US2311690A

US2311690A - Arc quencher

Info

Publication number: US2311690A
Application number: US339683A
Authority: US
Inventors: Frank J Pokorny
Original assignee: ITE Circuit Breaker Co
Current assignee: ITE Circuit Breaker Co
Priority date: 1940-06-10
Filing date: 1940-06-10
Publication date: 1943-02-23
Anticipated expiration: 1960-02-23

Description

Feb. 23, 1943. F. J. POKORNY 2,311,690

ARC QUENCHER Fil d June 10, 1940 3 Sheets-Sheet l Feb. 23, 1 943.

F. J. PQKORNY ARC QUENCHER Filed June 10, 1940 3 Sheets-Sheet 2 T I i .INVENI'OR.

' ATTORNEY Feb. 23, 1943. F. J; POKORNY ARC QUENCHER 3 Sheets-Sheet 3 Filed June 10, 1940 Patented Feb. 23, 1943 UNITED STATES PATENT OFFICE ARC QUENCHER Application June 10, 1940, Serial No. 339,683

18 Claims.

This invention relates to circuit interrupting apparatus and arc quenching means, therefore and more particularly to an arc quencher that is readily mountable and demountable as a unit.

The type of apparatus involved includes power switching equipment that may be required automatically to interrupt fault currents of great magnitude. These arcing currents, unless extinguished quickly will seriously damage metallic parts with which they come into contact. Such parts should be periodically inspected and replaced when necessary. As these parts are enclosed Within the arc quencher provision must be made for the easy removal of the extinguishing device and also for securely clamping it in operative position.

Further the type of power switching apparatus to which this invention may be applied, is frequently enclosed in compact metal cubicles as a protection for the operator and surrounding apparatus. In such an installation, vertical space within the compartment is limited so that it is advantageous to be able to withdraw the arc quencher forward horizontally without any vertical movement being required.

Is is, therefore, an object of this invention to provide an arc quencher that is readily mountable and demountable to and from operative relation with the separable contacts of a circuit interrupter.

It is a further object of this invention to .provide an arc quencher that is demountable by a simple horizontal forward movement without any vertical movement being required.

It is another object of this invention to pro vide an arc quencher that is a rugged unitary structure and that may be securely held in operative position by a single clamping means.

t is an additional object of the present invention to provide an effective compact arc chute that is composed of inexpensive parts and is easily manufactured.

There are many other objects and uses of the present invention and of the combinations and elements herein set forth. Many of them have already been pointed out. Many others will in part be apparent and where not intrinsically apparent will be pointed out in the following description and drawings, in which:

Figure 1 is a side elevation of the circuit break or of our invention.

Figure 2 is a front view of the circuit breaker arrangement of Figure 1.

Figure 3 is a cross-sectional view on line 3-3 of Figure 2 showing the circuit breaker in closed circuit position.

Figure 4 is a view corresponding to that of Figure 3 showing the circuit breaker in open circuit position.

Figure 5 is a cross-sectional view on line 5-5 of Figure 4 showing the arrangement of the arc quencher.

Referring now to Figures 1, 2, 3 and 4, I have here shown a three pole circuit breake comprising the elements of the present invention. The circuit breaker consists of a group of pole units 20, 2|, 22 (Figure 2) mounted on the face of an ebony, asbestos or slate panel 23 which forms the mounting plate of the entire circuit breaker arrangement.

M ain supporting members The main bracket or housing 24 which supports the operating members is secured to the panel 23 by means of

screws

25, 25 the heads of which are recessed in

openings

26, 26 in the back of the panel 23 and which pass through the perforations 21', 21 in said panel to engage the main bracket 24 (Figure 1).

As seen in Figures 1 and 2, the main bracket or housing preferably comprises two flanged

side plates

28 and 29 which extend on each side of a horizontal shelf 30 to which they are welded. The operating mechanism 3| comprising the toggles and other elements hereinafter described is bolted to the lower side of the shelf 30, the housing 300 of the said operating mechanism comprising flanges 32, Figures 3 and 4, through which bolts 33 may be passed to engage the shelf 30.

Link 34 connects the operating mechanism 3| to the lever 35 which is secured to the contact shaft and is rotatable therewith. As seen more particularly in Figures 3 and 4, the stationary contacts 36 and their back connection stud assembly are mounted on the panel above the housing or supporting bracket 24 and support the inner end of the arc chutes in the manner hereinafter described.

A bridge 31 of insulating material secured to the outer end of the main bracket 24 supports the outer end of the arc chutes in the manner hereinafter described.

Main and arcing contactsThe stationary main contacts The stationary main contacts 36 are bolted to the connecting stud 42 by means of the bolts 38 and the washers 39. The connecting stud 42 passes through the back panel 23 and is suitably arranged so that appropriate circuit connections may be made thereto. The path of the main current when the contacts are closed, as seen in Figure 3, is through the connection stud 42, the stationary contact 36, the stationary contact tip 46, the movable contact tip 4|, the contact lever 69 carrying the flexible connection 43 which in turn is electrically connected to the member 44.

Movable contacts support The movable contact shaft 45 is preferably a square steel bar covered with phenolic insulation molded in place and is rotatably supported in appropriate bearings as hereinafter described.

A contact arm for each pole is mounted on this shaft. The contact arm 46 is preferably a bronze casting reinforced by flanges 41 and 48. The lower end of the bronze casting which engages the square steel shaft is preferably formed in a V comprising the'members 49 and 50 set at approximately right angles to each other so that'they will engage the square sides of the shaft 45 to which they are to be clamped.

The clamping member comprises also a V- shaped member having the sides 52 and 53 which likewise may engage the sides of the square steel shaft and comprising also flanges 54 and 55 through which bolts 56 and 51 may bethreaded to engage the flange 58 and the flat portion 59'of the contact arm 46 in order to securely clamp the same to the contact shaft 45.

As will be noted, especially in connection with Figures 2 and 3, each of the main contact arms 46 may be secured to the contact shaft 45 so that rotation of the contact shaft 45 by the lever 35 will result in corresponding movement of the contact arms 46 for the purpose of opening or closing the circuit.

While any necessary number of contact carrying arms may be mounted upon the contact shaft as thespecific circuit connections may require only one lever 35 is necessary forthe opening and closing operations which result in rotation of the shaft 45 and the operation of the various contacts.

'In order to obtain a balanced structure it is preferred that the lever 35 be secured to the shaft 45 substantially at the center so that the mechanism may be properly balanced.

Movable main contacts Each contact arm 46 carries a pair of contact levers 60 formed and cut from a special copper extruded bar. Each of these two levers 66 carries at its upper end a silver nickel contact block 4| for engaging the stationary main contact tip 49. The back of the contact arm 46 has a part-cylindrical depression 6| and the tion between the base of the recess 68 and the spring cup 16 which is held in place on the spring link 66 by the cotter pin 1 I The spring link 66 in extending between the two main contact levers 60 has an eye 66' which engages a groove 65' in the pin 65 in order to prevent its moving to either side.

When the main contacts are disengaged in the manner shown in Figure 4, the lower ends 12 of the main contact levers 69 press against the contact arm 46 in the manner shown.

7 For simplified assembly the only element which retains the pin 63 in place is the pressure of In the closed position the pressure through the contact lever 60 between the spring 69 (bearfront of each of the contact levers has a similar depression 62. A bronze pivot pin 63 is placed in these depressions. Thi pivot pin has flanges at each side and also a flange in the center between the two contact levers 66 in order toprevent any lateral movement of the members with respect to each other.

Each of the contact levers is drilled at 54 so that a pin 65 may be inserted therein. The pin 65 is preferably of dumbbell shape and acts as an'equalizing yoke between the two contacts 6|l66. A link 66 engages the pin 65 between the two contact levers 6fl60 and is extended up through a perforation 61 in the contact arm 46 into the recessed area 68of said contact arm. A compression spring 69 forms the main contact spring and is retained in posiing on the pin 65) and the contact 4| serves to maintain the adequate pressure necessary to hold the pin 63 in place. In the open position, the pressure of the bottom end 12 of the main contact lever 60 against the contact arm 46 and the pull of the compression spring upon the p n 65 of the lever 60 using the member 12 as a fulcrum serves to maintain the pin 63 in place.

This design of pivot provides long wearing surfaces, The spring link and pressure equalizing pinmay be made of hard steel so that their area of engagement may be small. The area of engagement at the pin of the'contact levers may be of relatively soft material.

The pivot pin engaged by the half-cylindrical surfaces of the contact arm and the contact levers provides a maximum of area for the softer parts. This area could not be obtained in the same width or pin length by any other method.

If the levers were formed to rock in a'groove-in the arm, there would be copper and brassbearing surfaces which are far inferior to the steel pin between them.

During the closing movement there is no instant when there is any relaxation of pressure upon the pin 63, for until the main moving contact tip 4| is brought into contact with the stationary contact tip 40, the bottom end 12 of the contact lever 60 engages the'contact arm 46 in the manner shown in Figure 4.

Only after the moving contact tip 4| is in engagement with the stationary contact tip 40 is there a transfer of the fulcrum or the base of pressure from the portion 12 to the tip 4|. In such case, as has been seen in connection with the closed position of Figure 3, there is again sufficient pressure to maintain the pin 63 in place.

During the opening movement, pressure is maintained upon the pin 63 by reason of the fact that spring 69 by its pressure on the pin 65 forces contacts 40 and 4| against each other until, in the rotation of the contact shaft 45, the end 12 of the contact lever presses against clamping portion 48 of the contact arm 46, whereupon the base of pressure is transferred from contact tip 4| to end portion 12. In this manner, the spring pressure is always exerted to maintain pin 63 in position.

The rotation of the main contact lever 60 about the pin 62 during the closing operation necessarily results in a slight sliding motion of the movable contact tip 4| with respect to the stationary contact tip 49 so that a wiping action occurs tending to clean the contacts.

As seen also in Figures 3 and 4, the back of the contact levers are drilled and tapped for the securing screws 13 in order to attach the flexible conductor 43 thereto. I

The upper end of the flexible conductor 43 is slit so that separate screws 13 may attach the separate ends to the two separate contact members 60 to allow independent movement of the contacts. The arrangement of the lever arms above and below the contact pivot is such that during heavy current flow the magnetic forces set up will tend to increase the pressure between the moving and stationary contacts when the flow of current is between the stationary contact tip 40 and the movable contact tip 4 I.

By the use of two contact levers of this type for each pole of the circuit breaker, an adequate contact at each pole is ensured.

Movable arcing contacts The arcing contacts 81 are mounted in the upper part of the contact arm 45, and are supported by arcing contact levers 15. The arcing contact levers 15 preferably are each cut from a bar of extruded copper and in this case also we have found it preferable to use a pair of such contacts and levers for a single pole. Each of the arcing contact levers i is pivoted on the pin 76 which is grooved between the contacts to take a hair pin spring 'I'! which serves to keep the pin 16 in center position. A second pin 18 is mounted in the top of the contact arm 45 between two upwardly extending flanges 19 thereof.

An appropriate bushing may be placed between the flanges so that the pin may be securely riveted over them without bending them. The eye 80 of the spring link 8! is placed over the bushing, the said spring link 8! extending beyond the back of the arcing contact levers i5.

Pins 82 having rounded heads are driven into the upper part of the back of the arcing contact lever 15.

A spring cup 83 is pressed against these pins by the compression spring .84 which is held in place on the link 8| by the spring cup 85 at the opposite end which in turn is held in position by the cotter pin 86. The arcing contact 81 is mounted upon the arcing contact lever and is preferably formed or cut from an extruded copper bar and is provided with a contact face 83 preferably of Elkonite silver which is soldered to the copper. Each of the contacts 81 of each of the contact levers '15 is held in place upon its contact lever by a socket head cap'screw 89 and lock washer 90. As will be seen more particularly in Figure 18, the contacts 81 are held against turning or other displacements by the shoulder 9| which engages a corner of the arcing contact lever 15. The ends of the contact arm flanges bear against the outer sides of the two arcing contacts and the projection $2 of the spring link separates the two arc ng contacts 8'I-8'I from each other, thus serving adequately to position them.

As is seen in Figures 3, 4, the lower end of the arcing contact lever '55 is off-set at 93 to receive the end of a flexible conductor 93. The conductor 93 like the conductor 43 is also slit, the ends thereof being riveted at the off-set 93' to the arcing contact lever '15 by means of the rivet 94 passing through the washer plate 95.

The off-set 93' is curved away at 96 from the I flexible conductor and the washer plate 95 is curved away at 91 therefrom for the purpose of preventing kinking during operation. This flexible conductor 93 is led down to the lower terminal block 44 to which it is connected by the same screws 98 that hold the main contact lead 43.

The main contact levers, in contact open position, are held against their fulcrums and against a stop on the arm by a compression spring at the back of the arm, acting on a link connected to the two contact levers between the fulcrum and the stop. The contact surface is at the top of the lever above the fulcrum. The flexible conductor is secured to the bottom of the lever below the fulcrum.

When the shaft and arm are moved to contact closed position, the contact ends of the levers are rotated about their fulcrums and pushed back from their advanced position, moving the bottom stop clear of the arm. This compresses the spring and increases the contact pressure. The use of a single spring and link between the two levers permits the pin to act as an equalizing yoke.

The attachment of the flexible conductor below the fulcrum causes the magnetic forces to balance about the fulcrum so that the contact pressure may remain the same or increase during fault current.

The auxiliary or moving arcing contacts are mounted at the top of the arm. In this case the spring is above the fulcrum and below the detachable contact tips. Equalization of pressure is arranged in the same way. Maintained pressure during fault or inrush current is provided in the same manner.

Ooercurrent coil connections It should also be noted that the flexible lead I06 from the arcing horn hereinafter described also connected to the terminal block 44. It will thus be seen that the three flexible conductors I00, 93 and 43 are all led from the contact structure to the lower terminal 44 to which all three to the current rating of the circuit breaker, one

terminal of the coil being connected to the lower terminal post 44 and the opposite end of the coil being connected to the back connection stud II which has the securing block I I2 welded to it at the face of the panel 23.

The back connection stud III is held in place in the panel 23 by the screws H3 and II 4 which pass through and engage the clip I I5. The terminal post 44 is bolted in place on the panel 23 by means of the bolts I I6 and lock washers H 7. In other words, therefore, the current is not led di rectly to the back connection stud I I I but through the lower terminal post 44 and through the coil III] of the over current magnet to the back connection stud I I I through which the connection is made to the circuit.

The coil I I0 of the over current magnet is therefore connected in series with the contacts.

It might here be noted that the upper back con nection stud 42 is likewise connected through the panel 23 by means of screws I I8 and I I9 engaging and passing through the clip I23 and is therefore held in position in the same manner as the lower back connection stud III.

When the circuit breaker therefore is closed, the current flowing into the upper stud 42 enters the main contact block 36, passes through the mainstationary'contact surface 40 to the main movable contact surface 4| and into the main contact lever 60 passing therefrom through the flexible lead 43 to the lower terminal block .44 around and through the coil I I to the lower back connection stud III and thence back to the circuit to which the same is connected.

The over-current coil I I0 will thus be in series with the main contacts; and, after these are opened, with the arcing contacts; and, finally, with the arcing horns; since the leads 43, 93 and I00 each are connected to the pigtail post 44.

The arcing contact circuit is in parallel with the circuit through the main contact tips 40 and 4|. The arcing contacts are designed to make before and separate after the main contacts during the closing and opening so that as is hereinbeiore described, the arc particularly during the opening may be made between the arcing contacts so that the main contacts which carry the load' should not be roughened or distorted to offer any substantial resistance to the passage of current.

Blow out magnet and stationary arcing conta t The current path from the arcing contact tip 08 to the arcing contact lever I and through the flexible lead 93 to the lower terminal block 44 has been described. The movable arcing contact tip 88 engages the stationary arcing contact tip I2I. Current is led to the stationary arcing contact tip |2I in the following manner:

Current from the upper connection stud 42 flows into the lower terminal I25 of the blow out magnet coil I22 around the coil to its upper terminal I29 and thence to the stationary arcing contact I23. From the stationary arcing contact, the current flows to the stationary arcing contact tip I2I, thence to the movable arcing contact tip 88, thence through the arcing contact lever I5, flexible lead 93, the terminal block 44, the coil H0, and the connection stud III in the manner hereinbefore described.

The arcing contacts, particularly the movable arcing tip 81-88, may readily be replaced after the same have become worn. When the circuit breaker is closed, the resistance of the circuit through the

main contacts

39 and 60 is low as compared with the resistance through the arcing circuit so that a relatively small current flows through the latter.

The main stationary contact 36 is attached to the back connection stud as is the lower terminal of the blow-out magnet coil I22 by means of screws 38. Screws II9 passing through panel 23 serve to fasten the lower terminal of blow out magnet coil I22 and angle clip I to panel. Screws 8 in turn fasten back connection stud 42 to the angle clip I20. The electrical connection between the back connection stud 42 and the lower terminal I of the blow out magnet coil I22 is made by direct contact between the angle clip I20 and the screw I I9 as well as by the direct pressure of the terminal I25 against the connection stud 42.

The coil consists preferably of a strip of bar copper wound in a helix, the lower end at I26 being sweated and pinned by pins I21 and I28 to the lower coil terminal I25 and the upper end being secured to a fiat plate terminal I29 which lies against the panel I23. The coil is wound so that current flowing from the lower coil terminal to the upper coil terminal flows around the slotted cylindrical iron core I30 in a clockwise direction in the views of Figures 3 and 4.

A fiber tube |3| insulates the core I30 from the coil I22. Insulated side plates I32 are fastened on each side of the coil terminals. The arcing terminals I23 also cut from an extruded brass bar is secured to the upper coil terminal I29 and the panel 23 by screws I33, threaded into the nut plate I34 which is further anchored in position to provide a secure attachment of the members by the screws I35, the heads of which are embedded in the recess I36 so that they may not interfere with the securement of the coil terminal I29 to the panel.

The upper part I38 of the arcing contact I23 is extended along the panel and forms a hook I39 for anchoring the arc chute in the manner hereinafter described.

The arcing contact I23 curves around the blow out coil as seen in Figures 3 and 4 and forms an arcing horn. The arcing contact is preferably wider than the coil I22' and as seen in Figures 3 and 4, its under surface rests against theedges of the insulating side plates I32. As has been above described, the arcing contact tip I2I is at the lower end of the arcing contact I23 and is preferably a contact surface of Elkonite silver.

As seen in Figure 2, the contact shaft 45 is a square steel bar which as above described is covered with phenolic insulation molded in place. Each end of this shaft is drilled at |40a to receive the bearings I40. The shaft itself extends betwen the

side plates

28 and 29. The bearings are brass cylinders inserted in holes in the sides plates to which their drilled flanges |4| are secured by screws I42.

When the screws I42 are removed and the two bearings at each end are withdrawn, the shaft and the entire contact assembly may be removed from between the side plates provided of course that the flexible leads have been disconnected and also provided that the connection between the link 34 and the arm 35 of the contact shaft are separated.

Assembly and operation of the contacts The contact arms 46 are secured to the contact shaft by clamp members 5| which are held in place by a pair of screws 56 and 51 on each side of the shaft.

The outside poles are suitably positioned by the contact arm caps or clamps 5Ia while the middle pole arm is held in position by the cap 5|. As is seen more particularly in Figure 3 the clamp or cap 5| is extended to form the shaft actuating arm 35 and is drilled to receive pin 2I0 in the upper end of the main toggle link 34. A movement of the operating mechanism 3| will raise or lower the pin 2|0, therefore raising or lowering the shaft actuating arm 35 and so rotate the contact shaft 45 to move the contacts into and/or out of engagement.

As is more clearly seen in Figure 2 secured to either or both ends of the steel contact shaft 45, is a steel arm 220 and 22I. Each of these arms carries as will be noted, two studs 223 and 224 which are riveted in place.

Secured to one of the studs of each of the members 220 and MI is a contact opening spring the lower end of which may be attached to studs riveted to the insides of the bracket side plates. These two springs may bias the shaft towards opening position and assure quick opening.

The second of the studs for instance stud 223 on the arm 220 may be utilized to operate auxiliary switches or other devices by means, for instance, the vertical insulated shaft 230 attached to this stud and passing through the shelf of the bracket 30 (Fig. 2).

Thus, for instance, the vertical shaft 230 may operate auxiliary switch 234 in any suitable manner for any suitable purpose. The rotation of the contact shaft 45 towards opening position will through the arm 220 and the stud 223 force the vertical link 230 downwardly. The vertical link 230 is connected by pin 231 to the crank 232 on the shaft 233 of the switch 234. The downward motion of the vertical link 230 will result in rotation of the crank 232 and will therefore result in rotation of the shaft 233 and in the consequent operation of the various contacts and other portions of the switch suitably connected to and actuated by shaft 233.

Such switch 234 may be used where, for instance, the circuit breaker is to be connected with automatic reclosing circuits when it is open and such relay will obviously be reset to its original position when the solenoid or manual closing mechanism hereinafter described rotates the contact shaft 45 towards closing position thus raising the insulated link 230 and operating the switch.

As has been above pointed out, preferably three contact arms 46 are mounted on this shaft, one for each pole of the circuit breaker as seen in Figure 2. On each side of each arm, there is cemented to the shaft insulation a Bakelite washer I43 which improves the pole to pole and pole to ground insulation.

As will be noted in Figure 2, the inter-pole washers are bevelled and flanged so that the bevelled and flanged portions I44 thereof are spaced apart so that an inter-phase barrier I45 secured to the panel may extend between them. The cooperation of these parts makes it impossible for any'fiexible conductors of adjacent poles to be drawn together during heavy current flow while at the same time any possibility of arcing over is obviated.

In the construction and arrangement of the contacts, the movable main contact is supported by an operating arm on the contact bar or shaft and is connected to the lower stud by a flexible shunt of suitable size.

Pressurev on the main contact is obtained through the use of a compression type coil spring, mounted outside the current path, and, consequently, is unaffected by heating.

The pressure on the arcing contacts is also obtained by the same type of compression type coil spring protected from the arc.

The main contacts are protected by the sequence of operation in opening or closing of the device, since the main contacts close after the arcing contacts and open before them.

Although with the construction herein described, replacement of the contacts should not be necessary, the arrangement of the movable main contact lever and the movable arcing contact is such that access to both stationary and movable parts with a minimum amount of labor is possible.

As hereinafter described, accessibility of the main contacts is such that it is necessary only to remove one screw from the arc quencher assembly and lift it off manually so as to reach the contacts. In addition, as is hereinbefore described, the removal of the two bearings I40 of the main contact shaft and pigtails is sufficient to make available all parts of the contact mechanism for replacement, cleaning or repair.

The individual poles of the circuit breaker are each rigidly mounted on a rigid insulating shaft so as to insure the simultaneous opening and closing of all contacts. The use of a single trip free mechanism operating the main contact shaft also insures that all of the poles will operate simultaneously and precludes the possibility of opening individual poles without opening others.

An important feature of the present invention is that the same structure may be used for single pole or multi-pole operation, that is, as seen for instance in the structure of Figure 2, the circuit breaker mechanism is so arranged that three poles are simultaneously operated by a single closing and tripping mechanism. The same type of structure may be so arranged as to take one, two or four poles or more.

Arc chute, arc horns and blow out in the actual operation of the contact assemblies herein described, when the contacts are fully closed and the latches are then tripped, the contact shaft 45 and the contact arm 46 rotate in a counterclockwise direction in the views of Figures 3 and 4. As the arm and the contact pivot pins 76 and I53 move away from the stationary contacts, the springs 69 and 85 maintain the moving contacts in engagement with the. stationary contacts until in the rotation of the contact levers these levers l5 and 60 strike their respective stops.

During this movement, the lower end 12 of the contact lever 60 strikes the part of the contact arm 45 which surrounds the shaft 45. At this point in the movement, the main contacts separate while the arcing contacts are still engaged. It is thus seen that the circuit through the main contacts is interrupted and all the current is transferred to the circuit of the blow out coil I22 and the arcing contacts. The core I35 therefore and its associated pole pieces are highly magnetized in proportion to the current flowing.

As seen in Figures 2, 3, 4 and 5 surrounding each pole is an arc chute I55 comprising side plates I5I of insulating material and supporting between them five shorter parallel spaced plates I52 also of fiber.

The entire group is held together preferably by rivets I53, I53 making as far as possible a rigid assembly. Preferably, the rivets comprise, as seen in Figure 5, a central metal tube-like arrangement I54 and an outer insulating cylinder I55.

As seen in Figures 5 and 4, near the panel 23, the inside plates I52 are separated by fiber members I56 which prevent the arc gases from coming in contact with the panel and which also comprise hooks I51 which engage under the hook or lip I55 of the stationary arcing contact member I23 in order to assist in supporting the are quencher assembly. This is effected by the fact that the fiber hook on the barrier herein described is held snugly between the hook of the arcing horn and the upper current surface of the horn. Near the front of the arc chute is secured an arcing horn I55 which is electrically connected to an angle-clip IBI, being connected thereto by the screw I62 passing through the flange I63 of the arcing horn and a flange of the angle clip. 7

The metallic clip I5I is secured by the screw I54, and lock washer I55 to the bridge 37 of molded insulating material. This metallic clip I6I is electrically connected to the flexible conductor I which in turn connects it to the lower terminal 04. At the end of the opening movement of the arcing contact the tip 61 of the movable arcing contact 15 moves under the stationary arcing horn I60 in the manner shown in Figure 4 so that the arc terminal is transferred to the stationary arcing horn I60 and the current flows through the conductor I00 to the lower terminal block 44. The current is first transferred from the main contacts to the arcing contacts, and, when the arc is then transferred to the stationary arcing contact or horn I60, the movable arcing contact is shunted out of the circuit.

As seen in Figure 2, the blow out core I30 extends beyond the sides of the blow out coil 22 a distance equal to the thickness of the insulating side plates I5I. I

The insulating side plates are notched at I15, as seen in Figure 1, so that they may embrace the core I30 while their edges rest against the panel 23. By this arrangement, any possible impediment to the magnetic fluxes induced by the core in the pole pieces hereinafter described is obviated.

Ferrous blow out plates or pole pieces I16. Figures 1, 2 and 5, are secured to the outer surfaces of the side plates I5I of the arc chute by means of rivets or other suitable attaching means I11. These blow out plates or pole pieces, as seen particularly in Figure 1, cover a part of the notch I15 in the insulating plates I5I so that when the arc chutes are in position against the panel 23 and in proper relation to the contact assembly, the surface of each end of the core I is in contact with a corresponding iron blow out plate or pole piece I16.

Each of the side plates has its back edge I80 (Figure l) bevelled on the inner side thereof so that it may be slid in position easily past the notches of the insulated bridge hereinafter described.

The notch I15 around the blow out core I30 (Figure 1) and the lip I39 on the stationary arcing contact I23 which engages the hook I51 of the fiber spacer I56 of the arc chute I50 (Figure 3) assist in positioning the back end of the arc chute in proper relation to the panel 23 and the various other portions of the contact assembly.

The front of the arc chute is supported by the metallic clip I6I which is secured to the insulating bridge 31 and in current carrying contact with the conductor I00 by the screws I64 and its lock washer I65. The screw I62 provides a releasable clamping means between the arcing horn I60 and the clip I6I to maintain the arc chute in operative position. v

The front end of the arc chute is therefore securely positioned in place by means of the screws I64 and I62. It will be noted that removal of the screw I62 will permit the withthe arcing contact I23 and as seen in Figure l, the notch I15 of the outer plate I5I may by the same motion slide out of engagement with the blow out core I30. The are chute therefore is so arranged that a simple unscrewing of the screw I62 will permit removal thereof.

" It should be notedthat the screw I62 is so arranged that it need not be completely removed but it may be rotated a sufficient number of turns to disengage it from the clip I6I and may remain in the portion I63 of the arcing horn I during removal of the arc chute. By this simplified means involving rotation of a single screw, the arc chute may be securely mounted in place or quickly removed by a single motion in a horizontal direction.

The are splitting plates I52 (five in number in the preferred embodiment) have, as seen in Figures 3 and 4, their lower edges shaped in two arcs I and I9I which are concave in a; downward direction with the cusp I92 between them rounded. This cusp lies approximately midway between the stationary arcing horn I23 and the front arcing'horn I60. The downwardly extending cusps facilitate the entrance of the are into the slots between the plates and are so arranged that a relatively small longitudinal length of the arc is first forced between the plates and so that as the arc is blown upwardly, progressively greater lengths of the arc are forced between the plates.

As is also seen in Figures 3, 4 and 5, the lower edges of the plates I52 are of different heights, the middle one I52a being the highest and the outer plates I520 being the lowest, that is, extending downwardly a greater distance. The intermediate plates I52b are of a height so that the lower edges extend in planes substantially between the position of the edges of the middle and outer members.

As is also seen in Figures 3 and 4, the five plates here shown have perforations I95 of suitable size and shape, spaced and arranged to permit the flow of arc gases from the slot I96 (Figure 5) between one pair of plates to the slot between another. In order to provide a more turbulent condition of the arc gases and in order to insure contact of the arc gases with the various plates, the holes or perforations I95 of each of the plates are in staggered relation with respect to those in adjacent plates.

Upon opening of the main contacts and formation of the are between the arcing contacts 14 and I23, the arc is immediately transferred from the arcing tip 14 to the arcing horn I60.

The current flowing through the coil I22 energizes the magnet comprising core I30 and ferrous plates I16 producing a flux across the arc space. This flux forces the arc upwards towards and into the arc chute I50. "When the arc reaches the lower edges of the arc splitters or plates I52 it is squeezed or .fiattened to be forced between the two outer plates I520 and I520. Further movement forces the arc between the intermediate plates I52b-I52b further reducing its horizontal width.

As the arc is pushed further it may enter one of the slots I96 or it may be divided longitudinally in two or more slots. ln'either case, the arc gases have an opportunity to expand through the holes I95 in the plates I52.

This provision for permitting the arc gases to expand from slot to slot reduces the back pressure and hence permits the blow out magnet to force the arc upward at full speed.

The tendency of the ionized gases discharged from one slot to enter another through the perforat1ons I95 permits parallel arcs to exist over sections of the are. This causes greater instability and increased tendency to'speed the extinguishing of the arc.

By this means also a large cooling area is provided which further contributes to shorten the arcing time. Preferably the arc gases are sufficiently cooled and deionized by the arc quencher so that when, in the case of alternating current, the current passes through zero in the cycle immediately following the formation of the arc, the gases will be sufliciently deionized to provide an extremely difficult path for an arc and thus prevent the re-striking thereof. The are therefore may be quenched with of a second of the formation thereof.

I rater-phase barriers Suificient inter-phase barriers are provided by the side plates l5! of the arc chute. However, additional inter-phase barrier plates M5 (Figures 1-4 inclusive) may be used to make it impossible for any flashing over of the are from one pole to the other. These inter-phase barriers are placed between the arc chutes and carried up so that they are aligned with the top of the panel 23 and may be secured to the panel by suitable blocks 200 of insulating material; the blocks 200 of insulating material are secured to one side of the inter-phase barriers at the top. These blocks are drilled to receive the screw 28! which threads into a plug in the panel to secure the barrier in position.

As will also be seen in Figure l, the interphase barrier I45 extends beyond the arc chute both at the top and the front. The front lower corner rests on the insulation bridge 31 while as has been before pointed out, the back end bears against the panel and extends down between the shaft. insulation disks I43-l43.

Lower inter-phase barriers Iilfia (Figure 1) are aligned with the upper inter-phase barriers and secured to the panel 23 by screws Hlla and [02a thus preventing any tendency of the flexible leads to approach each other or any current at that point from arcing over.

The lower back corner of the upper interphase barrier is supported by a strip of insulating material secured to the panel just above the top of the housing brackets. The lower interphase barriers align with the upper ones and are secured to the panel by screws threaded into their edge. These lower barriers are notched to surround the shaft. They prevent the flexible conductors from being drawn together during fault current.

Various other elements may, of course, be utilized in connection with the circuit breaker mechanism. Thus, for instance, as seen in Figure 2, a suitable time delay element 950 may be providedin connection with the over current coil Hi] to permit the breaker to carry normal load above its trip setting for short periods of time. The specific details of the time delay elements are not herein discussed since they constitute no part of the present invention.

The operation and function of each of the parts of the arc chute of the present invention and the cooperation thereof with the elements of the circuit breaker have been set forth in connection with the specific description of each of said parts.

In the foregoing, I have described only those parts of the circuit breaker necessary to fully understand the operation of the arc quencher and the arc-splitting plates. The various constructions herein described may be modified in many ways which will now be obvious to those skilled in the art.

Accordingly, I prefer to be bound, not by the specific disclosures herein, but only by the appended claims.

This application embodies portions of the structures of the application of Frank J. P0- korny, for Circuit breaker operating mechanism, Serial No. 339,682, the application of William Maxwell Scott, Jr., for Circuit breaker, Serial No. 339,687, the application of William Maxwell Scott, Jr., for Stationary contact structure, Serial No. 339,688, and the application of William Maxwell Scott, Jr., for Circuit breakermovable contacts, Serial No. 339,689, all filed June 10, 1940. In this application I have claimed those inventions and portions of the structure devised by me.

I claim:

1. An arc extinguisher comprising a plurality f spaced parallel barrier plates insulatedly mounted between a pair of side plates, said plates extending in planes parallel to the axis of the arc, ferrous plates mounted on the outer sides of said side plates forming a path for magnetic blow-out fluxes, said ferrous plates being registerable with the ends of the magnetic core of a blow-out coil, said barrier plates, side plates and ferrous plates forming a single integral unit mountable and removable as a unit upon a circuit breaker, said unit carrying a hook at the rear end engageable with coacting means on the circuit breaker panel and a single releasable screw threaded means at the front end engageable with cooperating means on the circuit breaker for securing the front of the are extinguisher in position.

2. An arc extinguisher for extinguishing an are drawn between opposed contacts, said are extinguisher comprising a plurality of spaced parallel barrier plates insulatedly mounted between a pair of side plates, said plates extending in planes parallel to the axis of the arc, ferrous plates mounted on the outer sides of said side plates forming a path for magnetic blow-out fluxes, said ferrous plates being regis terable with the ends of the magnetic core of a blow-out coil, said barrier plates, side plates and ferrous plates forming a single integral unit mountable and removable as a unit upon a circuit breaker, said unit carrying a hook at the rear end engageable with coacting means on the circuit breaker panel and means at the front end engageable with cooperating means on the circuit breaker, said coacting means on the circuit breaker panel comprising an extension of an arcing horn, said unit carrying an arcing horn at the front end, and means for connecting said latter arcing horn in the arcing circuit. said unit being removable from said circuit breaker panel by a movement substantially parallel to the movement of the contacts.

3. An arc extinguisher comprising a plurality of spaced parallel barrier plates insulatedly mounted between a pair of side plates, said plates extending in planes parallel to the axis of the arc, ferrous plates mounted on the outer sides of said side plates forming a path for magnetic blow-out fluxes, said ferrous plates being registerable with the ends of a magnetic core of a blow-out coil, said barrier plates, side plates and ferrous plates forming a single integral unit mountable and removable as a unit upon a circuit breaker, an insulating supporting bridge at the front of the circuit breaker, the forward bottom edges of the side plates engageable with said bridge for supporting the forward end thereof, and means at the rear end of the unit engageable by horizontal movement of the unit with coacting means on the circuit breaker for supporting the rear end thereof.

4. In a circuit breaker mounted on a panel, an insulating supporting bridge supported at a distance from the panel; a blow-out coil including an arcing horn secured to said panel and an arcing contact structure secured to said panel and partially encasing said blow-out coil, a hooked. extension on said arcing contact, said blow out coil having a core extending beyond the ends of said coil, an arc extinguisher having side plates of insulating material provided with notches engageable with said extensions of said core, said side plates carrying ferrous plates registerable with the ends of said core, and a hooked member in said are extinguisher engageable with said hooked extension on said arcing contact by horizontal movement of said are extinguisher, an insulating bridge supported by and spaced from said panel the other end of said arc extinguisher being supportable on said insulating bridge, an arcing horn supported in said are extinguisher at said other end.

5. In a circuit breaker mounted on a panel, an insulating supporting bridge supported at a distance from the panel; a blow-out coil secured to said panel and an arcing contact structure secured to said panel and partially encasing said blow-out coil, a hooked extension on said arcing contact and a removable arc extinguisher, said blow out coil having a core extending beyond the ends of said coil, said are extinguisher engageable with said extensions of said core, said side plates carrying ferrous plates registerable with the ends of said core, and a hooked member in said are extinguisher engageable with said hooked extension on said arcing contact, the other end of said are extinguisher being supportable on said insulating bridge, an arcing horn supported in said are extinguisher at said other end; said arcing contact structure also comprising an arcing horn, a metallic member on said insulating bridge and means for connecting said first arcing horn to said metallic member, said member being connected to a terminal of the circuit, said second mentioned arcing horn being connected through the blow-out coil to another terminal of the current supply.

6. In a circuit breaker mounted on a panel, an insulating supporting bridge supported at a distance from the panel; a blow-out coil secured to said panel and an arcing contact structure secured to said panel and partially encasing said blow-out coil, a hooked extension on said arcing contact and a removable arc extinguisher, said blow out coil having a core extending beyond the ends of said coil, said are extinguisher engageable with said extensions of said core, said side plates carrying ferrous plates registerable with the ends of said core, and a hooked member in said are extinguisher engageable with said hooked extension on said arcing contact, the other end of said arc extinguisher being supportable on said insulating bridge, an arcing horn supported in said arc extinguisher at said other end; said arcing contact structure also comprising an arcing horn, a metallic member on said insulating bridge, and means for connecting said first arcing horn to said metallic member, said connecting means comprising a releasable member engageable with said metallic member and an end of said first arcing horn, said are extinguisher being removable from the circuit breaker assembly upon release of said releasable member.

'7. In a circuit breaker mounted on a panel, an insulating supporting bridge supported at a distance from the panel; a blow-out coil secured to said panel and an arcing contact structure secured to said panel and partially encasing said blow-out coil, a hooked extension on said arcing contact and a removable arc extinguisher, said blow-out coil having a core extending beyond the ends of said coil, said arc extinguisher engageable with said extensions of said core, said side plates carrying ferrous plates registerable with the ends of the core, and a hooked member in said are extinguisher engageable with said hooked extension on said arcing contact, the

, other end of said arc extinguisher being supportable on said insulating bridge, an arcing horn supported in said are extinguisher at said other end; said arcing contact structure also comprising an arcing horn, a metallic member on said insulating bridge, and means for connecting said first arcing horn to said metallic member, said connecting means comprising a screw engageable with openings in said metallic member, and an end of said first arcing horn, said are extinguisher being removable from the circuit breaker assembly upon rotation of said screw.

8. In a circuit breaker mounted on a panel, a removable arc extinguisher, means for positioning said extinguisher comprising means on said panel engageable with cooperating elements on one end of said extinguisher and an insulating member supported in spaced relation to said panel engageable with the other end of said extinguisher, said other end of said are extinguisher carrying an arcing horn, and a. single means for securing said end of said arcing horn to said insulating member and connecting said arcing horn in an arcing circuit.

9. L1 a circuit breaker mounted on a panel, a blow-out coil secured to said panel, and an arcing contact structure secured to said panel and partially encasing said blow-out coil, a hooked extension on said arcing contact and a removable arc extinguisher, said blow-out coil having a. core extending beyond the ends of said coil, said are extinguisher engageable with said extensions of said core, said side plates carrying ferrous plates registerable with the ends of said core, said arc extinguisher comprising a series of barrier plates with hooked shaped members therebetween, said hook members being engageable with said hooked extension on said arcing contact.

10. In a circuit interrupter an arc chute comprising a pair of spaced side plates of insulating material, magnetic plates positioned on the outside of said insulating plates, spacing means between said insulating plates, means securing said magnetic plates, insulating plates and spacing means together, insulating supporting means, a pair of contact structures on said supporting means for connection in an electric circuit, one of said structures comprising a conducting coil and a magnetic core therefore extending axially beyond the dimensions of said coil, notches in said insulating plates adapted to embrace the ends of said core when said are chute is in operative position, said magnetitc plates covering said notches to engage the ends of said core, an arcing horn associated with said coil and secured to said supporting means, a horizontal groove in said arcing horn, one of said spacing means for said plates cooperating with said groove for positioning one end of said are chute, a bracket mounted on said insulating supporting means and additional spacing means cooperating with said bracket for positioning the other end of said are chute.

11. In a circuit interrupter an arc chute comprising a pair of spaced side plates of insulating material, magnetic plates positioned on the outside of said insulating plates, spacing means between said insulating plates, means securing said magnetic plates, insulating plates and spacing means together, insulating supporting means, a pair of contact structures on said supporting means for connection in an electric circuit, one of said structures comprising a conducting coil and a magnetic core therefor extending axially beyond the dimensions of said coil, notches in said insulating plates adapted to embrace the ends of said core when said arc chute is in operative position, said magnetic plates covering said notches to engage the ends of said core, an arcing horn associated with said coil and secured to said supporting means, a horizontal groove in said arcing horn, one of said spacing means for said plates cooperating with said groove for positioning one end of said arc chute, a bracket mounted on said insulating supporting means and addi tional spacing means cooperating with said bracket for positioning the other end of said are chute, said additional spacing means comprising clamping means cooperating with said bracket to preclude movement of said are chute relative to said insulating supporting means until after release of said clamping means.

12. In a circuit interrupter an arc chute comprising a pair of spaced side plates of insulating material, a plurality of spacing means between said plates and means for securing said insulating plates and spacing means together, insulating supporting means, a contact structure mounted on said supporting means, said contact structure comprising a groove having its opposed surfaces in horizontal planes, one of said spacing means cooperating with said groove for positioning one end of said arc chute, a bracket mounted on said insulating supporting means and additional spacing means cooperating with said bracket for positioning the other end of said chute.

13. In a circuit interrupter an arc chute comprising a pair of spaced side plates of insulating material, a plurality of spacing means between said plates and means for securing said insulating plates and spacing means together insulating supporting means, a contact structure mounted on said supporting means, said contact structure comprising a groove having its opposed surfaces in horizontal planes, one of said spacing means cooperating with said groove for positioning one end of said arc chute, a bracket mounted on said insulating supporting means and additional spacing means cooperating with said bracket for positioning the other end of said chute, said additional spacing means comprising a metallic arcing horn.

14. In a circuit interrupter an arc chute comprising a pair of spaced side plates of insulating material, a plurality of spacing means between said plates and means for securing said insulating plates and spacing means together, insulating supporting means, a contact structure mounted on said supporting means, said contact structure comprising a groove having its opposed surfaces in horizontal planes, one of said spacing means cooperating with said groove for positioning one end of said arc chute, a bracket mounted on said insulating supporting means and additional spacing means cooperating-with said bracket for positioning the other end of said chute, said additional spacing means comprising a metallic arcing horn; a, second contact structure mounted on said insulating supporting means and conducting means connecting said additional spacing means and said second contact structure.

' 15. In a circuit interrupter an arc chute comprising a, pair of spaced side plates of insulating material, a plurality of spacing means between said plates and means for securing said insulating plates and spacing means together, insulating supporting means, a contact structure mounted on said supporting means, said contact structure comprising a groove having its opposed surfaces in horizontal planes, one of said spacing means cooperating with said groove for positioning one end of said arc chute, a bracket mounted on said insulating supporting means and additional spacing means cooperating with said bracket for positioning the other end of said chute, said additional spacing means comprising a metallic arcing horn; a second contact structure mounted on said insulating supporting means and conducting means connecting said additional spacing means and said second contact structure, one end of said conducting means being insulatedly secured to said bracket, for cooperation with said additional spacing means and the other end of said conducting means being secured to said second contact structure.

16. In a circuit interrupter an arc chute comprising a pair of spaced side plates of insulating material, a plurality of spacing means between said plates and means for securing said insulating plates and spacing means together, insulating supporting means, a contact structure mounted on said supporting means, said contact structure comprising a groove having its opposed surfaces in horizontal planes, one of said spacing means cooperating with said groove for positioning one end of said arc chute, a bracket mounted on said insulating supporting means and additional spacing means cooperating with said bracket for positioning the other end of said chute, and detachable clamping means between said additional spacing means and said conducting means for precluding movement of said are chute relative to said insulating supporting means until after release of said clamping means.

17. In a circuit interrupter an arc chute comprising a pair of spaced side plates of insulating material, magnetic plates positioned on the outside of said insulating plates, spacing means between said insulating plates, means securing said magnetic plates, insulating plates and spacing means together, insulating supporting means, a pair of contact structures on said supporting means for connection in an electric circuit, one of said structures comprising a conducting coil and a magnetic core therefor extending axially beyond the dimensions of said coil, notches in said insulating plates adapted to embrace the ends of said core when said arc chute is in operative position, said magnetic plates covering said notches to engage the ends of said core, an arcing horn associated with said coil and secured to said supporting means, a horizontal groove in said arcing horn, one of said spacing means for said plates cooperating with said groove for positioning one end of said arc chute, a bracket mounted on said insulating supporting means and additional spacing means cooperating with said movable contact structure and operating mech- 10 anism therefor, .a member .of insulating material secured to said bracket and .a plurality of .arc extinguishers each having one end supported by the respective stationary contact structure ,and the otherlend releasablysecured to said member; andan arcing horn carried in said other end .of each .arc extinguisher; the means for securin saidother end to said member ,also connecting said arcing horn in the arcing circuit.

FRANK J. POKORNY.