US1902357A - Circuit interruption - Google Patents

Description

March 21 1933. w. s. EDSALL 1,902,357

CIRCUIT INTERRUPTION Filed Feb. 17, 1950 3 Sheets-Sheet l 2 (ALLAN M March 21, 1933. w s EDSALL 1,902,357

CIRCUIT INTERRUPTION Filed Feb. 17, 1930 3 Sheets-Sheet 2 y w l4 (9 24 i; A

#4 M6 [do I I A r A Mam March 21, 1933. w, s, EDSA L 1,902,357

CIRCUIT INTERRUPTION Filed Feb. 17, 1930 5 Sheets-Sheet 3 L22 fiver-(702% M g M Patented Mar. 21, 1933 UNITED STATES PATENT OFFICE WILLIAM S. EDSALL, OF BBOOKLINE, MASSACHUSETTS, ASSIGNOR TO CONDITELEC- TRICAL MANUFACTURING CORPORATION, OF SOUTH BOSTON, MASSACHUSETTS, A.

CORPORATION OF MASSACHUSETTS CIRCUIT INTERRUPTION Application filed February 17, 1930. Serial No. 428,894.

This invention relates to circuit interrupters and to methods and apparatus for extinguishing circuit interrupting arcs.

. It has been proposed to extinguish electric arcs by drawing a submerged arc in an arc extinguishing body, as a body of oil, or a mass of gravel, or by playing a heavy solid stream of an arc extinguishing fluid, usually a liquid, against the arc. In all of these instances, however, the arc maintains its integrity in that it merely forms a hole inthe submerging body, or dodges the fluid stream and maintains itself just beyond the border of the stream. Thus, while the arc extinguishing medium has some action on the arc, the medium is in no manner fully effective.

I have discovered that, if the arc-extin guishing medium is presented to the arc in isolated particles the size of which is small compared to the thickness of the arc, they can be brought into intimate contact with the are without diverting the arc sensibly away from them, and thus can exercise their utmost effect in extinguishing the arc. This constitutes one of the objects of the invention.

A further object of the invention is to force such a quantity of small discrete and dispersed arc extinguishing particles into and through the arc, as to cause the arc to be extinguished and its restoration prevented; Preferably the particles are hurled forcibly into and through the arc as a spray, wherein the particles travel with considerable speed and momentum and are dispersed within the spray, that is, each particle is separated from all others, so that they can penetrate the arc independently in different places without causing the arcto be diverted away from them. This constitutes a further object of the invention.

The amount of the particles thrown into the arc is intended to be such as to cool and extinguish it, and therextinguishing action of the particles may be supplemented by the attenuation of the arc, by separating the arcing members of. the switch.

A further object of the invention is to extinguish the circuit interrupting arc by forcibly hurling into and through the arc,

and the zone thereof, and against the supporting surfaces between which the arc plays, small, cold, discrete, and dispersed, solid, particles of an arc-extinguishing material which preferably is electrically insulating, and is physically unchanging, at least for so long as it remains in effective contact with the arc, whereby to cool the arc and the arcing surfaces, and thus extinguish the arc. Sand is a highly suitable material and the use of sand for this purpose constitutes another object of the inven tion.

The electric arc consists of electrically charged ions, which are mainly negatively charged, and which act as carriers for the circuit current in the arc zone. If the electrified ions are absent from the arc zone, there can be no arc.

It is an object of the present invention to capture these ions by introducing into the arc zone moving particles having electric charges of such polarity as to nullify the charges of the ions in the arc zone, and thereby to destroy the conductivity of the arc zone and restore the dielectric strength thereof. Since the ions in the arc zone are mainly negatively charged, the electrified ion-capturing particles will be mainly positively charged. When the arc is formed by 'alternatin current and thus momentaril ceases at each zero point of the alternating current wave, the introduction of charged particles will take place at such time, whereby'to remove the conducting ions from the arc zone at the time of reduced formation of ions, thereby to facilitate the work of restoring the dielectric strength of the nor mally insulating medium in which the usual arc is formed. This is a further object of the invention.

Another object of the invention is to electrifythe discrete arc-extinguishing particles above mentioned and inject themforcibly into and through the arc and against the faces of the arc-supporting members, whereby not only to cool the arc and thereby render it nonconducting but also electrically to capture the conducting ions in the arc zone and also at the main zones of origin of the A yet further object is generally to improve methods and apparatus for circuit interruption. I

Fig. l diagrammatically illustrates'a circuit interrupting and arc-extinguishing apparatus embodying certain of the features of the present invention. v

'Fig; 2 is an end view or" thenozzie of Fig.

Fig. 3 is a View generally similar to Fig. l but illustratin a modified form oi apparatus for introducing electricallyQcharged particles into the arc.

Fig. 4 is. a section alongline 4 4 of Fig.

Fig. 5 is aview generally simil arto Fig.3, but wherein the airstream 1S removed from the blast of solid particlesprior to their introduction into thearc. I

Fig. 6 1s a perspective View of the separating and electricjchargingmember of Fig. 5;

Fig. 7 is adi'agrammaticyiew of a modifled system, wherein electrified liquid particles are discharged into' the arc zone.

Fig. 8 is a diagrammatic illustration of a further modified form of the invention,

wherein the arc-extinguishing particles pass into and through the arc' z'one mainly by gravity. H r

Fig. 9 is a diagrammatic illustrationfof another form of the invention'wherein the arc extinguishing particles are brought into the are by movement lengthwise of the are.

As shown in Fig. l, the circuit interrupter includes the stationary contact or arcing member 10 and the cooperating movable contact or arcing member 12. The arcing member 12 is movable'into and out of engagement with the stationary arcing memher by any suitable operating mechanism which, as here shown, includes the'pivoted lever 14, which lever is latched releasably in the engaged condition of the contacts by a latch16 that releasably engages a latch pin 18 of the lever. The latch is adapted to be released from holding engagement with the pin by an electro-magnet 20 upon overload or other abnormal condition of the circuit in ch dingconductors 22and 24 which are connected with the contact members of the switch,.whereby to effect the opening of the switch. The electromagnet maybe energized by means of a relay 26 from'a source of power 28. The relay can be operated by a current transformer 30 included in the c conductor 22 and adapted to closeits contact I between them.

uponoverload in said conductor.

hen the contact members 10 and l2.are separated under load, an arc is established In accordance with one of the features of thisinvention, means are pros vided to extinguish the are by forcing into;

and through the are cold, discrete particles 0f material which act to cool the arcand thus to cause it to become extinguished. To

this end, the contact members 10 and 12 are separable within or in the path of material discharged through a nozzle 31 which, preferably, is formed of insulating material and e is small at the inlet end 32 andlarge at theoutlet end 34 and tapers uniformly between.

the inletand outlet. A pipe'T 36 is'co'nnected with the inlet 32 of the corresponding nozzle and has a pipe 38 connected therewith which extends to an electrically-controlled the ,material is formed and maintained in the passage of the T. A manually'controlled valve 53 is interposed between the ends of said pipe 50 and constitutes'means for regulating the amount of the material discharged into the arc-zone. A pipe 54 communicates with the pipe 38 and the 111-- teriorof the hopper above the.material therein, and between said "hopper and the valve 40, sothat when fluid pressure is admitted to said pipe 38, it-is alsoadmitted'to the top of said hopper whereby'to cause the material to flow positively into the T and min le with the fluid flowing therethrough.

The flow of'fluid is controlled by a solenoid 56 which is energized by the operation of the relay 26 tofopen the valve 40 and admit fluid to flow through the T and the nozzle. A dash pot 58'preferably is associated with the valve 40 so as to delay the closing of the valve for a considerable period. after separated.

the contact members have.

Asxthus arranged, when theswitch is opened upon overload'and contact members 10 and 12 are separated and an arc is drawn the valve 40 also is opened by; the solenoid 56 and fluid is caused to flow therebetween,

rapidly through the T 36 and" into and through the expanding nozzle 31'. During its passage through the T, it picks up particles of the material46 which are therein and which are constantly flowing intothe fluid stream for so long as the stream maintains its flow, and thereby hurls the particles into.

and through the arc, the particles being dispersed throughout the gas blast. The particles are or can be at room temperature and thus are cold; with respect to the arc and so-cool the arc and quench it. If the i are is an alternating current arc, the How of the particles is adapted to continue be;

yond the period of the zero point of the current wave so that the particles act'upon the hot medium between the contact members and cool it at the time there is little potential on the contact members, whereby to restore the dielectric strength of the medium before full voltage is restored to the contact members so that the voltage cannot break down the medium. The contact members meanwhile are moving in a circuit opening direction and thereby increasing the distance between them, whereby to assist the arc extinguishing action of the particles by attenuating the arc. I prefer to use sand as the arc quenching material since sand is an insulator, is noncombustible, and is not physically altered by the arc for the time it is present therein. Other material can be employed, however. Small conducting particlescan be used with discretion, in certain instances, especially where their speed through the arc is so great that they do not become heated sufiiciently to give ofi conducting ions. An insulating material is much to be preferred, however, over a con ducting material. The speed of material through the arc preferably is relatively high so as to drive a large amount of cooling particles so rapidly into and through the are that they are not heated to an ionemitting temperature therein.

In the modified form of the apparatus illustrated in Fig. 3, I have illustrated means for discharging electricallycharged particles into and through the arc, the particles having a charge the polarity of which is opposite that of the charge of the conducting ions in the arc, whereby to capture said particles and nullify the charges thereof and render the arc space non-conducting. To this end, I provide the insulating nozzle 31 with an intermediate conducting section 60 which is spaced from the electrically conducting T 36 by an insulating portion of the nozzle. Said conducting section 60 is provided with a plurality of conducting guide vanes 62 .which are extended generally lengthwise of the nozzle. A source of high continuous electric tension 64 is connected with the conducting section 60 and the vanes 62 and thereby maintains them at a suitably high tension which preferably is positive since the conducting ions of the are are for the most part negatively charged. The discrete and dispersed particles of arc extinguishing material 46, as they are blown through the nozzle by a blast of fluid from the pressure tank 44, are caused individually to impinge against the conducting section and the vanes and thereby to acquire electric charges having the polarity of the conducting section. The charged particles are further impelled into the arc zone and capture the oppositely charged conducting ions therein and nullify the charges and thereby cause the arc zone to become non-conducting whereupon the arc ceases. If the arc is an alternating current arc, the flow of the charged particles is maintained at least throughout one current zero and preferably for a number of current zeros so that the residual ions in the arc zone existing at the time the arc current is-zero and the arc is momentarily out are rendered non-conducting whereby to restore the dielectric strength of the normally insulating medium between the contact members and prevent the reestablishment of the arc when potential is again built up at thecontact members.

The ionized particles also travel over the arcing faces of the contact members, which are the main sources of origin of the ions, and impinge thereagainst whereby to cool the surfaces and capture the ions at their sources. Theblast of gaseous fluid which carries the arc extinguishing particles also assists in attenuating and extinguishing the arch Fig. 5 illustrates the principle of the ap paratus of Fig. 3 except that the blast of discrete, solid particles, at the time the particles pass into the arc, is free from the gas stream which in Fig. 3 carries them. In Fig. 5 the nozzle discharges into the arc zone between the arcing members 10 and 12 contained in a closed chamber 72. The con ducting section 74 of the insulating nozzle is provided with a plurality of plates or vanes 76, see especially Fig. 6, adjacent pairs of which vanes are connected together at their front or entering edges 78. The vanes thus provide passages 80 through which the solid particles and gas arefree to pass. The spaces 82 between the pairs of connected plates are in communication with a chamber 84 which is connected by a pipe 86 formed preferably of insulating material or having an insulating section. Said pipe is connected with a suction device 88 which may be a centrifugal exhauster operated by the electric motor 90. Thus, when the exhauster is operated, air is withdrawn from the chamber 72 so that a blast of air is caused to enter into the open end 92 ofthe T 36a and pick up the arc extinguishing material therein and so carry the material through the nozzle. The air passing through the passages 80 is caused to curl around the edges of the plates 7 6 that confront the arc and thus to enter the passages 82 and to pass into the exhauster. The particles of solid material, however, have such momentum that they can not follow the air stream and consequently continue to move rapidly with little change of direction into and through the arc zone. The conducting section 74 and the plates 76 are connected to a suitable source of continuous high tension 64 as in the previous modifications so that the arc extinguishing particles become charged priorto their entrance into the arc zone. The charged particles thus act to capture the conducting ions in the arc zone and thereby render the arc zone nonconduc ing'in'the manner heretofore explained.

Because of the absence of the gas blast in the arrangement illustrated in Fig. 5, the arc is not displaced and is caused to become extinguished by the action of the spray of arc extinguishing particles alone.

Under certain conditions, the arc extinguishing material can be a liquid .which is capable 01" passing into and throughthe are without being ignited or without'dccomposing in any deleterious manner when the liquid is discharged as a spray of discrete dispersed particles into and through the are .li-quid under pressure.

. like. The operation of the spray is cont-rt and against the seats of the are on the contact members.

Fig. 7 illustrates an apparatus fordischarging such a liquid spray. A spray noz zle 100 has an orifice 102 directed to discharge a spray of fluid into the arc zone between the separated contact members of the circuit interrupter. The characteristics of the spray of atomized liquid are controlled by the adjustable valve member 10 1. The. liquid passage106in the valve casing is connected through a pipe 107, which can be of insulating material, and an electrically controlled valve 108 with a receptacle 110 containing, a supply of the Theliquid can be carbon tetrachloride, pure water and the 7 led heretofore by the solenoid 112' which opens the valve 108 coincidently with the separation of the contact members o1 the interrupter on overload. The closing of the valve isdelayed by a dash pot ll. The spray of dispersed liquid particles passes through the arc and. thereby cools it and renders the arc zone non-conducting. The liquid particles can be electrically charged by belng impelled through a charging ring 116 which is maintained at a suitably high continuous potential by the source of potential 64. The other terminal of said source can be connected with the valve caring 100. The liquid particles issuing forciblyfrom the nozzle 100 and passing through the charging rig 116 become electrically chargedand thus when in the arc zone capture the conducting ions and render them non-conducting essentially in the manner previously set forth. I A

In the modification illustrated in Fig. 8, the force of gravity is substituted for the air blast to carry the arc-extinguishing particles into the 'arc zone. 7

A supplysG of the particles, as sand, is contained in a'suitable' container lsa which is elevated above the separable contact members or" electrodes 10 and '12 anddischarges a. stream orblast of sand from the bottom,

of the container, through the fan-shaped nozzle 118, which blast falls by gravityinto the arc zone between the separated electrodes. The discharge of sand is controlled by a valve 53athe operation of which is effected by a solenoid 56w under the control of the overload relay 26. The weight of the sand and gravity closes the valve after the arc has been interrupted and the relay 26 ole-energized. The falling sand is electrically charged, prior to its entrance into the arc zone, bypassing through the metal screen 62a which is energized at a positive potential by the voltage source 6 1; at least for so long as an arc persists. The action of the apparatus is essentially as has been described heretofore.

-In the further modification illustrated in Fig. 'Qfthe' arc-extinguishing, particles are movedinthe direction of the length of the arc. Thecircuit interrupting are between the contact members 10 and 12 takes place in the preferably insulating tube 31a along the length of which the sand blast is directed by the air blast in the manner here tofore described. The arc is drawn covaxially of the tubeand the sand. and air blasts pass longitudinally of the arc and both are caused to be closely confined in the arc stream by the closely surrounding tube. Conical baffles 120 are disposed withinthe tube at spaced intervals to direct the sand and air positively into the are so as to render the blast more effective. The sand blast is electrified by passing through the electrified screen 122 which is disposed between the outlet'o'f the hopper 48 and the entrance torthe tube 31a. The screen is maintained at a suitably elevated and preferably positive potentialby the high potential source 2;" An electric circuit interrupter having arc-supporting members and means to discharge discrete and'dispersed particles of 7 an. arc extinguishing material into the arc zone betweensaid members so asto penetrate the gases of a circuit interrupting are drawn therebetween,,which particles carry electric chargeshaving'a polarity opposite that of the major current-carrying ions oi the arc of sufiicient intensity to'neutralizethe charges carried'by said ions, s.

3. An electric circuit interrupter having arc-supporting members, and means to introduce into the arc zone between said members, an electrically charged medium which de-ionizes the current-carrying medium in said are zone and renders it non-conducting.

4. An electric circuit interrupter having arc-supporting members, and meansto deionize the ionized medium of the arc zone between said members including means to introduce an electrified de-ionizing medium into said ionized medium.

5. An electric circuit interrupter having arc-supporting members between which an ionized atmosphere exists at the time an arc is present between said members, and means to de-ionize said ionized atmosphere including means to introduce electrically charged de ionizing particles into said ionized atmosphere, the amount and sign of the charges of which are sufiicient to deionize said atmosphere.

6. An electric circuit interrupter having arc-supporting members between which negatively charged ions exist when an arc is formed therebetween and means to neutralize the conductive efiect of said ions including means to introduce into the arc zone between said members particles having electric charges which are opposite to and sufii cient to neutralize the charges of said ions.

7 An electric circuit interrupter having arc-supporting members between which negatively charged ions exist when an arc is formed therebetween and means to neutralize the conductive effect of said ions includ ing means to introduce into the arc zone between said members electrically charged carriers having charges the amount and sign of which is suflicient to neutralize the charges of and capture said ions.

8. An electric circuit interrupter having arc-supporting members and means to capture the conducting ions of and thereby to extinguish the are including means to direct into the are zone, between said members, moving carriers of electric charges which capture suflicient quantities of the arc ions to extinguish the arc.

9. An electric circuit interrupter having arc-supporting members and means to capture the conducting ions of and thereby to extinguish the are including means to direct into the arc zone between said members moving carriers of electric charges having a polarity which is opposite that of the ions, and having charges the amount of which is equal to the charges of said ions, whereby the ions are attracted to said carriers and are rendered inert.

10. An electric circuit interrupter having arc-supporting members between which an arc can form, and means to extinguish the are including means to introduce electrically charged particles into the arc, said particles having electric charges of such capacity and sign as to destroy the conductivity of the are medium.

11. An electric circuit interrupter having separated are supporting members between which an electric arc can form and means to extinguish the are including means to introduce electrically charged particles into the arc in sufficient amount to extinguish the are.

12. A circuit interrupter having separated arc-supporting members between which an arc can form, and means to extinguish the are including means to introduce into the are solid discrete particles of arc extinguishing material which are electrically charged, the volume of said material and the amount and sign of the charges of the particles being sufiicient to destroy the conducting property of the are medium.

13. An electric circuit interrupter having arc-supporting members, -means to extinguish the are between said members including means to impel discrete particles of arc extinguishing material into the arc, and means to charge said particles electrically prior to their introduction into the are.

14. An electric circuit interrupter having arc-supporting members, means to extinguish, the are between said members including an electrically charged member, and means to pass discrete particles of arc-extinguishing material into engagement with said electrically charged member and thence into the are.

15. An. electric circuit interrupter having arc-supporting members, and means to extinguish an are between said members including an electrically charged member, and

neumatic means to im )el a uantit of discrete arc-extinguishing particles into engagement with said electrically charged member to become electrically charged thereby, and thence to pass said charged particles into the arc zone between said are supporting members.

16. The method of extinguishing a circuit interrupting are which consists in introducing into the are rapidly moving free carriers of electric charges having a polarity opposite that of the current-carrying ions in the arc zone, whereby said carriers are caused to capture said ions and thereby extinguish the are.

17 The method of extinguishing an elec tric are which consists in neutralizing'electricallycharged ions in the are by oppositely electrically charged free discrete particles.

18. The method of extinguishing an electric arc consisting of electrically charged particles which consists in capturing said particles by introducing into the are rapidly moving discrete particles which are oppositely electrically charged.

19.The method of extinguishing an elec-' tric are which consists in discharging into the arc an arc-extinguishing medium in the form-of a spray of discrete dispersed particles which carry electric charges the polarity of which is opposite that of the currentcarrying ions of the arc.

20. A circuit interrupterhaving electrodes 7 which support an electric are, including a 10 gas blast means to direct an arcextinguishing medium into the arc, and means to remove the medium from the blast prior to the are, said medium being in the form of dispersed particles which are so small com- 1 v V V pared with the thickness of the arc and bej l ing free from the gas blast which impels them so that they can penetrate the arc without diverting the are away from them and can act efliciently on the arc to de-ionize it.

21. An electric circuit interrupter having arc-supporting members, means to direct a stream of discrete arc-extinguishing particles into the arc in the direction of the length of the arctand means to electrically charge said particles prior to their entrance into the arc. 7

22. An electric circuit interrupter having arc-supporting members, means to direct a combined blastof a fluid and discrete areextinguishing particles into the arc in the direction of the length of the arc and means to electrically charge said discrete particles prior to their entrance into the arc.

; In testimony whereof, I have signed my name to this specification WILLIAM S. EDSALL.

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