US2215797A - Circuit interrupter - Google Patents

Description

L. E. SAUER CIRCUIT INTERRUPTER Filed July 20, 1938 Sept. 24, '1940.

4 Sheets-Sheet l lNVENTOR L ozlz's [57 501/637.

- ATTOREY WITNESSES:

S p 1940- E. SAUER 2,215,197

CIRCUIT INT ERRUPTER Filed July 20, 1938 4 Sheets-Sheet 2 //6 32 4 83 72 74 WITNESSES: INVENTOR L 02/1325. Sal/er:

Wa am I 1 5813i. 24, 1940. SAUEfi 2,215,797

CIRCUIT INTERRUPI'ER Filed July 20, 1938 4 Sheets-Sheet 3 WITNESSES: 50 INVENTOR v LozlzlsEf Sauer:

Sept. 24, 1940.

L. E; SA-UER CIRCUIT INTERRUPTER Filed July 20, 1958 4 Sheets-Sheet 4 a R v.. w .l. A 3

W a a a /20 I k m WITNESSES:

Patented Sept. 24, 1940 UNITED STATES PATENT OFFICE CIRCUIT INTERRUPTER vania'v Application July 20, 1938, Serial No. 220,205

Claims.

This invention relates to circuit interrupters and more particularly to improvements in arc extinguishing devices for circuit interrupters of the air break type.

The general practice heretofore employed in power distribution systems involved almost exclusively the use of a substation building for housing the various pieces of equipment such as transformers, lightning arresters, high and low 10 voltage circuit interrupters, various relays and other automatic control apparatus. customary to distribute the several pieces of electrical equipment about the building which required considerable space. Circuit breakers of the air break type for protecting the lower voltage side of transformers are preferred over oil circuit breakers in installations of this kind due to the freedom of the air breaker from fire hazard during severe interrupting operations. However, for this type of service the air breaker must utilize an arc extinguishing device that will suppress flame during a circuit interrupting operation to such an extent as to prevent injury to adjacent pieces of apparatus. The desirability 25 of eliminating the substation building and housing the entire substation equipment in a single metallic enclosure only slightly larger than the tank required for the power transformer, at once becomes apparent due to the great saving in space and the initial cost of construction.

The use of unitary metallic enclosures, however, places an additional burden upon the arc extinguishing devices. Although a certain amount of flame may be tolerated within a substation building, the issuance of flame from an arc extinguisher within a metallic enclosure would produce disastrous results. Furthermore, the problem of flame suppression becomes more acute in power substation applications in that 40 power companies frequently suspend their high voltage lines upon the same poles with and above the low voltage lines. It sometimes occurs that during a storm or other adverse weather conditions, the high voltage lines are brought into direct contact with the low voltage lines, thereby subjecting the low voltage breaker to many times its normal voltage rating.

The main object of my invention is to provide an arc extinguishing device for an air circuit breaker which will effectively suppress the arc flame even though the breaker is subjected to voltages considerably above its rating.

A further object of 'my invention is the provision of an arc extinguishing device for an air circuit breaker having a higher interrupting It also was,

capacity but having considerably smaller dimensions than the devices heretofore known in the art.

Another object of my invention is the provision of an arc extinguishing device for air break 1' circuit interrupters which is capable of withstanding a sustained arc of voltage considerably higher than its normal rating without impairing its interrupting ability thereafter.

A more specificobject of my invention is the provision of an arc extinguisher for an air break circuit interrupter which employs an enclosure substantially completely surrounding the breaker contacts and in which arc deionization is accomplished by driving the are into a plurality of closely spaced metallic plates separated by insulating members so arranged as to provide a narrow undulated arc passage of considerable length between adjacent plates, and into which passages short sections of the are initially drawn are adapted to be moved.

Other objects and advantages relate to details of the arc extinguishing structure and will appear more fully in the following description when taken in connection with the accompanying drawings in) which:

Figure 1 is a side elevation view of a circuit interrupter showing an embodiment of my invention; e 4

Fig. 2 is a side elevation view partially in section showing the arc extinguishing device of my invention on a somewhat enlarged scale as that shown in the assembly view of Fig. 1;

Fig. 3 is a cross-sectional view of the are extinguishing device of my invention taken along the line III-III of Fig. 2;

Fig. 4 is an exploded perspective view showing a section of the deionizing plate structure of the arc extinguishing device of my invention;

Fig. 5 isa side elevation view, partially in section, of a modified form of arc extinguishing device, and

- Fig. 6 is a cross-sectional view of the arc extinguishing device of Fig. 5 taken along the line VIV'I of that figure.

Referring to Figure 1 of the drawings, the reference numeral III designates a pair of frame members between which the contact mechanism on the circuit interrupter is disposed. The contact mechanism in this instance comprises a fixed contact support l2 secured between the frame members ill by the bolts I 4. The contact support l2 carries a fixed contact i6 which may be secured thereto by means of a screw I 8 as shown. Adapted to cooperate with the fixed contact IO is a movable contact 28 carried by a contact support 22 which in turn is pivotally supported at 24 to a contact carrying arm .26. Contact arm 28 is pivotally supported between the frame members l8 by shaft 28. The contact support 22 is provided with a downwardly extending projection 38 to which one end of a compression spring 82 is secured for the purpose of biasing the movable contact 28 into engagement with the fixed contact IS. The other end of the spring 32 preferably engages the shaft 28. Connection from the contact support 22 to a line terminal 84 is made by means of a flexible shunt 36.

The movable contact 28 is actuated to the open and closed position through a link member 38 pivoted at its upper end to the contact arm 28 and at its lower end to an actuating arm 48, which arm is pivoted to the frame members l8 at 42. The actuating arm 48 is provided at its outermost end with a roller 44, which, in turn, is adapted to engage a cam actuating mechanism indicated at 46. The moving contact 28 is biased to the open position by means of a compression spring 48 bearing upon the actuating arm 48.

The open position of the circuit interrupter is indicated by the dotted lines showing the outline of the movable contact 28, a designation of the associated parts for moving the contact being omitted for the sake of clarity.

An are established between the fixed contact I6 and the movable contact 28 is adapted to be received by the arc extinguishing device generally designated at 58 in Fig. 1 and more specifically illustrated in Figs. 2 to 4, inclusive. The are extinguishing device 58 comprises a pairof spaced side wall members 52 of insulating material having a lower triangular portion 54 provided with aligned openings 56 for receiving a support bolt 58, the outer ends of which are adapted to engage suitable notches 68 provided in the frame members I8 as shown in Fig. '1. The upper port on of the arc extinguishing device 52 is provided with a slotted member 62 secured between the side wall. members 52 by a bolt 64. The upper or slotted portion of the member 62 is adapted to be brought into registration with a clamping bolt 66 secured to a fixed portion 88 of the circuit breaker frame and is provided with a wing nut 18 for clamping the arc extinguishing device into Position. B removing the wing nut 18 the arc extinguishing device 58 may be rocked in a 0100!;- Wise direction about the bolt 68 until the upper edges of the side walls 52 clear the adjacent portions of the breaker structure whereupon the arc extinguishing device may be lifted from the notches 68 in the frame members l8. This construction permits easy removal and replacement of the arc extinguishing device so -as to obtain. access to the contact structure in'the event such accws becomes necessary.

In order to effectively extinguish the arc drawn between the contacts l6 and 28, I have provided are deionizing means disposed between the side wall members 52 which will now be described. Adjacent the lower side of the side wall members 52 of insulating material which, in efiect, form side wall members of an arc chute, is provided a spacing member 12 of insulating material securely clamped between the side wall membrs 52 by means of bolts 14. Adjacent this lower spacing member I2 is placed an arc horn 16, preferably in the form of a copper plate having an upstanding projection '18 at the left-hand side thereof, which terminates adjacent the movable contact 28 when the latter is in the open circuit position and a downwardly projecting member 18 which extends through the spacing member 12 and makes connection with the line terminal 34 by way of connector 8 I.

Disposed above the lower arc horn 18 are a reference number 88.

The plate members of insulating material are designated at 82 and are preferably of such material as horn fibre, which has suitable properties to withstand the direct action thereupon by an arc. The ends of the metallic plates 88 disposed adjacent to the contacts l8 and 28 are provided with a V-shaped are receiving slot or notch 84.

The plate members 82 of insulating material are also provided with a V-shaped notch 86 at the left-hand end thereof and a through slot 88 of undulated form which, in reality. causes the plate member to be constituted by two separate sections. The slots 88 extending through the insulating members 82 provide an elongated 'arc passage of relatively constricted area between each adjacent pair of plates 88 of conducting material. Alternate insulating members 82 are reversed so that the arc passages 88 between the successive plates 88 are not in alignment except at the entrance and terminate upon alternate sides of the center line of these plates, thus providing a greater break-down surface between the discharge openings of these passages;

It will be noted thatthe metallic plates 88 are somewhat shorter than the plates 82 of insulating material, which would normally introduce a gap between adjacent plates of insulating material. This gap is filled in by a suitable filling member 98 of insulating material which forms a continuation of the plate 88 of conducting material. In

accordance with this construction the discharge end of the arc passage 88 is completely boxed in by insulating material which, as will appear more fully hereinafter, assists in preventing the emismaterial are of wedge shape and arranged so that the plates 88 of conducting material diverge from each other in the direction away from the contacts l6 and 28. This feature permits a more rapid flow of arc gases from the arc receiving end of the deionizing structure towards the discharge end in that the volume of the arc passages 88 increases per unit length in the direction in which the arc is adapted to be moved.

In order to hold the plates 88 and 82 in position with respect to the side wall members 52, I havev provided the inside surface of each side wall member 52 with at least two undercut channels 82, and I have provided the respective plates 88 and 82 with tongues 94. The tongues 94 have an outline which conforms with the cross-section of the grooves 92 so that when the tongues are brought into registration with the grooves the respective plates are securely anchored in position.

The uppermost plate of conducting material of the deionizing structure is provided with a projection 96 which constitutes the upper arc horn and terminates adjacent the fixed contact I8. Electrical connection to the arc horn 88 from the fixed contact 16 is made by means of a contact spring 98 secured to the fixed contact I 8 by the screw l8. The entire stack of arc extinguishing plates 80 and the spacing plates 82 of insulating material, as well as the lower arc horn I6 and the upper arc horn 88 are held in compression by means of two screws I threaded through a spacing member I02 and which in turn engage a pressure plate I04 contiguous to the upper arc horn 86. I

In order to prevent a blast of arc gases rearwardly of the contacts I6 and 20 into the contact actuating mechanism at the instant of arc formation, I have provided a movable barrier member 95 of insulating material carried by the movable contact 20. The barrier member 95 extends between opposed recessed portions 91 within the side wall member 52 and is slidable in these recesses upon movement of the contact 20 to the open circuit position so as to cause the lower end of the barrier 95 to engage the lower wall member I2 and eflectively close the back part of the arc extinguishing device.

Movement of the are from the contacts I6 and 20 onto the arc horns I6 and 06, and subsequently into the plates 80, is obtained by magnetic blow-out means including a series coil I06, one end of which connects to the line terminal block I08 and the other end of which terminates in a terminal block I I0 which in turn is bolted to the fixed contact support I2 by means of the bolts I4. The blow-out coil I06 surrounds an iron core II2, the ends of which abut against a pair of laminated'yoke members H4.

The yoke members I I4 extend diagonally downward and lie adjacent a pole piece II6 countersunk in each of the side wall members 52 of the arc extinguishing device. The pole'pieces I I6 extend on either side of the contacts I6 and 20 and cover substantially the entire area occupied by the edges of the plates 80 of conducting material. It will thus be seen that the pole pieces II6 are effective to distribute the flux produced by the coil I06 uniformly along the path of arc movement.

The operation of the circuit interrupter is as follows: Upon separation of the contacts I6 and 20, an arc is drawn therebetween which, due to the transverse fiow of flux across these contacts between the pole pieces II6 as set up by the series flow of current through the coil I06, is moved laterally from the contacts I6 and 20 onto the arc horns I6 and 96. The magnetic field continues to act upon the are driving it into the V- shaped slots 84 in the plates 80 of metallic material. When the arc reaches the closed ends of the slots 84, it is split up into a plurality of short arcs. The continued action of the magnetic field upon these short arcs causes each of the short arcs to be moved along its respective circuitous arc passage 88 as defined by the plates 82 of insulating material. 7

During movement of the short arcs between the conducting plates 80, deionization takes place as is well understood in the art to effect are ex.- tinction. The provision of a relatively long and tortuous-arc path for the individual short arcs permits impressing a voltage across. the interrupter which is considerably in excess of the rated voltage of the interrupter without causing endwise abutment.

' I22 serve as stop members.

arcs are driven to the end of the conducting plates.

Should the arc reach the end of the plates, it will be subjected to excessive lengthening as a result of the combined magnetic and gas blowout action, so as to cause arc extinction before the arc is blown completely throughout the open end of the passage.

By staggering the outlet openings of the passages 88 in the manner previously described, the creepage distance between adjacent openings is materially increased thereby lessening the danger of flashover exteriorly of the arc extinguishing device which may result from the escape of gases from the arc passages 88 which are not completely deionized. By way of example, the particular circuit interrupting structure above described, which was designed for 2300-volt service, successfully confined a 433 ampere are at 20,000 volts. within the structure. The specific test results also indicated that the arc extinguishing structure could have withstood 60 cycles or moreof arcing without causing destruction of the device. Following this particular high voltage-test, structures of the type herein described were immediately connected in a lower voltage circuit and successfully interrupted 3630 amperes' at 3170 zolts within one and one-half cycles of arcing ime.

In Figs. and 6 I have shown a modified form of arc extinguishing device which differs from the device shown in Figs. 2 and 3 in the method of forming the side wall members, the method of supporting the 'deionizing structure comprising the plates 80 of metallic material and the plates 82 of insulating material. As shown in these fi ures, each of the side wall members comprise two plates I20 of insulating material. The innermost plates are provided with a short plate I22 against which the metallic plates 80 and the plates 82 of insulating material are brought into In other words, the plates The plates 80 and 82 are held in engagement with the stop plates I22 by means of a flexible band I24 of insulating material anchored at its upper end to a spacing member I26 and secured at its lower end to a tensioning member I28 which, in turn, is pivotally secured between the side wall members I20 by a bolt I30.

A tensioning screw I32 is screw-threaded through the tensioning member I28 and bears upon a compression plate I34 having contiguous contact with the lower arc horn of the are extinguishing device. The alternate plate members 82 of insulating material, as well as the filling in members 90, are held in proper relative\position with respect toeach other by a pair of flexible rods I36 which pass through the respective plate members substantially perpendicular to the plane surfaces thereof.

The are extinguishing device as shown in Figs. 5 and 6 also differs from the device previously described in that the plates 82 of insulating material are so formed that the successive tortuous arc passages 88 provided thereby terminate on opposite sides of the arc extinguishing device as shown at I38, thereby further increasing the creepage distance between successive discharge openings. provided for rendering the distribution of the magnetic field more uniform and differ in arrangement from pole pieces II6 primarily in that the pole pieces I40 are not countersunkbut secured to the outer surface of the side wall mem- In this instance pole pieces I40 are bers I20. Although this i'orm of arc extinguishing device diiIers somewhat in structural details from the device shown in Figs. 2 and-3, the operation thereof is substantially thesame except that the discharge of arc gases takes place on alternate sides of the device, whereas the discharge of arc gases from the successive passages 88 in the first described structure takes place from the end of the device, but in staggered relation.

Although I have shown and described a particular circuit interrupting device and specific arc extinguishing structures therefor, it is to be understood that the same is for the purpose of illustration and that changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. In a circuit interrupter, means for establishing an arc, a plurality of layers of spaced conducting material, means for moving said arc into said spaced layers of conducting material to produce a plurality of short arcs, and means of insulating material disposed between said layers of conducting material defining a plurality of elongated narrow arc passages having at least two opposed sides enclosed by said layers of conducting material and along which said short arcs are adapted to be moved, said narrow arc passages being so positioned that adjacent passages cross each other at least once throughout their length.

2. In a circuit interrutper, means for estab-.

lishing an arc, a plurality of layers of spaced conducting material, means for moving, said are into said spaced layers of conducting material to produce a plurality of short arcs, and means of insulating material defining a narrow wavy through arc passage between each pair of adjacent layers of conducting material, said narrow arc passages terminating alternately in laterally displaced relation with respect to each other.

3. In a circuit interrupter, means for establishing an arc, means for extinguishing said arc comprising a plurality of plates of conducting material having are receiving notches in one end thereof, means of insulating material for spacing said plates of conducting material from each other and to provide a narrow circuitous arc passage between each pair of adjacent plates extending from the notched portion of said plates of conducting material to a distance beyond the opposite end thereof, said means of insulating material being so arranged that adjacent arc passages cross each other at least once throughout their length, and means for moving said are into said plates to produce a plurality of short arcs therebetween and to move said short arcs along said narrow arc passages.

4. In a circuit interrupter, means for establishing an arc, means for extinguishing said arc comprising a plurality of plates of conducting material having are receiving notches in one end thereof, spacing members of insulating material disposed between said plates of conducting material to provide a narrow wavy arc passage between each pair of adjacent plates extending from the notched portion of said plates to the opposite end thereof, said narrow arc passages being arranged tocriss-cross and terminate in staggered relation, and means for moving said arc into said plates to produce a plurality of short arcs therebetween and to move said short arcs along said narrow arc passages.

5. In a circuit interrupter, arc extinguishing means comprising a plurality of spaced metallic plates having aligned notches in one end thereof, means of insulating material disposed between said plates defining a circuitous arc passage between each pair of adjacent plates, said passages extending from said notches'to the opposite end of said plates and terminating in free space exteriorly of said are extinguishing means, adjacent means for establishing an are adjacent the notched end of said plates, are passages crossing each other at least twice throughout their length, and means for moving said are into said plates to divide the are into a plurality of short arcs, each of said short arcs being moved along a respective passage until extinguished.

6. In a circuit interrupter, means for establishing an arc, an enclosure for receiving said arc, means within said enclosure for deionizing said are including a plurality of narrow crisscrossed arc passages, each of saidlpassages' having a pair of arc terminal members between which a short are may be moved, said are passages terminating in vent openings disposed in staggered relation at the exterior of said enclosure, and means for moving the are initially,

established into said deionizing means.

7. In a circuit interrupter, means for establishing an are, an enclosure for receiving said arc, means within said enclosure for deionizing said arc including a plurality of arc passages,

said are passages having aligned converging entrance portions into which said are is adapted to be moved, and means for moving said arc into said entrance portions to form a plurality of short horns for deionizing said arc, and a barrier member movable upon separation of said contacts to effect closure of said arc chute in back of said contacts.

9. In a circuit interrupter, a pair of separable contacts at least one of which is movable for establishing an arc, an arc chute having substantially parallel side walls between which said pair of contacts are disposed, means .within said are chute located in front of said contacts for receiving said arc from said contacts and for deionizing the arc, and a barrier member of insulating material carried by said movable contact adapted to be moved with said movable contact during contact separation to effect closure of the arc chute in back of said contacts.

10. In a circuit interrupter, means for establishing an are, an arc chutehaving substantially parallel side walls between which said are is established, means for deionizing said are comprising alternate members of conducting and insulating material disposed transversely between the side walls of said are chute and having a V-shaped notch at the end thereof adjacent said contacts for receiving said arc, each of said members of insulating material having an undulated slot extending from the notched end to the opposite end thereof to provide a narrow elongated arc passage in which a short portion of the are initially established is adapted to play, the slots in alternate plates of insulating material crossing each other at least once throughout their length, each of said are passages terminating in free space exteriorly of said arc chute, and means for holding said members 'of conducting and insulating material in compression.

11. In a circuit interrupter, means for establishing an arc, an arc chute having substantially parallel side walls between which said arc is established, means for deionizing said are comprising a plurality of plates of conducting material disposed transversely between the side walls of said arc chute and having a slot in the end thereof adjacent said arc establishing means, means for moving said arc into said slots to establish a short are between adjacent plates of conducting material, and wedge shaped spacing members of insulating material disposed between adjacent plates of conducting material, said spacing members of insulating material providing a narrow arc passage from the slotted end of said plates to the opposite end thereof and being so arranged that said plates of conducting material diverge in a direction away from said are establishing means.

12. In a circuit interrupter, means for establishing an arc, an arc chute having substantially parallel side walls between which said arc is established, the inside surfaces of said are chute walls having at least one pair of opposed dovetail grooves formed therein, means for deionizing said are comprising a plurality of alternate plates of conducting and of insulating material disposed transversely between the walls of said are chute, said plates of conducting and insulating material having projecting dovetail tongues along opposite sides thereof shaped to conform with the cross section of said grooves in registration with said grooves for anchoring the plates to the side walls of said chute, said plates of insulating material having a .narrow through passage between adjacent plates of conducting material, and means for moving said arc into said. plates of conducting material to cause a short are to play in each of said narrow passages.

13. In a circuit interrupter, a frame, a pair of passages.

movable with said movable contact during the opening operation of said interrupter to effect closure of the arcchute in back of said pair of contacts and means for releasably mounting said are chute upon said frame independently of said contacts and said barrier member.

14. In a circuit interrupter, an arc chute having a pair of side walls, means for deionizing an arc comprising a plurality of plates of conducting material disposed transversely between the side walls of said are chute, means for establishing a short arc between adjacent plates of conducting material, and wedge-shaped spacing members of insulating material disposed between adjacent plates of conducting material, said spacing members of insulating material providing a narrow arc passage between adjacent plates of conducting material from one end of said plates to the opposite end thereof and in which one of said short arcs is adapted to play.

15. In a circuit interrupter, means for establishing an are, an arc chute having substantially parallel side walls between which said are is established, means for deionizing said arc comprising a plurality of alternate plates of conducting and of insulating material disposed transversely between the walls of said are chute, each opposite inner surface of said are chute walls having at least one undercut groove therein extending in a direction substantially normal to said plates of conducting and insulating material, said plates of conducting and insulating material having tongues along the sides thereof shaped to conform with the cross-section of said grooves and projecting into said grooves for interlocking said plates with the side walls of said are chute, said plates of insulating material having a narrow through passage between adjacent plates of con" ducting material, and means for moving said are into said plates of conducting material to cause a short are to play in each of said narrow LOUIS E. s'AUEa,

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