US1861128A - High-power circuit-breaker - Google Patents

Description

May 31, 1932. MlLUKEN 1,861,128

HIGH POWER CIRCUIT BREAKER Filed Dec. 28, 1928 2 Sheets-Sheet 1 gnucnhw May 31, 1932. H. MILLIKEN HIGH POWER CIRCUIT BREAKER File 1360- 8, 28 2 Sheets-Sheet 2 17/ Hum 55 MAN/{HY dam PM May 31, 1932 ,orxonmsncmmm men-rowncmcurrf.

Application ma muons; 1m. Serial Io. assoc.

This invention relates to that ty of highpower circuit-breaker in which a last of air or other fluid is em loyed for quenching the are which occurs w on the contacts are separated, and the special purpose of the present invention is to increase the arc-rupturing capacity of the device and thus prevent the arc coming into accidental contact with the main blade of the main contactsor some extraneous electric conductor, which of course would defeat the urpose of the air blast, as more fully hereina r set forth.

Referring to the drawings annexed Fi 1- is a vertical sectional view of a is circuit-breaker embodying one form of my invention;

Fig. 2 is a horizontal sectional v1ew on the line 2-,-2 of Fig. 1;

Fig. 3 is a-horizontal sectional view taken so on the line 3-3 of Fig. 1 gFig. 4 is a vertical sectional view taken on t e line of Fi 1 the electro-magnetic device being omitte Fig. 5 is a view similar to Fig 1 showmg a modified form of the device; ii 6 1s a sec- 25 tional view on the line 6'-6 of ig. 5; F g.

-7 is a plan view of another form of my 011- cuit-breaker; Fig. 8 is a vertical sectional view of the device shown in Fig. 7 and Fig.

9 is a similar view of the modification shown so in Fig. 7 taken at aggroximatel a right angle to the line on whic ig. 8 is ta en.

Referring to Figs. 1 to 4 of the drawings annexed by reference=numerals, designates I an air storage tank which is in common- 35 tion, by means of a valved pipe 16, with the lower end of an insulator blast-tube 17. Mounted on the upper end of the insulator tube 17 is a nozzle 18 whose exit is directed upwardly and whose lower inlet end 1s 1n 4o commumcation with the upper end of the blast-tube 17. This nozzle, as shown, is preferably in the form of a flattened or fanshaped flmnel and has its interior transversely ivided by integral bafile-walls 19, these a baflle-walls bein arranged in two groups,

one at either si e of the vertical center of.

the nozzle, to thus form a free central passage 20 and two end passa s numbered, re- :pectively, 21 and 22. e bafile-walls, as 60 own particularly in Fig. 3, project alter-v nately from the opposite side walls of the nozzle, their lower ends terminating a suitable distance from the downwardly-and-inwardly-inclined edge walls of the nozzle.

The main contacts 23 are mounted on a metal sleeve-like support 24 which is supported on the insulator sleeve 17 by means of a plurality of well-known type of mushroom insulators 25. The main blade 26 of the switch is pivotall mounted on a vertical insulator structure 2 of suitable type. The terminals 28.and 29 of the circuits are connected, respectively, to the metal sup ortingsleeve 24 and the pivotal end of t e main blade 26. The shunt circuit is formed by attaching to the main blade 26 a horn 30 whose curved contact-rod extends horizontall through the nozzle, the holes in the edge wa throu h which this contact-rod portion of the cm extends being surrounded by two inte -ral tubes 31 which project laterally from t e nozzle a suficient distance to prevent the arc-flame from escaping from the funnel at these points.

The other termihal of the shunt is indicated by 32; it extends through a hole in one of the tubes 31 so as to lie in the path of the contactarm of the born 30 and make contact there with, the position of this shunt contact 32 being such as to draw the are, when the shunt contacts separate by lateral movement of the horn 30 (with the blade 26) into the fansha ed nozzle, where it will be acted on by the last. It will be observed that this fixed shunt contact 32 is virtually in the interior of the nozzle, since the tube 31 is a lateral extension thereof. It will also be observed that this contact 32 is connected to the metal sleevesupport 24 through a terminal 33.

In the circuit between the fixed shunt 32 and the terminal 33 is an electromagnet 34: which is provided with three core- bars 35, 36 and 37 which have their pole-pieces extended laterally and upwardly so as to lie along-side of the outer faces of the walls of the nozzle, it being desirable to extend these pole-pieces entirely to the top-edge .ofthe nozzle, as shown. The pole-pieces 36 are desirably located adjacent the passage 22 in the nozzle and the polepieces adjacent the central p m; 20

while the remaining pole-pieces ar'elocated adjacent the passage 21. i

Any suitab e mechamsm ma be employed for admitting the comprsqod air into the nozzle at the moment breaki the shunt contacts, and of course any suita le mechanism may be employed for operating the main switch-blade. s w suc mechanisms in my Patent No. 1,756,374 dated April 29, 1930.

When the main blade is separated from its contacts, the circuit is, of course, shunted through the shunt contacts 30-82 and the electromagnet 34, thus energizing the polepieces 35, 36 and 37. The air blast from insulating pipe 17, having its shape chanfid by the fan-shape of the attenuator 18, lows through the passage 22, carrying the arc with it. At the same time, the magnetic polepieces 36 tend to force the arc outwardly reduced by injecting into the .air blast 66 re uce its conductivity. Also compresed a straight tube provided with a plurality of at I through passage 22, thus greatly assisting the air blast in reducing the time of are deflection and extinction. 4 If the current is so large that the arc is not broken in the first passage 36, the horn, continuing its ra id motion, will draw-the end of the arc fart er to the left, and the air blast, aided by the magnetic poleieces and 37, will force the arc upwa into successive passages. As the arc is b own upwardly, it has no 8:121). to follow. except the tortuous passages tween the alternate baflles 10, and the length of the arc is thereby multiplied many times while its cross-section .is confined to very small dimensions. The expansion of the arc atmosphere, due to heat, also assists in hastening the upward movement. The volume increase is entirely lengthwise of the arc.

The attenuator nozzle 18, together with its integral parts, is made of any insulating ma-1 teri which will not be dama d by an arc; material of this kind is now 0 tainable commercially, such as pyrex lass .used for highvoltage insulators, this much better than porcelain in that respe It will be observed that with my construction the arc' is prevented from coming into accidental contact with the main blade or main contact and also that the arc is confined by the insulating walls to a small crosssection, but is stretched out to a great length while within the air blast, this increase of length of are taking place much faster than the motion. of the arcing horn. The are is also cooled by coming into intimate contact with a great 1 of cool surface of the confining walls. t will be noted also that the deflectm' motion of the arc is tly accelera by specially-arranged electromagnets.

Instead of air alone for the blast, the conductivity of the are per unit volume may be 01 finely divided material, either 801i 1i uids,servingtocoolthearc orotherwise carbon dioxide, either in liquid or gaseous form, may be used for the purpose of providing a non-oxidizing atmos here to extinguish flame due to burning 0 metal vapor; any other non-oxidizing material may be used, such as carbon tetrachloride.

It will be observed that-the walls 19 are omitted at points 20, 21 between the polepieces of the magnets, this being for the purpose of reducing the air-gap of the magnetic circuits to a minimum and to thereby give a maximum magnetic force. The arc passage 20 21 and 22 just at the point between 0 poles of the magnet may be made extremely narrow, such as inch thick. This extreme construction of the arc-spaced will increase its electrical resistance, thereby acelerat' the redution of the current to zero. The cc of the ma et 34 carries no current except while the circuit-breaker is in the act of opening, which is only a fraction of a second; this coil, therefore, ma be made of smaller conductor than the mam circuit, and low-voltstfie insulation between turns and between e iron core-pieces and the coil will be suficient, as these parts are at the same potential substantially. The air-blast is opened slightly before the born 30 is opened, as described in my aforesaid previous patent applications; this necessarily results in a slight waste of the air suppl but, in order to conserve the air supply t e contact-rod portion of the horn is made nearly as wide as the air-pass through the nozzle, so as to thereby delay t e full flow of air until the instant it is required i. 0., when the arc arrives. The contact-rod .portion of the-horn may be made with a stream-line cross-section vertically, as shown particularly in Fig. 4, to avoid the. formation of a partal vacuum on the up r side of the horn, which vacuum would uce the dielectric strength of the atmosphere at that point. The attenuator-nozzle 18 ma be sectional to facilitate its manufacture; 1 have shown, in Fig. 3 a nozzle made in two parts.

n the modifications shown in Figs. 5 and'6, the arcin -horn moves in a vertical plane. The main lads, not shown may be arranged to move in either a vertical lane or a horizontal plane, and the arcingorn may be arr to open faster than the main blade. In is structure, the main discharge of the air is directed upwardly and aterally through a nozzle 18a divided by a partitionwall 18b. B vaging the design, the portion of the air w ich ws out through the nozzle at o posite sides of the division-wall 186 may varied, and it will be understood also that the two passages between this divisionwall 186 and the end-walls of the nozzle may be provided with a baflle arrangement similar to that shown in Fig. 1.

In the modified form shown in Fi 7 8 and 9, the attenuator-nozzle 180 is vi rz ually vertical baflles 19a. In this form of device, one of the tubes 31 is closed at its outer end to thus prevent escape of the air-blast at this point.

The switch is shown with a main contact and a shunt contact. It is quite possible, however, to omit the main contact and allow the shunt contact to become the main and only contact, in which case it would have m to carry the normal current continuously without overheating and would be made of suitable dimensions.

What I claim as new is:

1. In a circuit-breaker a blast-pipe having an insulator nozzle connected to its exitend, and a pair of separable contacts whose contacting faces are located in said nozzle so that the are formed when the contacts are separated shall be subjected to said blast entirely within the nozzle at a point distant from the exit-end of said nozzle, so that the arc will be confined by and attenuated within said nozzle, the side-walls of said insulator nozzleibeing depressed to bring them close 5 together at one point to form a narrow airgap within the nozzle, and an electro-magnet included in the circuit and having its pole-pieces extending longitudinally of'the nozzle and lying in theaforesaid depressions 80 in the nozzle.

2. In a circuit-breaker, a blast-pipe having an insulator nozzle connected to its exit-end, and a pair or separable contacts whose contacting faces \are located within said nozzle as so that the are formed when the contacts are separated shall be subjected to said blast entirely within the nozzle at a point distant from the exit-end of said nozzle, so that the arc will be confined by and attenuated within 40 said nozzle, the movable one of said contacts being in the fornt of a horn which extends through said nozzle and into the blast-pipe, so that the blast will be directed against the end of said horn and assist in quickly actuatus ing it in circuit-breaking direction.

In testimony whereof I hereunto aflix my signature.

HUMPHREY S MILLIKEN.

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