US2615109A

US2615109A - Zigzag magnetic labyrinth arc muffler

Info

Publication number: US2615109A
Application number: US140414A
Authority: US
Inventors: John A Favre
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1949-12-10
Filing date: 1950-01-25
Publication date: 1952-10-21
Anticipated expiration: 1969-10-21
Also published as: GB687897A; FR1042680A; GB687886A

Description

Oct. 21, 1952 J, A FAVRE 2,615,109

ZIGZG MAGNETIC LABYRINTH ARC MUFFLER Filed Jan. 25, 1950 Inventor -JOHT-l A.1:a\/1^e f His Attorney Patented oct. 21,v 1952 UNIri-:D STATES PATENT' TOFFICE .101m A. FenomeniHurra., mignrmoenf -,-'eral-Elec.tric Company, a. corporation. ot New yAimiitaoon January-25, 191.50;` sommo. noa-ri f -The invention relates toarcmuiiers, particular-- lyfcf atype suitable for suppressing the hash from the cooperating arc quenchers of .enclosed or semi-enclosed 'circuit breaker-sor in other similar service where a severe arc nashresemblingan explosion must be' 'suppressedwithin a lrelatively small Aspace.

The principal object is to provide an improved nesting'type of double offset or zigzag .corrugated magnetic labyrinthv arc muiiier capable of .estab--l lishl'ng magnetic attractionffor drawing the arc into la loop inside `a restricted arcequenching space',474 providingabrupt changesin direction of the 'zig-zag p'assageformed between. nesting zigzag magnetic members so that any incandescent particles projected with the gases arey intercepted bylthedouble offset corrugated kmembers and depositedy thereon, aswell-as providing aplurality of'heat-absorbing zigzag l.passages `spaced to .secure good turbulence and. scouring and hence rapid cooling or quenching of .the hot arc gases, allwithout yunduly drawing the arc into the mufileror unduly restricting .theffio'w of the gases therethrough...

Another object is to providean improved arc muiiier unit` assembly having 'a plurality of parallel tortuous'paths formed-by nesting double offset zigzaglmagnetic plates. `of .sufficient mass and spacing'adjacent the path of. the arc tolsuccesstullyiwithstandthe maxixnumarcing action and insure eiclent heat absorption of several arcing, actionsiin 4close succession and with the nesting double-oifset zigzag corrugations of the plates serving to minimize buckling or warping thereof under maximumarcing conditions.

`.Qtlfier objects and advantagesof the invention winappear in the foiiowingfdescription of the accompanymg drawin'g'in which Fig. 'l is a partial front view voione pole rvof a semi-enclosed 'circuit breaker rhaving an arc quencher provided with anarc muler embodying the improvements of the-*present invention; Fig. 2 is a sectional view of thecircuit breaker pole shown in Fig. 1 along the sectioniine 2-2and showing the. spaced operating relation ofr the arc muffler with respect tothe arc quencher whereinv the arc is drawn be tween'the. stationary and-movable circuit breaker contacto;v and. Fig. 4v3 is .an .enlarged vperspective viewfshowing the. details of construction of 'a ino'dication` of the. rimproved zigzag magnetic type of arc quencher of thepresent invet'ion suitable 'for heavy current service.

.ffRferrng to Figs. l and 2,'the single vpole 'of semienclosed multi-'slot circuit breaker indicated 'generallyby the reference character I0 is sciame. (ci. coef-14m),

provided' with a pair of shunt yconnected. movable contact rarms rII having contact facing-s- T22-operable .into and out of abutting engagementwith the contact facings I3 of the cooperating station` ary contact members I4. The'movableswitch contacts I`I are'. carried byk cross arm I5 thatfalso carriesthe contacts of 'theo'ther poles of thecir-v cuit breaker, not shown. and is. operated by `sui-ttable operating mechanism, also not shown. "The arc-produmedv upon separation `of contact facings I3l `'is quenched inan -arc quencher I6 and-fthe flash lis suppressed? -by vthe rimproved 'magnetic labyrinth arc muiiier Hof the present invention.

As shown, the two movable switch membersk II operate in parallel slots 2| formed between arcquenching" barriers 22, 23 and' 2-'4 that are of the improved transverse slotted type more fully described and claimed-in the patent application, .Serial No. 132,258,- -led December 1'0, 1949 by Charles Titus fand assigned vto the assignee of thev present invention'. Thus, the arc drawn between-the-:contact 'faces -I 2 and I 3 upon opening of the'circuit breaker is immediately brought into intimate contact with the are-quenching barriers 22, v'23 and 2'4 vand subjected to the arc-quenching action thereof which is materially-improved by'theprovision `of the series Vof parallel intercommunicating

vslots

26, 21, 28 and 29 4in each of the barriers. fy The rimproved zigzag Imagnetic labyrinth @arc muiiier -`I-`I of the'presentinverition serves to a'ttractfthearcs and to suppress the flashis'suing'*V from the slots 2| when parallel arcs are drawn? thereinto interrupt the circuit. `As shown inFig. 2,'-the arc muiiier ITis composed of a'plu'rality'of nested zigzag magnetic -members 3| that are mountedin juxtaposition'along the edge 'of the

arcrquencher plates

22, 23, and 24 tofform a plural offsetzigzag pathmagnetic labyrinth having'each zigzag path traverse the'pa-th of the arc in each s1ot2l; Each of the magnetizable members :3| isprovided with central ydoubleoffset zigzag corrugationsi32 kprojecting laterally on opposite sides thereof andwith parallel 4poles 33 and r34 that project beyond the zigzag'edges of the corrugatlons32 to form mounting lugs 35 as more clearly shownin'the perspective view of Fig. 3. .A pair of'sidebarriers 36 and 31 are formed of suitable insulating material for abutting the zigzag edges of members 3i 'and provided with a series of slots 38 inthe opposite edges thereof for receiving the projecting lugs 35 therein so as to mount the magnetic members 3| with the oppositely projecting corrugations 32 of adjacent members in par-r allel nested spaced-apart relation Von opposite sides of the longitudinal axis of the zigzag passage formed therebetween and with each zigzag passage laterally closed by the insulating side barriers 36 and 3l. As shown, each of the

side barriers

36 and 31 is formed of two duplicate piecesof insulating material in order to facilitate punching of the slots therein.

Upon the opening of the circuit breaker to establish parallel arcs in the slots 2|, magnetic members 3| are magnetizable by the current in the arcs and due to the concentration of the magnetic mass resulting from the nesting of the oppositely projecting zigzag corrugations 32 provide suicient magnetic attraction for drawing the arcs into a loop inside the slots 2|, thereby elongating the arcs and facilitating the arcquenching action of the transversely slotted

insulating barriers

22, 23 and 24. At the same time,

the plurality of nested spaced-apart zigzag magnetic members 3| a provide a plurality of heat absorbing zigzag passages therebetween spaced to provide good turbulence and scouring, and hence rapid cooling or quenching of the hot arc gases that are recived from the slots 2|. Any incandescent particles carried in the gases are intercepted by the members 3| in their passage through the magnetic labyrinth and deposited thereon. The double offset zigzag corrugation of the members 3| also serves to minimize buckling or warping thereof under maximum arcng conditions. Hence, the improved nested zigzag magnetic labyrinth arc muffler I1 is able to successfully withstand several arcing actions in close succession.

The modified form of the invention shown in Fig. 3 is particularly adapted for heavy current service wherein somewhat less concentrated magnetic attraction and somewhat more restriction to gas ow is required of the magnetic labyrinth arc muller due to the increased loop selfexpanding action of the arcs carrying the heavier currents. To reduce the magnetic attraction, a suitable number of the magnetic members 3| may be removed from the muiler il at spaced intervals, thus leaving the remaining rmembers 3| in spaced-apart groups A, B, C, and D, as shown in Fig. 3. Then, in order to further restrict the passage of the arc gases through the enlarged passages in the muilier insulating pins 40 are interposed to substantially close the spaces between the aligned groups of magnetic members 3| forming the labyrinth. Thus, with the improved nested zigzag plural path magnetic labyrinth muiiler modified as shown in Fig. 3, the overall restriction to gas flow through the zigzag members is somewhat increased but without correspondingly decreasing the insulation between the members. Furthermore, with thegpins 40 located adjacent the top of the enlarged passage between the groups of magnetic members 3|, as shown, pockets for stagnant gas are provided by the enlarged closed space between the groups so as to act as insulators therebetween and also enable portions of the arc to be momentarily vented therein while the main now of arc gases passes through the plural labyrinthine paths provided by the remaining spaced-apart groups of nested zigzag magnetic membersl 3|.

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

l. An arc muffler having in `combination a plurality of magnetic members, each provided v. ith oiset zigzag corrugations projecting laterally on opposite sides thereof, and insulating means for mounting the members in juxtaposition with the oppositely projecting corrugations of adjacent members in nested spaced-apart relation on opposite sides of the longitudinal axis of the zigzag passage formed therebetween to concentrate the magnetic mass of the members for attracting the arc and to intercept particles projected with the arc gases into the zigzag passage.

2. An arc muiller having in combination a plurality of magnetic members, each having parallel mounting lugs and offset zigzag corrugations projecting laterally on opposite sides thereof, and insulating side barriers abutting the zigzag edges of the corrugations and provided with slots for receiving the parallel lugs to mount the members in juxtaposition with the oppositely offset corrugations of adjacent members in nested spaced-apart relation on opposite sides oi' the longitudinal axis of the zigzag passage formed therebetween to concentrate the magnetic mass of the members for attracting the arc and to intercept particles projected with the arc gases into the zigzag passage.

3. An arc muiler having in combination a plurality of magnetizable plates, each having central double offset zigzag corrugations projecting laterally on opposite sides thereof and parallel poles projecting beyond the zigzag edges of the corrugations to form mounting lugs, and insulating side barriers abutting the zigzag edges yof the corrugations and provided withslots forkregceiving the lugs to mount the members in juxtaposition with the oppositely projecting corrugations of adjacent members in parallel nested spaced-apart relation on opposite sides of the longitudinal axis of the zigzag passage formed therebetween to concentrate the magnetic mass of the members for attracting the arc and to intercept particles projected with the arc gases into the zigzag passage.

4. An arc Amufller having in combination plurality of magnetic plates, each having parallel poles at the ends thereof and central` double oilset zigzag corrugations projecting laterally on opposite sides of the poles, and insulating means for mounting the plates with the poles n juxtaposition and with the oppositely projecting corrugations of adjacent members in nested spacedapart relation on opposite sides of the longitudinal axis of the zigzag passage formed therebetween to concentrate the magnetic mass of the plates for attracting the arc and to intercept particles projected with the arc gases into the zigzag passage. t y

5. An arc muiller having in combination a plurality of magnetizable members, each having double offset zigzag corrugations projecting laterally on opposite sides thereof and parallel poles extending beyond the zigzag edges of the corrugations to form mounting lugs, a pair of linsulating side barriers in spaced apart parallel relation Vfor abutting the zigzag edges of the corrugations and having slots for receiving the lugs to mount the members in juxtaposition in spaced-apart groups with the oppositely projecting corrugations of adjacent members of each group in nested spaced-apart relation on opposite sides of the longitudinal axis of the zigzagrv passage formed therebetween to concentrate the magnetic mass'of the members for attracting the arc and to intercept particles projected with the arc gases into each passage, and insulating means closing the space between the groups to prevent the passage of particles and arc gases therebetween.

le of this patent:

6 UNITED STATES PATENTS Number Name Date JOHN A- FAVRE- 2,293,513 Linde Aug. 18, 1942 2,337,949 Walle Dec. 28, 1943 REFERENCES CITED 5 2,408,352 Titus sept. 24, 1946 The following references are of record in the 2,442,199 Dickinson May 25, 1948