US3114815A - Fluid-blast circuit interrupter with improved current-transformer housing means - Google Patents

Description

1963 G. J. EASLEY ETAL 3,114,315

FLUID-BLAST CIRCUIT INTERRUPTER WITH IMPROVED CURRENT-TRANSFORMER HOUSING MEANS Filed Nov. 18, 1959 5 Sheets-Sheet 1' INVENTORS Robert L. Hess, James M. elford and Gilbert J. Eosley BY W m E W ATTORNEY WlTNiZS/MH W 93? Dec. 17, 1963 G. J. EASLEY ETAL 3, 5 FLUID-BLAST CIRCUIT INTERRUPTER WITH IMPROVED CURRENT-TRANSFORMER HOUSING MEANS Filed Nov. 18, 1959 5 Sheets-Sheet 4 Fi .5. 8 9 g as O 86 Dec. 17, 1963 G. J. EASLEY ETAL 3,114,815

FLUID-BLAST CIRCUIT INTERRUPTER WITH IMPROVED Filed Nbv. 18, 1959 CURRENT-TRANSFORMER HOUSING MEANS 5 Sheets-Sheet 5' United States Patent FLUID-BLAST CIRCUIT INTERRUPTER WITH IM- PROVED CURRENT-TRANSFORMER HOUSING MEANS Gilbert 3. Easley, Edgewood Borough, Robert L. Hess, North Versailles Township, Allegheny County, and James M. Telford, Penn Hills Borough, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Nov. 18, 1959, Ser. No. 853,974 4 Claims. (Cl. 200-148) This invention relates to fluid-blast circuit-interrupters, in general, and, more particularly, to improved arcextinguishing structures, mounting arrangements and ourrent-transformer housing means therefor.

In :United States patent application filed September 15, 1959, Serial No. 840,133, by Robert E. Friedrich, Carl G. Lentjes, and George B. Cushing, and assigned tothe assignee of the instant application, there is disclosed and claimed a fluid-blast circuit-interrupter of the puffer type, in which a relatively movable operating cylinder, carrying the movable contact structure, slides axially over a stationary hollow insulating pedestal having a relatively fixed piston attached thereto, to compress gas, and to force the compressed gas through an orifice structure to effect extinction of the are drawn between the relatively movable contact and a cooperabl-e stationary contact. It is a general object of the present invention to improve upon the circuit-interrupting structure of the aforesaid application, rendering the same particularly suitable for a simplified mounting construction, eliminating the terminal bushing, and employing a pair of current-transformer structures, between which any internal fault current flows to ground to obtain overlapping relay protection.

Another object of the present invention is to provide an improved simplified, puffer-type, circuit-interrupting structure, in which the number of parts are kept to a minimum, and assembly and disassembly operations are readily achieved.

Another object of the present invention is to provide an improved current-transformer arrangement, in which an insulating shield is employed to prevent the currenttransformer being surrounded by a short-circuited turn of metal.

Another object of the present invention is to provide an improved fluid-blast-type of circuit-interrupter in which a pair of spaced current-transformers are arranged so that any fault occurring within the circuit-interrupting structure will pass to ground between the two currenttransformers, and be reflected as an internal fault, causing thereby the tripping not only of the circuit-interrupter itself, but also the tripping of the remote circuit breakers connected to the considered circuit breaker.

Another object of the present invention is to provide an improved elongated circuit-interrupting structure in which the guiding functions for the movable contact assembly are facilitated, and the resulting structure is trouble-free in operation.

Yet a further object of the present invention is to provide an improved circuit-interrupter of the putier type, which is particularly suitable for the use of a high-dielec trio-strength, effective, arc-extinguishing fluid, such as sulfur hexafluoride (SP Still a further object of the present invention is to provide an improved fluid-blast circuit-interrupter in which improved crank means are employed to effect the axial opening movement of the movable contact structure.

Another object of the present invention is '00 provide an improved circuit-interrupter in which the servicing and maintenance operations are readily achieved by the removal of only a few parts.

ICE

Another object of the present invention is to provide an improved simplified type of circuit-interrupter in which the movable contact structure, and the guiding support therefor, may readily be removed out of one end of the circuit-interrupting structure with a minimum of disassembly of parts.

Another object of the present invention is to provide an improved circuit-interrupter in which the adjustment of the parts is readily achieved.

Another object of the invention is to provide an improvedgaseous-type of circuit-interrupter in which the enclosed gas is not only employed to create an arcextinguishing blast of gas, but is also utilized as a gaseous dielectric medium between the high-voltage parts of the breaker and the grounded interrupter housing. As a result, a terminal-bushing construction is not necessary with associated organic insulation, which is subject to aging and possible eventual failure over a period of years.

'Further objects and advantages will readily become apparent upon reading the following specification, taken in conjunction with the drawings, in which:

FIGURE 1 is a front elevational view of a three-pole circuit-interrupting assemblage embodying the principles of the present invention;

FIG. 2 is a side elevational view of the circuit-interrupting assemblage of FIG. 1;

FIG. 3 is a fragmentary, enlarged, longitudinal, vertical sectional view taken through one of the three areextinguishing pole units, with the contact structure being illustrated in the closed-circuit position;

FIG. 4 is a similar fragmentary, longitudinal, vertical sectional view taken through the other end of the pole unit of FIG. 3, but illustrating the position of the contacts in the fully open-circuit position;

FIG. 5 is a ventical sectional view taken along the line V-V of FIG. 3;

FIG. 6 shows schematically the association with a single pole unit of remote protective circuit breakers and a differential protective relaying scheme for distinguishing between internal and external faults occurring at the pole unit; and,

FIG. 7 illustrates a modified type of current transformer mounting arrangement to reflect porcelain flashover faults associated with the circuit-interrupter as external faults, as contrasted with internal faults.

Referring to the drawings, and more particularly to FIGS. 1 and 2 thereof, the reference numeral lgenerally designates a three-pole circuit-interrupting assemblage, which is mounted at the upper end of a frame support 2, the latter being welded to angle feet 3, which may rest upon a suitable base. The reference letters A, B and C designate the three individual circuit-interrupting pole units, which are all identical in construction and opera tion.

FIG. 2 shows more clearly how the three circuit-interrupting pole units A, B and C, constituting a three-phase circuit-interrupter, are mounted at the upper end of the frame support 2. The frame support 2 preferably includes a pair of upstanding channel members 4, which have cross-braces 5, 6 welded thereacross. Disposed between the uprights 4, and positioned between the cross-braces 5,

'6 is a mechanism compartment 7, housing a suitableoperating mechanism, which effects simultaneous opening and closing movement of three identical pole units A, Band C of the circuit-interrupting assemblage 1.

A rotatable operating shaft 8 mechanically interconnects the three pole units A, B and C. As well known by those skilled in the art, a crank-arm assembly 11 (FIG. 5) is employed within a compartment 9 (FIG. 1) and is pivotally connected to a pull-rod extending downwardly within an enclosing tube 10 to be connected to the operating mechanism enclosed within the mechanism compartment 7. Generally, the actuating mechanism disposed within compartment 7 may be of any suitable type, and is operated to effect upward thrusting motion of the operating rod within the tube 10 during the opening stroke. This action is facilitated by opening accelerating springs, not shown, also disposed within the vertical housing tube 10. A suitable operating mechanism, not shown, is provided to effect the closing of the circuit-interrupter and a charging of the aforesaid accelerating spring.

The operating mechanism may be of any desired type such as pneumatic, hydraulic, or may comprise a solenoid for effecting downward closing motion of the operating rod disposed within enclosing tube 10.

With reference to FIG. 5, it will be noted that the rotatable operating shaft 8 is keyed to an internally disposed operating crank-arm 12, which is welded to a forked member 13. The ends of the furcations, or arms 14, of the resulting bifurcated crank-arm construction are pivotally connected by pins 14a, 15a (FIG. 3) to links 16 disposed externally of a movable puffer cylinder 17. Jutting laterally outwardly from diametrically opposite sides of the puffer cylinder 17 are a pair of pivot pins 17a to which the driving links 16 are connected. Thus, as viewed in FIG. 4, the counterclockwise rotation of the operating shaft 8 is effective to force the links 16 toward the left, and to effect leftward working motion of the operating puffer cylinder 17 over a stationary piston 18 secured to the right-hand end of a hollow insulating guide tube, or pedestal 19. As shown, the hollow insulating guide tube 19 is threadedly secured, as at 20, to a collar 21, which is secured to an annular mounting plate 22, the latter being bolted, by bolts 23, to a closure plate, or combined end support plate 24 of a grounded interrupter housing, generally designated by the reference numeral 25.

As illustrated in FIG. 3, the operating cylinder 17 carries a movable contact support 26, the latter having integrally formed movable main contact fingers 27 and is secured, by a stud portion 360, of guide rod 36, to a centrally-located movable arcing electrode 28. The movable arcing electrode 28 engages within a hollow portion 29 of a relatively stationary rod-shaped contact 30.

The relatively stationary rod-shaped contact 30 is fixedly secured, as at 31, to a conducting support tube 32, the latter being adjustably secured within a mounting boss 33, disposed at the right-hand end of the circuit-interrupting pole unit.

It will be noted that jutting outwardly in opposite directions from the centrally disposed interrupter housing are a pair of identical insulating casings 34, preferably composed of a suitable Weather-proof material, such as porcelain. Corrugations 35 may be formed along the external surface of the porcelain casing 34 for providing an increased surface breakdown path.

As shown in FIG. 3, it will be observed that the movable contact support 26 is threadedly secured, by the stud portion 36a, to the conducting guide rod 36, which is guided at its left-hand end, as viewed in FIG. 4, by a plurality of resilient fingers 37, which carry current therefrom to a terminal plate 38.

The terminal plate 38 is fixedly secured by bolts 39 to an annular mounting flange 40, cemented to the left-hand end of the left-hand porcelain casing 34. The right-hand end of the left-hand casing 34 similarly has cemented thereto an annular mounting flange 41, which is bolted by bolts 42 to the closure plate 24 of the interrupter housing 25.

A pair of current- transformers 43, 44 are provided in spaced relation externally of the tubular portion 45 of the grounded interrupter housing 25. They are so arranged that any internal breakdown, or internal fault condition occurring within the circuit-interrupter pole unit will pass to ground between them, to be reflected as an internal fault condition, and, consequently, will result in a tripping of the remote circuit breakers 46, 47, respectively connected, by line connections 48, 49 to the terminals 50, 51

as more clearly shown in FIG. 6 of the drawings. Thus, the line L passes through the circuit breaker 46, the circuit-interrupter pole unit, and through the other remote circuit breaker 47 to the remote line L Current- transformers 52, 53 are associated with the lines L L and measure the current passing through circuit- interrupters 46, 47, respectively.

A pair of differential protective relays 54, 55 are provided, their windings being connected in parallel with the secondary windings of the current- transformers 52, 44 and 43, 53, respectively, as illustrated in FIG. 6 of the drawing.

When the differential relay 54 picks up to close the bridging contact 56 across the stationary contacts 57, a tripping circuit 53 is made up, to energize the coil 59 of a tripping magnet 60, which releases a latch 61 to permit opening of the movable bridging contact 62 of the remote circuit-interrupter 46.

Tripping the circuit-interrupter 46 open results in the opening of an auxiliary set of contacts 63, which deenergizes the tripping circuit through coil 59. As shown in FIG. 6, the tripping circuit 58 also energizes a solenoid 64 to move an armature 65 upwardly, which results in releasing the latch 66 to permit opening of the circuitinterrupting pole unit 1. More specifically, an operating rod 67 is shown as being biased in an opening direction by an accelerating spring 67a to effect opening, rotative counterclockwise motion of the operating shaft 8. Upon tripping the breaker, the winding 64 is de-energized by the opening of a set of contacts 71, which open upon opening motion of the circuit-interrupter pole unit.

Similarly, the differential relay 55 is operative to pick up a bridging contact 72, which bridges a pair of stationary contacts 7'3, and makes up a tripping circuit 74. The tripping circuit 74 energizes a trip winding 75, which moves an armature '76 upwardly and releases a latch 77 to effect opening of the remote circuit-interrupter 47.

The opening of the circuit-interrupter 47 results in downward movement of an operating rod 78 associated therewith which effects opening of an auxiliary bridging contact 79 from a pair of stationary contacts 80 to deenergize the winding 75.

In addition, the tripping circuit 74 also energizes a coil 81, which releases the latch 66 in a manner as pre viously explained, to effect opening of the circuit-interrupter pole unit. Auxiliary contacts 82, associated With the operating rod 67 of the circuit-interrupter pole unit, effect, upon opening of the circuit-interrupter pole unit, de-energization of the tripping solenoid 81.

Should an external fault condition occur from the line 48 to ground 68, as indicated by the reference numeral 83, and assuming that the current flows from the line L toward the line L it will be obvious to those skilled in the art that only the differential relay 54 is picked up, the differential relay 55 remaining de-energized. The result of the foregoing condition is that only the circuitinterrupter pole unit and interrupter 46 are opened, with the remote circuit-interrupter 47 remaining closed, which is desirable.

If the current flows from the direction of the line L toward the line L and a fault condition occurs externally of the circuit-interrupter pole unit, as at the location 83, again the differential relay 54 will be picked up by the measurement of current from the current transformer 44, and no current being indicated in the secondary winding of the current-transformer 52. On the other hand, since the current- transformer windings 43, 53 measure the same fault current, the differential relay 55 will not be picked up. Similar conditions would arise should an external fault take place at the location 84, that is, opening of only one differential relay, this time differential relay 55, differential relay 54 remaining deenergized. As a result of this action, only the circuitinterrupters 1 and 47 would open, circuitinterrupter 46 remaining closed, which is desirable.

Assume, however, that an internal fault condition takes place, such as designated by the reference numeral 69 in FIG. 3, or 70 in FIG. 5, which the breaker 1 is unable itself to clear. As mentioned previously, the fault current in such cases will flow to ground 68, (FIG. 1) between the two current- transformers 43, 44. This arises because of the fact that each of the current- transformers 43, 44 has an external insulating cover 43a and 4411, which compels any fault current, such as the fault current 69 to flow to ground 68 between the two currenttransformers 43, 44. As well known to those skilled in the art, such a passage of fault current between the two current- transformers 43, 44 will effect the energization of both differential protective relays 54, 55, regardless of the direction of current flow, and will, consequently result in the tripping of all the breakers, namely, circuitinterrupters 1, 46 and 47.

Reference may be had to United States patent application filed March 31, 1958, Serial No. 725,286, now United States Patent 3,032,689, issued May 1, 1962, to Benjamin P. Baker and Robert F. Karlicek, and assigned to the assignee of the instant application, for a theoretical discussion of overlapping differential protective relay operation in distinguishing between external faults, which the breaker can clear, and internal faults, which the breaker cannot clear and require opening of both remote breakers.

By Way of retrospect, during the opening operation, the mechanism disposed interiorly within the mechanism compartment 7 is effective to cause, through the linkage disposed within enclosing tube 10, rotative opening movement of the operating rod 8 and extending between the three pole units A, B and C.

The counterclockwise rotative opening motion of the operating shaft 8, as viewed in FIGS. 2 and 3, is transmitted interiorly of the interrupter housing by way of gas-tight seals 86 (FIG. to effect counterclockwise, rotative, opening motion of the bifurcated crank-arm 12.

As viewed in FIG. 3, the counterclockwise opening rotative motion of the bifurcated crank-arm 12 results, through the linkage 16, in leftward opening movement of the outer operating puffer cylinder 17 over the inner stationary tubular pedestal 19, which supports the fixed piston 18. The result of this relative movement is compression of a suitable arc-extinguishing fluid, such as sulfur hexafiuoride (SP gas, within the compression chamber 87 (FIG. 3). The raising of the gas pressure within the compression chamber 87, defined by the operating puffer cylinder 17 and the stationary piston 18, results in the ejection of compressed arc-extinguishing gas past the movable contact support 26, and out through the orifice 88, carried by the movable puffer cylinder 17, as indicated by the arrows 85 in FIG. 4.

A l-though FIG. 4 shows the fully open-circuit position of the circuit-interrupter 1, nevertheless, for purposes of illustration, the established are 95 has been indicated as well as the direction of the fluid blast.

The contact fingers 27 first separate from the outer sides 30a of the tip portion of the stationary rod contact 30, and subsequently the arcing electrode 28 moves out of the recess 29 to effect drawing of the are 95 between the tip extremity 28a and the arc-resisting stationary ring portion 89' of the stationary rod contact 30. This are 95, shown in FIG. 4, is blasted by a flow of compressed sulfur-hexafiuoride gas issuing from the compression chamber 87 and passing through the orifice 88. Arc-extinction rapidly follows, and in the fully open-circuit position of the interrupter 1, as indicated in FIG. 4, the position of the several parts is such that a stationary rod contact 30* is disposed externally of the movable orifice 88.

It will be observed that during the opening motion, the puffer cylinder 17 is guided over the stationary inner pedestal tube 19. In addition, the guide rod 3 6, movable with the movable contact structure, is guided by the guide and contacting fingers 37, shown in FIG. 4.

During the closing operation, the operating shaft 8, as viewed in FIG. 3, is rotated in a clockwise direction. This effects through the linkage 16, rightward closing travel of the outer pufier opera-ting cylinder 17 and movable contact structure to result in closing of the contact structure, and a drawing of compressed gas from the region '90 into the region 87 interiorly of the operating cylinder 17; Since this is fresh gas and is uncontaminated, the interrupter 1 is in a suitable condition for a subsequent reopening operation, if this is necessary.

The circuit-interrupting structure 1, disclosed in FIG. 3, is particularly suitable for a moderate-rating circuitinte-rrupter, say operable on a circuit extending up, say, through 69 kv. By employing suitable dimensions higher voltages may be interrupted, and it is to be understood that the invention is not restricted to the lower voltages. Merely for purposes of illustration is the invention shown applied to a 46 kv. circuit-interrupter. Preferably, an effective arc-extinguishing fluid or gas, such as sulfur hexafiuoride (SP gas, at several atmospheres pressure, is disposed interiorly within the interrupting unit. The puffer-type interrupter, which is employed, is highly effective and is simple in operation. The sulfur hexafluoride (SP gas is used for both the dielectric medium and for the interrupting medium. It is to be noted that the present interrupter has a centrally disposed, grounded interrupter housing 25 with symmetrical, identical, gasfilled porcelains 34 to form the bushings. In addition, it is to be noted that the current- transformers 43, 44 are disposed outside of the casing 25, defined partially by the tubular portion 45, and use an insulated cover 43a or 44a for the outside transformer casings to prevent the current- transformers 43, 44 being surrounded by a shortcircuited turn of metal. Being isolated from the pressure tank 25 eliminates the need for gas-tight seals for leads for connection to the current- transformers 43 or 44.

The outer operating cylinder 17, being connected to the operating lever 12 by means of the connecting rod links 16, perm-its the interrupter 1 to be disconnected from the operating lever 12 when the bushing casing 34 is removed from the left-hand end of the interrupter housing 25.

Relatively stationary contact adjustment is made by turning a threaded stationary contact rod 32, as at 32a, within the mounting boss 33. This may be done, of course, following removal of the cover plate 91 following unscrewing of the bolts 92.

A particular advantage of the circuit-interrupting assemblage -1 is that the mechanism compartment 7 hang-s under the circuit-interrupter, making the whole unit adaptable for either pole or frame mounting.

A valve assembly may be associated with the grounded interrupting casing 25 to feed sulfur-hexafluoride (SP gas into the interrupter casing. A pressure gauge 94 may be employed which is visible downwardly so that a station attendant may check the pressure conditions within the interrupter casing. A low-pressure switch 96 may be utilized to effect opening of the interrupter -1 upon the occurrence of low-pressure conditions, or to sound an alarm.

A rupture diaphragm 9111 may be employed to rupture upon excess pressure due to an internal fault and thereby prevent shattering of the porcelain casings 34. An act'- vated alumina getter may be used to absorb moisture and decomposed are products.

From the foregoing description, it will be apparent that there has been provided an improved, simplified type of circuit-interrupter embodying few parts, which may be readily assembled and disassembled. Accessibility for service and maintenance is provided, it merely being necessary to remove one of the two porcelain casings 34 from the end plates 24, 93 of the interrupter housing 25. By employing a rotatable operating shaft 8, the gas-tight 7 seals 86, illustrated in FIG. 5, are small and compact. Such ring-type seals 86 have proved, in practice, to be highly effective.

It will be noted that no terminal bushing, having organic insulation, is employed which might age and deteriorate through years of service. The enclosed gaseous medium, such as sulfur hexafiuoride, is used not only for an effective arc-extinguishing blast of gas but also for dielectric strength between the high-voltage parts and the outer grounded interrupter casing 25. It is self-healing in the event of breakdown.

FIG. 7 illustrates a modified current-transformer mounting arrangement in which the surrounding currenttransformers 98, 99 are surrounded by a conducting shield 100. The shield 100 may be welded, as at 101, to a mounting flange 102. Bolts 103 and nuts 1.04 clamp a second mounting flange 105 intoposition, the latter being cemented at 106 to the left-hand end of the insulator 34.

The current-transformer mounting arrangement, illustrated in FIG. 7, is suitable for those utility customers who desire all porcelain casing flash-over faults associated with the circuit-interrupter 1 to be reflected as external faults, as contrasted with internal faults. Any fault current, such as represented by the fault condition 107, flashing over the surface 188 of the porcelain casing 34 on one side of the breaker 1, will pass to ground independently of the current-transformers 98, 99. Since currenttransformers 98, 99 are unaffected by such a fault condition 107, only a single remote breaker, such as breaker 47 on the same side of breaker 1, is aifected together with the circuit-interrupter 1. The other remote breaker 46 on the other side of breaker 1 remains closed, which may be desirable in some circumstances.

In a similar manner, a flashover 108 on the other side of breaker 1, as indicated in FIG. 7, will cause opening only of breaker 1 and remote breaker 46, the breaker 47 remaining closed.

Thus the circuit-interrupter of the present invention may be arranged to have all faults associated therewith reflected as internal faults to open all breakers 1, 46, 47 by the arrangement according to FIG. 6. Or, as mentioned, where it is desirable to prevent opening of the remote breakers 46, 47 as much as possible, then the current-transformer arrangement of FIG. 7 may be employed, where interrupter 1 and only one of the two remote breakers 46, 47 open, keeping the rest of the system connected.

Although there have been shown and illustrated particular types of circuit-interrupting structures, it is to be clearly understood that the same were merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art, without departing from the spirit and scope of the invention.

We claim as our invention:

1. A fluid-blast circuit-interrupter including an upright grounded frame support, a cylindrically-shaped, horizontally-extending, grounded, metallic interrupter housing extending substantially at right angles to said upright frame support and supported thereby, a pair of oppositely-extending insulating hollow cylindrical casings secured to opposite ends of said cylindrically-shaped interrupter housing, a line terminal disposed at the outer end of each horizontally-extending insulating casing, a pair of spaced current-transformers surrounding the grounded interrupter housing and supported thereby and having outer at least partially insulated concentrically-arranged currenttransformer housing means so that any fault condition associated with the circuit-interrupter will pass to ground between the two current-transformers and be reflected as an internal fault condition, said current-transformer housing means including as an inner portion thereof said metallic interrupter housing, an end support plate closing one end of said current-transformer housing means and disposed adjacent one end of the metallic interrupter housing, a stationary horizontally-extending pedestal guide cylinder having a fixed piston secured adjacent one end thereof and disposed substantially concentrically within said cylindrically-shaped metallic interrupter housing, means securing said guide cylinder adjacent the other end thereof to said end support plate so that upon removal of the end support plate from the metallic interrupter housing the pedestal guide cylinder will be removed therewith as well as exposing said current-transformer housing means, a movable operating puffer cylinder carrying a movable contact and orifice slidable over said horizontally-extending guide cylinder and guided thereby, a rodshaped stationary contact extending along one of said hollow insulating casings interiorly thereof and cooperable with said movable contact, a reciprocally movable conducting guide rod connected to said movable contact and extending through the other hollow cylindrical casing, and guiding current transfer means conductively engaging the outer portion of said guide rod to transfer current therefrom to the respective line terminal, whereby upon removal of said end support plate exposing said concentrically-arranged current-transformer housing means the pedestal guide cylinder, puffer operating cylinder, and movable contact will be removed therewith for inspection and possible replacement.

2. The combination of claim 1, wherein the hollow casings and the interrupter housing are filled with a highdielectric-strength gas comprising sulfur hexafluoride (SP6)- 3. The combination of claim 1, wherein rotatable operating crank means extending within the interrupter housing are employed to effect reciprocal movement of the puffer operating cylinder.

4. The combination of claim 1, wherein the currenttransforrner housing means includes a separate spaced housing for each of two current transformers and each housing has an end plate associated therewith.

References Cited in the file of this patent UNITED STATES PATENTS 2,788,418 Owens et al. Apr. 9, 1957 2,804,576 Coggeshall et al Aug. 27, 1957 2,866,045 7 Leeds Dec. 23, 1958 FOREIGN PATENTS 599,970 Great Britain Mar. 25, 1948 477,005 Great Britain Dec. 20, 1937 1,146,902 France May 27, 1957

Claims (1)

1. A FLUID-BLAST CIRCUIT-INTERRUPTER INCLUDING AN UPRIGHT GROUNDED FRAME SUPPORT, A CYLINDRICALLY-SHAPED, HORIZONTALLY-EXTENDING, GROUNDED, METALLIC INTERRUPTER HOUSING EXTENDING SUBSTANTIALLY AT RIGHT ANGLES TO SAID UPRIGHT FRAME SUPPORT AND SUPPORTED THEREBY, A PAIR OF OPPOSITELY-EXTENDING INSULATING HOLLOW CYLINDRICAL CASINGS SECURED TO OPPOSITE ENDS OF SAID CYLINDRICALLY-SHAPED INTERRUPTER HOUSING, A LINE TERMINAL DISPOSED AT THE OUTER END OF EACH HORIZONTALLY-EXTENDING INSULATING CASING, A PAIR OF SPACED CURRENT-TRANSFORMERS SURROUNDING THE GROUNDED INTERRUPTER HOUSING AND SUPPORTED THEREBY AND HAVING OUTER AT LEAST PARTIALLY INSULATED CONCENTRICALLY-ARRANGED CURRENTTRANSFORMER HOUSING MEANS SO THAT ANY FAULT CONDITION ASSOCIATED WITH THE CIRCUIT-INTERRUPTER WILL PASS TO GROUND BETWEEN THE TWO CURRENT-TRANSFORMERS AND BE REFLECTED AS AN INTERNAL FAULT CONDITION, SAID CURRENT-TRANSFORMER HOUSING MEANS INCLUDING AS AN INNER PORTION THEREOF SAID METALLIC INTERRUPTER HOUSING, AN END SUPPORT PLATE CLOSING ONE END OF SAID CURRENT-TRANSFORMER HOUSING MEANS AND DISPOSED ADJACENT ONE END OF THE METALLIC INTERRUPTER HOUSING, A STATIONARY HORIZONTALLY-EXTENDING PEDESTAL GUIDE CYLINDER HAVING A FIXED PISTON SECURED ADJACENT ONE END THEREOF AND DISPOSED SUBSTANTIALLY CONCENTRICALLY WITHIN SAID CYLINDRICALLY-SHAPED METALLIC INTERRUPTER HOUSING, MEANS SECURING SAID GUIDE CYLINDER ADJACENT THE OTHER END THEREOF TO SAID END SUPPORT PLATE SO THAT UPON REMOVAL OF THE END SUPPORT PLATE FROM THE METALLIC INTERRUPTER HOUSING THE PEDESTAL GUIDE CYLINDER WILL BE REMOVED THEREWITH AS WELL AS EXPOSING SAID CURRENT-TRANSFORMER HOUSING MEANS, A MOVABLE OPERATING PUFFER CYLINDER CARRYING A MOVABLE CONTACT AND ORIFICE SLIDABLE OVER SAID HORIZONTALLY-EXTENDING GUIDE CYLINDER AND GUIDED THEREBY, A RODSHAPED STATIONARY CONTACT EXTENDING ALONG ONE OF SAID HOLLOW INSULATING CASINGS INTERIORLY THEREOF AND COOPERABLE WITH SAID MOVABLE CONTACT, A RECIPROCALLY MOVABLE CONDUCTING GUIDE ROD CONNECTED TO SAID MOVABLE CONTACT AND EXTENDING THROUGH THE OTHER HOLLOW CYLINDRICAL CASING, AND GUIDING CURRENT TRANSFER MEANS CONDUCTIVELY ENGAGING THE OUTER PORTION OF SAID GUIDE ROD TO TRANSFER CURRENT THEREFROM TO THE RESPECTIVE LINE TERMINAL, WHEREBY UPON REMOVAL OF SAID END SUPPORT PLATE EXPOSING SAID CONCENTRICALLY-ARRANGED CURRENT-TRANSFORMER HOUSING MEANS THE PEDESTAL GUIDE CYLINDER, PUFFER OPERATING CYLINDER, AND MOVABLE CONTACT WILL BE REMOVED THEREWITH FOR INSPECTION AND POSSIBLE REPLACEMENT.

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