter, and for causing closing of said pairs of contacts in a predetermined sequence during closing operation of the circuit interrupter, and spring means operable to reclose 'said arcing contacts after the compressed air for opening the circuit interrupter is shut off.

11. A circuit interrupter comprising a base, supporting insulator means mounted on said base, an arc extinguishing device carried by said insulator means, said arc extinguishing device having a pair of separable arcing contacts for establishing a current interrupting break, a pair oi disconnect contacts connected in series with said arcing contacts, one of said disconnect contacts being movable to establish an isolating break, and being electrically connected to one of said arcing contacts, compressed air operating means for opening said pairs oi contacts in a predetermined sequence, and for closing said pairs of contacts, said operating means comprising a cylinder and double acting piston therein for opening and closing said arcing contacts, another cylinder and double acting piston therein for opening and closing said disconnect contacts, a source of compressed air for operating said pistons, said pistons and cylinders being disposed at line potential and supported by said insulator means, opening valve means for controlling the iiow of compressed air to one end of the arcing contact operating cylinder to effect opening operation of the circuit interrupter, closing valve means for controlling the iiow of compressed air to an end of one of said cylinders to effect closing operation of the circuit interrupter, and means including a pair of air passages connecting predetermined points of said cylinders together for causing said disconnect contacts to be opened only after said arcing contacts have opened a predetermined distance during opening operation of the circuit interrupter and for causing said pairs of contacts to close in a predetermined sequence.

LEON R. LUDWIG. BENJAMIN P. BAKER. ANDREW H. BAKKEN.