US2997564A - Circuit interrupter - Google Patents

Description

Aug. 22, 1961 B. P. BAKER CIRCUIT INTERRUPTER :5 SheetsSheet 1 Filed 59p? 19, 1958 Pole C Pole B Fig.l.

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WETNESSES:

Aug. 22, 1961 B, p, BAKER CIRCUIT INTERRUPTER 3 Sheets-Sheet 5 Filed Sept. 19, 1958 United States Patent ice 2,997,564 CIRCUIT INTERRUP'IER Benjamin P. Baker, Monroeville, Pa., assignor to Westlnghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Sept. 19, 1958, Ser. No. 762,026 5 Claims. (Cl. 200-4148) This invention relates to circuit interrupters in general, and more particularly to circuit interrupters of the type which force a fluid-blast into the interrupting arc to effect the extinction thereof.

A general object of the present invention is to provide an improved circuitinterrupter, particularly adapted for high-voltage application, in which a common piston means is employed to simultaneously force fluid under pressure into a pair of serially related interrupting assemblies.

Another object of the invention is to provide an improved fluid-blast circuit interrupter, involving a pair of serially related interrupting assemblies, in which a simplified mechanical operating arrangement is employed to simultaneously effect separation of the contact structure in each interrupting assembly, and also to effect actuation of a common piston assembly operable to force fluid under pressure into both interrupting assemblies.

A more specific object of the present invention it to provide an improved high-voltage circuit interrupter supported up in the air, a safe distance above ground potential, and to employ a single operating rod extending vertically between ground potential and the live interrupter parts, in which the movable contact structures and the common piston assembly, located at high potential, are simultaneously actuated by the aforesaid upstanding insulating operating rod.

Yet a further object of the present invention is to provide an improved fluid-blast circuit interrupter involving a pair of serially related interrupting assemblies disposed in a generally Y-configuration having a common piston assembly, in which voltage gradation means are employed to evenly distribute the voltage across the interrupting assemblies, and at the same time to pro vide a rugged interbracing arrangement for resulting in a strong and rigid circuit interrupter, capable of withstanding earthquake shocks and other disturbances.

A more specific object of the present invention is to provide an improved fluid-blast circuit interrupter employing a common piston assembly, in which rack means are employed, involving a pinion gear meshing with racks operating both movable contact structures of a pair of serially related interrupting assemblies, and in which another rack disposed at the upper end of an upstanding operating rod is employed to effect pinion-gear rotation from ground potential.

Another object of the invention is to provide an improved circuit interrupter of the fluid-blast type in which piston-type movable orifice assemblies move with the movable contact assemblies of two serial-1y related interrupting units, and in which, in addition, a common auxiliary high-capacity piston structure is provided operable to force additional fluid under pressure through said two piston-type movable orifice assemblies. Preferably improved operating means is provided correlating movement of the common piston structure with movement of the piston-type movable orifice assemblies.

Patented Aug. 22, 1961 A further object of the invention is to provide an improved high-voltage circuit interrupter in which a good portion of the operational and control equipment is located at ground potential for easy accessibility; in which during hand-check operation both serially related interrupting units are mechanically tied together; in which a single operator may be employed for threepole operation; in which large diameter porcelain casings are not required; and in which a return path is provided for the used fluid to flow back into the common compressing chamber.

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

FIG. 1 is a side elevational view, partially in vertical section, of an improved circuit interrupter embodying the principles of the present invention, and the contact structure being illustrated in the open-circuit position;

FIG. 2 is an enlarged fragmentary, vertical sectional view taken through the right-hand interrupting assembly of the circuit interrupter illustrated in FIG. 1;

FIG. 3 is a plan view, in section, taken along the line IIIIII of FIG. 2; and

FIG. 4 is an enlarged, fragmentary, vertical sectional view taken through a modified type of valve plate, which may be substituted for the valve plate of FIG. 1.

Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral 1 generally desig nates a circuit interrupter of the fluid-blast type, particularly adapted for high-voltage and high-power interrupting requirements. However, it will be obvious to those skilled in the art that certain features of the present application are also adaptable to low-voltage and low-power inter rupting applications.

Generally, the circuit interrupter 1 includes a pair of serially related interrupting assemblies, generally designated by the reference numerals 2 and 3, and disposed in a generally Y-shaped configuration as shown. The interrupting assemblies 2, 3 are supported diagonally outwardly from an intermediately disposed mechanism housing casting 4, surmounted upon an upstanding, hollow, insulating casing 5, preferably formed from some suitable weatherproof material, such as porcelain.

As illustrated in FIG. 1, the upper end of the mechanism housing casting 4 is extended, as at 6, to form an operating cylinder or compression chamber, within which reciprocally moves a common piston 7 secured to the upper end of an upstanding operating rod 8. The operating rod 8, as shown, extends axially interiorly through the hollow upstanding porcelain casing 5, and has a rack 9 forming an upper part thereof. The rack 9 meshes with a pinion gear 10, the latter also meshing with racks 11, 12, constituting respectively the lower ends of operating rods -13, 14 for actuating the movable contact and piston structures 15, 16, respectively associated with the interrupting assemblies 3 and 2.

Cooperating with the pinion gear 10 is an idler 17, which assists in guiding the longitudinal movement of the operating rods 13, 14 and the rack 9 associated with the upper end of operating rod 8.

The concept of mechanically tying two interrupting assemblies together for simultaneous positive operation is set forth and claimed in United States patent application filed October 30, 1957, Serial No. 693,306, by Winthrop 3 M. Leeds and assigned to the assignee of the instant application.

The interrupting assemblies 2 and 3 will now be described. The interrupting assemblies 2 and 3 are identical; consequently, a description of one interrupting assembly will sufiice for an understanding of both interrupting assemblies. With reference to FIGS. 2 and 3 of the drawings, it will be noted that the interrupting assembly 3 includes a hollow weatherproof casing 18 having a conducting cap structure 19 disposed at its outer end. The cap structure .19 is removable, and may be securely fastened by bolts, not shown, to a mounting flange ring '20, the latter being cemented to the outer end of the porcelain casing 18. The conducting cap structure 19 supports interiorly within the casing 18 a downwardly extending stationary contact rod 21, the lower end of which is hollow, as at 22, as shown in FIG. 2.

The lower end of the weatherproof casing 18 preferablyhas a mounting flange ring 23 cemented thereto, as by cement 24, to corrugations 25 externally formed on the lower end of the casing 18. For certain applications it is desirable to have a gas-tight, sealed casing structure,

as more fully described hereinafter, and to effect this purpose resilient gaskets, such as gasket 26 (FIG. 2) are employed to effect a gas-tight seal between the casing 18 and the mechanism housing casing 4.

Cooperable with the lower hollow end of the stationary contact rod 21, as indicated -by the dotted lines 27 of FIG.

2, is a movable contact rod 28, having a surrounding movable, slotted, finger contact structure 29, both the movable contact rod 28 and the surrounding slotted movable finger contact structure 29 being secured to the upper end of the operating rod 13 by means, such as illustrated in FIG. 2. As shown, the lower end of the movable contact rod 28 has a reduced shank portion 30, which has the lower end thereof externally threaded, as at 31. The threaded portion 31 is threadedly secured into a tapped bore 32 formed at the upper extremity of the metallic operating rod 13. In addition, a conducting spider plate 33, having a centrally located bore 34 is secured into position by being threaded upon the shank portion 30 of movable contact rod 28. The outer circumferential edge portion 35 of conducting spider plate 33 has a threaded upstanding flange ring 36 integrally formed therewith. The flange ring 36 is threadedly secured, as at 37, to a lower threaded portion 38 of an insulating sleeve 39,

"having integrally formed therewith an orifice 40. Thus, the sleeve 39 and orifice 40, movable with the movable in FIG. 3. The movable puffer assembly 98 moves longitudinally within the operating cylinder 42, and compresses the fluid below spider plate 33, forcing the fluid under pressure through the orifice 40 to extinguish the are 41.

As illustrated in FIG. 3, it will be observed that the plurality of contact bores 43 open, as at 44, interiorly of the guide sleeve or operating cylinder 42. Contact bars 45 are disposed in each of the contact bores 43, and are biased radially inwardly by resilient leaf springs 46 formed of any suitable resilient material, such as Phosphor bronze. As shown, the leaf springs 46 are in electrical parallel, and being of U-shaped configuration tend to expand outwardly during high-current conditions, thereby exerting a higher contact pressure upon the contact bars 45 than duringlow-current conditions.

The outer ends 47 of the U-shaped leaf springs 46 bear outwardly against companion, contact bars 48, the

latter bearing against the inner side walls 49 of the contact bores 43.

From the foregoing construction it will be observed that longitudinal movement of the contact surface 50* of conducting spider piston plate 33 will cause the contact surface 50 thereof to slide along theinner sides 51 of the contact bars 45. The plurality of electrically parallel leaf springs 46 then carry the current through the mating bars 48 to the mechanism housing casting 4. The current is then conducted through the mechanism housing casting 4 to the other serially related interrupting assembly 2.

For purposes of voltage gradation, to insure equal voltage division between the two serially related interrupting assemblies 2, 3, a pair of serially related insulating casings 52, 53 are provided, as illustrated in FIG. 1, each hollow casing 52, 53 enclosing a plurality of serially related capacitor blocks 54, each having button end contacts 55. If desired, the capacitor blocks 54 may be of the type set forth and claimed in United States Patent 2,840,670, issued June 24, 1958, to Robert E. Friedrich,

Winthrop M. Leeds and Benjamin P, Baker and assigned to the assignee of the instant application.

The inner ends of the hollow porcelain casings 5'2, 53 are joined together, as at 56, and have secured thereto downwardly depending support bars 57 for effecting interbracing engagement with an upstanding lug 58, disposed at the upper extremity of the cap 59 closing the upper end of the operating cylinder 6. The foregoing construction, involving substantially Y-shaped interrupting assemblies, the voltage- gradation casings 52, 53 and the support bars 57, constitutes a very strong and rugged circuit interrupter, capable of withstanding earthquake shocks or other disturbances, such as high-velocity wind storms, etc. Also, the conducting bars 57 form an electrical circuit between the midpoint of the balancing capacitors 52, 53 and the midpoint of the interrupting assemblies 2, 3.

As illustrated in FIG. 1, a valve plate 60, having a centrally provided hole, slides loosely over the piston rod 61 constituting the upper extremity of the operating rod 8. The loosely slidable valve plate 60 controls the venting through a plurality of holes 62, provided in a metallic diaphragm 63, disposed at the upper extremity of the mechanism housing 4. By having the metallic diaphragm 63 located at the upper extremity of mechanism housing 4, the volume of the non-displaced fluid is a minimum and consequently rapid compression of the arc-extinguishing fluid is more readily achieved.

The lower end 64 of the operating rod 8 has a slotted pin connection, as at 65, to a bell crank 66, stationarily pivotally mounted at 67 to a fixed bracket 67a. The other leg 68 of the bell crank 66 is pivotally connected, as at 69, to a longitudinally resilient toggle link 70, having an overcenter compression spring 71 thereabout. The lower end of the resilient toggle link 70 is stationaril-y pivoted, as at 72, to a stationary bracket 73.

Pivotally connected to the overcenter knee 69 of the overcenter toggle 74, comprising the toggle links 68, 70 is an operating rod 75, which may be connected laterally to any suitable operating mechanism.

It will be observed that the overcenter toggle 74 is biased, by the overcenter spring 71, to the open, full-line position illustrated, or to the closed, dotted-line position 76. Thus, the movable contact structures 15, 16' of the interrupting assemblies 2, 3 are biased, by the disclosed linkage, to either the open-circuit full-line position shown, or to the closed-circuit position shown in dotted lines.

By means of a common operating shaft 77, diagrammatically illustrated in FIG. 1, a plurality of hell cranks 166, 266 may be employed to effect the actuation of the operating rods 164, 264 associated with poles B and C associated with a three-phase, circuit-interrupting assemblage. Thus, as will be obvious to those skilled in the art, FIG. 1 represents only a single pole A of a threephase circuit interrupting assemblage, poles B and C being omitted, and the common operating mechanism being only diagrammatically illustrated.

The transmission line connections L and L are secured to terminal brackets 78, 79, which may constitute integral extensions of the mounting flange rings 20, 80. As shown, threaded studs 97 and fastening nuts 81 may be employed to secure the shunting voltage-dividing casings 52, 53 to the terminal brackets 78, 79. The threaded studs 97 may be suitably secured, as by a cemented construction, or otherwise, to the outer ends of the weatherproof voltage gradation casings 52, 53 as desired.

Connecting the region 82, above the piston 7, with the region 83, below the diaphragm 63, is an externally extending connecting conduit 84, the purpose for which will appear hereinafter.

The operation of the improved circuit interrupter 1 will now be described. In the closed-circuit position of the circuit interrupter 1, as indicated by the dotted lines 76 of FIG. 1, and dotted lines 27 of FIG. 2, the electrical circuit extends from the transmission line L to the terminal bracket 79, conducting cap structure 19, stationary contact rod 21, movable contact rod 28, and main contact fingers 29, conducting spider plate 33, contact bearing portion 50, resilient contact bars 45, leaf springs 46, outer contact bars 48, mechanism housing casting 4, and directly through the other serially related interrupting assembly 2, in a similar fashion, to the other terminal bracket 78, and hence to the other transmission line L To elfect the opening operation of the circuit interru'pter 1, the operating rod 75, shown in FIG. 1, is actuated to the left, to the open-circuit position shown by the full lines in FIG. 1. This will effect, through the bell crank 66, downward movement of the operating rod 8. The downward motion of the rack 9 will effect clockwise rotative motion of the pinion gear 10, causing downward movement of the racks 11, 12 associated respectively with the first and second operating rods 13, 14. This occurs at the same time that the third operating rod 8 effects downward working motion of the common piston rod 61. The movable contact structures 15, 16 in both interrupting assemblies 2, 3 are separated from the stationary contact structures 21 by the foregoing motion of the racks 11, 12.

The downward working motion of the piston 7, within operating cylinder 6, will force fluid, under pressure, through the passages 85 and outwardly through the apertures 86 of the spider plates 33. The fluid under pressure will be forced outwardly, about the split movable contact finger structure 29, and out through the orifice 40, associated with the movable orifice member 39. Thus, the arcs 41, drawn within each interrupting assembly 2, 3, are blasted by fluid under pressure ejected through the orifices 40. The serially related arcs 41 in both interrupting assembles 2, 3 are quickly interrupted, and continued opening travel of the operating rods 13, 14 inserts an increasing gap distance between the separated contact structures 21, 28.

In addition to the effect created by compression of fluid by common piston 7 movable within common operating cylinder 6, each interrupting assembly 2, 3 has the benefit of the pumping action created by its own piston 39-40 movable longitudinally within operating cylinder 42. This likewise compresses fluid and ejects the same through orifice 40 to assist in arc extinction.

It will be noted that during the downward working travel of the common piston 7, the slidable valve plate 60 is forced over the apertures 62 in diaphragm 63, thereby closing the same. On the other hand, during the closing operation of the circuit interrupter 1, that is, during upward travel of operating rod 8, the valve plate 60 is raised from the apertures 62 of diaphragm 63, by the cavitation formed within region 87 below piston 7. Thus, fresh fluid from exhaust region 83 is drawn through apertures 62 and into the compressible region 87 below piston 7. The fluid Within region 82, above piston 7, is forced,

through side opening 88 and downwardly through by- I FIG. 4 illustrates a modified type of valve plate 60a, which is spring-biased by compression springs 90 downwardly to close the vent opening 91, provided in modified metallic diaphragm 63a. The structure functions in the same manner, as described heretofore, except here the valve plate 60a is positively biased closed by the compression springs 90, interposed between the spring-seat caps 92, supported upon mounting studs 93, and the valve plate 60a. The mounting studs 93, as shown, are preferably threadedly secured into tapped openings 94, provided in the modified diaphragm 63a.

It will be observed that compressed fluid, which is ejected through the orifices 40 and into the exhaust region associated with each interrupting unit 2, 3 within hollow casings 18, is provided with a return passage 96, through mechanism housing 4, to the common exhaust region 83 interiorly of mechanism housing 4. Thus, circulation of the arc-extinguishing fluid takes place over the interrupting cycle.

The present invention may, with advantage, be applied to the type of interrupting structure, such as set out in United States patent application filed October 30, 1957, Serial No. 693,309, by Albert P. Strom, and assigned to the assignee of the instant application. The compressed fluid employed in the interrupting chambers of the Strom patent application is sulfur hexafluoride (SP gas, or selenium hexafluoride (SeF gas, or mixtures of one, or both of the aforesaid gases, with air, argon, helium, nitrogen or hydrogen. Obviously, the present invention is not confined to these particular gases, and may, with advantage, be employed with any suitable arc-interrupting fluid. By the term fluid, it is intended to cover gases, liquids, vapors and sprays.

From the foregoing description, it will be apparent that there is described an improved circuit interrupter in which the operational and control equipment is located at the bottom of the interrupter 1 at ground potential, and only a single upstanding, operating rod 8 is employed to interconnect the operating mechanism at ground potential with the movable contact structures 15, 16 and the movable operating piston 7 at high potential. It will also be apparent that since the interrupting assemblies 2, 3 are mechanically tied together, during hand operation, for checking contact movement, one assembly will always move with the other, which is desirable.

With the mechanical construction illustrated, there is no necessity for the provision of several insulated oil lines connecting grounded parts with high potential parts. Also a return path is provided for the fluid flow so that a complete circulation of the interrupting fluid is present. If desired, position indicators may be associated with the bell crank 66 located at ground potential. To inspect the stationary contact 21, it is only necessary to remove cap '19. To inspect the movable contact structure 15 or 16, caps 19, 59 are removed. Pin 65 is also removed, and rod 8 is raised sufficiently until racks 11, 12 run ed the pinion gear 10. Then the movable contact structures 15, 16 may be pulled out the open ends of casings 18.

By employing the generally Y-shaped interrupting arrangement with the voltage-gradation casings. 52, 53, a very strong and rigid structure is provided.

Although there is illustrated and described only a single interrupting structure, it is to be clearly understood that the same was 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 appended claims.

I claim as my invention:

1. A circuit interrupter including a longitudinally movable contact, one or more elongated contact bars oriented substantially parallel with the direction of longitudinal motion of the contact and making sliding engagement with said longitudinally movable contact over an appreciable distance of the axial length, one or more longitudinally extending spaced contact bores opening at one side along the direction of motion of said movable contact and accommodating one or more contact bars, the longi- 2. A circuit interrupter including means defininga cylindrical support, .a movable contact assembly longitudinallymovable within said cylindrical support and including a movable contact, one or more spaced longitudinally extending contact bores provided circumferential around tact over an appreciable distance of its axial length.

3. A circuit interrupter including means defining a cylindrical support, a movable contact assembly longitudinally movable within said cylindrical support and including a movable contact, one or more spaced contact bores provided in said cylindrical support having open elongated sides facing said movable contact assembly, pairs of elongated contact bars disposed within each contact bore,

resilient means including one or more U-shaped leaf springs biasing the contact bars apart, and one of the two elongated contact bars of each pair of contact bars extending into the elongated open side for resilient contacting engagement with the movable contact over an appreciable distance of its axial length.

4. A fluid-blast circuit interrupter of generally Y-shape including an upstanding insulating hollow supporting column, a generally box-shaped mechanism housing supported at the upper end of the supporting column, said -mechanism housing having an upstanding common pump cylinder supported upwardly thereby, a pair of diagonally-extending serially related interrupting assemblies supported by the mechanism housing and, together with the supporting column forming a Y-shaped interrupting structure, each interrupting assembly including an insulating casing having a terminal-cap structure disposed at the outer free end thereof, a relatively stationary con- -tactsupported by each terminal-cap structure, a movable contact carrying an orifice-shaped pumping piston cooperable with each relatively stationary contact to establish an arc within each of the two interrupting assemblies, an operating cylinder within each interrupting assembly within which the respective pumping piston reciprocates to pump fluid into the respective arc during theopening operation,va first movable operating rod EfOl' one of the two movable contacts having an inwardly disposed rack portion within the generally box-shaped mechanism housing, a second similar operating rod for .the other of the two movable contacts, the first and second operating rods being reciprocally movable through the walls of the generally box-shaped mechanism housing, pinion-gear means disposed within the mechanism housing and meshing with the two rack portions of the first and second movable operating rods, a third insulating movable operating rod extending upwardly within the hollow supporting column, the third insulating operating rod having a common fluid-driving piston carried atthe upper extremity thereof which is reciprocally movablewithin said upstanding common pump cylinder, said third operating rod having an intermediate rack portion disposed within the mechanism housing which meshes with said pinion-gear means to effect simultaneous opening and closing movement of the two movable contacts and their associated pumping pistons, the mechanism 8 housing having an upper wall which constitutes the lower end of the common pump cylinder, the third operating rod passing through an opening in said upper wall of the mechanism housing, valve means associated with said upper wall to permit drawing of fluid through said upper wall only during the closing operation of the interrupter and charging motion of the common piston, relatively short pump passage means disposed intermediate the lower end of said common upstanding pump cylinder and the interior end of each operating cylinder within the interrupting assemblies for highly effective pumping ac- .tion, and downward movement of the common piston forcing fluid outwardly from the common pump cylinder to supplement the individual pumping effort within the individual interrupting assemblies.

5. A fluid-blast circuit interrupter of generally Y-shape including an upstanding insulating hollow supporting column, a generally box-shaped mechanism housing constituting an exhaust region supported at the upper end of the supporting column, said mechanism housing having an upstanding common pump cylinder supported upwardly thereby, a pair of diagonally outwardly extending serially related interrupting assemblies supported by the mechanism housing, the pair of diagonally outwardly extending serially related interrupting assemblies together with the supporting column forming a Y-shaped interrupting structure, each interrupting assembly including an insulating casing having a terminal-cap structure disposed at the outer free end thereof, each casing constituting a second exhaust region, a relatively stationary contact supported by each terminal-cap structure, a movable contact carrying an orifice-shaped pumping piston cooperable with each relatively stationary contact to establish an arc within each of the two interrupting assemblies, an operating cylinder within each interrupting assembly within which the respective pumping piston reciprocates to pump fluid into the respective arc during the opening operation and into the second exhaust region, a first movable operating rod for one of the two movable contacts having an inwardly disposed rack portion within the generally box-shaped mechanism housing, a second similar operating rod for the other of the two movable contacts, the first and second operating rods being reciprocally movable through the walls of the generally boxshaped mechanism housing, pinion-gear means disposed within the mechanism housing and meshing with the two rack portions of the first and second movable operating rods, a third insulating movable operating rod extending upwardly within the hollow supporting column, the third insulating operating rod having a common fluid-driving piston carried at the upper extremity thereof which is reciprocally movable within said upstanding common pump cylinder, said third operating rod having an intermediate rack portion disposed within the mechanism housing which meshes with said pinion-gear means to effect simultaneous opening and closing movement f the two movable contacts and their associated pumping pistons, means interconnecting the first-mentioned exhaust region with the pair of second exhaust regions, means defining a by-passing conduit interconnecting the first-mentioned exhaust region with the space within the upstanding pump cylinder on the top side of the common piston, valve means associated with the upper wall of the mechanism housing which closes the lower end of the upstanding pump cylinder for circulation of the fluid, and downward movement of the common piston forcing fluid outwardly from the common pump cylinder to supplement the individual pumping effort within the individual interrupting assemblies.

References Cited in the file of this patent UNITED STATES PATENTS 874,229 Net Dec. 17, 1907 (Dther-references on following page) 10 UNITED STATES PATENTS FOREIGN PATENTS 1,774,801 Macke et a1. Sept. 2, 1930 396,190 Great Britain Aug. 3, 1933 ,025,456 Kagi Dec. 24, 1935 412,403 Great Britain June 28, 1934 2,095,441 Howe Oct. 12, 1937 580,699 Germany July 14, 1933 2,303,425 Bickham Dec. 1, 1942 5 539,236 Great Britain Sept. 2, 1941 2,520,681 Hanson Aug, 29, 1950 681,985 Germany Oct. 5, 1939 3,7 3 Sharp Dec. 12, 1950 926,016 Germany Apr. 4, 1955 ,7 ,581 Bruno Jan. 10, 1956 755,016 Great Britain Aug. 15, 1956 6 MacNeill et a1. May 29, 1956 760,355 Great Britain Oct. 31, 1956 2,781,435 Heilmann et a1. Feb. 12, 1951

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