US1798861A - Circuit breaker - Google Patents

Description

March 31, 1931. o. zlNGG CIRCUIT BREAKER Filed April 1s. 1927 @5M/Wy Patented Mar. 31, 1931 UNITED STATES PATENT OFFICE OSCAR ZINGG, OF BADEN, SWITZERLAND, ASSIGNOR TO LKTIENGESELLSCHAFT BROWN BOVERI & CIE., OF BADEN, SWITZERLAND, .A CORPORATION OF SWITZERLAND CIRCUIT.` BREAKER Application led April 13, 1927, Serial No.

5, wherein arcing contacts are employed in addition to the main contacts.

The general object of the invention is the provision of improved mechanism of the sort specified above which will open and close the main contacts and the arcing contacts in sequence, the opening and closing movements of the arcing and main contacts being effected at different speeds.

Another object is the provision of mechanism of the sort specifiedv which is certain and positive in operation, of simple and stable construction, and not liable to structural or functional disorders.`

Other and further objects ofthe invention will be pointed out or indicated hereinafter,

or'wi'll be apparent to one skilled in they art upon an understanding of the invention or its employment in practice;

In the accompanying drawing forming i.

26 part of this specification, I show, by way of example, one form of device embodying the invention, but it is to be understood. that this is not to be construed in any fashion having the effect of limiting the appended claims 30 short of the vtrue and most comprehensive scope of the invention in the art.

In the drawing,

Fig. 1 is a sectional elevation of an oil circuit breaker; and

Fig. 2 is a sectional elevation taken at right angles to Fig. 1, some of theoperating parts beingA shown in section on the line 2 2 of Fig. 1.

The length of the arc formed when an electric current is interruptedL depends primarily on' the voltage and current density, but the speed at which the contacts move constitute another factor of particular importance in the case of oil immersed switches.

Inl apparatus for handling currents up t0- 183,278', and in Germany October 8, 1926.

two thousand amperes, satisfactory results may be obtained with switching` speeds of from one to three meters per second, and oil switches in which the main brushes and the arcingcontacts are rigidly connected can be operated at these speeds without difficulty. Vith heavier apparatus, however, suitable for dealing with heavier currents, it is of advantage to operate the heavy main brushes and the lighter arcing contactsseparately, so that the heavy main contacts may be operated at a slower' speed and shorter travel that may be most advantageous in effecting a quick termination of the arc. The present invention provides an effective apparatus for accomplishing this result in a positive manner without involving the employment of delicate parts such as catches, trip springs or the like. By thus operating the heavy main contacts at a considerably lower velocity than is desirable and permissible in the K operation of the relatively light arcing contacts, and moving them through only a fraction of the distance, the work required for accelerating the contacts and breaking the circuit may be kept at a minimum, and the apparatus as a whole relieved of shocks and stresses attendant upon the starting and stopping of heavy masses incident to tneir rapid movement through substantial distances.

The nature of the invention may be most readily ascertained by reference to the example shown in the drawing. Here the reference numeral 10 designates the tank or casing of the oil switch, which houses the operating parts and retains them immersed in a body of oil. The leading-through bushings are designated 11, and carry the station ary main Contact members 12 and the stationary arcing contact members 14. The operating shaft 15 enters the upper portion of the casing and is connected with a coiled spring 16 which is tensioned by rotation of the shaft in one direction, so that upon release of the yshaft the spring will throw it back. in the opposite direction. The shaft carries crank arms 17 to which are connected links 18 and 19. The links 18 are connected to the upper main contact yoke 20, while the links 19 are connected to the lower main contact yoke 21, said yokes being guided on the guides 22 which depend from the cover ot the casing. According to this arrangement, the main cont ct yokes 2O and 21 will be moved apart in a vertical direction by rotation ot the shaft in one direction, and will be caused to approach each other by rotation of the shaft in the other direction. The yoke 2O carries the upper main contact brushes 24, while the yoke 21 carries the lower main Contact brushes 25. These brushes engage respectively the top and bottom sides ot the main contacts 12 under counterbalancing pressures, so that the mountings of the main contact members do not have to support these closing pressures. These yoke members 2O and 21, of course, are of non-conductive material` The yoke carries two downwardly extending rack rods 26 which mesh at opposite sides with two independently rotatable pinions 27. These pinions are journalled in a sliding trame 28 which has guiding support on said rack rods and flexible support on the lower yoke member 21 through the medium of a coiled spring 29. Attached to the sliding frame 28 and extending down through the spring 29 and through a bore in the lower yoke 21, is a stop rod 30 carrying at its lower end a coiled spring 31. Slidably mounted in the frame 28 and meshing with the pinions 27 on the sides opposite the rack rods 26, are the rack rods 82 which support at their lower ends the arcing contactyoke 34 which carries the movable arcing contacts positioned for cooperation with the stationary arcing contacts 14. The rack bars 26, at their lower ends, pass through guides 3G on the yoke 21, and the rack bars 82 likewise pass through said guides and through guides 37 on the yoke 20.

In the drawing, the apparatus is shown with both the main and arcing contacts in the closed positions in. which condition or the device the spring 29 is compressed. ln the opening operation, rotation oi' the shaft 15 moves links 19 downwardly and links 18 upwardly at like'speed. Links 18 move yoke 2O upwardly, while links 19 move yoke 21 downwardly, causing the main brushes and 25 to be separated vfrom contacts 12.

Arcmg contact yoke 84 meanwhile remains stationary, so that the arcing` contacts remain closed. The upward movement of yoke 20 moves rack rods 26 upwardly so that pinions 27 are rolled upwardly on rack rods 82, carrying sliding frame 28 and stop rod 30 with them. rlhisA upward movement ot stop rod 30, and the downward movement of yoke 21, brings stop spring 31 against the lower side of yoke 21, whereuponthe continued downward movement of yoke 21 moves slid* ing frame 28 downwardly. Thereupon, by virtue orn the coupling through pinions 27, the continued upward movement of rack rods 2G and downward movement of frame 28 causes rack rods 32 to be moved downwardly, thereby separating the arcing contacts 84 and 14. This downward movement of rack rods 32 and consequently the movement of arcing contact yoke 34 and arcing contacts 35 is at a velocity three times that of the velocity of the main brushes 24 and 25. This is obtained as follows:

It s equals the velocity oi the yoke 21 which carries the axle of pinions 27 downwardly, and also the velocity ot yoke 20 which carries rack rods 26 upwardly, it follows that the peripheral velocity of pinions 27 is 2s. This would represent the velocity atV which the rack rods 82 are moved downwardly if the axle of the pinions were stationary, but since the pinions have a downward movement bodily at velocity s, this must be added to the velocity oi the rack rods 32, making their total velocity 3s, or three times the velocity ot the main brushes 24 and 25. Since the distance is proportional to the speed, it is evident that the arcing contacts 35 will be moved through three times the distance traversed by the main brushes 24 and 25, less the distance ot relative movement between frame 28 and yoke 21. It is to be observed, theretore, that by this arrangement the main brushes may be permitted to have a much shorter travel and much slower speed than may be requisite or desirable for eecting a quick termination of the` arc.

ln the closing of the switch, the operations above described take vplace in the reverse sequence and directions. With the rack rods 32 and the trame 28 at their lower positions, the initial approaching movement of yokes 20 and 21 will elevate the rack rods 32 and the arcing contacts 35 at a velocity three times that ot the brushes 24 and 25, but the arcing contacts 35 will close on the contacts 14 in advance of the closing` ofthe brushes 24 and 25 on the contact 12, by adistance representative of the extent to which the spring 29 is compressed when all the contacts are closed, which is the distance of relative ymovement between frame 28 and yoke 21. From the time the arcing contacts close, the yokes 2O and 21 traverse respectively a distance equal to the distance of relative movement of frame 28 and yoke 21, and during thisV time, the rack rods 32 remain stationary, and the pinions 27 are rolled downwardly on rack rods 32 so that frame 28 is moved downwardly to compress the spring 29. The energy of spring 29, when it is thus compressed, is eX- erted through pinions 27 and rack rods 82 to hold the arcing contacts closed. To add to the closing pressure and prevent the arcing contacts being kicked open by a current lll) surge as they come into contact, it may be desirable to make them of the solenoid type, as described in the co-pending application of Gottfried Bruhlmann, Serial No. 671,583,

iiled October 29, 1923.

What I claim is:

l. In electrical switch apparatus, in combination, main Contact carriers, actuating` means for moving` said main contact carriers in 'opposite directions, arcing contacts, a pinion cperable to move said arcing contacts, and means operable'from the main contact carriers for actuating said pinion.

2. In electrical switch apparatus, in combination, main contact carriers, means for moving' the same in opposite directions, main contacts carried by said carriers, a pinion shiftable relatively7 to said carriers, arcing contacts operable by said pinion, and operable connections between said pinion and said contact carriers for driving the pinion.

3. In electrical switch apparatus, in combination, relatively movable main contacts, actuating means for moving the same in opposite directions, arcing contacts movable relatively to the main contacts, a pinion having driving` connection with one of the main contacts and a lost motion connection with the other main contact, and a driving connection between said pinion and the arcing contacts.

4. In electrical switch apparatus, in combination, relatively movable main contact carriers, actuating means for moving the same in opposite directions, main contacts carried by said carriers, arcing contacts movable relatively to said carriers, transmission mechanism carried by said carriers, and a driving connection between said transmission mechanism and said arcing contacts operable to provide for actuation of the latter.

In electrical switch apparatus, in combination, relatively `movable main contact carriers, main contacts carried thereby, an arcing contact carrier shittably supported on the main contact carriers, an arcing contact carried by the arcing contact carrier, means operable by the main contact carriers for shifting the arcing contact carrier relatively thereto, and means for actuating the main contact carriers.

6. In electrical switch apparatus, in combination, a guide member, stationary contacts, main contact carriers movable on the guide member, main contacts carried by said main contact carriers for cooperation with the stationary contacts, an arcing contact carrier supported on the main contact carriers, an arcing contact carried by said arcing contact carrier for cooperation with the stationary contacts, means operable from the main contact carriers for moving the arcing contact carrier relatively thereto, and means for actuating the main contact carriers.

7. In switch apparatus, contacts disposed for movement toward and away from each other into and out of contacting position, second contacts disposed for movement into and out of contacting position, and gearing comprising cooperable toothed elements operable upon such movement of said firstnamedl contacts to effect such movement of said second contacts.

In testimony whereof I have hereunto subscribed m name at Zurich, Switzerland, this 30 day of arch, A. D. 1927.

OSCAR ZINGG.

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