US3070681A - Face wound blowout coil - Google Patents

Description

Dec. 25, 1962 J. D. WOOD FACE WOUND BLOWOUT COIL Filed Oct. 29. 1958 3 Sheets-Sheet 1 f IlllHlllHHlll NR U I'll l I I l i l I Ill Q l I I I I I I l I i II II lllll M 1 INVENTOR.

Dec. 25, 1962 J. D. WOOD 3,070,681

FACE WOUND BLOWOUT COIL Filed Oct. 29, 1958 3 Sheets-Sheet 2 TOR. Jana/w .0. 11/099 Dec. 25, 1962 J. D. WOOD ,0

I FACE WOUND BLOWOUT COIL Filed Oct. 29, 1958 s Sheets-Sheet :5

E52. 5 6 2/010 Aer) /02 /32 H6 M0 4 //8 m4 INVENTOR. JOJ'Pf/ .0. W000 arra/e vixr Unite My invention relates to a blowout structure for circuit breakers and more specifically relates to a face wound blowout coil which encompasses substantially all of the arc chute area and is the primary source of magnetic flux for the arc chute.

As is well known in the circuit breaker art, an are appearing across disengaging contacts is effectively interrupted by drawing the arc into an arc chute to thereby lengthen, cons-trict and cool the arc. The driving force which drives this are into the arc chute is provided by a properly directed magnetic field which coacts with the magnetic field of the art. The force driving the arc in the arc chute is therefore proportional to the product of the flux density of the magnetic field and the magnitude of the current in the arc. Therefore, if it is possible to increase the flux density of the magnetic field, the force on an arc of a given current will be increased to provide more effective arc interruption.

In present day blowout structures a large portion of the magnetic flux for driving the arc is lost as leakage flux. That is to say, the blowout coils have a portion which communicates with areas external of the magnetic structure whereby substantial leakage flux will flow.

The essence of my invention is to wind the blowout coils on the face of the magnetic structure adjacent to the arcing area whereby leakage flux is decreased to a zero or negligible value. More specifically, the coils are so wound as to have their axis perpendicular to the are which will be formed and perpendicular to the plane of motion of the movable contact of the circuit breaker. Since all of the flux generated by the coil must pass through the center of the coil, it therefore follows that all of the flux will pass through the arcing area. Furthermore, the coil diameter is large enough to encompass substantially all of the arc chute area.

Face wound coils have been suggested in the past, but have been utilized in a substantially different manner than that proposed by the present invention. By way of example, in U.S. Patent No. 1,606,808 issued November 16, 1926, entitled Control Apparatus to L. G. Riley, a face wound coil is provided which has a diameter which does not substantially encompass the complete arc chute area. Accordingly, the face wound coils are terminated by enlarged pole faces which are intended to distribute the magnetic flux throughout the arcing area of the arc chute. This concept differs from the present inventive concept, first, because it does not reduce the leakage fillX in the manner in which the present invention reduces leakage and secondly, since the apparatus is primarly for DC. purposes while applicants device is applicable to A.-C. purposes.

A second use of face wound coils is suggested in Patent Number 2,831,947 to I. M. Kozlovic, dated April 22, 1958, and entitled Circuit Interrupters. In this patent an auxiliary face wound coil is used as a compensating member for a second and main source of magnetic flux. However, the patent fails to teach that the face would coil alone can be the primary flux source so as to eliminate the requirement for two independent coils and to substantially eliminate all leakage flux.

Accordingly a primary object of my invention is to provide a novel blowout structure which substantially eliminates leakage flux.

Another object of my invention is to provide a blow- States Patent out structure utilizing a face wound coil which encompasses substantially all of the arcing area.

A further object of my invention is to provide a novel blowout structure wherein the blowout coil has an axis which is perpendicular to the arc and is perpendicular to the plane of motion of the movable contact.

Another object of this invention is to provide a novel blowout structure in which at least a single face wound coil supplies all of the blowout magnetic flux.

A further object of my invention is to provide a novel blowout structure in which leakage flux is substantially eliminated and a given number of ampere-turns applied to a given blowout winding will produce a high and uniform magnetic flux.

These and other objects of my invention will become apparent from the following description taken in conjunction with the drawings, in which- FIGURE 1 is a side view of one type circuit breaker which can be adopted with my novel blowout structure.

FIGURE 2 is similar to FIGURE 1 and shows the do cuit breaker movable contact in its disengaged position.

FIGURE 3 is an exploded perspective view of my novel blowout structure.

FIGURE 4 is a top cross sectional view of the blowout structure of FIGURE 3.

FIGURE 5 illustrates a typical prior art type of blowout structure which has substantial leakage flux.

FIGURE 6 schematically illustrates principle of the present invention wherein the leakage flux is substantially eliminated.

Referring now to FIGURE 5, it has been the practice to provide a magnetic structure 10 having a blowout winding 12 which generates magnetic flux as indicated by the magnetic lines of force in the arc area 14. Coil 12 is generally energized by inserting terminals 16 and 18 into the current carrying circuit when the circuit breaker contacts (not shown) are opened. As is clear from FIGURE 5, a substantial amount of leakage flux such as magnetic flux lines 20 are permitted to flow so that the available flux for arcing area 14 is substantially decreased.

The essence of the present invention is to provide a face wound winding such as windings 22 and 24 of F1"- URE 6 which are face wound on poles 26 and 23 respectively. Arcing area 30 of FIGURE 6 is similar to arcing area 14 of FIGURE 5, the purpose of windings 22 and 24 being to generate a magnetic field in this area when the circuit breaker contacts are opened. When the circuit breaker contacts are opened, the terminals 32 and 34 are inserted into the current carrying circuit whereby a flux will be forced to circulate in the magnetic structure as indicated by the arrows of FIGURE 6. Since the windings 22 and 24 are completely enclosed within the magnetic circuit, it is clear that all of the flux generated by coils 22 and 24 will necessarily pass through the arcing area 34) which is substantially encompassed by the blowout windings 22 and 24.

FIGURES 1 through 4 illustrate a preferred embodiment of my invention.

FIGURES l and 2 specifically illustrate the type of circuit breaker which has been shown in my application Serial No. 545,956 filed November 9, 1955, entitled Closed Magnetic Core Blowout With Series Coils, and assigned to the instant invention and now issued as U.S. Patent 2,831,946 on April 22, 1958.

However, my novel blowout structure may be applied to any type of circuit interrupting device requiring a magnetic flux generating means.

In FIGURES 1 and 2, a first and second terminal 36 and 38 respectively pass through the circuit breaker support frame rear wall 39 in the usual manner and terminal 38 is terminated by the stationary contact structure 40. A movable contact arm 42 is pivotally mounted and electrically connected to member 44 which terminates terminal member 36. The movable contact arm 42 carries a main movable contact 46 which cooperates with a main stationary contact 48 fastened to stationary contact structure 40. Movable contact arm 42 further pivotally carries the arcing contact 59 which cooperates with the relatively stationary arcing contact 52 of stationary contact structure 40. Movable contact arm 42 is movable from the engaged position of FIGURE 1 to the disengaged position of FIGURE 2 by means of member 54 which is pivotally carried by member 44 of terminal 36 on the same pivot as the movable contact arm 42 and has an upper portion thereof fastened to the movable contact arm. An extending portion of member 54 is then connected to output link 56 of any desired type of operating mechanism. v

An arc chute structure 58 is then provided which carries arcing plates of any well known type which will extinguish an are which is drawn by the separation of the movable contacts. Positioned within the arc chute 58 are the rear arc runner 60 and front are runner 62 where the front are runner 62 is electrically connected to terminal member 44 through the conductor 64. The rear arc runner 60 is supported on top of a jump gap 66 in the usual manner.

My novel blowout structure which will be more fully described hereinafter is seen as including the magnetic structure 68 which carries a face wound coil on one or preferably on either side of the arc chute structure and encompasses substantially all of the arc chute structure. Only one of these windings 70 is seen in FIGURES 1 and 2. The winding 70 is provided with input leads or terminals 72 and 74 wherein lead 72 is connected to a portion of the rear arc runner 60 while lead 74 is electrically connected to the stationary contact 40.

In operation, under normal current conditions for the circuit breaker there will be no voltage impressed across leads 72 and 74 since lead 72 is normally isolated from the electrical circuit by means of the jump gap 66. When the circuit breaker contacts are closed, a current path is formed from terminal 38, main stationary contact 48, main movable contact 46, contact arm 42, member 44, terminal 36. In the event of a fault, the movable contact 42 will be automatically driven to a disengaged position in the usual manner whereby initial movement of contact arm 42 causes disengagement between the main contacts 46 and 48 with the arcing contacts 50 and 52 being maintained is engagement in the well known manner. cause of further movement of contact arm 42, an arc will be drawn between these contacts and this are will tend to move upwardly and into the arc chute. The upward motion of the arc will cause it to jump the jump gap 66 and from the arcing contact 52 to the arc runner 60 whereby the coil 70 is connected in the newly formed circuit which includes terminal 38, stationary contact 40, lead 74, coil 70, lead 72, rear arc runner 60 and movable arcing contact 50. The continued motion of contact arm 42 to the disengaged position finally brings the movable contact structure in close vicinity with the front are runner 62 whereby the arc transfers from the arcing contact 50 to the arc runner 62 so that the circuit now includes terminal 38, stationary contact 40, lead 74, wincling 70, lead 72, rear arc runner 60, (the arc), front are runner 62, conductor 64 and terminal 36. The full arc current is therefore seen to flow through the coil 70 so as to generate a substantial magnetic flux in the arc chute area whereby this flux interacts with the current in the are so as to drive the arc up into the arc chute where it may be efficiently extinguished. Note that the blowout coil 70 is the sole flux source and that it substantially encompasses the complete arcing area or area in which the arc will move.

The blowout magnet and coil are specifically shown in Once arcing contacts 50 and 52 are disengaged be- 4 FIGURES 3 and 4 for the case of a blowout coil positioned on either side of the arc chute.

Thus, in FIGURE 3, the arc chute is schematically illustrated in the dotted box 80 which contains a plurality of arc plates such as typical arch plate 82 of well known construction. The are chute 80 has coils 84 and 70 positioned on its both respective sides where the coils are seen as comprising four spirally wound turns in the illustrated embodiment. The output leads 72 and 74 of coil 70 are connected to leads 86 and 88 respectively of coil 84, so that the coils 70 and 84 are connected in series as schematically illustrated in FIGURE 6. FIGURE 4 specifically shows the essential current directions for coils 70 and 84 as illustrated by the conventional crosses and dots. Note that coils 70 and 84 could have been connected in parallel.

Each of coils 70 and 84 are associated with lower clamping means 90 and 92 respectively, which are fastened to their respected coils by U-shaped straps such as straps 94 and 96 of clamp 90 and coil 70. Each of clamps 90 and 92 are provided with flange surfaces 98 and 99 respectively. Clamp 90 is positioned beneath a stack of laminations 100 which form the first pole for the magnetic structure while clamp 92 is similarly positioned with respect to lamination stack 106.

The laminated stack 100 has cutout sections 102 and 104 which receive the coil 70 in the manner illustrated in FIGURE 3 and best seen in FIGURE 4, while the other pole face is formed by stack 106 which has similar cutouts 103 and 105 to receive coil 84 as shown in FIG- URE 3. Each of the pole face sections 102 and 106 are then completed to form a closed magnetic structure by laminated side pieces 108 of FIGURES 3 and 4 and 110 seen only in FIGURE 4.

The flange 98 of support 90 and flange 99 of support 92 are provided with apertures such as apertures 112 and 114 of support 90 which align with notches 116 and 118 in the rear of pole face 108 and similar notches 120 and 122 in the rear of pole face 106. An upper support member 124 and 126 having apertures such as 128 and 130 of upper support member 124 in alignment with notches 116 and 118 of pole face 100 receives and fastens one end of support rods 132 and 134 which fit into notches 116 and 118 respectively with the bottom of rods 132 and 134 being received and fastened in apertures 112 and 114 of support 90. In a similar manner, upper support member 126 serves as an upper clamp for the clamping system including rods 136 and 138 which terminate in the flange 99. Accordingly the upper and lower support members such as supports 124 and 90 respectively operate to clamp the laminated stack 100 together as well as to support coil 70 with respect to pole face 100. This clamping action is best seen in FIG- URE 3 for the case of coil 84 and clamps 92 and 126.

It is to be noted that the laminating of the magnetic core may be done in any desired manner whereby the conventional over-lapping of the laminations at their joints may be used. However, any system of forming a closed core may be used. Furthermore, the coils may be supported with respect to their pole faces in any desired manner.

Although I have described preferred embodiments of my novel invention, many variations and modifications will now be obvious to those skilled in the art, and I prefer therefore to be limited not by the specific disclosure herein but only by the appended claims.

I claim:

1. A blowout structure for .a circuit breaker having a pair of cooperating contacts movable between an engaged and a disengaged position, and an arc chute positioned above said contaots; said blowout structure including a rectangular magnetic core; said rectangular magnetic core having an elongated rectangular opening therein defining an area for receiving arc extinguishing plates; said circuit breaker having a pair of cooperable contacts movable within said rectangular opening and generating an are within said rectangular opening; said are being movable over a predetermined area within said rectangular opening and into said are extinguishing plates; said blowout structure further including a blowout coil; said blowout coil being supported within said rectangular opening and being fitted in notched portions in either end of said rectangular opening; the axis of said blowout coil being perpendicular to the plane of motion of said cooperable contacts; jump gap 'means connected between one of said cooperating contacts and said blowout coil; said jump gap means being adapted to energize said blowout coil when said cooperating contacts move to said disengaged posit-ion and to maintain said blowout coil deenergized when said cooperating contacts are in said engaged position; said blowout coil encompassing substantially all of the area through which said arch generated by said cooperating contacts is moved to generate a uniform magnetic field throughout said area of arc motion, support means affixed to said blowout structure for securing said blowout structure to an arc chute wherein said support means is so constructed as to be readily mountable to an arc chute.

2. A blowout structure for circuit breakers having a pair of cooperating contacts movable between an engage'd and a disengaged position, and an arc chute positioned above said contacts; said blowout structure including a magnetic structure and a blowout coil for energizing said magnetic structure; said magnetic structure including a first and second pole face spaced with respect to one another and defining an arc area for arcs moving substantially parallel to said pole faces; said blowout coil being wound on at least one of said pole faces; the internal diameter of said blowout coil encompassing substantially all of the area of arc motion to generate flux across substantially all of said area of said arc motion responsive to current flow through said blowout coil; said blowout coil having its axis parallel to the direction of flux flow across said arc area; jump gap means connected between one of said cooperating contacts and said blowout coil, said jump gap means being adapted to energize said blowout coil when said cooperating contacts move to said disengaged position and to maintain said blowout coil deenergized when said cooperating contacts are in said engaged position; said blowout coil being the sole source of supply of magnetic flux; support means positioned between said winding and said magnetic core for mechanically securing said core to said winding, said support means including a flange; fastening means to secure said magnetic core to said flange.

3. A blowout structure for circuit breakers having a pair of cooperating contacts movable between an engaged and a disengaged position, and an arc chute positioned above said contacts; said blowout structure including a magnetic structure and a blowout coil for energizing said magnetic structure; said magnetic structure including a first and second pole face spaced with respect to one another and defining an arc area therebetween for arcs moving substantially parallel to said pole faces; said blowout coil being wound on at least one of said pole faces; the internal diameter of said blowout coil encompassing substantially all of the area of arc motion to generate fiux across substantially all of said area of said are motion responsive to current flow through said blowout coil; said blowout coil having its axis parallel to the direction of flux flow across said arc area; jump gap means connected between one of said cooperating contacts and said blowout coil; said jump gap means being adapted to energize said blowout coil when said cooperating contacts move to said disengaged position and to maintain said blowout coil deenergized when said cooperating contacts are in said engaged position; the outer ends of said first and second pole faces being magnetically connected to completely encompass said blowout coil with said magnetic structure; said blowout coil being the sole source of supply of magnetic flux; support means positioned between said winding and said magnetic core for mechanically securing said core to said winding, said support means including a flange; first fastening means to secure said magnetic core to said flange; second substantially U-shaped fastening means for securing said blowout coil to said support means.

References Cited in the file of this patent UNITED STATES PATENTS 1,606,808 Riley Nov. 16, 1926 2,632,075 Rawlins et al. Mar. 17, 1953 2,831,946 Wood Apr. 22, 1958 2,831,947 Kozlovic Apr. 22, 1958 FOREIGN PATENTS 588,724 Great Britain June 2, 1947 705,463 Great Britain Mar. 10, 1954 922,834 Germany Jan. 27, 1955

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