US3023291A

US3023291A - Compressed gas circuit interrupter

Info

Publication number: US3023291A
Application number: US837227A
Authority: US
Inventors: Otto H Soles; Richard E Kane
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1959-08-31
Filing date: 1959-08-31
Publication date: 1962-02-27
Anticipated expiration: 1979-02-27

Description

Feb. 27, 1962 o. H. SOLES ETAL COMPRESSED GAS CIRCUIT INTERRUPTER 5 Sheets-Sheet 1 Filed Aug. 31. 1959 Feb. 27, 1962 o. H. sou-:s ETAL 3,

COMPRESSED GAS CIRCUIT INTERRUPTER Filed Aug. 31, 1959 5 Sheets-Sheet 2 Feb. 27, 1962 o. H. SOLES ETAL 3,023,291

COMPRESSED GAS CIRCUIT INTERRUPTER Filed Aug. 31, 1959 5 Sheets-Sheet 3 Fig.3.

Feb. 27, 1962 o. H. soLEs ETAL 3,023,291

COMPRESSED GAS CIRCUIT INTERRUPTER Filed Aug. 31, 1959 5 Sheets-Sheet 4 -|e| 17a -|ao 269 268 i Q I73 I65 I66 7 11 I77 I64 I67 E I72 47a.

Feb. 27, 1962 o. H. SOLES ETAL 3,023,291

COMPRESSED GAS CIRCUIT INTERRUPTER Filed Aug. 51, 1959 5 Sheets-Sheet 5 I39 I27 L l T /%W [27,4 m\\\\\\ Fig.6

Fig.7

l 56 ri-i United States Patent 3,023,291 COMPRESSED GAS CIRCUIT INTERRUPTER Otto H. Soles, East Pittsburgh, and Richard E. Kane,

Monroeville, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Aug. 31, 1959, Ser. No. 837,227 6 Claims. (Cl. 200148) This invention relates generally to compressed gas circuit interrupters, and, more particularly to compressed gas circuit interrupters particularly adaptable for automatic reclosing operation.

This invention is an improvement upon the compressed gas circuit interrupter as disclosed and claimed in copending application Serial No. 590,066, filed on June 7, 1956, by Benjamin P. Baker, now Patent No. 2,965,735, issued December 20, 1960, and which is assigned to the same assignee as the present application. Therein is disclosed for each pole of a three-phase interrupter a pressurized tank containing an interrupter assembly, each assembly comprising a main current interrupter unit having a movable contact mounted on a piston and an impedance interrupting unit having a movable contact on a piston and connected in parallel with the main current interrupter. A first dumping means is operable to eX- haust gas from the pressurized back side of the current interrupter piston to eilect opening movement of the movable main contact, thus forcing the current through the parallel disposed impedance interrupting unit. A valve responsive to movement of the interrupter piston operates to exhaust the gas from the pressurized back side of the impedance piston to effect opening of the impedance contact only after the opening operation of the main contact, thus maintaining the impedance in the circuit for a particular time after an opening operation of the interrupter contacts to control the rate of rise of recovery voltage to prevent voltage build-up across the interrupter unit. The operation of the first dumping means is effected by a conducting cross-arm which moves downwardly through lap-type sliding contacts until opening of the contacts has been obtained whereafter continued downward motion of the cross-arm releases the main dumping means which returns to its original condition, and whereafter the cross-arm disengages the sliding contacts and moves to full open position. The reseating of the main dump-valve restores pressure behind the main interrupter contact piston which closes the main contacts and recloses the valve, whereafter incidental leakage of gas into the valve chamber restores pressure behind the movable impedance piston to reclose the movable impedance contact.

Where it is desired to utilize the system of the above described apparatus of the copending application on automatic reclosing duty, the relatively large amount of time consumed in reclosing the contacts and the impedance contacts in the described sequence provides a disadvantage in that the connection of the cross-arm for opening and closing operation in response to automatic reclosing apparatus may effect reclosing of the circuit to begin another interruption operation before the impedance contacts have had time to reclose, thus eliminating the protection against voltage build-up as normally provided by the impedance.

Accordingly, it is an object of this invention to provide in a compressed gas circuit interrupter of the type described, means for rapidly reinserting the impedance means in the circuit after a circuit interruption operation to thus adapt the compressed gas circuit interrupter for use on automatic reclosing duty.

More specifically, it is an object of this invention to provide in a. compressed gas circuit interrupter of the type 3,623,291 Patented Feb. 27, 1962 described, means for reclosing the interrupter contacts and the impedance contacts substantially simultaneously rather than sequentially.

More specifically, it is an object of this invention to provide in a compressed gas circuit interrupter of the type described, a reclosing valve attachment for effecting reclosing of the impedance contacts in direct response to reclosing of the dumping means after a circuit interruption.

Still more specifically, it is an object of this invention to provide in a compressed gas circuit interrupter of the type described, a reclosing valve responsive to an opening operation of the first dumping means to set up the impedance contacts for opening only after the main contacts have opened, and which valve responds to a closing operation of the main dumping means to effect reclosing of the impedance contacts independently of the main contacts.

Other objects will, in part, be obvious and will, in part, be explained hereinafter.

For a better understanding of the nature and objects of the invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a vertical sectional View taken through one pole of a three pole interrupter;

FIG. 2 is an enlarged vertical sectional view taken through the right-hand interrupting assembly of the pole unit illustrated in FIG. 1, taken substantially along the line IIII of FIG. 1;

FIG. 3 is an inverted assembly of FIG. 2;

FIG. 4 is an enlarged view of the dump-valve mechanism and the latch therefor, which is operated by the conducting bridging member, the dumpmalve being illustrated in the closed circuit position;

FIG. 5 is a top plan view of the dump-valve of FIG. 4;

FIG. 6 is a cross sectional view of the reclosing valve as connected in the compressed air system of the circuit interrupter of FIGS. 1 through 5;

FIG. 7 diagrammatically illustrates the current flow through one interrupter assembly in the closed-circuit position of the interrupter;

FIG. 8 diagrammatically illustrates the initial opening of the main contacts associated with the main current interrupting unit, during the initial portion of the opening operation;

FIG. 9 diagrammatically represents the interruption of the current through the impedance interrupting unit at a subsequent stage in the opening operation;

FIG. 10 diagrammatically represents the conditions which take place following a separation of the lower bridging member from the disconnecting contacts of the interrupting assembly, while the continuing gas blast maintains the circuit open at the main current interrupting unit and at the impedance interrupting unit; and

FIG. 11 diagrammatically illustrates the fully openedcircuit position of the interrupter wherein there is a re closure of the contacts in the main current and impedance interrupting units and the disconnecting gap is provided by the bridging member.

The basic compressed gas circuit interrupter of this application is identical to that disclosed and described in the hereinbefore mentioned copending application by Benjamin P. Baker, and will now be described as the en vironmental apparatus for the present invention.

Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral 2 refers to one of three pressurized tanks or enclosures, each tank relating to one pole of a three pole interrupter. A pneumatic operating mechanism (not shown) is provided to effect longitudinal, horizontal motion of an operating rod 18,

plan view of the interrupter which moves to simultaneously actuate the interrupting asemblies within each of the tanks 2. Associated with each tank 2 is a pair of hollow terminal bushings 27 each topped by an exhaust muffier 218 including a bushing type current transformer 28 for connection to a relay mechanism (not shown) associated with the previously described pneumatic mechanism. It will be observed that each hollow terminal bushing 27 has a hollow terminal stud 32 associated therewith constituting an exhaust conduit leading out of the pressurized tank 2.

Referring next to the pole unit 33, illustrated in PEG. 1, which may be the middle pole unit of the three-phase compressed-gas circuit interrupter. It will be observed that disposed interiorly within the enclosure or tank 2 are a pair of interrupting assemblies 34, which are electrically interconnected by a conducting bridging member 36. The conducting bridging member 36 is vertically actuated in a reciprocal manner by an insulating lift rod 37, which may be connected to a straight line linkage 38, which may be of the type illustrated in United States Patent 2,743,337. The linkage 38 is, in turn, connected to the previously mentioned horizontally movable operating rod 18.

Secured to the left-hand side of the tank 2, as viewed in FIG. 1, is a potential device 39 having a connection 41 with a suitable potential tap 42 provided by the terminal bushing 27.

It will be observed that associated with the inner end of each hollow terminal bushing 27 is a contact foot 43, which serves to support the interrupting assembly As shown in detail in FIG. 2, the main current interrupting unit 44 and the impedance interrupting unit 45 are in electrical parallel relationship. The reason for this is more apparent from an inspection of FIGS. 7-11 of the drawings.

Referring to FIG. 7, it will be observed that the bridging member 36 makes contact with the lower end of the interrupting assembly 34. The relatively movable contact structure 49 of the main current interrupting unit M is closed. Also the relatively movable contact structure 50- of the impedance interrupting unit 45 is also closed. It is obvious, therefore, that in the closed-circuit position of the interrupter that the current passes through the main current interrupting unit 44- in he manner indicated by the arrows 52.

FIG. 8 shows the state of affairs during the initial portion of the opening operation, when the bridging member 36 moves downward slightly to efiect opening of the movable contact structure 49 in a manner described hereinafter, and thereby causes a blast of gas to flow through the contact structure 49 and extinguish the main current arc. This action forces the current to flow through the impedance interrupting unit 45 in a manner indicated by the arrows 53. However, because of the presence of the impedance 54, the amperage of the current is considerably reduced and the power factor is improved.

FIG. 9 illustrates the conditions arising when the relatively movable contact structure '50 of the impedance interrupting unit 45 opens, by means hereinafter described, to thereby effect a blasting of the residual current are drawn at the contact structure 56 effecting its extinction. It will be noted that the bridging member 36 still continues to make contact with the disconnecting fingers 56 of the interrupting assembly, but current fiow through the interrupting assembly 34 has ceased.

FIG. illustrates a subsequent step in the opening operation where the bridging member 36 has parted contact with the disconnecting fingers 56, but during this time the gas blast, indicated by the arrows 57, continues to prevent any are reignition and to maintain the circuit open.

FIG. 11 illustrates the fully open-circuit position of the interrupter when, by means hereinafter described, the gas blast has ceased, and the contact structure 4%, Sill has reclosed. However, the isolating gap between the end of the bridging member 36 and the disconnecting fingers 56 is sufficient to hold the voltage and to maintain the circuit open. It will be obvious that during a closing operation the bridging member 36 will move upwardly, and the moment it contacts the disconnecting fingers 56 there will be an immediate re-establishment of the circuit through the interrupting asembly 34, since the relatively

movable contact structures

49, 50 associated respectively with the main current interrupting unit 4d and the impedance interrupting unit 45 will already have been closed.

Referring more particularly to FIGS. 1, 2 and 3, it will be noted, referring particularly to FIG. 2, that the contact foot 43 is fixed to a hollow exhaust chamber 53. The hollow exhaust chamber 58 is'in free communication with the region interiorly of the hollow terminal bushing 27. Secured to the lower end of the hollow exhaust chamber 58 is a relatively stationary orifice contact 59 constituting a part of the relatively movable contact structure 49 of the main current interrupting unit 44. The relatively stationary orifice contact 59 is provided by an orifice plate 6%, which is bolted as at 61 to the lower end 62. of the exhaust chamber 58. This lower end of the exhaust chamber 53 has one or more ribs 63 integrally formed therewith, which serve to hold fixedly in position an arc terminal 64, the function of which will be described hereinafter. Preferably the arc terminal 64 has a bore 66 passing therethrough to assist in are extinction and to provide less resistance to the exhaust of gas.

Associated with the other side of the exhaust chamber 58, as viewed in FIG. 2, is a relatively stationary orifice contact 67, constituting a part of the relatively movable contact structure 56' of the impedance interrupting unit 45. This relatively stationary orifice contact 67 is provided by an orifice plate 69' bolted by bolts 76 to an apertured Wall 71 of the exhaust chamber 58. As shown, gaskets 72 and 73 associated with the orifice plates 69 and 6t respectively, insure a gas-tight connection. As mentioned previously, the pressure within the tank 2, and consequently in the region around the interrupting assemblies 34-, is at relatively high pressure, say 250 pounds per square inch. The pressure within the region 74 of the hollow exhaust chamber 58 and in the region within the hollow terminal stud is at a considerably lower pressure, say two or three atmospheres gauge, as controlled by a control valve (not shown). As mentioned heretofore, there is a free communication from the region 7 within the exhaust chamber 58 through the contact foot and into the interior of the hollow terminal stud. It is, therefore, necessary to insure a gas-tight seal between the region 77 within the tank 2 and the region 74 within the hollow exhaust chamber 58.

Encircling the relatively stationary orifice contact 59 is a gasket 78 serving as a blast-valve seat, which is retained in place by a retaining ring Cooperating with the blast valve seat 78 is a movable blast-valve 31. The movable blast-valve S1 constitutes the upper portion of 'a first piston member 82, which slides within an operating cylinder 83. The first piston member 82 is adapted to strike a plurality of shock washers 35 at the end of the opening stroke. The operating cylinder 83 is bolted, by one or more bolts 86, to a dump-valve casting 87. The dump-valve casting 87 is provided with a plurality of upstanding fingers 38, which bear against a side wall portion 89 of the first piston member 32 to collect current therefrom. Disposed interiorly of the first piston member 82 is an annular segmental main contact 90, having fingers $4 which in the closed-circuit position of the inter-- rupter contact a vertical wall surface 91E of the orifice plate 6 Thus the main current, which passes through the relatively movable contact structure 49 of the main current interrupting unit 44-, passes between the annular main contact it comprising resilient fingers and the vertical wall portion 91 of the orifice plate 6%.

Disposed concentrically within the annular main con:-

tact 90 is a rod-shaped arcing contact, or stud 92 having an upper arc-resisting portion 93. The arc-resisting portion 93 cooperates with the aforementioned arcing terminal 64 to locate the main current are axially through the orifice of the orifice contact 59.

Biasing the main movable contact 9 5, comprising the annular main contact 919 and the arcing contact 92,, in an upward closing direction is a battery of compression springs 96, having their lower ends seated within a recess 97 of the dump-valve casting 87. The springs 96 constitute a biasing means to maintain the relatively movable contact structure 49 closed except when compressed gas is dumped from the rear side of the first piston member 82 by operation of a first dump-valve means, hereinafter described.

The rod-shaped arcing contact 92 has a reduced extension 98 which passes through an aperture in a slotted cup-shaped member 191, and which also passes through an aperture provided at the lower end of the first piston member 82. A nut 196 is threaded along a threaded portion of the reduced stem 98. The lower end of the stem 98 has a recess 103 interiorly provided with threads, which may accommodate a threaded tool utilized in the assembly process to compress the springs 96.

During the actual operation of the interrupter, the cavity 198 in the stem 93 may strike a valve stem 113 of a second drum-valve 115 biased to its closed position against a valve seat 116 by a compression spring 117. The second dump-valve 115 has a lower guide stem portion 118, which is guided through an aperture 119 provided in a lower cap 121 as shown more clearly in FIGS. 2 and 3 of the drawings. The lower cap 129 is secured by bolts 121 (FIG. 2) to the durnpvalve casting 87.

The actuation of the second dump-valve 115 by opening movement of the main movable contact 95 effects an intercommunication between the region 122 under the first piston 82 and the region 123 under a second piston member 125 associated with a movable impedance contact 126, more clearly shown in FIG. 2 of the drawings. This is brought about by an exhaust pipe 127 which connects through a connector 127 with a second pipe 129 (FIG. 3) which communicates through an aperture (not shown) of the dump-valve casting 87.

The movable impedance contact 126 also includes an annular blast-valve portion 131, which cooperates with a blast-valve seat 132 provided by a gasket and inserted within the orifice plate 69.

The movable impedance contact 126 is biased upwardly toward its closed position by a compression spring 133 having its lower end seated within a cavity 134 provided in an operating cylinder casting 136. This casting 136 is secured by clamp lugs (not shown) to a semi-cylindn'callyshaped insulating support plate (not shown). The lower end of the latter support plate is secured by similar clamp lugs (not shown), to the lower base casting plate 139 as shown in detail in U.S. Patent 2,965,735, previously mentioned. Disposed between the operating cylinder casting 136 and the bottom casting 139 is an impedance assembly 54, in this particular instance including a plurality of resistor grids 141. These resistor grids 141 are stacked in superimposed relation upon a pair of insulating tie rods 142 and are maintained in the compressed condition by a spring plate 143 which slides upon the tie rods 14-2, and which serves as an upper seat for a plurality of compression springs 14-4. The lower ends of the compression springs 144 seat in a plurality of recesses 146 provided in a base casting 147, to which is secured the lower ends of the tie rods 142.

Each resistor grid 141 is in a zigzag shape, and the general method of interconnecting. the resistor grids 141 is described and illustrated in United States Patent 2,632,- 078. Reference may be had to this patent for a detailed knowledge of the method of assembly and construction of the resistor grids 141, which construction forms no part of the present invention. It will be noted, however, that the upper plate 148 of the resistor assembly 54 has a terminal stud 149, to which is secured a flexible connector 150. The other end of the flexible connector 150 is clamped to the lower threaded end of the contact stud 151 of movable impedance contact 126 which passes through an aperture 152 of an upstanding guide portion 153 of the casting 136.

At the upper end of the movable impedance contact 126 is an arc-resisting tip portion 154, which serves as an arc terminal during the opening operation.

The dump-valve means for exhausting high-pressure gas from the region 122 below the first piston member 82 will now be described. As mentioned previously, a conducting bridging member 36 electrically interconnects the two interrupting assemblies 34. The outer extremity of the bridging member 36 has a vertical hole provided therein. A latching pin 158 shown in FIG. 1 is fixedly secured diametrically across the hole and is used to latch onto a latch member 159, the configuration of which is more readily apparent from an inspection of FIG. 4 of the drawings. The latch member 159 is pivotally secured by a pivot pm 160 to a lower flattened portion 162 of a dumpvalve stem 163. The upper end of the dump-valve stem 163 actuates a first dump-valve 164, comprising an annular gasket member retained in place by a washer 165 and a nut 166 threaded about an upper threaded extension 167 of the valve body 168. The first dump-valve 164 slides within a valve casing 169 having a lateral outlet opening 171. The opening 171 communicates with a connector 172 bolted, as at 173, to the valve casing 169. The connector 172 has an opening 174, within which is secured a dump-valve pipe 175, more clearly shown in FIG. 3 of the drawings.

The dump-valve pipe 175 is secured into an opening 176 of the dump-valve casting 87, and hence communicates with the region 122 below the first piston member 8 Referring again to FIG. 4, the first dump-valve 164 cooperates with a valve seat 177 provided by a cap 178 having a recess 180, within which is a packing 181 compressed by a gland 182. The gland 182 is bolted into place by bolts 133. The gland 182 and the cap 178 surround the lower end of a conduit 184, which extends upwardly between the main current interrupting unit 44 and the impedance interrupting unit 45 and leads into the hollow exhaust chamber 58. Referring to FIG. 2 in this connection, it will be observed that the upper end of the conduit 184 extends through an aperture 135 of the exhaust chamber casting 58, and a packing 186 and a gland 187 secured by bolts 18% insures a gas-tight connection thereat.

As mentioned previously, the latching pin 158 associated with the extremity of the conducting bridging member 36 latches to a nose 189 of a latching member 159 and forces the first dump-valve member 164 downwardly against the upward biasing action exterted by a battery of compression springs 191 disposed within the valve casing 169. The latching member 159 has an upper bifurcated portion 192, the legs of which 193 straddle the reduced section 162 of the dump valve stem 163. Also, the bifurcated portion 192 has a pair of integrally formed hook members 194, which engage a cross-pin 195 supported by a pair of bracket members 196 integrally formed with a lower cap 197. The hook members 194 have extending thereacross a pivot pin 199, to which is pivotally connected a spring guide rod 200. A washer 201 encircles the spring guide rod 260 and bears against the upper ends of the hook members 194.

During the opening operation, the latch member 159 is pulled downwardly by the latch pin 158 movable with the conducting bridging member 36 against the opposition afiorded by the compression springs 191. This opens the first dump-valve 164 away from its seat 177 to permit the region 202, which is initially at high pressure to communicate with the region 203, the latter being in free communication with the region 74 within the exhaust chamber 58.

The compression spring 2%, encircling the spring guide rod 2%, insures that the stop pin 295 disposed transversely between the legs 193 will be maintained against the valve stem 163 insuring that the nose 189 will remain under the latch pin 158 until the hook members 19- 5 strike the cross-pin 195. When this occurs, the latch member 159 will pivot in a clockwise direction about the cross-pin 195 releasing the pin The compression springs 191 will, at this time, attempt to immediately return the first dump-valve 16 5 to the closed position against the valve seat 177, but this upward motion will be retarded because of high pressure gas which has entered through an opening 2% in the valve casing 169 and into a region 207 above a piston ring 299. The high pressure gas, which is entrapped within the region 207 during the opening movement of the first dump-valve 164, will retard the return closing movement of the first dump-valve 164, and this action is desirable to insure that the blast adjacent the movable contact structures will be continued long enough to insure arc interruption and to prevent subsequent arc reignition until the bridging member 36 has separated an adequate isolating distance away from the disconnecting fingers S6 to insure that the circuit will be open.

In general, it will be noted that there is provided an actuating means, generally designated by the reference numeral 21%) associated with each interrupting assembly 34. The cross-arm or bridging member 36 constitutes an actuating member, which initiates the opening operation by opening the first dump-valve member 164. In addition, the actuating means 2% for each interrupting assembly comprises a first operating means 211 for opening the movable main contact 95 of the main interrupting unit 44 and a second operating means 212 for causing the opening of the movable impedance contact 1 .26 associated with the impedance interrupting unit 45. The first operating means 211 includes a first piston 32 and a first dump-valve means 213, the latter including the first dump-valve 164. The second operating means 2'12 includes a second piston member 125 and a second dump-valve means 214, which includes a second dumpvalve 115.

From the foregoing description, it will be apparent that in the closed-circuit position, illustrated in FIG. 1, the electrical circuit through the pole unit 33 includes the hollow terminal stud 32 of one terminal bushing 27, conducting contact foot 43, exhaust chamber 58, orifice plate fill, conducting surface 91, annular main contact 90, vertical side wall portion 89 of first piston member 82, and through the fingers 88 to the dump-valve casting 87. The circuit then extends through a plurality of support feet 215, which secure the casting 37 to the bottom casting 1. 29. The circuit then extends through the disconnecting fingers 56 to the conducting bridging member 36. Because of the resistance 54 practically no current flows through the parallel impedance interrupting unit 45.

The circuit extends through the other interrupting assembly 34 of the pole unit 33 in a similar manner and through the other hollow terminal bushing 27 to the upper end thereof, to which a line connection is made.

When it is desired to open the electrical circuit passing through the interrupter, suitable means (not shown) are provided to actuate the pneumatic mechanism. This will release or unlatch the mechanism to permit accelerating springs (not shown) associated with each interrupting assembly 34, at the outer end of the operating rod 18, to force the several conducting bridging members 36 downwardly. This initial downward motion is quite rapid, but the design of the several shock absorbers 23 is such that the initial downward opening motion is quickly slowed down. During this initial rapid downward opening motion of the several cross-bars 36, the latch pins 158 engaging the noses 189 of the several latch members 159 eifect opening of the several first dumpvalve means 213. in other words, the downward move ment of the latch members 159 effects opening of the first dump-valves 164 to open the connection between the region 2% (FIG. 4) and the region 232, which communicates directly with the region 122, on the lower side of the first piston 82. Because high pressure exists within the region 7'7 within the tanl; structure 2, and because there is now a low pressure within the region 122, the first piston member 82 will be forced downwardly to open the movable blast-valve 31 away from its cooperating blast-valve seat '73. This will provide a radially inward blast of gas through the orifice contact 59 the moment the annular segmental main contact 9% separates away from the vertical main contacting surface 91 of the relatively stationary orifice contact 59. The radially inward blast of gas wiil then carry the are, which is initially established between the annular main contact Q and the lower edge of the vertical surface 91, inwardly through the orifice contact 52 so that the upper end of the arc terminates at the arcing terminal 64, whereas the lower end of the arc is blown onto the arc-resisting tip portion $3 of the main movable contact )5. The region '74, which is at a much lower pressure than the tank pressure, will receive the exhaust gases and will permit them to exhaust upwardly through the hollow terminal bushing 27.

hen the main current are has been extinguished in the main current interrupting unit 4 5, the current through the interrupter is forced to take the parallel path through the impedance interrupting unit 45, which path includes the relatively stationary orifice contact 67 and the movable impedance contact 125. The circuit through the impedance interrupting unit then includes the flexible connector 15th, terminal of resistor assembly 54 and, by way of the compression springs 144, through the base casting 147 to the lower casting 139, and hence to the disconnecting fingers 56 to the cross-bar 36.

However, this parallel electrical path. including the impedance 5d is soon interrupted, since, near the end of the opening stroke of the movable main contact 95, the valve stem 113 of the second dump-valve 115 is struck by the lower extension m7, and this opens the second dump-valve ill-,5 away from its seat 1 16 thereby permitting communicaticn between the region 122 and the region 123 by way of the conduit pipe 129 and the vertical conduit 127. Thus, the region 123 below the second piston member associated with the movable impedance contact 126, is exhausted, thereby permitting the high-pressure gas within the tank 2 to force the second piston member 125 downwardly against the upper biasing action exerted by the compression spring 133. This action first breaks the seal between the movable blastvalve 131 and its seat 132, thereby permitting a radially inward blast of gas to take place through the orifice contact 67 and causing the extinction of the are drawn thereat. This residual current are has its lower end terminating at the tip portion 54 of the movable impedance contact 126, whereas the upper end of the residual current are is blown into the hollow exhaust chamber 58 to be extinguished.

When the residual current are, (not shown), is extinguished, the circuit through the entire pole unit 33 is interrupted, and continued downward opening travel of the conducting actuating member 36 will bring about the interposition of two isolating gaps between the disconnecting fingers 56 and the upper side of the conducting bridging member 36.

In the meantime, of course, the latch 15% associated with the first dump-valve means 213 has been rotated by the hook portions 194 engaging the stop pin 1%, thereby releasing the latch pin 158. However, rapid return movement of the first dump-valve 16 iis not achieved because of the previous entrapment of compressed gas through the opening 2% and into the region 207 (FIG. 4) above the piston ring 2%. When this entrapped gas has leaked out sufficiently, the first dump-valve 164 recloses over its seat 177, thereby sealing off the

regions

202 and 203. Ordinarily, this will permit high-pressure gas to leak from the region 217 below the valve body 168 to pass by means of the opening 218 (FIG. 4) into the region 202. This will raise the pressure within the region 122 and permit the compression springs 96 to eilect reclosure of the movable main contact 95'. The increase of pressure within the region 122 will act through the second dump-valve 115 and through the exhaust tube 127 to raise the pressure within the region 123, thereby permitting the spring 133 to effect reclosure of the removable impedance contact 126. Aswill be presently described, a reclosing valve may be added to the basic interrupter whereby the impedance contact 126 may be reclosed in direct response to pressure increase in region 202.

Thus, in the fully open-circuit position of the interrupter, both

movable contact structures

49, 50 have reclosed, and the isolating gaps between the disconnecting fingers 56 and the conducting cross-bar 56 are sufiicient to hold the voltage and thereby maintain the circuit open through the interrupter.

From the foregoing description, it will be apparent that the external dimensions and general outline of the compressed-gas circuit interrupter are similar in size and shape relative to that of a comparable oil breaker. The basic interrupter includes steel tanks 2, normally inflated to approximately 250 pounds per square inch, pairs of condenser bushings 27 associated with the tanks 2, together with their associated current transformers 28 and potential devices 39. The interrupting assemblies 34 are carried at the lower ends of the bushings 27, and the crossarm 36 not only operates the interrupting assemblies 34, but also carries the current from one assembly 34 to the other. In addition, the conducting cross-bar 36 serves to establish two isolating position of the interrupter.

The moving parts of the main interrupter 44 consist of the blast-valve 81, the finger contacts 9 and the centrally disposed arcing contact 92, all rigidly attached together and biased towards the closed position by compression springs 96.

The moving parts of the resistor current interrupter 45 consist of the blast-valve 131 and the arcing contact 154, both of which are biased toward the closed position by compression spring 133.

The cross-arm 36 forms the isolating switch, as in a conventional oil breaker, and makes electrical engagement with disconnecting fingers 56. In the closed posi tion, it also engages a latch 159, which, in turn, operates first dump-valve 164 through the valve stem 163.

During the opening of the breaker, the cross-arm 36, moving downwardly in a conventional manner, first opens dump-valve 164 by means of the latch 159. This connects the space 122 under the blast-valve 81 to atmospheric pressure through the terminal bushing 27, conservator 53 and the connecting tubing 175. As a result of this reduced pressure, a high pressure on the blast-valve area at 219 forces it open against the compression springs 96. The first motion unseats the valve at 73, then disengages the fingers 94, from which the arc is immediately blown upon the arcing contacts 64, 93, where it is extinguished.

Paralleling this contact is the resistor 54 and its interrupter 45. As the base of the valve 81 approaches the end of its travel, it engages valve stem 113 unseating the valve 115 and connecting space 122 with the region 123 through the interconnecting

exhaust tubes

127, 129. By thus connecting space 123 to atmospheric pressure, or at least to a relatively low pressure, valve 131 is opened in a manner similar to Valve 8 1. When this valve 131 opens, the resistor current is drawn in an are between contacts 67 and 154 and is extinguished.

As the conducting cross-bar 36 moves downwardly, the latch 159 releases latch pin 158 thereby allowing first dump-valve member 164- to reseat. The open period gaps in the fully open-circuit U of valve 164 is determined :by the velocity of the bridging member 36, as well as by the dashpot action exerted by the air or gas entrapped within the region 207 above the piston ring 209, as shown in FIG. 17. Upon the reseating of the first dump-valve 164, the

regions

122 and 123 return to high pressure, and the valves 81 and 13d together with their associated contacts move to the closed position after all arcs are interrupted, but before the contacts reclose, cross-arm 36 has previously disengaged disconnecting fingers 56, thus removing voltage from the entire interrupter and resistor assemblies 34.

During the closing operation, the pneumatic mechanism 11 is actuated by the admittance of gas through the closing valve 2 1 to force the piston 13 downwardly within the operating cylinder 12, moving the link 16 and operating rod 15 in the closing direction charging the accelerating springs. This will effect an upward movement of the several conducting cross-arms 36 within the tank structures 2, bringing the bridging members 36 into engagement with the disconnecting fingers 56. Since this closing occurs in a 250 pounds per square inch atmosphere, disconnecting fingers 56 and conducting crossarm 36 are very close before an arc is established. Thus, firm metallic engagement is made is made before the crest fault current is reached.

In accordance with the present invention, a reclosing valve attachment 25% (FIGS. 3 and 6) may be provided on the previously described compressed gas circuit interrupter to automatically provide a more rapid reclosing action of the movable impedance contact 126 after a circuit interruption operation, as previously described, so that both the interrupter contact and the movable impedance contact 126 will close within a predetermined minimum time, approximately 20 cycles, thus adapting the circuit interrupter for operation on automatic reclosing duty. I

The reclosing valve 250 is comprised of a valve body 251 attached as by bolts 252 (FIG. 3) over an aperture 253 tapped in the previously described connector 127, which aperture 253 connects with the

conduits

127 and 129. The valve body 251 includes a piston cavity 254 connected through a port 255 in the body 251 to communicate with the aperture 253 when the valve body 251 is bolted to the connector 127 as previously indicated.

The cavity 254 contains a piston 256 slidably fitted therein. The piston 256 comprises an open-ended hollow upper portion 257 having side walls 253, a constricted neck portion 259 aligned with the port 255 when the valve is in the extreme upper position in the cavity 254, and having a lower open-ended hollow portion 260 having side walls 261. A port 262 on the upper end of the body 251 provides connection between the hollow upper portion 257 and the pressurized atmosphere externally of the piston, the aperture being smaller than the cavity 254 to provide a flanged end for abutting the walls 258 on upper end portion 257 to establish the upper terminal position of piston 256. A port 263 is provided in body 251 in transverse alignment with the port 255 to provide communication between conduit 12? and the pressurized atmosphere through port 263 and around neck 259 and through port 255 when the piston 256 is in the extreme upper end of the cavity 254 as illustrated in FIG. 6. A cap 264 closes the open lower end of valve body 251 and is attached to the valve body 251 as by bolts 255 (FIG. 3). A depression 266 is provided in the cap 264 to axially align with the longitudinal axis of cavity 254 to serve as a seat for one end of a compression spring 267 situated longitudinally of the cavity 254, which spring extends upwardly within the lower hollow portion 265 of piston 256 to normally bias the piston in the uppermost position within piston chamber cavity 254, as illustrated in FIG- 6. The cap 264 includes an open cavity 267 having a threaded portion around the lip portion to receive the threaded end of a conduit 26%. A port 269 is provided centrally of the depression 266 in the cap 264 to provide communication between the cavity 267 and the hollow lower portion of piston 256. The other end of the conduit is threadedly connected to one end of a hollow plug 269 (FIGS. 3 and 4) composed of insulating material. The other end of the hollow plug 2 39 is threadedly received through the wall of connector 172 to provide direct communication between the space 262 within connector 172 and the lower hollow portion are of the piston 256.

When the reclosing valve and the attending conduit 368 are provided on the basic compressed gas circuit interrupter in the manner hereinbefore described, the resistor circuit may be reclosed within a much shorter time than that normally required, to thus adapt the basic circuit interrupter for automatic reclosing circuit interrupter duty, which requires that the resistor be inserted in the circuit prior to a cycle limit.

The operation of the basic compressed gas circuit interrupter, with the reclosing valve and the conduit Z68 attached will now be described.

When it is desired to open the electrical circuit passing through the interrupter, suitable means (not shown) are provided to actuate a pneumatic mechanism (not shown). This will release or unlatch the pneumatic mechanism to permit accelerating springs associated with each interrupting assembly to operate the rod 18 to force the several conducting bridging members 3:? downwardly. During this initial rapid downward opening motion of the several cross-bars as, the latch pins 158 engaging the noses of the several latch members 15? efifect opening of the several first dump-valve means 213. in other words, the downward movement of the latch member\) 159 effects opening of the first dump-valve 16 3 to open the connection between the regions 2% (FIG. 4) and the region 2%, which communicates directly with the region 122, on the lower side of the first piston 82., and which also communicates directly through the added conduit to the lower hollow portion 266 of piston 256 in reclosing valve 256 of the present invention. Because high pressure xists within the region 77 within the tank structure 2, and because there is now a low pressure within the region lli, the first piston member will be forced downwardly to open the movable blast-valve Ell away from its cooperating blastvalve seat 78 providing an inward blast of gas from the pressurized area 77 to extinguish the arc in the manner previously described. Because high pressure exists in the area surrounding reclosing valve applying pressure through port 262 against the inside of upper hollow portion 257 of the piston ass, the low pressure within region 2&2 arising out of operation of dump-valve 164 extends through conduit 268 to the lower hollow portion 260 of piston 25d providing a pressure diiierential which forces the piston 25o downwardly to compress the spring 267 and close the ports 2:53 and 253 to isolate the conduits 127 and 325 from the pressurized area through these ports.

Vhen the main current are has been extinguished in the main current interrupting unit the current through the interrupter is forced to take the parallel path through the impedance interrupting unit 45, which path includes the relatively stationary orifice contact 67 and the movable impedance contact The circuit through the impedance interrupting unit then includes the flexible connector 15%, terminal 14% of resistor assembly 54- and, by way of the compression springs 114d, through the base casting 147 to the lower casting 139, and hence to the disconnecting fingers 55 to the cross-bar 3-5.

However, this parallel electrical path including the impedance 5d is soon interrupted, since, near the end of the opening stroke of the movable main contact 95, the valve stem 113 of the second dump-valve 115 is struck by the lower extension 1 7, and this opens the second dumpvalve 13.5 away from its seat 116 thereby permitting communication between the region 122 and the region 123 by way of the conduit pipe 129', connector 127 and the vertical conduit 127. Thus, the region 1.23 below the second piston member 125, associated with the movable impedance contact ll26, is exhausted, thereby permitting the high pressure gas within the tank 2 to force the second piston member downwardly against the upper biasing action exerted by the compression spring 133.

When the residual current are (not shown) is extinguished, the circuit through the entire pole unit 33 is interrupted, and continued downward opening travel of the conducting actuating member 36 will bring about the interposition of two isolating gaps between the disconnecting fingers es and the upper side of the conducting bridge member 36.

in the meantime, the latch 159 associated with the first dump-valve means 213 has been rotated by the hook portions 194- engaging the stop pin 395, thereby releasing the latch pin 158. However, rapid return movement of the first dump-valve 164 is not achieved because of the previous entrapment of compressed gas through the opening 2% and into the region 2527 (FIG. 4) above the piston ring 269. When this entrapped gas has leaked sufficiently, the first dump-valve 1-64 will reclose over its seat 177, thereby sealing oil the regions 2&2 and 293. This will permit high pressure gas to leak from the region 217 below the valve body 168 to pass by means of the opening 215 (FIG. 4) into the region 2%. This will raise the pressure within the region 122 and permit the compression springs 96 to effect reclosure of the movable main contact 95. At the same time, the increased pressure in region 2% extends through conduit 26? of the present invention to the lower hollow portion 260 of the piston 256 in the reclosing valve 253 of the present invention to equalize the downward pressure on the upper hollow portion 257 of piston 2S6, whereupon the compressed biasing spring 267 operates to return the piston 256 to the upper position as illustrated, thus opening the

ports

263 and 255. The high pressure condition of the atmosphere externally of the reclosing valve 256 now extends through

ports

263, 255, 253, connector 127' and conduit 127 to immediately raise the pressure within region 123, thereby permitting spring 133 to reclose movable impedance contact 1.26.

Thus, the presence of reclosing valve 250 and its conduit 268 provides rapid enclosing or" the movable impedance contact 126 in direct response to reclosing of the main dump-valve 164, whereas, as previously described in the description of the basic compressed gas interrupter, the movable impedance contact 126 could not reclose until after the movable main contact was closed by the dump-valve 115.

When an automatic reclosing mechanism (not shown) actuates the operating rod 18 in the closing direction, the conducting cross-arms 36 are moved upwardly within the tank 2, bringing the bridging members 36 into engagement with the fingers 56.

From the foregoing it is apparent that this invention provides a simple unitary reclosing valve attachment which, when added to the basic compressed gas circuit interrupter as described, adapts the circuit interrupter for operation on automatic reclosing duty. The attachment is simple and may be readily added to the basic circuit interrupter in the field, the only required modification of the basic interrupter being the addition of three taps in the connector 127 for the port 253, the addition of two bolts 252, and the addition of a tap in connector 172 to receive the plug 2% for the added conduit 268.

Although there is shown and described specific structures, it is to be understood that changes and modifications therein may be readily made by those skilled in the 13 art without departing from the spirit and scope of the present invention.

We claim as our invention:

1. A compressed gas circuit interrupter including means defining an enclosure containing pressurized gas, an interrupting assembly disposed interiorly within the enclosure and including a main current interrupter unit and an impedance interrupting unit connected in electrical parallel with each other, said main current interrupting unit having a movable main contact associated therewith, first operating means including a piston movable with said movable main contact and also including first dumping means for exhausing gas from the back side of said piston to effect opening movement of said movable main contact to force current to flow through the parallel disposed impedance interrupting unit, second operating means including a piston movable with said movable impedance contact and also including second dumping means for exhausing the gas from in back of said last-mentioned piston to effect opening movement of said movable impedance contact, means responsive to operation of the first operating means for actuating said second operating means subsequent to the actuation of said first operating means to effect opening movement of the impedance contact only after the opening of the movable main contact, and reclosing valve means operable in response to reclosing of the first dumping means to directly connect the back of the movable impedance piston to the pressurized gas enclosure toeffect rapid reclosing of the movable impedance contact.

2. A compressed gas circuit interrupter including means defining an enclosure containing pressurized gas, an interrupting assembly disposed interiorly within the enclosure and including a main current interrupter unit and an impedance interrupting unit connected in electrical parallel with each other, said main current interrupting unit having a movable main contact associated therewith, first operating means including a piston movable with said movable main contact and also including first dumping means for exhausting gas from the back side of said piston to effect opening movement of said movable main contact to force current to flow through the parallel disposed impedance interrupting unit, second operating means including a piston movable with said movable impedance contact and also including second dumping means for exhausting the gas from in back of said lastrnentioned piston to efiect opening movement of said movable impedance contact, means responsive to operation of the first operating means for actuating said second operating means subsequent to the actuation of said first operating means to effect opening movement of the impedance contact only after the opening of the movable main contact, a channel directly connecting the back of the movable impedance piston to the pressurized gas enclosure, a reclosing valve in the pressurized enclosure and including a piston operable to open and close the channel, and conduit means connecting the back of the reclosing valve piston to said first dumping means whereby an opening operation of the first dumping means exhausts gas from in back of the reclosing piston to effect closing of the channel to maintain a normal opening sequence of the main interrupter contact followed by opening of the impedance contact, and whereby reclosing of the first dumping means etfects restoration of gas pressure in back of the reclosing valve piston for opening the channel to effect restoration of gas pressure in back of the movable impedance piston for rapidly reclosing the impedance contacts.

3. A compressed gas circuit interrupter including means defining an enclosure containing pressurized gas, an interrupting assembly disposed interiorly within the enclosure and including a main current interrupter unit and an impedance interrupting unit connected in electrical parallel with each other, said main current interrupting unit having a movable main contact associated therewith, first operating means including a piston movable with said movable main contact and also including first dumping means for exhausting gas from the back side of said piston to effect opening movement of said movable main contact to force current to flow through the parallel disposed impedance interrupting unit, second operating means including a piston movable with said movable impedance contact and also including second dumping means for exhausting the gas from in back of said last-mentioned piston to effect opening movement of said movable impedance contact, means responsive to operation of the first operating means for actuating said second operating means subsequent to the actuation of said first operating means to effect opening movement of the impedance contact only after the opening of the movable main contact, a port connecting the gas chamber to the back side of the second operating means to effect reclosing of the impedance contacts, reclosing valve means operable in response to an exhaust operation of the first dumping means to close the port and operable in response to reclosing operation of the main dumping means to open the port.

4. A compressed gas circuit interrupter including an enclosure containing pressurized gas, an interrupter assembly disposed within the enclosure and including a main interrupter unit and an impedance interrupting unit connected in parallel, each unit having a relatively movable contact mechanism and an operating means including a piston for efiecting opening and closing movement of the contact mechanism, first dumping means for exhausting gas from the back side of said main interrupter piston to effect opening movement of said movable main contact, second dumping means for exhausting gas from in back of the impedance unit piston to effect opening movement of said movable impedance contact, means responsive to operation of said first operating means for effecting operation of the impedance interrupter operating means subsequent to the operation of the main interrupting operating means, a switch operable to be opened and closed in response to operation of an automatic reclosing mechanism, said switch means having separable contacts and connected in series with the parallel connected main interrupter and impedance interrupter, means releasably connecting the switch to open the first dumping means during initial opening movement of the switch and including means for releasing the connecting means subsequent to the opening of the interrupter contacts and the impedance contacts to effect reclosing of the dumping means, and reclosing valve means operable in response to reclosing of the first dumping means to directly connect the back of the movable impedance piston to the pressurized enclosure to effect rapid reclosing of the movable impedance contact.

5. In an automatic reclosing circuit breaker system: a main circuit interrupter unit and an impedance interrupter unit connected in parallel; contact means for each interrupter unit, a switch operable to be opened and closed in response to operation of an automatic recloser mechanism and connected in series with said parallel connected interrupter means; interrupter operating means responsive to the initial portion of an opening operation of said switch to open the main interrupter contacts; means responsive to opening of the main interrupter contacts to subsequently open the impedance interrupter contacts; means for automatically closing the main interrupter contacts and the impedance interrupter contacts independently and substantially simultaneously after the switch is opened to effect reinsertion of the impedance interrupter unit in circuit with the main interrupter unit before the switch is reclosed by a reclosing operation of the auto matic recloser apparatus.

6. In an automatic reclosing circuit breaker system: a main circuit interrupter unit and an impedance interrupter unit connected in parallel; each interrupter unit having contacts and means for opening and closing the contacts; a switch operable to be opened and closed in response to the operation of an automatic reclosing mechanism and connected in series with said parallel connected interrupter means; main operating means actuated in response to the initial portion of a switch opening operation to effect and maintain a contact opening operation of the main contact operating means until the main operating means is deactuated; means responsive to an opening operation of the main contacts to effect a contact opening operation or" the impedance contact operating means subsequent to the opening operation of the main contacts but before the switch is opened and to maintain the opening operation until the main contacts reclose; means operable to deactuate the main operating means after the switch is opened; and means responsive to deactuation of the main operating means to override the means effecting and maintaining operation of the impedance contact operating means to effect an immediate reclosing operation of the impedance operating means whereby the main contacts and the impedance contacts reclose substantially simultaneously to reinsert the impedance unit in circuit with the main interrupter unit before the switch is reclosed by a reclosing operation of the automatic reoloser mechanism.

References Cited in the file of this patent UNITED STATES PATENTS 2,470,628 Ludwig May 17, 1949 2,903,788 Forwald Oct. 13, 1959 FOREIGN PATENTS 582,599 Great Britain Nov. 21, 1946 151,019 Sweden Aug. 9, 1955 1,063,682 Germany Aug. 20, 1959

Claims

1. A COMPRESSED GAS CIRCUIT INTERRUPTER INCLUDING MEANS DEFINING AN ENCLOSURE CONTAINING PRESSURIZED GAS, AN INTERRUPTING ASSEMBLY DISPOSED INTERIORLY WITHIN THE ENCLOSURE AND INCLUDING A MAIN CURRENT INTERRUPTER UNIT AND AN IMPEDANCE INTERRUPTING UNIT CONNECTED IN ELECTRICAL PARALLEL WITH EACH OTHER, SAID MAIN CURRENT INTERRUPTING UNIT HAVING A MOVABLE MAIN CONTACT ASSOCIATED THEREWITH, FIRST OPERATING MEANS INCLUDING A PISTON MOVABLE WITH SAID MOVABLE MAIN CONTACT AND ALSO INCLUDING FIRST DUMPING MEANS FOR EXHAUSING GAS FROM THE BACK SIDE OF SAID PISTON TO EFFECT OPENING MOVEMENT OF SAID MOVABLE MAIN CONTACT TO FORCE CURRENT TO FLOW THROUGH THE PARALLEL DISPOSED IMPEDANCE INTERRUPTING UNIT, SECOND OPERATING MEANS INCLUDING A PISTON MOVABLE WITH SAID MOVABLE IMPEDANCE CONTACT AND ALSO INCLUDING SECOND DUMPING MEANS FOR EXHAUSING THE GAS FROM IN BACK OF SAID LAST-MENTIONED PISTON TO EFFECT OPENING MOVEMENT OF SAID MOVABLE IMPEDANCE CONTACT, MEANS RESPONSIVE TO OPERATION OF THE FIRST OPERATING MEANS FOR ACTUATING SAID SECOND OPERATING MEANS SUBSEQUENT TO THE ACTUATION OF SAID FIRST OPERATING