US3176103A

US3176103A - Blow-in effect on jump gap

Info

Publication number: US3176103A
Application number: US90750A
Authority: US
Inventors: Joseph D Wood
Original assignee: ITE Circuit Breaker Co
Current assignee: ABB Inc USA; ITE Circuit Breaker Co
Priority date: 1961-02-21
Filing date: 1961-02-21
Publication date: 1965-03-30
Anticipated expiration: 1982-03-30

Description

March 30, 1965 J. D. WOOD 3,176,103

BLOW-IN EFFECT ON JUMP GAP Filed Feb. 21, 1961 s Sheets-Sheefl IN V EN TOR. dflffl fl 0 W000 BY fi zemfme, 57,652 7598 Sap/,4

March 30, 1965 J. D. WOOD BLOW-IN EFFECT ON JUMP GAP 3 Sheets-Sheet 2 Filed Feb. 21, 1961 March 30, 1965 J. D. wooo BLOW-IN EFFECT ON JUMP GAP 3 Sheets-Sheet 3 Filed Feb. 21, 1961 United States Patent 3,176,103 BLQW-IN EFFECT ON JUMP GAP Joseph D. Wood, Haverford, Pa, assignor to l-T-E Circuit Breaker Company, Philadelphia, Pa, a corporation of Pennsylvania Filed Feb. 21, 1961, Ser. No. 9%,750 3 Claims. (Q1. filth-147) This invention relates to air magnetic circuit breakers in general and more particularly to a circuit breaker of this type having a novel configuration for the jump gap runners whereby the arc is blown into the jump gap for rapi transfer of arc current to the main blowout coils.

In air magnetic circuit breakers a magnetic circuit energized by the arc current is utilized to drive the are deeply into a parallel plate are chute where the arc is forced to take a tortuous path. This causes the arc to become elongated and make contact with the plates of the arc chute. The latter causes cooling of the arc which combines with the elongation of the arc to bring about rapid extinction thereof.

Prior to and at the moment of contact separation the magnetic means is not energized. It is only after the arc is drawn that the magnetic means is energized. The transfer of this are current to the magnetic structure is brought about by a so-called jump gap which is positioned adjacent to the stationary contact structure and connected in electrical parallel with the magnetic means.

Upon separation of the contacts, an arc is drawn which extends from moving to stationary arc contacts so that the magnetic means is initially deenergized. As the arc rises into the arc chute, the arc impinges upon the arc runner above the jump gap and a portion of the arc is across the jump gap. As this are portion moves toward the rear of the jump gap, the impedance of the jump gap increases forcing more and more of the current through the impedance of the magnetic means. Finally, all of the arc current transfers to the latter and when extinguished across the jump gap, forces all the current to pass through the magnetic means. The energized magnetic means establishes a flux field which is so positioned in relation to the are chute that the arc is driven deeply into the arc chute for rapid extinction.

In devices of the prior art, as illustrated in my US. Patent 2,831,946, issued April 22, 1958, entitled Closed Magnetic Core Blowout With Series Coils, assigned to the assignee of the instant invention, the runners for the jump gap are not properly positioned to urge the arc toward the rear of the jump gap. With prior art arrangements, it has been found that under less than ideal conditions interrupting time is materially extended since the magnetic means did not become energized soon after parting of the magnetic contacts.

The instant invention overcomes the dil'liculty outlined above by providing a circuit breaker in which he runners of the jump gap are constructed so that the current flow in these runners aids in driving the are into the jump gap. As this portion of the arc moves toward and into the jump gap a current loop is formed.

The magnetic field generated by the current loop acts upon the portion of the are within the jump gap to urge this portion or" the are even more deeply into the jump gap elongating the are so that the impedance presented thereto is rapidly increasing in value, forcing more and more current through the magnetic means. Thus, the arc current transfers to the magnetic means and when the arc is extinguished across the jump gap all the current passes through the magnetic means. Thus, the magnetic means is energized very shortly after the arc is first generated and urges the main portion of the are into the main interrupter.

$375,193 Patented Mar. 30, 1965 ice Accordingly, a primary object of this invention is to provide a novel construction for a circuit breaker which achieves more eliicient circuit interruption.

Another object is to provide a circuit breaker having novel means for driving a portion of the electric current are into the jump gap whereby this are portion is rapidly extinguished and are current flows in the magnetic means shortly after the formation of the arc.

Still another object is to provide a circuit breaker having novel jump gap runners which so direct the are current that the arc is blown into the jump gap where it is rapidly extinguished.

A further object is to provide a jump gap so constructed and positioned that the initial arc extending across the jump gap runners is positioned externally of the jump gap and is thereafter driven toward the rear of the jump gap by the magnetic field established by current fiow in the jump gap runners.

A still further object is to provide a circuit breaker having a novel combination of arc runners for both the interrupter and jump gap whereby the direction of the currents in these runners is such that rapid arc extinction is achieved.

These as well as other objects of this invention shall become readily apparent after reading the following description of the accompanying drawings in which:

FiGURE l is a schematic illustrating the electrical connections for a circuit breaker in which the main blowout coil is energized by utilization of a jump gap.

FIGURES 2-5 are side elevations of a circuit breaker constructed in accordance with the teachings of the instant invention. In FIGURES 3 and 4 the main arc chute and forward arc runner are omitted. In FIGURE 2, the contacts are closed while in FIGURES 35 the movable contact is in the process of moving away from the stationary contact. In FIGURES 3 and 4 the blowout coil is not energized, while in FIGURE 5 the blowout coil is energized.

FEGURE 6 is a plan view oi the jump gap utilized in the circuit breaker of FIGURES '25.

New referring to the schematic of FIGURE 1. Circuit breaker 10 comprises a stationary contact structure 11 mounted to upper stud 12; and a movable contact structure 13 carried by conducting bridge 14 pivotally mounted at 15 to lower study 16 movable between circuit open and closed positions by an operating mechanism of a type well known to the art. Upon separation of contact structures 11, 13 an arc is drawn therebetween which is driven into parallel plate are chute 17 positioned above contacts 11, 13. With an are present in chute 17 the ends of the arc terminate at rear 18 and front 19 runners.

Prior to energization of main blowout coil 20 the arc is driven upward into chute 17 under the influence of convection currents of air heated by the arc and the magnetic forces set up by the are acting to expand the loop of the are, as is well understood by those skilled in the art. Main blowout coils Ell, 20 associated with magnetic core 20:: are connected in electrical series by jumper 61. This series combination is connected in parallel with jump gap by jumper 62 extending from junction 23 between the rear runner l8 and top runner 2d and jumper 63 extending to the left end from conducting member 22.. Member 22 is connected through conducting means to station ary contact structure 11 and includes a portion 25 which forms a bottom runner for jump gap 5'0.

Runners

24, 25 are positioned at the top and bottom respectively of the spaced plates forming jump gap 56. As will be more fully explained hereinafter, blowout coil 20 is energized when a portion of the are drawn between contact structures 11, 12 is extinguished by jump gap 59.

In the description of FIGURES 2-5 which follows, the reference numerals utilized in describing elements of FIGURE 1 will be retained wherever possible and a heavy broken line is utilized to illustrate the current path. Movable contact structure 13 comprises movable main contact 23 and movable arcing contact 29 both fixedly mounted to bridge 14 with contact 23 positioned below contact 29. Stationary contact structure 11 comprises main contact 32 and stationary arcing contact 33 engageable and disengageable by movable main 2% and arcing 29 contacts respectively. Stationary arcing contact 33 is carried by horn 34- whose lower end is mounted to fixed pivot 35 carried at the right hand end of block 36 fixedly mounted to the right hand end of upper stud 12.

Stud 37 mounts U-shaped bracket 38 and L-shaped reinforcing member 39 to block 36. The free ends of the U arms carry resilient finger means 49 which engage conducting member 22 when the main arc chute 1'7 is in the position of FIGURES 2-5. As is well known in the art, conducting member 22 is disengaged from finger means 49 when chute 17 is displaced for inspection of contact structures 11, 13.

Horn 34 is biased clockwise about its pivot 35 by compression spring 41 which surrounds pin 42. Pin 42, at one end 43 thereof, is pivotally secured to horn 34 while the other end of pin 42 is threaded and projects through aligned apertures in seating washer d4, bracket 33 and re iniorcing member 39 and is engaged by nut 45". Main stationary contact 32 is carried by element 47 which is urged in a counterclockwise direction about pivot 48 by means of compression spring 4? which bears against element 47 and bracket 26. Studs 51, 52' fixedly secure bracket 26 to block 36. The engagment between element 4? and bracket 2d as illustrated in FIGURES 3-5 limits the counterclockwise movement of element 47 about pivot 48.

The right hand end of conducting member 22 is provided with a U-shaped portion, one arm 25 of which forms the bottom runner for jump gap 59. The top runner 24 for jump gap 19 is joined at the right hand end thereof to the lower end of rear runner 13 for the main arc chute 17. Jump gap 50 comprises a plurality of parallel spaced plates 51 constructed of either metal or heat resistant non-conducting material. Plates 51 are each provided with a wide-mouthed slot 52 at the forward end of jump gap 50 which narrows toward the rear and final- 'ly terminates in a rearwardly extending arrow elongated portion 53. Insulating sheets 1%, 1&1 are positioned at the top and bottom respectively of the stack of plates 51 comprising jump gap 56. Sheet 100 is between runners l8 and 24 to keep the arc from striking on 18 instead of on 24.

As is well known in the art, movement of bridge 14 in a clockwise direction from the position of FIGURE 2 to the position of FIGURE 5 initially separates

main con tacts

28, 32 and thereafter separates arcing contacts 29, 33. When bridge 14 moves in the reverse direction, arcing contacts 29, 33 engage prior to the engagement of

main contacts

28, 32.

Shortly after separation of arcing contacts 29, 33, the current flow is for the most part along the path indicated by the broken line A of FIGURE 3. It is noted that a portion of this path includes an arc which extends from the upper end of horn 34 to the upper end of bridge 14. Portion (a) of this are extends across the gap between top 24 and bottom 25 runners of jump gap 50. It is to be noted that are portion (a) at its inception is forward of the forward end of jump gap 5th.

At the portion of the opening cycle indicated in FIG- URE 3, the currents in

runners

24, 25 are in opposite directions so that the magnetic field generated thereby tends to move arc portion (a) to the free ends of

arc runners

24, 25 or to the left with respect to FIGURE 3.

As the arc portion between

runners

24, 25 moves more to the left toward the position of FIGURE 4, the blow in effect becomes more pronounced since the loop formed by the current in arc runners 2d, 25 traverses long paths so that a larger magnetic field is produced. It is noted that in FIGURE 4, a portion of the current flows through rear runner 18. As the arc portion between

runners

24, 25 moves even more to the left, this are portion is constricted by the slot formation 53 or" jump gap plates 51. The blow in effect urges this are portion to the left thereby forcing it to traverse a tortuous elongated path which is of the nature of an elongated path formed due to the action of arc plates in any well known arc plate as sembly.

It is noted that up to this point in the opening cycle not all or" the arc current is across jump gap 50. That is, a portion of the arc current flows through blowout coils 2 h, 20 and the remainder through jump gap 50 in inverse proportion to their impedances. The deeper the arc is driven into jump gap 50 the greater is the impedance presented to this arc portion. Finally, a point is reached where the impedance of jump gap 59 is so high that all are current transfers to coils 2G for complete energization thereof. The magnetic field generated by the fully energized coil 20 urges the are deeply into arc chute 17 for efiicient circuit interruption.

Thus, it is een that current how in jump gap runners 24-, 25 is always in a direction to generate a magnetic field which interacts with the arc in the gap between

runners

24, 25 to urge this arc deeply into jump gap 50 where this are is rapidly extinguished. This is in addition to the field due to the magnetic structure 20 and to the magnetic phenomena present when jump gap plates 51 are constructed of iron.

In the foregoing, the invention has been described only in connection with preferred embodiments thereof. Many variations and modifications of the principles of the invention within the scope of the description herein are obvious. Accordingly, it is to be bound not by the specific disclosure but only by the appending claims.

I claim:

1. A circuit breaker comprising a first contact structure, a second contact structure operable into and out of engagement with said first contact structure, an arc chute operatively positioned to receive and extinguish electric current arcs drawn between said contact structures upon disengagement thereof, a magnetic means energizable by are current and which when energized drives the are deeply into said are chute, a jump gap operatively positioned in close proximity to said first contact structure and connected in electrical parallel with said magnetic means for extinguishing an arc portion near said first contact structure whereby said magnetic .eans is energized; said jump gap comprising an arc extinguishing means having a first end positioned in close proximity to said first contact structure, a top runner and a bottom runner positioned on the top and bottom, respectively, of said are extinguishing means; said top and bottom runners each having a first end positioned in close proximity to said first contact structure; said runners being operatively positioned so that arc current flows therein in opposite directions; the first ends of said top and bottom runners extending beyond the first end of said are extinguishing means in the direction of said first contact structure so that are current flowing therethrough establishes a magnetic field which urges said arc portion toward the rear of said arc extinguishing means; said arc chute including a front and a rear runner; said rear runner being electrically connected to one end of said top runner; said rear runner having a portion confronting said top runner to form a substantially U-shaped configuration therebetween, whereby current flows in 0pposite directions in said rear runner portion and said top runner.

2. A circuit breaker comprising a first contact structure, a second contact structure operable into and out of engagement with said first contact structure, an arc chute operatively positioned to receive and extinguish 16G 6 current arcs drawn between said contact structures upon disengagement thereof, a magnetic means energizable by are current and which when energized drives the are deeply into said are chute, a jump gap operatively positioned in close proximity to said first contact structure and connected in electrical parallel with said magnetic means for extinguishing an arc portion near said first contact structure whereby said magnetic means is energized; said jump gap comprising an arc extinguishing means having a first end positioned in close proximity to said first contact structure, a top runner and a bottom runner positioned on the top and bottom, respectively, of said are extinguishing means; said top and bottom runners each having a first end positioned in close proximity to said first contact structure; said runners being operatively positioned so that are current flows therein in opposite directions; the first ends of said top and bottom runners extending beyond the first end of said are extinguishing means in the direction of said first contact structure so that are current flowing therethrough establishes a magnetic field which urges said are portion toward the rear of said are extinguishing means; said arc chute including a front and a rear runner; said rear runner being electrically connected to one end of said top runner; said rear runner having a portion confronting said top runner to form a substantially U-shaped configuration therebetween whereby current flows in opposite directions in said rear runner portion and said top runner; one end of said bottom runner being electrically connected to said first contact structure whereby, following separation of said contact structures, are current initially flows across a gap between said top and said bottom runners at said ends thereof external of said are extinguishing means.

3. A circuit breaker comprising a first contact structure, a second contact structure operable into and out of engagement with said first contact structure, an arc chute operatively positioned to receive and extinguish electric current arcs drawn between said contact structures upon disengagement thereof, a magnetic means energizable by arc current and which when energized drives the are deeply into said are chute, a jump gap operatively positioned in close proximity to said first contact structure and connected in electrical parallel with said magnetic means for extinguishing an arc portion near said first contact structure whereby said magnetic means is energized; said jump gap comprising an arc extinguishing means, a top runner and a bottom runner positioned on the top and bottom, respectively, of said arc extinguishing means; said runners being operatively positioned so that are current fiows therein in opposite directions; said runners being oriented so that are current flowing therethrough establishes a magnetic field which urges said are portion toward the rear of said are extinguishing means; said are chute including a front and a rear runner; said rear runner being electrically connected to one end of said top runner; said rear runner having a portion confronting said top runner whereby current flows in opposite directions in said rear runner portion and said top runner to form a substantially U- shaped configuration therebetween; one end of said bottom runner being electrically connected to said first contact structure whereby, following separation of said contact structures, are current initially flows across a gap between said top and said bottom runners at said only ends thereof external of said are extinguishing means; said top and said bottom runners being operatively positioned so that thereafter arc current across said gap is moved by the action of its accompanying magnetic field toward the other ends of said top and said bottom runners deeply into said are extinguishing means; said one ends of said top and said bottom runners being positioned forwardly of the front edge of said are extinguishing means; said other ends of said top and said bottom runners being positioned intermediate the front and rear edges of the arc extinguishing means a substantial distance from the front of the arc extinguishing means.

References Cited by the Examiner UNITED STATES PATENTS 2,616,007 10/52 Dickinson et al. 200-147 2,697,154 12/54 Strom 200147 2,916,588 12/59 Wood 200-147 BERNARD A. GILHEANY, Primary Examiner.

MAX L. LEVY, E. JAMES SAX, Examiners.

Claims

1. A CIRCUIT BREAKER COMPRISING A FIRST CONTACT STRUCTURE, A SECOND CONTACT STRUCTURE OPERABLE INTO AND OUT OF ENGAGEMENT WITH SAID FIRST CONTACT STRUCTURE, AN ARC CHUTE OPERATIVELY POSITIONED TO RECEIVE AND EXTINGUISH ELECTRIC CURRENT ARCS DRAWN BETWEEN SAID CONTACT STRUCTURES UPON DISENGAGEMENT THEREOF, A MAGNETIC MEANS ENERGIZABLE BY ARC CURRENT AND WHICH WHEN ENERGIZED DRIVES THE ARC DEEPLY INTO SAID ARC CHUTE, A JUMP GAP OPERATIVELY POSITIONED IN CLOSE PROXIMITY TO SAID FIRST CONTACT STRUCTURE AND CONNECTED IN ELECTRICAL PARALLEL WITH SAID MAGNETIC MEANS FOR EXTINGUISHING AN ARC PORTION NEAR SAID FIRST CONTACT STRUCTURE WHEREBY SAID MAGNETIC MEANS IS ENERGIZED; SAID JUMP GAP COMPRISING AN ARC EXTINGUISHING MEANS HAVING A FIRST END POSITIONED IN CLOSE PROXIMITY TO SAID FIRST CONTACT STRUCTURE, A TOP RUNNER AND A BOTTOM RUNNER POSITIONED ON THE TOP AND BOTTOM, RESPECTIVELY, OF SAID ARC EXTINGUISHING MEANS; SAID TOP AND BOTTOM RUNNERS EACH HAVING A FIRST END POSITIONED IN CLOSE PROXIMITY TO SAID FIRST CONTACT STRUCTURE; SAID RUNNERS BEING OPERATIVELY POSITIONED SO THAT ARC CURRENT FLOWS THEREIN IN OPPOSITE DIRECTIONS; THE FIRST ENDS OF SAID TOP AND BOTTOM RUNNERS EXTENDING BEYOND THE FIRST END OF SAID ARC EXTINGUISHING MEANS IN THE DIRECTION OF SAID FIRST CONTACT STRUCTURE SO THAT ARC CURRENT FLOWING THERETHROUGH ESTABLISHES A MAGNETIC FIELD WHICH URGES SAID ARC PORTION TOWARD THE REAR OF SAID ARC EXTINGUISHING MEANS; SAID ARC CHUTE INCLUDING A FRONT AND A REAR RUNNER; SAID REAR RUNNER BEING ELECTRICALLY CONNECTED TO ONE END OF SAID TOP RUNNER; SAID REAR RUNNER HAVING A PORTION CONFRONTING SAID TOP RUNNER TO FORM A SUBSTANTIALLY U-SHAPED CONFIGURATION THEREBETWEEN, WHEREBY CURRENT FLOWS IN OPPOSITE DIRECTIONS IN SAID REAR RUNNER PORTION AND SAID TOP RUNNER.