US2777036A

US2777036A - Circuit interrupter

Info

Publication number: US2777036A
Application number: US405322A
Authority: US
Inventors: Russell E Frink; Samuel A Bottonari
Original assignee: Westinghouse Electric Corp
Current assignee: Westinghouse Electric Corp
Priority date: 1954-01-21
Filing date: 1954-01-21
Publication date: 1957-01-08
Anticipated expiration: 1974-01-08
Also published as: FR1128483A

Description

5 Sheets-Sheet l Filed Jan. 21, 1954l Fig. i.

1 9. mm n r a n n illrrl Niiflf rlr nl lrn INVENTORS Russell E. Frink 8 Samuel A. Bottoncri. dg' BYQJ ATTORNEY Jan. 8, 1957 R. E. FRINK ET AL 2,777,036

CIRCUIT INTERRUPTER Filed Jan. 2l, 1954 3 Sheets-Sheet 2 F ig. 2.

4 A 2 a 35 a? 22 '-5 I6 2 25 r 3e lo u s .r I f, 47 47 29 38 30 34 24 2e 37 l5 23 2O 35 26 34 patented dan. 8, 1957 fico CHEQUE? 1N EERRUE'EER Russell E. Friuli and Samuel A. lottonnri, Pittsburgh, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application .lanuary 21, i954, Serial No. $5,322

11 Claims. (Cl. 26d-dfi?) This invention relates generally to circuit interrupters, and, more specifically, to arc-extinguishing structures for magnetic air circuit interrupters.

The general object of our invention is to provide an improved circuit interrupter, in which improved and more etective arc-extinguishing action takes place.

Another object is to provide an improved transfer arcextinguishing means for a circuit interrupter of the type having an electrically floating blowout coil.

Still, a further object is to speed up the transfer into series circuit of the magnetic blowout coil so as to bring about more rapid and effective operation. l

A further object is to provide an improved venting arrangement for a circuit interrupter of the type having a floating blowout coil.

Another object is to use the core or yoke portion of t te magnetic circuit in a magnetic circuit interrupter to eX- tinguish the transfer arc portion in electrical parallel with the terminals of the blowout coil.

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

Figure l is a side elevational view, partially in vertical section, of a circuit interruptor embodying the principles of our invention, and the Contact structure being shown in the closed circuit position;

Fig. 2 is a plane sectional view of the circuit interrupter of Fig. l taken along the line ll-ll thereof;

Fig. 3 is a vertical sectional view taken along the line III-III of Fig. l;

Figs. 4 and 5 are end and side elevational views, respectively, of a blowout coil mounting plate utilized in the embodiment of our invention illustrated in Fig. l;

Figs. 6 and 7 are end and side elevational views, respectively, of the magnetic plates utilized in the yolre'portion of our improved circuit interruptor;

Fig. 8 is a vertical sectional view taken along the line VIll--Vlll of Fig. l, looking in the direction of the arrows;

Fig. 9 is a fragmentary vertical sectional view through a modified type of transfer arc-extinguishing means; and

Fig. l is a sectional view taken along the line of Fig. 9.

Referring to the drawings, and more particularly to Fig. l thereof, the reference numeral l generally designates a circuit interruptor, in this instance being one of the air-break type. Although the illustrated specific embodiment of our invention is an air-break type of circuit interrupter, it is to be clearly understood that certain features of our invention may be applicable to other types of circuit interrupters, say for instance one of the liquid-immersed type or one operating in a gaseou medium. Merely for purposes of illustration do we describe a specilic embodiment of our invention which operates in air.

Generally, the circuit interruptor l includes contact structure 2 operable to establish an arc, which is moved upwardly into an arc-chute structure 3, including a pair of arc-extinguishing sections 4 and S of substantially identical construction.

As well understood by those skilled in the art, one terminal L1 of the circuit interrupter is connected to the stationary contact 6 of our device, whereas the other terminal LZ of the interruptor is electrically connected to the movable Contact 7 of the device. if desired, suitable bridging and secondary contacts may be employed to relieve the stationary and movable arcing contacts 6, 7 from carrying the current in the fully closed-circuit position, as shown in Fig. l.

During the opening operation, the moving arcing contact 7 moves away from the stationary arcing contact 6 to establish an arc S, as shown by the dot-dash line of Fig. l. This arc, generally designated by the reference character 3, may be considered as composed of three sections 8a, Eb and Sc. The arc 8, of course, bows upwardly because of the natural convection current of air, which is heated by the hot arc 5, and also because of the magnetic forces set up by the arc 8 which act to expand the loop of the arc, as well understood by those skilled in the art.

Adjacent the top portion of the arc S is a pair of transfer arc horns lll, T5., between which is disposed a transfer arc-extinguishing means, generally designated by the reference numeral i3. The arc portion 3a extends between the movable arcing contact 7 and the transfer arc horn lll. The arcportion Sb extends within the transfer arc-extinguishing means i3 between the transfer arc horns lil and lll. The arc portion 8c extends between the stationary arcing contact o and the transfer arc horn 11.

The function of the transfer arc-extinguishing means i3 is to interrupt the arc portion ab, and so bring into series circuit the pair of serially related, centrally disposed blowout coils l5, lr6, the location of which is more clearly shown in Fi. 2 of the drawings. Such coils, of course, have insulating windings. As mentioned, the centrally disposed blowout coils l5, lo are connected in series circuit together, as by a connection 17 (Figs. 1 and 3), and the other ends lll, l@ of the blowout coils i6, l5, respectively, are secured to the transfer arc horns lll, lll, respectively, as shown more clearly in Fig. 1 of the drawings.

Because of the reactance of the blowout coils l5, 16, it is difficult to force current to liow through them because of the countervoltage set up in the coils. The transfer arc-extinguishing means lli, is therefore, desirable to assist in this transfer into series circuit of the blowout coils 15, lo by extinguishing the arc portion 8b. Generally, the transfer arc-extinguishing means i3 includes a plurality of spaced magnetic plates 2t), the conguration of which is more clearly shown in Figs. 6 and 7 of the drawings. As shown, each magnetic plate 2li has a slot 2l provided therein, within which the arc portion 3b is moved. lThe spaced magnetic plates 20 are spaced laterally apart, as shown more clearly in Fig. 2, by insulating Vspacers 22 cemented between their outer edges.

it will be observed that the several spa-ced magnetic plates E@ collectively provide the interconnecting core portion, or yoke 23 which magnetically linterconnects the two side pole plates 24, which extend lengthwise along the outside of the arc :chute jaclret 2S, the latter enclosing the several plates Z6, collectively dening the arcextinguishing sections l and 5 of the circuit interruptor l.

Following extinction of the arc portion flb within the transfer arc-extinguishing means 13, the

blowout coils

15 and 16 are serially connected into the circuit, and the energization of these coils 15, lo sets up a magnetic liux within the magnetic circuit 27, which includes the pair of side magnetic pole plates 24 and the interconnecting arenoso 3 yoke .23. Preferably, the pole `plates 24 .are formed of vertically extending sheets of a suitable magnetic material to form 'a laminated structure, more clearly shown in Fig. 2.of vthe drawings. Magnetically interconnecting the side pole plates 24 is the central interconnect-ing core or yoke portion v23, about which encircles 'the two serially related blowout `coils 1S and 16.

As will be obvious to those skilled in the art, theH-type ofmagnetic circuit 27 shown, upon the energization thereof, .causes magnetic flux to flow between the pole plates 2.4 inthe manner indicated by the `arrows 28 in Fig. 8. This magnetic yflux extending transversely between the pole plates 24 causes upward movement of the arc portions Sa, 8c upwardly into the arc-

extinguishing sections

4,5 of the arc-chute structure 3.

The left-hand end of the are portion Sa, as viewed in Fig. 1, quickly transfers to the outer arc horn 29, the lowerfend of which is connected, las shown, to the movable arcingcontact 7 and hence to the lowerterminal L2 ofthe device. Also, the right-hand end of the arc-portion 8c quickly transfers tothe right-hand arc horn 35) of `the device, which is electrically connected to the stationary .contact 6 by the connection 12 and hence to the upper terminal L1 of the interrupter.

Disposed within the arc-extinguishing sections 4, are the plurality of spaced, slotted, ceramic Vplates 26, the

t configuration of which is more clearly shown in Fig. 8 of the drawings. As shown, each ceramic plate 26 has a slot 32 provided therein, the .upper closed end 33 of which is slightly `off-center. The plates v26 are staggered during the assembly .operations so as to form a horizontally d-isposed, zigzag arc passage 9 throughout-the length of the arc-.chute sections 4, f5 to quickly bring about extinction ofthe arc'portions 8a, 8c. The plates26 are spacedlaterally apart, as shown more clearly in Fig. 1, by sections of asbestos rope 34fcemented between the plates 26 adjacent the outer edges thereof, the method being identical to that previously referred to in `spacing the magnetic plates 20 of the transfer .arc-extinguishing means 13 apart.

Certain features of the disclosed structure `have been set out and claimed in United States patent application, filed November 28, 1952, VSerial No. 323,009, now United States Patent 2,769,065, issued .October 30, `1956, to Russell E. Frink, entitled Circuit Interrupter, and assigned to the assignee of the instant application. This yapplication, in part, claims the disposition of the serially

related blowout coils

15, 16 in the plane of the arc-chute jacket 25m-brace the blowout coils against the magnetic forces occurring during the interruption of `l'ligh-fault currents.

'Proper operation of thetransferarc-extinguishing means 13 `is necessary to ensure rapid blowout-:coil transfer, and it is an important object of our invention to provide a more effective transfer arc-extinguishing means 13, while at the same time providing a more compact and effective structure. We have found that in prior devices so far built and tested involving anH-type of magnetic-circuit, with a floating blowout coil, thata time interval of approximately 0.4 cycle (on a CSO-cycle basis) is required after Icontacts part totransfer'the blowout coil into the circuit. This time is not too important for a breaker having 5 orf8 cycles ratedinterrupting time. However, when this design is applied to high-speed D. C. breakers, or other breakers of lthe high-speed type, this time is a matter of concern. Breakers ofthe D. C. type may be applied on railway circuits, mercury arc rectifier circuits, etc. which are capable of delivering short-circuit .currents of such great magnitude that vthey would damage equipment if the current lis not interrupted just as quickly as possible. The breakers needed are, therefore, very high speed, and are relied upon to interrupt faults 'before they have reached anywhere near their ultimate value.

Higher speed .interruption is obtained with `the construction-disclosed lherein of thecenter-coil magnetic type because ,of lbetter venting between .the magnetic 1plates'20, and a `closer proximity of .the varc portionlb tozthe iron plates 20, giving a shorter time interval `from contactpart to blowout coil transfer. tion is more simple since the magnetic plates 20 collectively provide the magnetic yoke 23 interconnecting the pole plates 24 on the opposite sides of the circuit interruptor 1. The yoke 23 is made up of the spaced iron plates 20 having the shape indicated in Fig. 7. The plates are cemented together' with the insulating spacers 22 between the edges, and a thin sheetof insulating material 35 is placed between the yoke 23 and the pole plates 24 to prevent the pole plates 'Z4 shorting the iron plates 20 and hence the blowout coils 15 and 16. The magnetic circuit is preferably held together by a plurality of bolts 36 extending across tbe yoke 23.

To retain the blowout coils 15 and 16 within the cutout portions 37 provided in the arc chute jacket 25, rectangularly-shaped bracing plates 38 of an insulating material are .preferably employed, having a configuration more clearly set out in Figs. 4 and 5-of the drawings. The disposition of the bracing plates 38 is more clearly apparent from an inspection of Figs. l and 3 of the drawings. A pair of bolts 39 extend through two openings 40 at the lower ends of the insulating bracing plates 38 and through the pole plates 24 to maintain the bracing plates 38 in a fixed position on the inner sides of the blowout coils 15, 16. A second pair of bolts 41 extend through openings 40 at the upper ends o-f the bracing plates 38, and cooperate with externally mounted clamping plates 43 having a configuration more clearly vapparentfrom an inspection of Figs. l and 3 of the drawings. The two clamping plates 43 are preferably formed Gfan insulating material, and are disposed externally of the arc-chute jacket 25 immediately above the ton portion 44 of the pole plates 24.

.From the foregoing, it will be apparent that the insulating bracing plates 38 and the clamping plates 43, together with the

bolts

36, 39 and 41 maintain the structure in assembled condition, and are able to withstand high magnetic forces resulting from the interruption of large amperage fault currents.

From the foregoing description, it will be apparent that we have provided an improved and more effective circuit interrupter of the magnetic type involving an H- type of magnet with a transfer arc-extinguishing means. The useof magnetic material in the form .of the plates 20 having slots 21 therein causes rapid extinction of the arc portion 8b, the latter moving into the slots 21 in the manner indicated in Fig. 3 of the drawings. The arc portion 8b is attracted toward the closed ends 45 of the slots 21, and moves between the plates 20 in .the form of serially related arc portions 46, .as indicated in Fig. .1 of the drawings. Since the-surfaces of the plates 20 are cool, and since the venting passages 47 provided between the spaced magnetic plates 20 afford adequate venting, the arc portions 46 are soon extinguished, and the serially related blowout coils 15, 16 are connected into series circuit with the remaining arc portions 8a and 8c.

The construction described results in a shorter time interval from contact part to blowout coil transfer because venting occurs directly above the space Where the arc portion 8b is drawn, and because the arc portion 8b is drawn in closer proximity to the iron, or magnetic material 20, which results in a greater attractive force. At .the same time, the construction has been simplified over that in the foregoing application by making the plates 20 in the yoke 23 act as both tnansfer arc-interrupting plates, and also as a yoke for the magnetic circuit 27. A separate transfer arc-interruptor is therefore eliminated.

A device was built and tested, as described above, which reduced the coil transfer time by approximately 0.1 cycle, or 25% as compared to a similar sample with a separate ceramic transfer stack, as outlined in the aforegoing application. This is a veryworth-whilegain where the current is increasing fat Vthe rate of several million amperes per second.

At the same time, the construc-v From the foregoing description of our invention, it will be apparent that we have provided a compact and highly effective interrupter in which the magnetic plates 20 are not only used to provide the yoke portion of the magnetic circuit, but also they are utilized to provide an effective transfer arc-extinguishing means to more quickly bring the blowout vcoils into series circuit and cause rapid upward movement of the arc portions 8a, 8c, upwardly into the staggered arc passages '9 of the

arcextinguishing sections

4 and 5 to bring about circuit interruption;

Although we have shown an H-type of magnetic circuit interrupter with a ioating blowout coil, it is to be clearly understood that features of the invention are applicable to a conventional U-shaped magnetic circuit interrupter where a portion of the core could be used as a transfer arc-extinguishing means. Note U. S. Patent 2,632,075 to Rawlins et al. in this connection.

Figs. 9 and 10 collectively describe a modification of the transfer arc-extinguishing means 13a, in which every other magnetic plate 20 is shortened at its lower end to abut against an insulating plate portion 50. The plate 50 may have the notch 21 therein to align with the notches 21 in the longer magnetic plates 20. Thus the modified arc-extinguishing means 13a comprises alternately insulating and conducting plates to interrupt more voltage between the center arc horns 10, 11.

Although we have shown and described specific 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:

l. A circuit interrupter including means for establishing an arc, means for causing the extinction of the arc including a pair of cooperating magnetic pole plates and an interconnecting yoke portion, insulating means having edge portions for engaging at least a portion of said arc to elect the extinction thereof, a blowout coil for energizing the magnetic pole plates, and means including the yoke portion for extinguishing the transfer arc portion which is in electrical parallel with the terminals of the blowout coil, the yoke portion including a plurality of spaced magnetic plates which will cool and deionize the transfer arc portion, and the spaced magnetic plates opening to the space beyond said insulating means.

2. The combination in a circuit interrupter of contact means for establishing an arc, magnetic blowout means for extinguishing the arc including a pair of pole plates and an interconnecting core portion, insulating means having edge portions for engaging at least a portion of said arc to effect the extinction thereof, a blowout coil for energizing the magnetic blowout means, said arc having a transfer arc portion which is in electrical parallel with the terminals of the blowout coil and which must be extinguished to insert the blowout coil into series circuit, and means utilizing the core portion for eecting extinction of the transfer arc portion, the core portion including a plurality of spaced magnetic plates which will cool and deionize the transfer arc portion, and vsaid spaced magnetic plates extending alongside of said insulating means.

3. A circuit interruptor including means for establishing an arc, means for causing the extinction of the arc including a pair of cooperating magnetic pole plates and an interconnecting yoke portion, a blowout coil for energizing the magnetic pole plates, means including the yoke portion for extinguishing the transfer arc which is in electrical parallel with the terminals of the blowout coil, and the yoke portion including a plurality of spaced magnetic plates which will cool and deionize the transfer arc.

4. The combination in a circuit interrupter of contact means for establishing an arc, magnetic blowout means for extinguishing the arc including a pair of pole plates and an interconnecting core portion, a blowout coil for energizing the magnetic blowout means, said arc having a transfer arc portion which is in electrical parallel with the terminals of the blowout coil and which must be extinguished to insert the blowout coil into series circuit, means utilizing the core portion for effecting extinction of the transfer arc portion, and the core portion including a plurality of spaced magnetic plates which will cool and deionize the transfer arc portion.

S. A circuit interrupter including contact means for establishing an arc, an l-i-type magnetic circuit for effecting movement of the arc, the core portion of the H-type magnetic circuit having a blowout coil associated therewith, said arc having a transfer arc portion in electrical parallel with the terminals of the blowout coil, means utilizing the core portion to effect extinction of the transfer arc portion to insert the blowout coil into series circuit, and the core portion including a plurality of spaced magnetic plates having venting passages therebetween.

6. A circuit interrupter including means for establishing an arc, means for causing the extinction of the arc including a pair of cooperating magnetic pole plates and an interconnecting yoke portion, a blowout coil for energizing the magnetic pole plates, the interconnecting yoke portion including a plurality of spaced magnetic plates, at least some of the plates having notches provided therein, and means including the notched magnetic plates for extinguishing the transfer arc which is in electrical parallel with the terminals of the blowout coil.

7. The combination in a circuit interruptor of contact means for establishing an arc, magnetic blowout means for extinguishing the arc including a pair of pole plates and an interconnecting core portion, a blowout coil for energizing the magnetic blowout means, said arc having a transfer arc portion which is in electrical parallel with the terminals of the blowout coil, the interconnecting core portion including a plurality of spaced plates, one or more of the spaced magnetic plates being shortened, insulating plate portions abutting the shortened magnetic plates, and means utilizing the core portion for eecting extinction of the transfer arc portion.

8. A circuit interrupter including Contact means for establishing an arc, an H-type magnetic circuit for effecting movement of the arc, the core portion of the H-type magnetic circuit having a blowout coil associated therewith, a pair of arcing plates connected to the ends of the blowout coil, the core portion of the magnetic circuit including a plurality of spaced magnetic plates disposed between the arcing plates, and the arc moving into engagement with the :arcing plates and having the portion thereof between the arcing plates extinguished by the spaced magnetic plates.

9. A. circuit interruptor including contact means for establishing an arc, an H-type magnetic circuit for electing movement of the arc, the core portion of the H-type magnetic circuit having a blowout coil associated therewith, a pair of arcing plates connected to the ends of the blowout coil, the core portion of the magnetic circuit including a plurality of spaced magnetic plates disposed between the arcing plates, the arc moving into engagement with the arcing plates and having the portion thereof between the arcing plates extinguished by the spaced magnetic plates, :and one or more of the spaced magnetic plates having notches provided therein.

l0. A circuit interrupter including contact means for establishing an arc, an H-type magnetic circuit for effecting movement of the arc, the core portion of the H-type magnetic circuit having a blowout coil associated therewith, :a pair of arcing plates connected to the ends of the blowout coil, the core portion of the magnetic circuit including a plurality of spaced magnetic plates disposed between the arcing plates, the arc moving into mamas 7 engagement with the arcing plates vand having the portion'thereof between the arching plates extinguished by the spaced magnetic plates, one or more of the spaced magnetic `plates being shortened, and one vor more insulating plate portions abutting the shortened magnetic plates and being coextensive therewith.

1l. A circuit interrupter including means for establishing an arc, means for causing the extinction of the arc including a pair of ,cooperating magnetic `pole plates 'and an interconnecting yoke portion, .a blowout coil Jfor `8 energizing the magnetic pole plates, .and means forcing the transfer arc which Iisv in electrical parallel with the terminals of the blowout coil against 'the surface of the yokeportion to cool the same and to effect the extinction thereof.

.References Cited .in the -fle of this patent UNITED STATES PATENTS