US2639354A

US2639354A - Electric circuit breaker

Info

Publication number: US2639354A
Application number: US189026A
Authority: US
Inventors: Edward J Frank; Virgel E Phillips
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1950-10-07
Filing date: 1950-10-07
Publication date: 1953-05-19
Anticipated expiration: 1970-05-19
Also published as: DE939460C; CH309308A; GB720021A; FR1043588A

Description

y 9, 1953 E. J. FRANK EIAL 3 ,35

ELECTRIC CIRCUIT BREAKER Filed Oct '7. 1950 Their" Attorney.

Patented May 19, 1953 ELECTRIC CIRCUIT BREAKER Edward J. Frank, Springfield, and Virgel E. Phillips, Philadelphia, Pa., assignors to General Electric Company, a corporation of New York Application October 7, 1950, Serial No. 189,026

8 Claims. 1

This invention relates to electric circuit breakers and more particularly to circuit breakers having main current-carrying contacts and arcing contacts arranged in parallel therewith across which the arc to be interrupted is drawn during a circuit opening operation, such, for example, as the circuit breaker disclosed in U. S. Patent 2,280,616, Baskerville, which is assigned to the same assignee of this application.

In circuit breakers of this type and under certain interrupting conditions the arc may blow back from the arcing contacts to establish itself at the current-carrying contacts and as a result of such transfer, the breaker may fail to interrupt while the current-carrying contacts may suffer damage from such arcing which they are not well adapted to withstand. Circuit breakers of this type usually are provided with are blowout and quenching means such as an arc chute which is adapted to extinguish an are initiated across the arcing contacts only if the arc travels into the chute in a direction away from the main contacts. Thus, if the arc is allowed to strike back across the first-opened current-carrying contacts, its extinguishment may become diflicult or impossible for it has moved out from the efiective quenching zone. Transfer of the are back from the arcing to the current-carrying contacts may be caused by unstable magnetic conditions aggravated by an uncontrolled ionized gas condition emanating from the arcing zone into the region of the current-carrying contacts.

Accordingly, an object of the invention is to provide a novel arrangement of blowout means and an associated arc runner for a circuit breaker having main current-carrying contacts and areing contacts, which arrangement is 'efiective to segregate the fixed arcing contacts from the fixed current-carrying contacts and which efiectively According to the invention a barrier in the form of an arc runner is disposed in the region intermediate the arcing and main contacts, which barrier is provided with an opening therein .through which the movable arcing contact is Thus the arc is drawn in a region movable.

which is shielded from the main contact and so is prevented from transferring thereto during the initial opening movement before the movable arcing contact tip emerges from the opening in the arc runner. As the movable arcing contact is passing through the opening in the arc runner, magnetic blowout means become ehective to urge the arc in a direction into the arc chute and away from the main current-carrying contacts. Furthermore, we provide gas-deflecting means for efiectively diverting the hot ionized gases generated by the are into the chute, to thereby augment the blow-out efiect as well as diverting these gases away from the current-carrying contacts.

The invention will be better understood with reference to the accompanying drawing in which Fig. 1 is a side view partially in section of a circuit breaker embodying the invention; and in which Fig. 2 is a view along the line 2-2 of Fig. 1.

With reference to-Fig. 1 the circuit breaker shown therein includes a terminal I comprising a conductor stud and a corresponding stud terminal 2 which are fixed in position with re,- spect to the circuit breaker frame (not shown). The fixed contact structure generally designated at 3 is electrically connected with the terminal I while the movable contact arm 4 is pivoted and electrically contacted at 5 to terminal stud 2. Contact arm 4 is rotatable about pivot 5 by the insulated operating rod 0 which is pivoted to the operating arm 4 at I. Motivating force for the contacts is supplied through the actuatin member 8 and the coupling means of operating rod 6 is adjustable according to Patent No. 2,590,765, Frank et al., granted March 25, 1952, assigned to the assignee of this application. Fixedly mounted on and movable with the contact operating arm 4 is a broad movable current-carrying contact 9 and a narrow movable arcing contact I0.

Electrically connected with conductor stud I is a conducting member I I to which is fastened the curved contact retaining member He: thereby to form a pocket for receiving therein the anchored ends of the main contact fingers. Main currentcarrying fixed contact fingers I2 are biased for rotation in the clockwise direction about the pivot comprising the curved portion I3 of member II by means of compressional spring I4 whose associated guide pins i5 operate in the retainer member I la. Fixed arcin contact I6 is mechanically and electrically connected to the member II by means of the shouldered conducting pin II riveted over at I8. As is best seen in Fig. 2 fixed arcing contact I-B comprises a pair of finger type contacts which are biased toward each other about pin I! by compressional springs 13 and 2t to embrace between the tips thereof the cooperating tip of the movable arcing contact l0 As is clearly shown in both Figs. 1 and 2 movable arcing contact Ill is provided with a considerable wiping movement in order to insure that these arcing contacts w ill n'ct be separated to draw the interrupting arc until after a safe separation of movable main contact 9 from the fixed main contact fingers I2 has been established. In this way the contacting surfaces of contacts .9 and H 2 do not become pitted and merely serve as current carrying contacts when the breaker isclose'd.

As already explained, the arc 'iirawn between the 'chute which isc-a necessary prerequisite to'ex tinguish-mcnt. Thus it is perative that an arc must not strike orre'iorm across the main current-oarrying contacts 9 and I2.

In order to prevent such striking of the are between the main current-carrying contacts, an

are runner 2 in the form of a barrier or gas directing means provided according to the invention, and is inserted in the region between the fixed arc'ing contacts It and the hired current-carrying contact 'fingers 1%.. Insulation, such as Zia and 21b, is provided for electrically isolating the runner 2'] from the associated conducting parts so that runner 2! constitutes an effective shunt pa t-h independent of the contact structure. Thus, when the arc is drawn initially and before the arcing tip of movable arcing contact -l-0 moves through the slot-like opening 2-2 provided in the arc runner 2!, the arc cannot move "from the arcing contacts to the currentcarrying contacts 'due'to the barr'iereffect of the u are runner 21. Furthermore, in order to prevent ionized gases formed at the arcing contacts, which issue 'as a downward jet through the slot 22, from spreading toward the current-carrying contacts!) and 12 which might initiate a "break- A down, a deflecting "barrier 23 is provided as a further feature according to the invention. Bar- "ri'er -23 "constitutes a broad flange and is integral andim'ovahle with the arcing contact Ill "and, as is "clearly evident from Fig. 1, the flow of gases a downwardly through the opening 22 will impinge on the deflecting surface-oi baiiie23 so that the ases are directed toward the left into the arc chute structure generally designated by the numeral 2t. Of course'the bafiie 2'3'needn'ot beatfixed to the; contact in and could be fixed inposi tion with respect to the opening 22. If desired the barrier could be provided with an opening through which the contact iii would be movable.

As the arcing contact ill moves downwardly during an opening stroke, and as the arcing tip thereof is passing through "the slot 22 in the'ar'c runner 2i theupper arc root transfers from the fixed arcing contact It to the arc runner 2i thereby introducing in series with "the arc the first blowout coil "25 which is connected between conductor stud 'l and are runner 2|. At this point, it will 'b'e'understood that current flowing through the hinged contact mm ll and the arc then-proceeds" viavthe insulated arc runner 22 i and into the arc chute 24.

the coil 25, the current path through the runner and coil constituting an alternative path for the initial interrupting arc circuit comprising the arcing fingers: l6, pin I1 and conducting member I l. Thus, the runner 2| really constitutes a part turn coil in series with the blowout coil 25. As is well known, the effect of this blowout coil is to establish a magnetic condition which urges the arc in a direction toward the left end and As the contact In continues to move downwardly, the lower root of the are will transfer from the arcing contact II] to the arc runner 26 thereby introducing in series with the arc :and blowout coil 25 the lower blowout coil "2 to thus augment the blowout effect upon the arc toward the left. Because the coil 2%"! is connected with conductor stud 2 through the conducting strap 28, the interrupting circuit is now shunted completely around the contact arm 4. If not yet extinguished, the arc will continue to move to the left so that its upper root will transierirom the arc runner 2 I to-the upper arc runner 29. Thus, the third blowout coil 30 is inserted in series with blowoutcoils 2:5 and 121 by reason of its being connected across the sin sulating block 3 which separates the :lowertrum ner "21 from the upper runner 129 In the'partrcu-lar embodiment shown, the blowout eliieci; of these three coils u'pon'th'e arcwhereby' itlisdriven toextinction in the chute 2'4 will be "adequate to insure the interruption of all curr'ents the rating of the circuit breaker.

Thus by installing the fixe'd arcing contact within a pocket-compr-isedby the shielding are runner "2| havingbut one vent therefrom, viz. the opening 22, "all ionized gas products of the initially drawn are are directed therethrcugh a concentrated stream downwardly; after which the deflecting 'barrierassociated with the movable arcing contact is effective in diverting this ionized stream safely into the arc chute directly away from the main current-carrying contacts.

While we have shown and described aparticulair embodiment of the inventionwe d1) not wish to be limited thereto and intend in "the appended claims to cover all changes and modifications "as tall within (the true spirit and scope of the invention.

What weclaim as new and desire to secure by Letters Patent of the United States is:

1. An electric circuit breaker comprising-a pair of relatively movable current-carrying contacts, a ,pair of relatively movable arcing contacts, are runner means disposed in the region .intermedi ate said-pairs of contacts, an opening insaid arc runner through which a movable vone of said arcing contacts ismovable, and means for urging the are drawn between said arcing contacts in a direction away from said current-carrying con- .tacts.

2. An electric circuit breaker comprising fixed and movable current carrying contacts, .fixed and movable arcing contacts arranged in parallel with said current-carrying contacts, stationary gas directing means partially surrounding said fixed arcing contact and havinga por tion thereof disposed intermediate saidifixed-current-carrying and said fixed arcing contacts and insulated therefrom for causing the arc gases produced :at said arcing contacts to move in .0218

generaldirection, and vbaille means'di-sposed in the path of movement -of :said are gases when :said gases are moved in said one general direction, said 'ba'iiie means being effective to deflect :sai'd gases in another general direction away from said current-carrying contacts.

3. An electric circuit breaker comprising fixed and movable current-carrying contacts, fixed and movable arcing contacts arranged in parallel with said current-carrying contacts, gas directing means partially surrounding said fixed arcing contact and having a portion thereof disposed intermediate said fixed current-carrying and said fixed arcing contacts and insulated therefrom for causing the arc gases produced at said arcing contacts to move in one general direction, and baffle means movable with said movable arcing and current-carrying contacts and disposed in the path of movement of the arc gases when moved in said one general direction for deflecting said gases in another general direction away from said current-carrying contacts.

4. An electric circuit breaker comprising a pair of relatively movable current-carrying contacts, a pair of relatively movable arcing contacts, arc runner means disposed in the region intermediate said pairs of contacts, an opening in said arc runner through which a movable one of said arcing contacts is movable, means for urging the are drawn between said arcing contacts in a direction away from said current-carrying contacts, and gas-deflecting means disposed with respect to said arcing contacts so as to deflect the hot ionized gases caused by the are between said arcing contacts in a direction away from said current-carrying contacts.

5. An electric circuit breaker comprising a pair of relatively movable current-carrying contacts, a pair of relatively movable arcing contacts, barrier means including a portion of an arc runner disposed between one of said arcing contacts and one of said current-carrying contacts and partially surrounding said one arcing contact for directing the ionized gases formed upon separation of said arcing contacts in a predetermined direction, and gas-deflecting means disposed in the path of movement of said gases and arranged with respect to said barrier means so as to deflect effectively said gases in a direction away from said current-carrying contacts.

6. An electric circuit breaker comprising a pair of relatively movable current-carrying contacts, a pair of relatively movable arcing contacts, arc runner means disposed in the region intermediate said pairs of contacts, an opening in said arc runner through which a movable one of said arcing contacts is movable, means for urging the arc drawn between said arcing contacts in a direction away from said current-carrying contacts, and a gas-deflecting surface disposed on said movable arcing contact for deflecting the hot ionized gases caused by the are drawn between said arcing contacts issuing through said opening to be thereafter diverted in a direction away from said current-carrying contacts.

7 An electric circuit breaker comprising electrically interconnected fixed arcing and currentcarrying contacts, movable arcing and currentcarrying contacts movable into and out of engagement respectively with said fixed arcing and main contacts, an arc runner interposed between said fixed arcing and current-carrying contacts and insulated therefrom, said are runner being provided with an opening through which said movable arcing contact is movable, and magnetic blowout means interconnected between said fixed arcing and current-carrying contacts and said are runner for exerting a force on the are drawn between said arcing contacts in a direction away from said current carrying contacts.

8. An electric circuit breaker comprising electrically interconnected fixed arcing and currentcarrying contacts connected to one terminal of the breaker, movable arcing and current-carrying contacts connected to another terminal of the breaker and movable into and out of engagement respectively with said fixed arcing and ourrent-carrying contacts, said contacts and terminals being arranged in a loop circuit, an are runner interposed between said fixed arcing and current-carrying contacts and insulated there from, said are runner being provided with an opening through which said movable arcing contact is movable and being disposed with respect to said loop circuit so that the magnetic efiect thereof aids the arc in transferring from said fixed arcing contact to said arc runner, and magnetic blowout means interconnected between said fixed arcing and current-carrying contacts and said are runner for exerting a force on the are drawn between said arcing contacts causing the arc to move in a direction away from said ourrent-carrying contacts after transfer of the arc to said are runner.

EDWARD J. FRANK. VIRGEL E. PHILLIPS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,515,143 Candee Nov. 11, 1924 2,335,068 Linde Nov. 23, 1943 2,347,984 Baskerville May 2, 1944 2,480,622 Warnock Aug. 30, 1949