US2417134A - Arc chute - Google Patents

Description

March 11, 1947.

W. M. SCOTT, JR

ARC CHUTE Filed Jan. 12, 1945v 2 Sheets-Sheet 1 @MA ATMRNEY.

March 1l, 1947. w, M, SCOTT, JR 2,417,134

ARC CHUTE Filed Jan. 1.2, 1945 2 Sheets-Sheet 2 INVENToR. if M. fcorr JR.

/nm um A TToRNEY.

Patented Mar. 11, 1947 UNITED STATES PATENT OFFICE ARC CHUTE Application January 12, 1945, Serial No. 572,553

4 Claims.

My present invention relates to circuit inter rupters and more particularly to a novel arc quencher therefor comprising a plurality of spaced plates of insulating material arranged above and parallel to the arc, the said plates being intersected by a number of transverse metallic rods.

More speciically, my invention relates to a novel and simplied blow-out means readily adapted to be used in connection with the said metallic rods and which requires a minimum of additional parts and virtually no maintenance and repair.

This application embodies some of the principles of my application Serial No. 550,179, led August 19, i944, and embodies substantially the disclosure therein set forth together with the additional simple and novel blow-out mechanism.

Essentially, my invention contemplates that the upper transverse metallic rods have an iron core in order to provide a magnetic blow-out. These upper transverse rods may also extend through a pair of ferrous side plates in order to enhance the blow-out effect.

in the construction and operation of circuit interrupters, it is frequently necessary to provide means for extinguishing quickly the arc which is drawn between the contacts as they separate. Such circuit interrupters, which may be tripped open on the incidence of high currents, comprise a pair of main contacts (to carry the full current during normal'operation), which are arranged to make after and break before a pair of parallel -arcing contacts so that any arcing which may occur will not pit or otherwise destroy the contact surfaces of the main contacts.

slots are well known.

My invention contemplates as its essential function the provision of an arcv chute which utilizes both the principle of spaced insulating 'plates tc lengthen and squeeze the arc, together with a series of metallic surfaces with'which the arc is brought into contact and broken up into a series of small arcs and cooled.

More specifically, my invention contemplates a plurality ofV spaced insulating plates'extending (Cl. 20G-447) 2 in a direction parallel t0 the path of the arc into which the arc is forced by blow-out means, the said spaced insulating plates being used in combination with a series of transverse metallic members which will break the arc into a plurality of arcs in series and will also further cool the same.

Still more speciiically, my invention contemplates that these metallic surfaces be formed by a series of transverse pins, each of which extends through all of the insulating plates and each of which furnishes a conductive path between the various slots defined by the spaced insulating plates.

The primary object of the present invention is the provision of simplified blow-out means which comprises making a substantial portion of the transverse metallic rods or pins of the arc chute of a suitable conductive material, such as copper, but making the upper row or rows of transverse pins of iron in order to provide a suitable magnsti@ blow-out. These upper iron transverse pins may have a sleeve or coating of copper in order that these upper pins may also act as arc extinguishing pins.

Another object of my invention is the arrangement of the upper iron copper coated transverse rods or pins so that they may cooperate with or form a part of other blow-out means such as a pair of ferrous side plates.

These and many other objects of my invention will become apparent in the following description and drawings in which:

Figure l is anend View taken from line l--I of Figure 2 of my novel arc extinguisher.

Figure 2 is a view partly in cross section taken from line 2-2 of Figure l looking in the direction of the arrows and showing the compound upper two rows of transverse pins which have an iron core and copper coating or sleeve.

Figure 3 is a front View of a slightly modiiied form of arc extinguisher in which the construction of the upper two rows of compound pins is slightly varied so that these pins may coop- 'crate with a pair of ferrous Side plates.

Figure 4 is a side view of the arc chute of Figure 3 showing one of the ferrous side plates.

Figure 5 is a longitudinal cross sectional view taken on line 5-5 of Figure 3 showing the construction ci the compound copper-iron blowout pin.

Figure 6 is a cross sectionalview taken on line -i of Figure 5 further showing the construction of the compound copper-iron pin of the arc chutes of Figures 3 and 4.

Referring now to Figures 1 and 2, I have here shown an arc chute corresponding in every respect to the arc chute disclosed in my application Serial No. 550,179, except that the magnetic blow-out coil in series with the arcing horn is no longer used, but instead the upper two rows of pins in the embodiment shown have iron cores and copper coatings or sleeves.

The arc quencher 2b also has the construction and operation generally shown in my Patent No. 2,348,228. The arc chute 2li comprises a pair of side supporting plates 2l, 2l of insulating material, between which are mounted a number of spaced arc extinguishing plates 23, 2li, 25, 2li, 2l, also of insulating material. The plates are integrated as a single unit by the transverse bolts itil, SI, 32, 33, which are provided with insulated bushings 35, 35.

Bolts 3E and 3l are also provided with indiw vidual insulating washers or spacers 3l', 3l to maintain the spacing between the irrsulating plates at the iront of the arc quencher. Bolts 32 and 33 carry a set of insulating spacers S3 between each pair of plates which serve to space the back ends of the plates from each other; the said spacers 38 also each having a hook-shaped extension 39 to engage a hook 4t on the upper end of the arcing horn di, which is secured to the back panel 42 on which the circuit breaker is mounted. The plates 23-21 are accordingly insulated from each other and from the side plates 2|.

The side plates 2l, 2l also carry between them on the transverse bolts ill and l5 the opposite arcing horn llt. The said arcing horn i6 an extension :lll carrying a bolt i8 which may be secured tothe stationary flange member i9 carried by the transverse insulating bridging support 5B in order to secure the arc chute in position. A conductive connection is made to the arcing horn i5 through the flange member le and the pigtail 52.

The arc quencher 2i) is particularly characterized by a large number of transverse copper pins B, il@ which pass through perforations in the plates 23, 2li, 25, 26, 2l, as shown in Figures l and 2, and which are supported thereby. The pins Si? preferably do not contact the opposite supporting insulating members 2i, 2i. This will facilitate assembly and adjustment of the unit, permits the pins to be brought down close to the contacts which form the arc, removes the possibility of breakdown or creepage along the supporting plates 2l, 2l. IThe remainder of the structure shown corresponds to the circuit break er shown in my Patent No. 2,348,228.

Essentially, the circuit breaker here shown comprises a lower back connection stud (not shown) to which the main movable contact 'l2 (on the contact arm 65) the arcing horn ll8lll,

-and the. arcing contact i8 are connected respectively by a pigtail (not shown), pigtail 52, and pigtail 66. The circuit breaker also cornprises an upper back connection stud lil to which is secured the main stationary contact l l, which engages the main movable contact 'l2 mounted on the contact arm 65 to complete a circuit from the upper to the lower connection studs. And also mounted on the back connection stud 'lil is the connecting bracket 'i3 which is connected to the stationary arcing horn il at the end of which the stationary arcing contact 'il is carried.

When the main contacts 'il and l2 have separated, while the arcing contacts hereinafter described are engaged, current flows from the back connection stud l@ through the connecting blown upwardly thereon.

bracket 13 and the lower end of the arcing horn 4i, to the stationary arcing contact l?, then to the movable arcing contact 'iii mounted on the Contact arm 65, and then through the pigtail 66 to the lower back connection stud.

is arcing contacts il and it separate, an arc is drawn therebetween. As the opening move ment is completed, the root of the arc at contact TE is blown upwardly along the arcing horn lll while the root of the arc at movable arcing contact i8 is transferred to arcng horn 43 and The blow-out means, hereinafter more specically described, blows the center of the arc upwardly into the center ol the plates 23 to 2i. I"ihe plates to 2l are longest in a vertical direction at plates 23 and 2l; that is, the downwardly extending cusps 2li thereof extend further downwardly in the case of theseplates. The center plate 25 has the shortest cusp $2. The intermediate plates 2.4i and 26 have cusps ill of intermediate length, as shown more particularly in Figure 2 and in dotted lines in Figure 1.

Thus, in a transverse direction, the plates of the arc chute present a V-shape which tends to guide the arc toward the center of the chute. The downwardly extending cusps 80, 8l and 82 intercept the center of the arc and tend to guide the arc in its upward movement to squeeze into the coniined space between the plates.

The arc in being driven upwardly tends to be squeezed into but one of the spaces, for instance, in the space between plates 24 and 25 or in the space 85 between plates 25 and 26. It is not necessarily conned to either or both of these spaces but may be broken up into a plurality of parallel arcs in separate spaces.

While this type oi" arc chute having only the spaced insulating plates 23 to 2l has been eiective in use, it has been found that perhaps only one or two of the spaces, and usually only one, are actually effective in extinguishing the arc. That is, the arc is forced up into but one of the four spaces which it may normally enter, is squeezed between the surfaces of the plates defining the space, and is extinguished therein.

The arc, in addition to being initially compressed in one or two of the slots or spaces between the plates, is intercepted transversely by the plurality of metallic surfaces which dene the pins 69. I'hese pins B0, which are of highly conductive material, preferably copper, tend to break the arc up in series among them. That is, should the arc be squeezed, say, into the slot 85, it will encounter a number of pins 60, as shown by the dotted line 9i), and will be broken up into a series of small arcs between these pins.

In addition, as the arc is driven upwardly, the initia1 small series arcs will go out and new arcs, as indicated at Si, will be establishedacross other pins, which eiect a new cooling action on the arc. As the arc moves still further upwardly, it will encounter still more pins and be broken up into a larger number of small arcs in series. This continuous tearing of the roots of the small arcs from the lower pins and reestablishing the small arcs above the small arcs which have been extinguished, will render the arcs unstable and lead to quick extinguishment.

The surfaces of the pins 52 will tend further to cool the arc while the arc roots move along from pin to pin, and will result in quick extinguishment of the arc. Not only does this action take place within the vprincipal slot (for instance, 85) into which the arc is rst squeezed, butl by vand arc extinguishing means within the arc chute; said means for moving the arc inte the chute comprising a plurality of ferrous pins eX- `tending transverse to the arc path substantially remote from the point of entry of the arc into the arc chute; a pair of ferrous plates on either side of the arc chute enacting with said transverse ferrous pins to forni a U-shaped magnetic path; a plurality of insulating plates extending in planes parallel to the path of the are, said insulating plates supporting said transverse ferrous pins in spaced relation to each other.

2. An arc chute comprising means for drawing an arc; means for movin the are into the chute;

and arc extinguishing means within the arc chute; said means for moving the arc into the chute comprising a plurality of ferrous pins extending transverse to the arc path substantially remote from the point of entry of the are into the arc chute; a pair of ferrous plates on either side of the arc chute coacting with said transverse ferrous pins to forni a U-shaped magnetic path; said are chute having a pair of insulating side walls arranged parallel to the path of the arc; said transverse ferrous pins extending through and being supported by insulating side Walls; said ferrous plates being supported by said insulating side Walls; the ends of said transverse ferrous pins engaging said ferrous plates.

3. An arc chute comprising means for drawing an arc; means for moving the arc into the chute; and are extinguishing means Within the arc chute; said means for moving the arc into the chute comprising a plurality of ferrous pins extending transverse to the arc path substantially remote from the point of entry of the arc into the arc chute; a pair of ferrous plates n either side of the arc chute coacting With said transverse ferrous pins to form a U-shaped magnetic path; said arc chute having a pair of insulating Aside Walls arranged parallel to the path of the arc; said transverse ferrous pins extending through and being supported by said insulating side walls; said ferrous plates being supported by said insulating side walls; the ends of said transverse ferrous pins engaging said ferrous plates; said ferrous pins Jhaving an insulating sleeve extending along the length thereof at least up to the interior surfaces of said insulating side Walls.

4. An arc chute comprising means for drawing an arc; means for moving the arc into the chute; and arc extinguishing means within the arc chute; said means for moving the arc into the chute comprising a plurality of ferrous pins extending transverse to the arc path substantially remote from the point of entry of the arc into the arc chute; a pair of ferrous plates on either side of the arc chute coacting with said transverse ferrous pins to form a ill-shaped magnetic path; said arc chute having a pair of insulating side Walls arranged parallel to the path of the arc; said transverse ferrous pins extending through and being supported by said insulating side walls; said ferrous plates being supported by said insulating side Walls; the ends of said transverse ferrous pins engaging said ferrous plates; said ferrous pins having an insulating sleeve extending along the length thereof at least up to the interior surfaces of said insulating side Walls; and a conductive metallic coating over said insulating sleeve.

WILLIAM lVI. SCOTT, JR.

REFERENCES CITED The following referencesare of record in the lle of this patent:

UNITED STATES PATENTS Number Name Date 900,798 Corey Oct. 13, 1908 1,519,230 Aalborg Dec. 16, 1924 2,133,158 Ver Planck et al. Oct. 11, 1938 2,180,147 Hopp Nov. 14, 1939

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