US1398981A - Disruption of electric arcs - Google Patents

Description

J. F. TRITLE.

DISRUPTION 0F ELECTRIC'ARCS.

APPLICATION FlLED DEC. 4, 1919.

1,39 ,981, Patented Dec. 6, 1921,

Fig.3.

Insulation Switch Contact Inventor: John F. Tritl e,

His flctor-nen UNITED STATES PATENT OFFICE.

JOHN IE. TRITLE, OF SCHENECTADY, NEW YORK, ASSIGNOR 'lJO' GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK. I

DISRUPTION 0F ELECTRIC ARCS.

Specification of Letters Patent.

IZatented Dec. 6, 192i.

Application filed December 4, 1919. Serial No. 342,326.

My invention relates to disruption of elec- ,tric arcs and it provides an improved method and improved means whereby the are formed between arcing electrodes is quickly disrupted.

Although not necessarily limited thereto, my invention has a particular application -in the disruption of the arcs formed between cooperating circuit interrupting contacts of electric switches.

In one of its aspects,.my invention comprises an arrangement whereby the arc is caused to be formed in a confined space and to proceed directly from the arcing electrodes or the switch contacts in the same plane in which the arc lengthens, or a plane parallel thereto, through a chute which is narrower at its exit than at the space in which the arc is formed, thereby increasing the resistance and thecooling surface of the are for a given length of are by decreasing its cross-section.

. chute will be narrower than the arcing electrodesor the switch contacts at Which the arc is formed. Furthermore, when a. magnetic blowout is used in connection with the arc chute, the arc stream is caused to be practically perpendicular to the lines of force of the blowout.

In another of its aspects, my invention comprises the method whereby the arc is split longitudinally into a plurality of multiple connected parts. It has heretofore been proposed to lengthen the arc by interposing barriers which are transverse to the plane in which the arc lengthens in order to increase the length of the are or; split up the arc into a plurality of'smaller arcs in series relation so that it will be disrupted quickly. However, such schemes have the disadvantage, particularly where the arc is formed on a relatively high potential circuit, that a great difference of'potential exists between the parts of the are on oppo site sides ofthe barrier and the insulation between those parts of the are is required to be considerable or the parts ofthe' arc'will The exit of the arc goin, thereby defeating the object of the arriers. VVlth my method, since the arc is split into a plurality of multiple parts there i is practically no difference of potential between the parts of the arc; and the potential stress on the means which causes the arc to be formed into a plurality of parts is therefore very small, if any.

My invention, further, comprises an arrangement of apparatus whereby my improved method is-ca-rried into effect, and in one of its aspects a barrier of insulating material is disposed in the plane in which the are would ordinarily lengthen, or in a plane parallel thereto, or in the plane of movement of the switch contacts, whereby the arc is, split up longitudinally into a plurality of multiple connected parts between which there is ubstantially no difference of potential, so that the potentialstress on the barrier is therefore very small, if any.

In certain other of its aspects, my invention comprises an arrangement having in combination the feature of causing the arc to be formed in a confined space and to proceed directly from the switch contacts in the plane in which the arc lengthens or a plane parallel thereto through a chute which is narrower at its exit than at thespace in which the arc is formed, and the feature of splitting the are into a plurality of multiple parts which are substantially parallel to the plane in which the arc would ordinarily lengthen.

My invention also comprise the method of causing the arc to be split up into a plurality of multiple connected parts and causing the cross-section of the parts to be reduced.

For a better understanding of my invention reference is had to the accompanying drawings, wherein Figure 1 shows a drum type controller provided with barriers to form are chutes in accordance with my invention; Fig. 2 is a section of the controller shown in Fig. 1 talgen on the line 2-2; Fig. 3 is a simplified diagrammatic View for the purpose of showing how the arc is caused to proceed from the switch contact in the plane of movement of the switch contacts through a passage having a narrow exit; Fig. 4 is a top view of one of the barriers constructed in accordance with my inventhe part designated switch contact is one of a pair of circuit interrupting contacts, and the two cooperating barriers, one of which is designated insulation, are disposed adjacent the contacts so that the arc formed between the contacts is blown out throughthe chute formed between the barriers. Each of the barriers is so constructed that when assembled as shown, the are between the contacts is formed in a space. which is larger than the exit. The exit of constricted area -is located so as to be in the plane in which the arc would ordinarily expand, preferably in the same plane as the center line of the circuit interrupting contacts and in the plane of movement of the contacts. The greater part of the arc chute is narrower than the contacts, so thatwhen the arc is formed it will blow out through the arc chute as shown in the dotted lines which are-intended to show successive sections of the are as the arc lengthens. The arc will be gradually confined between the faces ofthe'barriers, so that when the arc reaches the narrow exit it is very greatly confined, its cross-section is less, its resistance and cooling effect are greater, and it will therefore disrupt itself very quickly. In this figure the force which causes the arc to proceed in the direction indicated is the heat ofthe arc, but, as will be later explained, the arc is caused to proceed in any direction desired by means of a magnetic blow-out' I am at present unable to state positively the theory upon which this action of quickly disrupting the arc is based, but repeated tests and comparisons with are chutes constructed in accordance with well known practice have shown the practical effectiveness of my invention, whatever may be the theory upon which it is based. It would appear, however, that the action is caused by increasing the resistance and cooling effect of the are by decreasing its cross-section. r

Referring now to Figs. 1 and 2, the controller shaft 18 has mounted thereon and insulated therefrom a. plurality of metallic segments, of which the segment 19 is a part. Cooperating with the segment 19 is'a stationary .circuit making contact 20 which, to-

gether with the segment 19, forms a part of an electric circuit completed and interrupted by the controller. From Fig. 1 it will be seen that there area plurality of these metallic segments and cotiperating contacts arranged serially along the shaft 18,'this in itself being a wellknown construction. The shaft 18 with the metallic segments thereon is rotated by means of a handle 21 throughout the successive positions for controlling an electric circuit, for starting motors, and the like. In a plane parallel to the plane of movement of the segment 19 and the stationary contact 20.is a barrier 22 of noninflammable heat resisting material, such as a hard fiber, an asbestos composition, or the like. This barrier is illustrated in more detail in Figs. 4 to 7 inclusive. It is constructed with a cutaway portion 23 on each of its fiat sides formed by beveling out a portion of each fiat side so that at the meeting of the two beveled surfaces a comparatively sharp edge is formed along part of the middle of the barrier, as shown in Figs. 5, 6 and 7.

On one end of the barrier a foot 24 is formed,

and on the other end a foot 25 is formed,

so that when the barriers areassembledas shown at 26, 27 and 28 in Fig. 1, the feet determine the spaces between adjacent bar-, The barriers are disposed with respect to the circuit interrupting contacts in riers.

a plane parallel to the plane of movement of the contacts, preferably with the sharp edge formed by the meeting of the two beveled surfaces at a point opposite the middle of the contacts as shown in Figs. 8, 9 and 10. In Fig. 8 the barriers 29 and 30 are equidistantly disposed on opposite sides of the segment 31, and the barrier 32 of a form similar to the barrier 22 shown in Figs. 4 and 7 inelusive has the sharp edge of its cutaway portion disposed in a plane substantially parallel to planeof movement of the circuit interrupting contacts along the center line of the contacts, of which the segment 31 forms a part. In the barriers 29 and '30 metallic plates 33 and 34 respectively of magnetic material are embedded,- these plates forming part of a magnetic blowout device.

For purposes of illustration, dotted lines are shown, illustrating a section of the arc andsections of the parts of the arc in order to illustrate the manner in which'the are formed between the switch contacts is split up into two parts which are substantially parallel to the plane of movement of the contacts,

equidistantly disposed from the center line of the contacts andparallel to the plane in and'each of the substantially parallel parts of the arc is substantially perpendicular to the lines of force of the magnetic blowout. The are will be caused to be disrupted quickly because of being split up into a plurality of parts, because each part is reduced in cross-section, and by reason of the a fact that the arcstream is so confined and directed that a large portion of the lines of force of the blowout are effective in rupturing the arc. In other words, the arc stream is prevented from wandering from one side of the wide chute to the other in such a way that part of the arc stream is parallel to the lines of force of the blowout and thus defeat the purpose of the blowout and make it difficult generally to disrupt the arc. Ordinarily the arc will be split up into parts, but the extent to which the parts lengthen will not be the same. One part will ordinarily be smaller and be disrupted quickly so that the final disruption of the arc occurs in the other arc chute. However, when very heavy currents are broken the arc may lengthen substantially equally in each arc chute.

In Fig. 9 I have shown an arrangement in which two circuit interrupting segments 35 and 86 are connected in multiple for opening an electric circuit, and the barriers 37 and 38 are equidistantly' disposed on opposite sides of the contacts. The barrier 39, having the sharp edge formed by the meeting of the two cutaway portions is disposed opposite the center line of the segment 35. A barrier 40 of similar construction is also disposed in a similar way opposite the contact 36. Three are chutes having narrow exits are thus formed, and the arcs formed at the contacts ,7 35 and'36 are split up and reduced in cross- 40 section in a'manner similar to that explained in connection with Fig. 8, and likewise quickly disrupted. It will be understood that since the segments 35 and 36 are electrically connected, if the mechanical construction of these segments and their cooperating contacts is perfect the arc will be broken at both segments simultaneously. However, in practice such perfection is ordinarily not obtained and the arc will be formed at either one of the segments. When a normal current is being broken with the are formed at segment 35, for instance, the arc will proceed out through either the upper or the middle chute, but if a very heavy current is broken the arc will be split up, part going'out through ea'chof the upper and middle chutes, or a part out each of the three chutes. In Fig, 10 the are formed between the contact finger 20 and the contact segment 19 is shown as being split in a line substantially parallel to plane of movement of the switch contacts opposite the center line of the contacts and in the plane in which the arc would ordinarily expand, the lower part of the are not being shown since it is covered by the barrier 22. A blowout coil 41 of the usual construction is also shown, and it will be understood that a part of the blowout device is embedded in the lower barrier 42 and a part in the upper barrier of similar construction which has been re moved in order to show the manner in which the barrier 22'splits the arc. It will be understood that the lower part of the arc will be blown out through the narrow exit 43 of the arc chute, and that the upper part of the arc will be blown out through the narrow exit of the arc chute formed between the barrier 22 and the upper barrier, which has been removed for purposes of illustration.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means.

What I claim' as new and desire to secure by Letters Patent of the United States, is:

1. In an electric switch, a pair of relatively movable cooperating circuit interrupting contacts between which an arc is formed when the contacts separate, and an arc chute having a comparatively long narrow exit with the long axis of the exit disposed in the planeof movement of said contacts for reducing the cross-section of the arc.

2. In an electric switch, an arc chute having apassage for the are which forms between the switch contacts, the said passage disposed in a plane substantially parallel to the plane in which the arc lengthens and narrower in the direction transverse to the direction in which the arc lengthens than the widthof the switch contacts.

3. Means for interrupting an electric circuit comprising a pair of relatively movable circuit interrupting contacts between which an arc is formed when the contacts separate, and means for causing the arc to proceed through a passage in the plane of movement of the switch contacts, the said passage having an exit narrower than the width of the switch contacts.

it. The combination in an electric switch of a pair of relatively movable cooperatin 'an arc is formed when the contacts separate,

a barrier on each side of the switch contacts,

the interior surfaces of the barriers forming an arc chute which is substantially parallel to the plane of movement of the switch contacts and which is narrower for a part of its length than the space in which the arc is formed:

6. The combination in an electric switch of a pair of relatively movable cooperating circuit interrupting contacts between which an arc is formed when the contacts separate, a barrier on each side ,of the switch contacts, the interior surfaces of the barriers forming an arc chute which is parallel to the plane of movement of the switch contacts and which is narrower for the greater part of its length than the width of the switch contacts.

7. The combination in an electric switch of a pair of relatively movable cooperating circuit interrupting contacts between which an arc is formed when the contacts separate, and means for causing the are formed between the contacts to proceed through a passage which is narrower for the greater part of its length than the width of the circuit interrupting contacts and which is disposed in a plane substantially parallel to the plane of movement of the switch contacts.

8. The combination in an electric switch of a pair of cooperating circuit interrupting contacts between which an arc isformed when the contacts separate,a barrier on each side of the switch contacts, the interior surfaces of the barriers forming a flat arc chute which is in the plane of movement of the said contacts and which is narrower for the greater part of its length than the width of the switch contacts, and a magnetic blow-out arranged so that the lines of force of the blow-out are substantiallv perpendicular to the path of the arc current.

9. The combination of a pair of arcing electrodes between which anarc is formed, and means for splittingthe are into a plurality of multiple connected parts.

10. The combination in an electric switch of a pair of cotiperating circuit interrupting contacts between which an arc is formed when the contacts separate, and means disposed in the path of the are opposite the contacts for splitting the are into a plurality of pailrts having a multiple relation to I each ot er.

11. The combination in an electric switch of a pair of cooperating circuit interruptin contacts between which an arc is forme 1 when'the contacts separate,and means for splitting the arc longitudinally into a plurality of parts and causing the parts to pro-' ceed through substantially parallel passages. 12. The combination in an electric switch of a pair of cooperating circuit interrupting contacts between which an arc is formed when the contacts separate, and means for splitting the are into a plurality of parts having a multiple relation to each other and are, each of the passages being substantially parallel to the plane in which the arc would ordinarily lengthen.

13. The combination with'a pair of arcing electrodes between which an arc is formed, and means for splitting the arc longitudinally into a plurality of parts, and reducing the cross-section of each part.

14:. The combination in an electric switch of a pair of cooperating circuit interrupting contacts between which an arc is formed when the contacts separate, and means for splitting the are into a plurality of parts having a multiple relation to each other and causing each part to pass through a restricted passage which reduces the thickness of the part.

15. The combination in an electric switch of a pair of cooperating circuit interrupting contacts between which an arc is formed when the contacts separate, and means disposed in the plane in which the arc lengthens for splitting the are into a plurality of multiple connected parts.

16. The combination in an electric switch of a air of relatively movable cooperating circuit interrupting contacts between which an arc is formed when the contacts separate,

and means disposed in the plane ofmovement of the switch contacts andprojecting into the path of the are for dividing the arc into a plurality of parts having a multiple relation to each other.

17. The combination in an electric switch of a pair of relatively movable coiiperating circuit interrupting contacts between which an arc is formed when the contacts separate, means disposed in the plane of movement of the switch contacts opposite the middle of 1 said contacts for splitting the are formed between the contacts into a plurality of parts,

and means for causing the said parts to proceed from the contacts parallel to each other in the plane of movement ofthe switch contacts.

of a air of relatively movable circuit interrupting contacts between which an arc is formed when the contacts separate, and means for splitting the are into two parts comprising a flat'barrier dis osed theplane of movement of the switch contacts,

the said barrier having a beveled surface on each flat side, the meeting of the two beveled 18. The combinationin an electric switch surfaces forming a comparatively sharp edge opposite the middleof the switch contacts.

19. The combination in an electricswitch of a pair of coiiperatin circuit interrupting contacts between wh1c an arc is formed when the contacts separate, means for dividthe plane of movement of the switch contacts opposite the middle of said contacts and a barrier disposed on each side of the first mentioned barrier for splitting the arc into a plurality of parts and causing each part to lengthen in a passage having an exit narrower than the width of the switch contacts in a plane substantially parallel to the of movement of theswit-ch contacts.

'21. The combination in an electric switch of a pair of relatively movable cooperating circuit interrupting contacts, between which an arc is formed when the contacts separate, means comprising a barrier disposed in the plane of movementof the switch contacts opposite the middle of said contacts; a barrier disposed on each side of the first mentioned barrier and a magnetic blow-out device arranged so that the lines of force of the blowout are substantially perpendicular to the passages between the said barriers, for disrupting the are formed between the contacts by splitting the are into a plurality of parts and causing each part to lengthen in a assage having an exit narrower than the wldth of the switch contacts in a plane substantially parallel to the plane of movementof the switch contacts.

22. The method of disrupting an arc which consists in splitting the are into a plurality of multiple connected parts.

plane cross section of the parts as the parts lengthen.

24. The methodv of disrupting an arc formed between a pair of relatively movable cooperating circuit interrupting contacts which consists in splitting the arc into a plurality of multiple connected parts in the plane of movement of the contacts, causing each part of the arc to be lengthened in the plane of movement of the contacts, and causing the cross section of each part of the arc to be decreased as the parts lengthen.

25. The method of disrupting an arc which consists in reducing the cross-section of the arc and splitting it into a plurality of multiple connected p rts.

26. The method of disrupting an are which consists in splitting the are into a plurality of multiple connected parts, and causing the cross-section of each part to be reduced.

27. The method of disrupting an are which consists of splitting the arc into a plurality of multiple connected parts, causing each part to be magnetically lengthened in a plane substantially parallel to the plane in which the arc would ordinarily lengthen, and causing the cross-section of each duced as it lengthens.

In witness whereof, I have hereunto set my hand this 2nd day of December, 1919.

JOHN F. TRITLE.

part to be re-

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