US1872387A - Circuit breaker - Google Patents

Description

AUS- 16 1932 B. P. BAKER ET AL 1,872,387

CIRCUIT BREAKER Filed Sept. 11, 1929 2 Sheets-Sheet l i l BY b o ATTORNEY Aug. 16; 1932. l B. P. BAKER ET AL 1,872,387

CIRCUIT BREAKER Filed Sept. 11, 1929 2 Sheets-Sheet 2 INVENTORS TTO'RNEY Patented Aug. 16, 1932 UNITED STATES' PATENT OFFICE BENJAMIN P. BAKER,` OF TURTLE CREEK, AND ROBERT C. DICKINSON, F WILKINS- BUBG, PENNSYLVANIA, ASSIGNOBS TO WESTINGHOUSE ELECTRIC AND MANUFAC- TUBING COMPANY, A CORPOBATIONOF PENNSYLVANIA CIRCUIT BBEAXEB Application nea september 11, 192s. serial mi. 391,7a4.

Our invention relates to circuit interrupters and particularly to circuit nterrupters of the air-break type which embody deionizing chambers and blow-out magnets.

One object of our invention is to provide a circuit interrupter having an arcing chamber of the above mentioned type with a blowout magnet which carries current only while the arc established upon the opening of the circuit interrupter is being extinguished.

Another object of our invention is to provide means for forcing the current through the circuit interrupter to energize the windings of -the aforesaid blow-out magnet.

It is another object of our invention to provide a blow-out magnet winding comprising a number of separate sections in series, and

to so systematically arrange these sections as to mirnmize potentlal gradients to ground and the amount of insulation required for the various structural elements of the dionizing chambers.

A further object of our invention is to provide means or causing the arcs established in the deionizing chamber to move radially inward toward the centers of the plates cmposing the deionizing arrangement.

The arrangement usedl for inserting the blow-in winding in th circuit is advantageous over the use of separate transfer contracts or connecting the winding in the circuit, since the mechanical operating mechanism is simplified and the additional contacts are eliminated. This structure is an improvement over placing the winding in the shunt circuit so that it is energized by the opening of the main contacts, since, with such a structure, there will be an arc at the main contacts when they are openeddue to the insertion of l" the winding in the circuit, unless intermediate auxiliary contacts. are provided on the main contacts. The structure of our invention is also desirable in that the' only arc drawn is within the deionizing chamber s where it may be most effectively extinguished.

Decreased over-all operating time of the circuit breaker is also obtained with this structure, since there is no time delay before the drawing of the .main arc to permit the operation of auxiliary main contacts or separate transfer contacts.

f Our invention will best be understood by referring to the following specification, taken in connection with the drawings, wherein n Figure l is a view, partly in section ,and partly in elevation, of a deionizing chamber embodying our invention.

Fig. 2 isa detail view in elevation, of one of the'metallic plates emp oyed in the arcdeionizing chamber disclosed in Fig. 1.

Fig. 3 1s a view in elevation of a pair of contacts of the general type shown 1n Fig. 1, but embodying a particular modification of our invention.

Fig. 4 is a view, similar to Fig. l, of another embodiment o our invention; and

Fig. 5 is a view partly in section of an upper portion ofthe deionizing chamber shown in Figs. 1 and 4.

Referring particularly to Fig. 1, the circuit interrupter embodying our invention comprises, in general, an arc extinguishing chamber 1 which encloses separable contacts 2 and 3. Above the contacts 2 and 3 are positioned deionizing plates 4. The arc incldent to the opening of the contacts 2, 3 under load is moved upward into the spaces between the plates 4 and is rotated about a recurrent path therein until it is extinguished when the current passes through the zero value course of its alternating cycle. Such a deionizing structure has been described and claimed in the co-pending application of J. Slepian, Serial No. 181,289, tiled April 6, 1927, and that of Benjamin P. Baker, Serial No. 187,987,1iled April 30,1927, and aigned to the Westinghouse Electric & Manufacturing Company, the assignee of the present application.

Adjacent the ends of the series of plates 4 during the are positioned arc forms comprising a set of plates 5 having ventilating spaces therebetween providing a means of exit for the air and gases that would otherwise be trapped ahead of the arc rotating within the chamber n 1. Such a structure is 'described in the condin application of Robert C. Dickinson,

. rial and aigned to the assignee of the present application.

A series of deionizin metal plates 6 is provided below one of t e above-mentioned sets of arc horn plates 5, the plates 6 being insulated from eachotherand from the lates 5 and from the line conducting mem r 7 which supports the stationary contact member 2. A winding 8 which surrounds the ath of the arc rovides a magnetic field for iorcing the arc rawn between contacts 2 and 3 into the deionizing plates 4. It will be evident upon examination that the winding 8 is normally not traversed by the current'ilowing through the contacts 2 and 3, but that it is ,energized immediately after the separation thereof. It will be seen that the current is forced to flow through the winding 8, as just described, by reason of the fact'that the terminals 9 and 11 of the winding 8 are connected, respectively, to the arc horn plates 5 and the conductor 7 and hence the winding 8 is made to shunt the insulated metal lates 6.

The operation of the above-described ar- 4 rangement is as follows. The arc, which is drawn when the movable contact member 3 is separated from the stationary contact 2, impinges on an extension- 12 of the arc horn plates 5 and is immediately divided into two sections, as indicated by reference numerals 13 and 14. The extension 12, or the arc horn plates 5, themselves, may, if desired, be made of a magnetic material. .As the movable conf tact member 3 completes its movement away fromv the venting plates 5, the terminus of the arc is transferred from member 3 to the plates 5 and the portion 14 of the arc will thereulpon assume the position indicated at ,15 in 'g At the same time, the arc 13 has been transferred to the plates 6 and is thus in parallel with the winding 8. The line current at once begins to flow t rough the winding 8. The arc 13 andthe winding 8 are then in parallel and each must have the same -voltage drop thereacross. If the voltage drop in the winding is less. than the high voltage re uired to maintain the arc when split up into s ort arcs between the deionizing plates 6, the arcs will be extinguished and the entire current will ilow through 'the winding 8 for providing the blow-in field. The length of time that will be required for the entire current to transfer from the arcs between plates 6 to winding 8 will depend on the inductance of the latter and the magnitude of the current. It will be seen that the voltage effective for transo. 317,617, filed November 6, 1928,A

Lamas? ferring current to the winding 8 is substantially the voltage drop across the series of arcs between lates 6. In order that this voltage drop all be suiciently great a plurality of plates are employed to make up the section 6. Noting that it is the magnetic field set up by winding 8 which forces the arc section 15 to move into the spaces between deionizing plates 4, it will be seen that the higher the transfer voltage, the quicker the aforesaid field will be set up and the sooner themain arc 15 will be driven into the deionizing chamber and extinguished.

For the foregoing reason, it will be seen that'the arc 13 should move only a short distance before it is broken up into a series of short arcs, thus greatly increasing the voltage necessary to maintain the arcs.

As previously stated, the main arc 15 is forced into the slot or channel 16 formed as indicated in Fig. 2, in the lowerfend of plates 4. By the time ythe arc has reached the apex of the slot 16 in the plates 4, which is the time that the' eatest amount of driving force is requi the magnetic ield induced by winding 8 has been built up to a sufiicient strength to exert the required force on it.

has proved satisfacto for most conditions of service, a modification thereof, shown in Fig. 3, ma be found desirable in certain instances. eferring to the latter ligure, a contact 34 is pivoted on'the venting plates 5 and is biased into contact engagement with the movable contact member 3.

When the contacts 2 and 3 rst separate, an arc is drawnin parallel relation with the windingl 8 due to the whole voltage drop across t e winding being impressed across the small space between'contacts 2 and 3 ,at the instant of contact separation. In consequence current rises ra idly in value in the latter and a considera le magnetic field is uickly built up. The main are is drawn s ortly afterward between the contacts 3 and 34,1and thus the latter is immediately acted on by a substantial blow-out field and moved vinto contact with the deionizing plates 4.

A structure similar to that just described in connection with' Fig. 1, is shown in Fig. 4, with the exception of the fact that a central portion of the series of deionizing plates 4 serves the same purpose as the separate series of plates 6 of Fig. 1. Considerable advantage is inherent in this structure, as will now be pointed out.

In Fig. 4 thecontacts 17 and 18 are both of the movable pe and are positioned adjacent a central section 19 of the deionizing plates. The outer plates 21 and 22 of the section 19 extend almost to the movable contacts 17 and 18'and are bent backwardly upon themselves, thus formingeushaped members. The plates 23, located tween the outer plates 21 and While the above-described arrangement' lll 22, are of greater length than the deionizing plates 4 and extend downwardly to a position adjacent the central ortion of the arc path. Iron members 24 an 25 may, if desired, be positioned at the bottom of the `U-sha ed plates 21 and 22, to strengthen the fiel at that point in order to effect a quick transfer of the arc from contacts 17 and 18 to plates 21 and 22. In circuit with the upper ends of the plates 21 and 22 are conductors 26 and 27 which overlap each other inthe middle of the deionizing structure. The plates 21 and 22 are insulated from the deionizing plates 4.

When the contacts 17 and 18 are separated, an arc is drawn and moves upwardly because of the magnetic effect of current in the arc and contacts. As aA result the arc immediately impinges on the ends of the plates 21 and 22 and is broken up into a plurality of arc sections designated by numerals 29, 31 and 32.

The flow of current through U-shaped members 21 and 22 sets up a magnetic field which acts upon the central arc 31 and the two-main arcs 29 and 32, thus forcing them upwardly while the blow-out field is being built up. A somewhat similar utilization of the blow-out effect of current flow in U- shaped plates is disclosed in the co-pending application of J. Slepian, Serial No. 331,469, filed January 10, 1929, and as signed to the assignee of the present application.

As soon as the arc 31 is established, the line current begins to flow through the conductors 26 and 27 to the winding 8, thus quickly placing the latter in series withthe portions of the arc designated by numerals 29 and 32.

It will be noted that the direction of flow of current in the conductors 26 and 27 will be such that it is parallel to and in the same direction with the flow of 'current through the arcs between, the upper portion of the plates 4. V

In addition to the magnetic field set up by windings 8, the radial field is induced by a plurality of coils 33 Which are positioned at intervals among the plates 4. Such an arrangement for inducing a radial field is described in the above-mentioned application y of Benjamin F. Baker.

The parallel paths of current in the conductors 26 and 27 and the arcs between plates 4 causes the latter to movetoward vthe said conductors and hence into astronger portion of the radial field provided by the coils 33. By thus utilizing the central portion of the radial field, its effectiveness in moving the arcsover the surfaces of the deionizing plates is raised to a maximum.

An advantage additional t6 that just described is inherent in the centrally located arc structure `just described for forcing cur- .line voltage is distributed in a potential the res ence in capacitance to ground of coils and plates. This difficulty may be corrected by providing an additional layer of tinfoil to cover a suitable portion of the enclosing wall of the deionizing chamber. But -by reason of the symmetry` of the Fig. 4 arrangement of coils and plates concentration of voltage gradient at one end of the structure is avoided, since the coil is at the potential of the center plates in the stack, rather than at the potential of either of the line terminals; and the foil layer just alluded to is not required. Fig. 5 shows at 41, 42, 43 layers of foil properly disposed to produce a uniform potential gradient in the structure shown in Fig. 4.

, The elimination of the layer of metal foil was found in a practical case to reduce the insulation required between the edges of plates 4 and ground by one-third.

Such being the nature of various structures embodying our inventions, the foregoing facts may be summarized by saying that we have provided a simple and effective means for transferring the current of an arc to a blow-out magnet Winding; that our structure most effectively utilizes a radial magnetic field in causing rotation of an arc in a deionizing chamber; and that we have disclosed an arrangement adapted to minimize electroof our invention. Therefore, we do not wish the appended claims to be limited except in ct made necessary by the prior art.

We c aim as our invention:

1. Circuit-interrupting means comprising means for establishing an arc, an arc-extinguishing device associated therewith, a normally deenergized winding associated with the said device, means including a portion of said arc for inserting said winding in clrcuitwith another portion of said arc, and magnetic means for initially moving the l .arc until said winding is energized. rent flow 1n the w1nd1ng8. In general, the

`means for establishing an arc, an arcex-.

5 arc actin to insert said winding in circuit with anot er portion of said arc, and conducting means energized by the arc current for initially moving the first said portion of the arc durin the time the current thereof is be- 16 ing trans erred to said winding.

3. Circuit-interrupting means comprising means for establishingan arc, an'arc-extinguishing device associated therewith, a winding formoving the arc and means for dividing the arc into a plurality of sections, one

of said sections being initially divided into a plurality of arcs in shunt with said winding.

4. Circuit-interrupting means comprising means for establishing an arc, an arc-extinguishing device associated therewith, means of magnetic material providing a magnetic circuit associated with said device, a winding for energizing said magnetic circuit and means for dividing the arc into a plurality7 of sections, one or more of which shuntsr said winding, means for rapidly moving that portion of said arc that shunts said winding and means for dividing the last said arc portion into a plurality of arcs.

5. The combination with a circuit inter-` rupter having separable contact members, of an arcextinguishing means associated therewith, a magnetizing winding associated with the said means, means adjacent said contacts for dividing an arc between said contacts into a plurality of sections, and means for initially moving said arc until said magnetizing winding is energized, said means comprising an arc terminal member in which the arc current fiows.

6. The combination with a circuit interrupter having separable contact members, of an arc-extinguishing means associated therewith, means of magnetic material providing a magnetic circuit associated with said means, an elet-rical circuit for energizing said magnetic circuit and means associated with said contacts for dividing an arc established thereby into a plurality of sections, one of which sections shunts said winding, and means for initially moving the arc under the actionof a magnetic field until said winding is energized.

7. The combination with a circuit interrupter having separable contact members, of an arc-extinguishing means associated'therewith, a winding for causing a magnetic field about said means, means associated with said contacts for dividing an arc established therebyinto a plurality of sections, the first of said sections which is established being in parallel with said winding, and means for initially moving said arcs before said winding is completely energized. t

8. The combination with a deionizing chamber wherein a radial magnetic field is provided to move a plurality of arcs o ri spacedv conducting plates, of a conductor in series with the said arc andA passing centrallyI a stack of spaced conducting plates, of .c on-` tacts associated with said chamber for drawing an arc, a winding for moving the arc into said chamber, and means includinga portion of said winding forming a parallel path with said arc for retaining the arc centrally on the said plates, said winding having its ends connected to a pair of said plates atA the central portion of said stack. l

10. The combination with a wound vcoil providing a radial magnetic field for rotat-l ing an arc within a stack of spaced conducting plates, a conductor passing through said coil and plates and forming a parallel pathl with said arc.

l1. In combination with a plurality of windings providing a radial magnetic field to move a plurality of arcs between spaced conducting plates, said windings having their ends connected between spaced pairs of said plates, a conductor passing through the windings in a manner such as to form a current path parallel with said arcs and in which the current flows in the same direction as in said arcs.

l2. In combination with 'a plurality of windings providing a radial magnetic field to move a plurality of arcs between spaced conducting fplates, a-conductor in series relation with sai arcs and associated with said magnetic field and said windings in such a manner so as to cause said arcs to traverse a path which is central in said field, said conductor having its ends connected to a spaced pair of said plates.

13. In a circuit interrupter, a pair of separable contacts, a pair of arc terminal niembers, one of said contacts, when in its closed position, being disposed closely adjacent one of said terminal members, but sliglitl spaced therefrom and at a distance from t e other of said terminal members, and a inagnetizing circuit connected between said contact member and terminal member which are disposed adjacent .each other when the contacts are closed, and the other of said contacts being movable to transfer the end of the arc drawn thereon to said other terminal member.

14. In a circuit interrupter, means for eX- tinguishing an arc comprising a plurality of spaced plates for splitting up the arc into a plurality of short arcs, a pair of separable contacts for drawing the arc outside of said lurality of plates in 4such a iio iis

v minal members into said plates to be extinguished.

r15. n a circuit interrupter,A means for drawing an arc, means for extinguishing said arc comprising a plurality of spaced metal plates, two of said plates having a portion which splits up the aro extending beyond the corresponding portion of other of said plates, and a conducting winding having its ends connected to said plates which have their extended portion.

16. In acircult lnterrupter, means for extinguishing an arc comprising a plurality of conducting members for splitting the arc into a plurality of arcs, means for initially drawing the arc in a path spaced from said extinguishing means, means for moving said arc into said extinguishing means comprising a magnetizing coil having its ends connected to a pair of said conducting members extending beyond other of said members to a point near the path where the arc is initially drawn.

17. In a circuit interrupter, means for extinguishing an arccomprising a plurality ,r of spaced conducting plates for separating the arc into a series of short arcs, meansior initially drawing 'the are at a point spaced from said extinguishing means, means for setting up a magnetic field for moving said arc into said plurality of plates comprising a conducting loop having its ends connected to a pair of stationary arc terminal members extending to a point near the path where the arc is initially drawn. ,7

for drawin the arc and a ma et' loo having its grids comiected to mi? side ci each of sa-id U-shaped plates. 20. In a circuit interrupter, means for drawing an arc, means for extinguishing said arc comprising a plurality of spaced metal plates, two of said plates being of U-shape with the bottom of ythe U extending beyond the other of said plates at a oint near that portion of the arc which is rst drawn, and a magnetizing loop having its ends connected to one side of each of said U-shaped plates. t

21. In a circuit interrupter, means for drawing an arc, means for splitting up said arc into a plurality of sections including arc terminal members on which the ends of said arc sections playmeans for later s litting 11p each of said arc sections into a p urali'ty of short arcs, and a magnetizing windn for moving the arc having its ends electrically connected to said arc terminal members.

22. In` an arc-extinguishing structure, a plurality of plates of conducting material means for splitting the arc into a plurality o sections between certain of said plates, and

@means connected between said arc sections for setting up a magnetic field formotingf each of said arc sections, the other of sai plates causin each of said arc sections to be split up into s ort arcs after the energization of said magnetic field means'has moved said arc sections thereinto.

In testimony whereof, we. have hereunto subscribed our names this 29th day of August, 192e. o

BENJAMIN P. BAKER. ROBERT C. DICKINSON.

18. Ina circuit interrupter, means for extinguishing an arc comprlsing a luralit of spaced plates for splitting u the arc `i'nto a plurality of short arcs, sai 'plates having holes therein, means for drawing the arc outside of said plates, means for moving the arc into said plates comprising a conducting loop i extending through the holes in said plates and so connected to a spaced pair of said plates that the arcl current flows in the porsame direction as the current in the arc.

19. In a clrcuit `mterrupter, means for v drawing an arc, means for extinguishing said 65 the other of said plates towards said means o tion of the loop through said holes in the g I

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