US3257532A

US3257532A - Arc-extinguishing circuit-breakers

Info

Publication number: US3257532A
Application number: US328704A
Authority: US
Inventors: Lerch Hans Werner
Original assignee: Sprecher und Schuh AG
Current assignee: Rockwell Automation Switzerland GmbH
Priority date: 1962-12-17
Filing date: 1963-12-06
Publication date: 1966-06-21
Anticipated expiration: 1983-06-21
Also published as: AT236502B; DE1207473B; CH409060A

Description

June 21, 1966 H. w. LERcH ARC-EXTINGUISHING CIRCUIT-BREAKERS Filed D60. 6, 1963 Fig 4 United States Patent O Gas-blast circuit breakers are known to the art'where in the arc-extinguishing current or stream is generated in the switch or circuit-breaker itself by means of a pump piston by virtue of the circuit-opening movement or the arc energy. This known technique is useable when employing air asthe extinguishing medium for only relatively small circuit opening or breaking capacity. If, on the other hand, electro-negative gases are `employed which are under a pressure greater than atmospheric pressure as the extinguishing and insulating medium, which leads to a gas-tight construction yand a closed circulation system, then a considerably higher circuit-opening capability can be achieved. The attainable circuit-opening capacity, however, is considerablyrdependent upon the utilization of the energy available for the generation of the stream of extinguishing medium, that is, from the efcaciousness of the construction.

lt is, therefore, a primary object of the present invention to'provide an improved construction of gas-blast switch, circuit-breaker or the like wherein the extinguishing effect is greatly improved and therewith its eilciency is increased.

A further important object of the present invention resides in the provision of an improved circuit-breaker or switch of the type described manifested by its relatively simple construction, yet highly reliable operation, particularly with respect to the arc-extinguishing function.

In the achievement of the aforementioned objects the present invention contemplates the provision of an improved gas-blast circuit-breaker incorporating an extinguishing compartment or chamber arranged in a housing closed at all sides, preferably lled with electronegative gases, and wherein a current or stream of extinguishing medium is generated by means of a pump piston due to the switching movement. In the circuitbreaker or switch of the subject invention the extinguishing chamber is provided with a stationary cylinder encirculing stationary contacts as Well as a movable cylinder operatively connected to the pump piston, said movable cylinder being capable of sliding past the aforesaid stationary cylinder. Further, the pump piston has seated thereon a sealing piston which partially encloses a movable contact and which in the circuit-closing position of .the circuit-breaker seals the stationary cylinder from the pump piston. Moreover, upon opening the circuitbreaker this sealing piston first then moves out of the stationary cylinder when the movable contact has moved through a path favorable for arc-extinguishing, and prior to reaching the terminal switching-out position the movable cylinder slides past the stationary cylinder, whereby .a chamber appears between the open confronting ends of both of these cylinders which `is completely lled by extinguishing medium. 4

Further objects and the entire scope of applicability of the present invention Will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and 3,257,532 Patented June 21, 1966 scope of the invention will become apparent to those skilled in the art from this detailed description.

In the drawing wherein like reference numerals have been generally employed for the same or similar elements:

FIGURE l is a sectional view through the active portion of a gas-blast circuit-breaker or switch constructed according to the invention provided with contactsv and depicted in closed-circuit condition, and which can continuously conduct the rated current;

FIGURE 2 depicts a modifications of the circuitbreaker of FIGURE l designed for handling larger rated currents and provided with additional parallel contacts, such circuit-breaker being illustrated in closed circuit position;

FIGURE 3 illustrates the circuit-breaker of FIGURE 2 in an intermediate operating position; and

FIGURE 4 illustrates the circuit-breaker of FIGURE 2 in its open circuit position.

Referring now to the drawing and, more specifically to the embodiment of FIGURE l, it is to be appreciated that a housing 1, conveniently shown in phantom lines, is advantageously closed at all sides and preferably filled with electro-negative gases, for example SP6 (sulphur hexauoride). A connecting terminal 2 conducts the current to stationary contacts 3. A movable contact 4 is displaced by means of any suitable actuating mechanism (not shown) and is rigidly operably connected with a pump piston 5 adapted to slide within pump cylinder 6. The actual extinguishing chamber of the circuit-breaker or switch, in accordance with the invention, embodies a stationary cylinder 7 encircling the stationary contacts 3 and a movable cylinder 8 erected at the pump piston 5. This movable cylinder 8 can advantageously telescopically slide past the stationary cylinder 7, as will be more fully explained hereinafter.

Furthermore, a sealing piston 9 is seated upon the pump piston 5 and partially encloses the movable contact 4, and in the closed-circuit position of the circuit-breaker obturates the stationary cylinder 7 in the direction of the pump piston 5. At the inner wall of the pump cylinder 6 there are arranged slide contacts l0; Thus, in the embodiment of circuit-breaker or switch incorporating the physical structure shown in FIGURE l, the entire current ilows from the connecting terminal 2 via the stationary contacts 3, the movable contact 4, the slide contacts 10 and the pump cylinder 6 to the other connnecting terminal 11 operatively associated with the aforesaid pump cylinder 6. Moreover, suitable openings or ports 12 are providedrat the pump piston 5, and in the Wall of the pump cylinder 6 there is arranged a one-way or nonreturn valve 13 which, as should be apparent, closes in the presence of internal pressure within pump cylinder 6.

If switches or circuit-breakers are to be designed for rated currents which are so large that they can no longer be continuously conducted by the switch contacts themselves, then the provision of additional parallel contacts comes under donsideratidn. Such a construction of circuit-breaker is shown in the variant embodiment of FIGURES 2, 3 and 4. Since the basic construction of the physical structure of this embodiment is quite similar to that previously described in conjunction with the embodiment of FIGURE l, like reference numerals have here again conveniently been employed for the same or analogous structure. However, in this embodiment there is provided a second current path which is parallel to the current path formed by the

contacts

3, 4 and 10. This second current path conducts a considerable portion of the total current coming from the connecting terminal 2 via the upper contacts 14, here shown arranged at the underside of the aforesaid connecting piece, to the movable sliding contact means 15, from there to the lower ICC URE 1 should then be apparent.

contacts 16 and then to the connecting terminal 11. In this embodiment it is particularly advantageous to construct the slide contact means as the jacket or covering for the movable cylinder 8, as well as to arrange the lower contacts 16 directly upon the electrically conducting pump cylinder 6.

The mode of operation of the aforedescribed circuitbreakers will be set forth in conjunction with the embodiment speciiically depicted in FIGURES 2, 3 and 4. Due to the general similarities in basic physical structure cornmon to both embodiments herein described, the mode of operation of the first embodiment as depicted in FIG- Thus, it should be understood that in FIGURE 2 the switch or circuitbreaker is shown in closed-circuit condition, that is, not only are contacts .3 and 4 closed but also the parallely connected

contacts

14, 15 and I6. In order to open the switch the non-illustrated actuating mechanism rapidly downwardly displaces the contact 4 together with the

members

5, 8, 9 and 15. Immediately after having initiated the open-circuit movement, the slide contact 15 moves away from the stationary contacts 1d andl 16, whereby the entire current now only flows via the

contacts

3 and 4. Hence, it should be appreciated that from hereon the remaining descriptive portion of the operation of the circuit-breaker is generally applicable to both embodiments herein described.

The pump piston 5, which also has been moved, downwardly compresses the extinguishing medium located in the pump cylinder 6 which initially cannot escape because the non-return valve 13 closes and the sealing piston 9 still extends into the stationary cylinder 7. Only after the

contacts

3 and 4 have also separated and there has been completed the interruption or break path most favorable for arc-extinction, does the sealing piston 9 move out of the stationary cylinder 7, as clearly shown in FIGURE 3, so that the extinguishing gas in pump cylinder 6, compressed by pump piston 5, ows through ports 12 into the stationary cylinder 7 to sweep-over and extinguish the arc between

contacts

3 and 4. The movable cylinder 8 slides past the stationary cylinder 7 already prior to reaching the end or terminal switch-out position, whereby there appears between the open, confronting

ends

7a and 8a (see FIGURE 4) of both of these

cylinders

7 and 8, respectively, a compartment or space 17 which is only filled with extinguishing gas, and eliminates, the possibility that la creepage path can form between the open switch contacts. FIGURE 4 illustrates the circuitbreaker in its switch-out terminal position. Upon renewed closing of the circuit-breaker, the contact 4, the pump piston 5 together with the thereon seated

members

8, 9 and 15 move upwardly, and the pump cylinder 6 again iills-up with the inftowing extinguishing gas which at the beginning of this operation streams-in from above and during the further course of the switching-in operation flows in through the now opened non-return or oneway valve 13. while the members 5, S and 9 of the aforedescribed embodiments can advantageously be formed as an integral unit, such could also obviously be formed as separate members which are connected together in any convenient manner.

The present invention permits achieving at least the yfollowing advantages with relatively simple constructional (a) By suitably designing the end of the sealing piston 9 at the side of the contacts 3 and by selection of its stroke or degree of penetration into the stationary cylinder 7 it is possible to conduct the stream of extinguishing gas towards the arc to be extinguished in the most effective direction and in the most favorable moment of the circuit-opening movement and, indeed, only after the extinguishing gas has already been precompressed.

(b) The movable cylinder 8 formed of insulating mate- It is here further to be mentioned thatV 4 rial simultaneously serves as carrier for the slide contact means 15 with circuit-breakers designed for larger rated currents.

(c) The pump cylinder 6 consisting of electrically conductive material simultaneously serves as carrier for the

contacts

10 and 16, respectively.

(d) Suppression of arcing with open-switch contacts is positively guaranteed by a purely extinguishing mediuminsulation path 17.

While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

Having thus described the present invention what is desired to be secured by United States Letters Patent is:

l. Arc-extinguishing circuit-breaker, comprising:

a closed housing; an arc-extinguishing medium within said housing; and having within said housing: a iirst stationary cylinder open at either end; stationary first electrical contact means located interiorly of said first stationary cylinder; a movable cylinder for sliding on the outer surface of said first stationary cylinder, and defining irst and second ends, said second end being remote' from said first electrical contact means; a piston means, surrounded by said movable cylinder, in slidable, sealing engagement with the interior surface of said first stationary cylinder, and having first and second ends, said second end being remote from said rst electrical contacts; second electrical contact means, rigid with said piston means, for contacting said stationary electrical contact means; a pump piston means, rigid with said movable cylinder at said second end, for supporting said piston means at said second end of the latter, said piston means, movable cylinder, and pump piston means thus moving as a unit between a iirst end position, wherein the circuit is closed, and a second end position, wherein the circuit is open and said piston means and movable cylinder are moved out of contact with said first stationary cylinder; a second stationary cylinder open at one end for slidably receiving said pump piston means, whereby said second stationary cylinder, in cooperation with the pump piston means and the second end of the piston means, forms a chamber; one-way valve means, located in a wall of said second stationary cylinder, for admitting said medium from said housing into said chamber; port means in said pump piston means for venting said chamber to the. region between said piston means and said movable cylinder; said piston means, first stationary cylinder, and second electrical contact means being of such relative lengths that contact between said rst and second electrical contact means is broken first; contact between the piston means and the first stationary cylinder broken second; and contact between the first stationary and movable cylinders broken lastly, to form, before reaching the second end position, a spacing between the respective confronting ends of said tirst stationary cylinder and the movable cylinder, which spacing is substantially completely filled with said medium;

whereby when said piston means is moved towards the second end position, the medium compressed in s aid chamber is first forced through said port means 'into one end of the first stationary cylinder, through the cylinder, where it completely surrounds the first and second electrical contact means and quenches the arc, and out the other end into said housing, and then is forced through said spacing into said housing.

2. The circuit-breaker of claim 1, including additional electrical contact means in parallel with said rst and 5 6 second contact means to provide a parallel electrical path, fourth contact means comprises an electrically conducsaid additional contact means being separated before said Uve lacke 011 the Outer Surface 0f the movable Cyllndelirst and second contact means during opening of the circuibbreaker. References Cited by the Examiner 3. The circuit-breaker of claim 2, wherein said addi- 5 UNITED STATES PATENTS tional contact means include at least one stationary third 2,246,171 6/1941 Grosse 20o- 148 contact means, located exterior of said movable-cylinder, 2,442,010 5/ 1948 Leeds et al 200-150 and at least one fourth contact means located on the 2,933,575 4/1960 Baker 200--150 outer surface of said movable cylinder. 10 3,158,723 11/ 1964 Buechner 200-*150 4. The circuit-breaker of claim 3, wherein the movable h t cylinder is of electrically insulating material and the ROBERT S' MACON Actmg Pnmmy Examm'er'

Claims

1. ARC-EXTINGUISHING CIRCUIT-BREAKER, COMPRISING: A CLOSED HOUSING; AN ARC-EXTINGUISHING MEDIUM WITHIN SAID HOUSING; AND HAVING WITHIN SAID HOUSING: A FIRST STATIONARY CYLINDER OPEN AT EITHER END; STATIONARY FIRST ELECTRICAL CONTACT MEANS LOCATED INTERIORLY OF SAID FIRST STATIONARY CYLINDER; A MOVABLE CYLINDER FOR SLIDING ON THE OUTER SURFACE OF SAID FIRST STATIONARY CYLINDER, AND DEFINING FIRST AND SECOND ENDS, SAID SECOND END BEING REMOTE FROM SAID FIRST ELECTRICAL CONTACT MEANS; A PISTON MEANS, SURROUNDED BY SAID MOVABLE CYLINDER, IN SLIDABLE, SEALING ENGAGEMENT WITH THE INTERIOR SURFACE OF SAID FIRST STATIONARY CYLINDER, AND HAVING FIRST AND SECOND ENDS, SAID SECOND END BEING REMOTE FROM SAID FIRST ELECTRICAL CONTACTS; SECOND ELECTRICAL CONTACT MEANS, RIGID WITH SAID PISTON MEANS, FOR CONTACTING SAID STATIONARY ELECTRICAL CONTACT MEANS; A PUMP PISTON MEANS, RIGID WITH SAID MOVABLE CYLINDER AT SAID SECOND END, FOR SUPPORTING SAID PISTON MEANS AT SAID SECOND END OF THE LATTER, SAID PISTON MEANS, MOVABLE CYLINDER, AND PUMP PISTON MEANS THUS MOVING AS A UNIT BETWEEN A FIRST END POSITION, WHEREIN THE CIRCUIT IS CLOSED, AND A SECOND END POSITION, WHEREIN THE CIRCUIT IS OPEN AND SAID PISTON MEANS AND MOVABLE CYLINDER ARE MOVED OUT OF CONTACT WITH SAID FIRST STATIONARY CYLINDER; A SECOND STATIONARY CYLINDER OPEN AT ONE END FOR SLIDABLY RECEIVING SAID PUMP PISTON MEANS, WHEREBY SAID SECOND STATIONARY CYLINDER, IN COOPERATION WITH THE PUMP PISTON MEANS AND THE SECOND END OF THE PISTON MEANS, FORMS A CHAMBER; ONE-WAY VALVE MEANS, LOCATED IN A WALL OF SAID SECOND STATIONARY CYLINDER, FOR ADMITTING SAID MEDIUM FROM SAID HOUSING INTO SAID CHAMBER; PORT MEANS IN SAID PUMP PISTON MEANS FOR VENTING SAID CHAMBER TO THE REGION BETWEEN SAID PISTON MEANS AND SAID MOVABLE CYLINDER; SAID PISTON MEANS, FIRST STATIONARY CYLINDER, AND SECOND ELECTRICAL CONTACT MEANS BEING OF SUCH RELATIVE LENGTHS THAT CONTACT BETWEEN SAID FIRST AND SECOND ELECTRICAL CONTACT MEANS IS BROKEN FIRST; CONTACT BETWEEN THE PISTON MEANS AND THE FIRST STATIONARY CYLINDER BROKEN SECOND; AND CONTACT BETWEEN THE FIRST STATIONARY AND MOVABLE CYLINDERS BROKEN LASTLY, TO FORM, BEFORE REACHING THE SECOND END POSITION, A SPACING BETWEEN THE RESPECTIVE CONFRONTING ENDS OF SAID FIRST STATIONARY CYLINDER AND THE MOVABLE CYLINDER, WHICH SPACING IS SUBSTANTIALLY COMPLETELY FILLED WITH SAID MEDIUM; WHEREBY WHEN SAID PISTON MEANS IS MOVED TOWARDS THE SECOND END POSITION, THE MEDIUM COMPRESSED IN SAID CHAMBER IS FIRST FORCED THROUGH SAID PORT MEANS INTO ONE END OF THE FIRST STATIONARY CYLINDER, THROUGH THE CYLINDER, WHERE IT COMPLETELY SURROUNDS THE FIRST AND SECOND ELECTRICAL CONTACT MEANS AND QUENCHES THE ARC, AND OUT THE OTHER END INTO SAID HOUSING, AND THEN IS FORCED THROUGH SAID SPACING INTO SAID HOUSING.