US2500429A - Electric gas blast circuit breaker - Google Patents

Description

5 Sheets-Sheet 1 March 14, 1950 H. A. HIDDE NIJLAND ELECTRIC CAS BLAST CIRCUIT BREAKER Filed Feb. 15, 1 946 March 14, 1950 H. A. HIDDE NIJLAND 2,500,429

v ELECTRIC CAS BLAST CIRCUIT BREAKER Filed Feb. 15, 194e s'sneets-sneet 2 Plas y 'FHM' 16 W wi 7 E9 v Z9 March 14, 1950 Hl A, H|DDE NlJLAND 2,500,429

ELECTRIC GAS BLAST CIRCUIT BREAKER Filed Feb. 15, 1946 3 Sheets-Sheet 3 Patented Mar. 14, 1950 ELECTRC GAS BLAST CIRCUIT BREAKER Hcndrik'A. Hidde Nijland, Laren, Netherlands Application February 15, 1946, Serial No. 647,864 In vthe Netherlands February 19, 1942 Section 1, Public Law 690, August S, 1-946 .Patent expires February i9, 1962 .6 `Claims.

This invention 4relates to .improvements in electric circuit breakers particularly of the type :in which a gas .blast is vused ifor extinguishing the .arc between vthe contacts.

An object of the invention is to provide a construction wherein the pressure of a :gas is utilized to initiate the breaking of the circuit and then after the circuit has been broken vand the arc `extinguislfled the .contacts are separated a safe distance .by independently operated means which alsoclose the contacts.

A further object is to provide a construction in which the contacts are in the form of a valve so as to .control the outlet for the extinguishing gas.

Another object .is to .providea -`piston which is coupled to one of the .electrical contacts only during the time Yol? the initial breaking of the circuit and is uncoupled during the further separation .of the contacts and during the closing of the contacts.

A still further object of the invention is to provide a construction wherein the movement of the .above mentioned piston is relatively small so that the size of the .cylinderl containing the arcing chamber is reduced.

A further object is Ato .provide `a `construction wherein one of the .contact Aelements may be withdrawn or inserted into the circuit breaker While the fixed terminal contacts remain energived and the arcing chamber and piston for initiating the circuit break `rernain in place.

A still further object is to provide a simplified construction wherein the .usual provision of two separate circuit breakers in series is eliminated.

With the above and other `objects in view which will become vapparent from the detailed description below several preferred embodiments of the invention are illustrated in the drawings, in which:

Fig. 1 is a longitudinal sectional view of a circuit breaker according to the linvention with the contacts'in closed position.

Fig. 2 is a similar view of a modified con struction.

Fig. k3 is a similar -view ofthe vconstruction shown in Fig. 2 4with the parts in the position which they occupy after the initial break of the circuit.

Fig. 4 is a similar yview ofzthe construction shown in Fig. 2 with `the parts in the position which they occupy after thecontacts have been rmoved -to a safe distancerfrom one another, and

Fig. 5 is ra diagrammaticview with :parts in elevation of the complete device-illustrating :the

zoo-14s) means for moving the contacts to a safe distance and for closing the contacts.

In the drawings like reference characters lrefer to like parts in the various figures.

Referring to Fig. 1 .a cylinder Iof insulating material is closed at its lower end by a metal cap which has at vits center -a iixed contact 2 in the forni of a valve seat. A movable rod shaped contact 3 cooperates with the Contact 2 and the contact 3 is in permanent sliding contact with the 'terminal contacts ft arranged in a circular series. The contact 2 through the metal .cap is electrically connected to the terminal ring l' the terminal contacts 4 are electrically connected `with the terminal ring 8. The rings 7 and 8 areirnounted on the casing 5 which is located within the casing E. The leads 4| and .4i-'i shown in Fig. 5 are connected to the terminal rings.

The arci'ng chamber within the cylinder l is closed at its upper end by a cover 9 provided with a conduit il! whereby gas under pressure `may be introduced into the arcing chamber through the ducts l I.

When the contacts 2 and 3 are initially separated such gas under pressure will passat high speed through contact v2 and the arc between contacts 2 and 3 is irst directed towards the pin it mounted in the'center oi a funnel shaped .gas outlet i2 and then'extinguished.

Contact rod 3 is secured to van intermediate rod l5 yby insulating tube I4 constituting an extension of contact rod 3. The rod I5 is recessed at its upper end to slidably t the operating mechanism shown in Fig. 5. The `rods l5 and i6 are interconnected by recaps of a pin l'l fixed to the rod i6 and the slots I8 provided in the rod i5 thereby providing a limited lost motion connection 'between the rods. A compression spring i9 located within the recess of the rod l5 acting against the end of the rod l5 urges the contact 3 against contact 2 `when the circuit is closed.

Slidably` mounted upon the rod 'l5 within the cover 5 is a piston 20. Such piston is movable within the cylindrical chamber .2| and is urged downwardly by a spring 22 bearing .at one end against the upper surface of the piston 20 and at the other end against the cover 9. The piston 20 is designed .to be lmoved by the pressure of the gas in the arcing chamber when it reaches a predetermined value upwardly as shown in Fig. 1 and on such upward movment the piston will contact a shoulder r.23 .provided upon .the rod I5. The upward movement of :the `piston pivoted lever 34 is pivotally connected at one end to the rod I6 and at its other end is pivoted to a fixed part upon the circuit breaker. The lever 34 is actuated by means of a piston 35 slidably mounted within a cylinder 33'.

rihe gas for operating the piston 20 and for extinguishing' the arc between contacts 2 and 3 when initially separated is supplied from a pressure tank 40. When the circuit is to be broken the valve 3l is opened which permits gas to flow through the conduit It to the inside of the cir- When the cuit breaker through the ducts II. gas reaches a predetermined pressure the piston 20 is moved upwardly which raises contact 3 a short distance from contact 2 breaking the circuit and gas can then escape through Contact 2 and extinguish the arc.

At the same time gas will pass through valve 35 and flow to the cylinder i3 to act upon piston 35 which in turn actuates the lever 34 thereby moving the rod I3 upwardly. rhe rod IE5 will then move the contact 3 from its initial separation point to its iinal position at a sate distance from the contact 2. The valve 38 acts as a throttle so that the operation oi piston 35 is delayed with respect to the action of piston 2!! which acts imn mediately. Valve 36 may be adjusted to regulate the delayed action desired.

The lost motion connection between the rods I5 and i6 provided by the pin Il' and the slots I8 permits the contact 3 to be moved a short dis tance by the piston 20 and thereby bring about the initial separation of contacts 2 and 3 without any movement of the rod IG. The mechanism for breaking the circuit .initially is therefore independent of the operating mechanism for moving the contacts to a safe distance from one another and closing the contacts.

In 'the embodiment shown in Figs. 3 and i the piston 2S is slidable upon an enlarged portion 25 constituting an extension of the Contact .d

rod The enlarged portion 25 is above the nxed terminal contacts 4. The upper end of the contact rod 3 is further enlarged so as to form an abutment 23' for the piston 20 and has a recessed sleeve portion is? therein which slidably engages the plug 2l with a lost motion connection formed by the pin IT and slots I8'. The plug 2l is secured by an insulating tube 28 to the rod I6. A compression spring I9 is located in the sleeve 26 between the plug 21 and the bottom of the recess.

The cylindrical chamber 28' in which the piston 2G' is movable is supported by an insulating tube 2Q secured to the cylinder I. A spring 22 located within the interior 2 I of the chamber 28' bears at one end against the piston 2U and at its other end against the top wall of the chamber 2B. The gas from the tank @lil for initiating the breaking of the circuit and extinguishing the arc is supplied through the space between the cylinder E5 and the cylinder I. Such gas then passes through the openings 3@ provided in the cylinder I in order to reach the arcing chamber. The upward movement of the piston 20' is limited by abutment 24.

The lower end of the chamber 28' is partially closed by a ring member 3I having a central opening whose diameter is less than the diameter of the piston 20. In the nonoperating position of the piston 20 this opening is closed by a reduced portion 32 upon the piston 20. The object of this construction will be explained below.

The operation of the circuit breakers described above is as follows:

When the contacts 2 and 3 or the contacts 2 and 3 are to be separated, gas under pressure flows into the arcing chamber either through the ducts II of the construction shown in Fig. l or through the openings 30 in the modincation shown in Figs. 2, 3, and 4. As soon as the gas reaches a predetermined pressure in the chamber the piston 20 or 20 is moved upwardly against the pressure of the spring 22 or the spring 22.

In the circuit breaker as shown in Fig. 1 the rod I5, the insulating tube I4 and the contact rod 3 immediately follow the movement of the piston 2li. In the circuit breaker as shown in -`Figs. 2 to l the piston 20 rst moves a slight distance freely before abutting the shoulder 23 and moving the Contact rod 3'.

both constructions since the rod I6 at first remains stationary the pressure exerted by the spring i9 or I9 must be overcome before the contact rod 3 or 3 is moved. When the piston 2li or Eil reaches its top position where it engages either the abutment 24 or the abutment 24 the contact rod 3 or 3 is spaced a short distance from the nxed contact 2. See Fig. 3. The cli cuit is thereby broken and the compressed air in the chamber escapes at high speed through contact The arc drawn by the separation of thc contacts is thus first directed towards the pin I3 and then extinguished. Consequently the arc is relatively small.

Shortly after the arc has been extinguished and the circuit broken the rod It is moved upwardly by the lever 34 and contact rod 3 or 3 is moved a substantial distance from the fixed Contact 2 in order to isolate them. See Fig. 5.

' The circuit is thus delinitely broken.

Simultaneously with or shortly after the upward movement of the rod I6 has been completed the supply of gas from the tank 4D is shut ofi. The closing of the circuit is achieved by moving the rod I6 downwardly and during this operation the piston 2Q or 20 is inoperative.

In order to prevent a slow separation of the contacts during the initial separation and thereby causing a wavering in the interruption of the current or preventing a good arc extinguishing action at the moment Contact is broken, the construction shown in Figs. 2, 3 and 4 is provided wherein the ring 3| cooperates with the reduced portion 32 of the piston 20 and the piston 2U may move freely a slight distance before contacting the abutment 23. In this construction the pressure of the gas must reach a predetermined high value in order that the pressure on the reduced portion 32 of the piston 2G becomes sufficient to overcome the action of the spring I9 and thereby move the piston upwardly. However, before the piston contacts the abutment 23 upon the rod 3' the reduced portion 32 will move out of the ring 3| and thereby expose the entire bottom surface of the piston 2D' to the high pressure of the gas. This will cause the rod 3 to be moved forceably and at high speed from Contact 2. This brings about an abrupt interruption of the circuit and prevents burning of the contacts.

In the illustrated circuit breakers the rod i6, the contact rods 3, 3 and the interposed connecting parts are arranged in alignment with one another. Also the diameters of the connecting parts have been so chosen that the diameters increase from the bottom upwardly. Therefore due to this construction the contact rod 3 or d' may be entirely withdrawn from the circuit breaker While the fixed contact 2 and the iixed terminal contacts 4 remain in the circuit breaker.

The embodiment as shown in Fig. l has advantage that the piston 20 and associated parts may be mounted directly on the cover of the circuit breaker so as to have earth potential. On the other hand, however, the piston has to lift not only the contact rod 3 but also the insulating tube i4 and the interconnecting rod l5. In the construction as shown in Figs. 2 to l the piston 2D has the same potential as the iixed terminal i contacts Il so that the piston 2li has to be insulated with respect to the earth. An advantage of this construction is that during the breaking of the circuit the piston 20 need only move the contact rod 3 which results in a more rapid interruption oi the circuit.

What I claim is:

1. An electric gas blast circuit-breaker comprising an arcing chamber having an inlet and an outlet, a rod-shaped movable contact, a xed contact cooperating with said movable Contact, said movable and said iixed contact being located in said chamber, a source of gas supply under pressure, means connecting said source to said inlet, said movable and fixed contacts forming a valve controlling said outlet so that upon separation of said contacts gas escaping from said chamber through said outlet will extinguish the arc drawn between said contacts, a fixed cylinder having one side in communication with said arcing chamber, an extension upon said movable contact extending through said cylinder, a spring loaded piston slidably mounted in said cylinder and slidable on said extension operable by the pressure of gas entering said chamber, a shoulder on said extension cooperating with said piston to move said extension and said movable contact slightly in one direction to separate said contacts, said piston being independent of said movable contact during all other movements thereof, a stop member arranged in iiXed relation to said movable contact engaged by said piston when actuated by said gas to terminate said slight move ment which interrupts the electrical circuit and permits the gas to extinguish the arc drawn between said contacts, means connected to said ei:- tension of said movable contact operable after the termination of said slight movement for moving said movable contact a further safe distance from said iixed contact and a lost motion con nection between said means and said movable contact to permit said piston to separate said contacts by said slight movement without at the same time moving said means for moving said contacts to a safe distance.

2. An electric gas blast circuit-breaker as set forth in claim l. wherein said extension includes an intermediate rod having said shoulder thereon to one end of which said movable contact is attached through an insulator.

3. An electric gas blast circuit-breaker as set forth in claim l wherein said lost motion connection comprises a spring loaded plugand sleeve-joint.

Ll. An electric gas blast circuit-breaker as set forth in claim 1 wherein said extension includes intermediate rod, said piston beingr slidably supported on said intermediate rod and said stop member being formed as a shoulder on said cylinder, which is engaged by said piston when the latter driven by the gas in the switching-01T direction.

Si. An electric gas blast circuit-breaker as set i'orth in claim 1 wherein said piston is Slidably mounted on a portion ci said extension of said rod-shaped movable contact, spaced terminal contacts connected to said movable and fixed contacts, said portion lying outside the space be tween said terminal contacts and said portion having said stop member formed as a shoulder, which is engaged by said piston when the latter is driven by the gas in the switching-oit direction, and said lost motion connection is constructed as a spring loaded plugand sleeve-ioint interconnecting said portion of the extension of said movable contact to an insulator, which is inserted between said plugand sleeve-joint and said means for moving said contacts to a Safe distance.

d. An electric gas blast circuit breaker as set forth in claim 1 wherein said extension of said movable contact includes an insulator and an intermediate rod, and said circuit breaker includes spaced terminal contacts connected to said movable and iixed contacts, and said movable contact, said lost motion connection, said insulator and said intermediate rod are arranged in alignment with one another and form a composite unit which may be withdrawn from the circuit breaker or inserted thereinto while said terminal contacts remain alive and the cylinder and its piston. remain in place.

HENDRIK A. I-IIDDE NIJLAND.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,898,900 Ruppel Feb. 21, 1933 2,125.525 'Ihommen Aug. 2, 1938 2,163,558 MacNeill June 20, 1939 2,240,233 Thommen Apr. 29, 1941 2,279,536 Thommen Apr. 14, 1942 FOREIGN PATENTS Number Country Date 510,502 Great Britain Aug. 2, 1939

Images