MXPA00004100A - Selector switch - Google Patents

Abstract

The invention relates to a selector switch for tapped transformers to enable continuous tap switching with respect to a tapped winding, whereby fixed stepped contacts are arranged inside a cylinder made of insulating material on a horizontal plane for each phase. A rotating actuating shaft is located inside the insulating cylinder. The actuating shaft has a moveable hinged contact carrier for each phase that is to be switched and vacuum switching cells are respectively and vertically arranged on said contact carrier.

Description

LOAD SELECTOR SWITCH Description of the invention The invention relates to a load selector switch for tapstream transformers in accordance with the preamble of the first patent claim. These load selector switches are already known from DE 38 33 126 C2. The load selector switches in the transformers are used to switch the sockets of the regulating windings of these transformers under • load, and thereby compensate in a specific way the voltage variations. The load selector switches are less complex to manufacture and apply because the otherwise separate separation of the selector and the load switch is dispensed with. During the switching process, arcs occur in various contacts of the load selector switch. In order to avoid this, in the abovementioned document DE 38 33 126 C2 a load selector switch is proposed in which, in each phase to be switched, two mobile mechanical switching contacts that rotate together simultaneously are provided in a common contact carrier. , and being that in series with Each of both movable mechanical switching contacts is provided in each case with a vacuum switching cell, also arranged on the contact carrier. The staggered fixed contacts of the load selector switch that can be switched by the rotating mechanical switching contacts are arranged in a concentric circle in the wall of a cylinder of insulating material. The vacuum switching cells are disposed horizontally on the contact carrier, and are controlled or actuated by a cam sliding surface disposed in another concentric circle, and axially between the circle of fixed staggered contacts and an additional slip ring. This known load selector switch suffers from several disadvantages. On the one hand, the horizontally disposed arrangement of the vacuum switching cells on the common contact carrier results in an undesirably large diameter of the cylinder of insulating material, and consequently of the load selector switch. The vacuum switching cells have certain 'Minimum dimensions according to their breaking capacity, in particular also a considerable extension longitudinal. To this, it must be added that in the longitudinal direction, outside the vacuum switching cell, the drive pushers also protrude. It is therefore obvious that the common contact carrier must have a radial extension dictated by the dimensions of the vacuum switching cell and the drive elements, which determines the total diameter of the load selector switch. Apart from these general problems concerning the dimensions, a particular disadvantage of horizontally installing the vacuum switching cells according to the state of the art is that when the load selector switch is filled with oil, in the upper folds of the bellows of the vacuum cells left remaining air that is not completely dislodged by the oil filling. This leads to that when the vacuum switch cell is operated, an unequal load occurs in the respective bellows of the vacuum cell, whereby there is a danger that it will break. In the case of a horizontal arrangement, a remnant of residual air in the bellows area of the vacuum cell can only be reliably avoided if the load selector switch is filled under vacuum; However, a vacuum filling at home, for example after making revisions, is impossible perform, or only incurring unjustifiably high expenses. In addition, it must be taken into account that the load selector switches in their entirety generally have a large axial longitudinal extension, that is, a considerable construction height. The stepped contacts of the individual phases to be switched are arranged circularly overlapping, also occupy the elements arranged at the head of the load selector switch, to drive the rotary shaft of the switch that supports the contact carriers of each phase inside the load selector switch, as well as the elements to accommodate this switch shaft in the bottom of the load selector switch, so that as explained, the load selector switch has a considerable longitudinal extension in total. This has the consequence that the aforementioned commutator shaft is also very long in its interior. Such commutating shafts are usually made of GFK or other insulating material, although metal commutation shafts have already been proposed, however. In the known load selector switch the contact holders are fixed to the switch shaft by fixing screws.

In DE 44 14 941 Cl another firm attachment of a contact carrier to the switch shaft is described by means of a clamping flange. Due to the tolerances, the different thermal expansions of the oil container and the column of switches, the combamientos and other causes, in the case of the known load selector switches can present interaction problems between the components arranged on the individual contact carriers - especially the vacuum switching cells - and the drive elements arranged in a circular form, in particular also because the drive pushers of the vacuum switching cells generally only have a relatively small linear drive path. It is the task of the invention to eliminate these disadvantages and to provide a load selector switch of the type under consideration that allows a space saving arrangement of the vacuum switching cells, and its safe and reliable operation under all operating conditions. This task is solved by a load selector switch with the characteristics of the first patent claim. The subordinate claims are related with particularly convenient refinements of the invention. In the load selector switch according to the invention, the vacuum switching cells are arranged vertically on the contact carriers. The contact holders have sliding contacts, they are precisely guided in a bypass ring with rollers.

By means of cams in this bypass ring, the vacuum switching tubes are controlled. The blade sliding contacts housed in the contact carrier discharge the current through the bypass ring. Other slide contacts of the blade holder allow the power supply. In accordance with another characteristic of the invention, the contact carriers are in each case movably arranged on the switch shaft. In addition to the small dimensions, the particular advantage of the load selector switch according to the invention resides in that all forces are supported axially for the operation of the vacuum switching cells as well as the contact forces through the bypass ring and the fixed contacts to the stable oil container. This prevents radial load on the switch column, in particular its movement and, as a result of this, a variation of the control intervals of the vacuum switching cells and a reduction of the contact forces. By means of the contact carrier mounted in a rotationally and axially displaceable manner, which is guided axially by the bypass ring, the development of the switching is ensured even in the case of height shifts due to different thermal tolerances and expansions of the oil container and the column of switches. The invention will now be further explained in more detail with reference to the drawings. FIG. 1 shows a first embodiment of a load selector switch according to the invention, in a partial side elevation view, in section, FIG. 2 a part of the contact carrier of this load selector switch in section representation , plan view, Figure 3 a second embodiment of a load selector switch according to the invention, in a partial side elevation, in section, 4 shows a schematic representation of the switching on which the load selector switch is based according to the invention, FIG. 5 a switch of this type modified, FIG. 6 a typical switching sequence of a load selector switch according to the invention. with the invention The load selector switch shown in FIG. 1 shows an embodiment of the invention with a contact carrier 3 rotatably mounted on a shaft 2 of the switch., and with vacuum switching cells 27, 28 arranged vertically on it. ,. With regard to the structure of the construction in detail: The load selector switch is constituted by a cylinder 1 of insulating material in which it is centrally located and so extending along the cylinder 1 of insulating material, a switch shaft 2, preferably of insulating material. The switch 2 of the switch rotates in a manner known per se; For this purpose, malt wheel drives that are not represented are usually used. The housing of the switch shaft 2 on the bottom of the cylinder 1 of isolating material. The shaft 2 of the switch supports in each plane the staggered fixed contacts 16 to be driven, which will be explained in more detail later, a contact carrier 3 which is mounted on the shaft 2 of the switch in a tilting manner on a bearing 4. Bearing block 4 is fixed to switch shaft 2 by screws 4.1, 4.2. The contact carrier 3 is constituted by a support part 5, a carrying case 6 and the contact box 7. The individual components of the contact carrier 3 are connected to one another by screws 8, 9. In the illustrated embodiment, the contact box 7 is again constituted by an upper part 10 of the contact box and a lower part 11 from the contact box; both parts are again connected to one another by means of other screws 12. It is possible to configure the one-piece contact box 7 equally well. The support part 5 has a bearing point 13 in which a bolt 14 is produced which establishes the connection with the bearing 4, and thereby allows the turning movement. The pin 14 is immobilized by a transverse pin 15. By this all the contact carrier 3 can to pivot as a complete assembly around the pin 14, and consequently with respect to the shaft 2 of the fixed (axially) commutator. In the wall of the cylinder 1 of insulating material are arranged - for each phase to be switched in each case in a separate plane - the staggered fixed contacts 16, which are electrically connected to the sockets of the regulating winding of the tap-changer which shall be switched. The staggered fixed contacts 16 can be switched by the corresponding contacts 17, 18. These contacts 17, 18 are arranged on the contact carrier in the horizontal direction in such a way next to one another that when the shaft 2 of the switch is rotated, and consequently the contact carrier 3, in each case one of the contacts 17, 18 reaches the new one. adjacent fixed stepped contact 16 before the other of these contacts has left the current fixed stepped contact. A contact 17 acts in this as a switching contact, the other contact 18 acts as an auxiliary contact. In Figure 2 the arrangement of both contacts 17, 18 is shown from above, one next to the other on the contact carrier 3, and its interaction with the respective staggered fixed contact 16. In the embodiment shown in Figure 2, the contact 17 that acts as a switching contact has double configuration, that is to say that it is constituted by two parts 17.a and 17.b electrically connected to each other, in order that its carrying capacity of current is as high as possible. Each of the contacts 17, 18 consists in each case of a upper contact part 17.1, 18.1 as well as in each case of a lower contact part 17.2, 18.2. In the case of the particular embodiment of the switching contact shown in FIG. 2, the contact 17 comprises a total of four parts, specifically two upper contact parts 17.1a and 17.1b as well as two contact parts 17.2a and 17.2b inferiors This double configuration of the contact 17 which acts as a switching contact makes sense for various modalities, but is however not necessary for the invention. Both the upper contact parts 17.1, 18.1 and also the lower contact parts 17.2, 18.2 of each of both contacts 17, 18 are housed in the contact box 7 so that they can be swiveled in each case around points 19, 20 , 21, 22 independent rotation. They are pushed by springs 23, 24, 25, 26 in the direction of one towards another in the direction of the staggered fixed contact 16, which in the switched state is between them.

In other words: The respective upper contact part 17.1, 18.1 as well as the respective corresponding lower contact part 17.2, 18.2 tighten with a contact force defined from both sides against the staggered fixed contact 16 in each switched case. By means of the bearing assembly described in these points 19, 20, 21, 22 of independent rotation makes it possible to slide access over fixed staggered contacts 16. In figures 1 and 2 you can only see the contact parts, turning points and springs that in the direction of the look are forward or up. In addition, on each contact carrier 3 are fixed two vacuum switching cells 27, 28, in each case by upper and lower clamping brackets 29, 30, 31, 32, so that the bellows 33, 34 as well as the pushers 35 , 36 for driving the vacuum switching cells 27, 28 extend upwards. Also of the components just described, in figure 1 you can only see that in the direction of the gaze is ahead. To operate the thrusters 35, 36 for driving the vacuum switching cells 27, 28, two levers 37, 38 are provided, each having at its free end a roller journal 41, 42 with a control roller 39, 40. With its other end respectively free act on the drive pushers 35, 36 already described. Both levers 37, 38 are pivotably housed around turning points 43, 44; It is also possible to provide a common pivot point. The rollers 39, 40 of both levers 37, 38 in turn correspond to a control ring 45 having an upper cam contour 46 and a lower cam contour 47. The control ring 45 extends radially along the inner wall of the cylinder 1 of insulating material. From figure 1 it can be seen that the first control roller 39 corresponds to the lower cam contour 47, that is to say that it rolls on it, and that in the same way the second control roller 40 rolls on the upper cam curve 46. Both cam curves 46, 47 therefore serve to drive the vacuum switching contacts 27, 28 when, when the corresponding control roller 39, 40 is accessed by a cam, the corresponding lever 37, 38 swings around its point 43, 44 and thus activates the corresponding pushers 35, 36 for actuating the vacuum switching cell 27, 28. On the internal side of the cylinder 1 of insulating material there is also a bypass contact ring 48 comprising a connection element 49 which leads to the outside and serves to derive the charge. From In a particularly simple manner, the control ring 45 and the bypass contact ring 48 can be combined into a single component of conductive material, as shown in FIG. 1. The bypass contact ring 48 in turn again corresponds to a mechanical shunt contact 50 disposed on the contact carrier 3 and which, very similar to that of the contacts 17, 18 described above, again consists of a upper branch contact part 50.1 and a lower contact part 50.2. In a very analogous manner, both these parts 50.1 and 50.2 of bypass contacts are independently housed swingably around other pivot points 53, 54 and are urged against each other by other springs 51, 52, so they adhere to the ring 48. of branch contact with a defined contact pressure. Finally, the contact carrier 3 still has two rollers 55, 56 which roll on both sides of the bypass contact ring 48 and thereby conduct the entire contact carrier 3. Through the described arrangement it is possible to compensate tolerances of all kinds, and especially also compensate for a combamiento of the long commutator tree. The contact carriers 3 arranged in a tilting manner around the shaft 2 of the commutator are in any case guided from defined by the bypass contact ring 48, so that despite the described tolerances there is precise control of the control rollers 39, 40 and thus of the operation of the vacuum switching cells 27, 28, a despite their drive paths that are only small. In FIG. 3, another embodiment of a load selector switch according to the invention is shown. In this case, unlike the example explained up to now, the contact carrier 103 is not arranged in a tilting manner, but in such a way that it can be displaced longitudinally. Inside a cylinder 101 of insulating material is again centrally disposed a shaft 102 of the switch that supports a contact carrier 103 longitudinally displaceable. The longitudinal displacement is achieved by means of a guide 104. In this case, too, two vacuum switching cells are vertically arranged, of which only the front vacuum switching cell 105 is shown. Again in each plane there are staggered fixed contacts 106 arranged in a circular form around the wall of the cylinder 101 of insulating material, these are again switched by means of a switching contact as well as an auxiliary contact, of which in the only a top contact part 107.1 and a corresponding bottom contact part 107.2 are shown. Similarly, inside the cylinder 101 of insulating material there is again a bypass contact ring 108 which is enclosed by a bypass contact which again consists of a top bypass contact part 109.1 and a bypass contact part 109.2. lower derivation. The driving of the complete contact carrier in this case is carried out by means of a roller 110 which rolls on the circumference of the bypass contact ring 108. The control of the vacuum switching cells is again carried out by means of two levers 115, 116 which at their free ends each comprise drive rolls 113, 114 which again roll on a lower cam contour 111 and an outline 112 of upper cams, thus actuating the operating pushers of the vacuum switching cells, of which only the actuating push-button 117 of the vacuum switching cell 105 can be seen, which in the direction of the gaze is forward. In FIG. 4, the switching performed by the load selector switch according to the invention is represented schematically. In figure 1, which corresponds to this representation, the electrical connections between the contacts 17, 18 to the vacuum switching cells 27, 28 and again to the branch contact 50 and consequently to the bypass contact ring 48. In FIG. 5, a switch is shown in which, as shown in FIG. 2, the switching contact 17 comprises two contact parts 17a, 17b arranged side by side. Also in figure 2 corresponding to this representation, the "electrical connections are only outlined." It can be seen that the principle of operation is not different, that is, both with the switch according to figure 4 and also with that of The same development of switching is obtained according to Figure 5. A development of the switching of this kind is shown in Figure 6. For this, a load selector switch with different switching stages is represented. In this case, the distance between centers between the fixed step contact located in the main winding and both staggered fixed contacts adjacent to this is greater than the distance between centers. between the other fixed adjacent contacts, this allows the Load selector switch can also be applied in tansformers with higher nominal voltages; a higher stationary impulse voltage can be achieved thereby. In this document, the staggered fixed contacts suitable for a selector switch of this type are already disclosed, which have a different configuration. Regardless of this, it is particularly advantageous not to design the staggered contacts 16 in curved form, ie parallel to the curvature of the insulation cylinder 1, as is usual according to the state of the art, but straight, as shown in FIG. figure 2. While according to the state of the art parts 17.1, 18.1; 17.2, 18.2 respectively upper and lower contact roll constantly on the same track of fixed staggered contacts 16, by means of the straight design it is achieved that other points on the surface of fixed staggered contacts 16 are constantly covered, which decreases their wear.

Claims (1)

1. CLAIMS Load selector switch for tap transformers for continuous switching between the sockets of a regulator winding of a tap transformer, where the load selector switch comprises as housing a cylinder of insulating material, being that inside the cylinder of insulating material are disposed circularly in a horizontal plane for each phase, the staggered fixed contacts that are in electrical contact with the intakes, being that in the center of the cylinder of insulating material there is a rotary shaft of the switch comprising a contact holder also rotating for each horizontal plane of staggered fixed contacts, each contact carrier having at least two mechanical contacts that can be connected to the staggered, fixed contacts of the respective horizontal plane, being that at least one of the contacts of each contactholder is in direct electrical contact with a first switch cell vacuum ion, and at least one other contact of each contact carrier is in electrical contact with a second cell of vacuum switching through a cross-connect resistor, and the other side of both vacuum switching cells of each contact carrier being in electrical contact with a load diverter, this switch being characterized in that all the contact carriers are articulated in mobile form to the switch shaft, independent of each other, and because the respective two vacuum switching cells are vertically disposed on the respective contact carrier, so that their drive pushers extend substantially in the axial direction. Charge selector switch according to claim 1, characterized in that each of the contact carriers is hinged to the commutator shaft so that it can swing about a pivot point. Load selector switch according to claim 1, characterized in that each of the contact carriers is articulated to the shaft of the commutator so that it can be moved axially along the shaft. Charge selector switch according to one of claims 1 or 2, characterized in that each of the contacts consists of at least one upper contact part and at least one lower contact part, and each contact part being pushed against the other against the force of a spring, so that when a fixed stepped contact is commutated it is mechanically clamped on both sides and electrically contacted. Charge selector switch according to one of claims 1 to 4, characterized in that the horizontal extension of the staggered contacts fixed inside the cylinder of insulating material does not adapt to the internal cor of the cylinder of insulating material but develops in particular in the form straight. Charge selector switch according to one of claims 1, 2, 4 or 5, characterized in that for each phase to be switched and consequently for each horizontal plane of staggered contacts fixed on the inner wall of the cylinder of insulating material, a ring is provided. control comprising an upper cam cor as well as a lower cam cor, on each contact carrier there is arranged for each of both vacuum switching cells a lever mounted to swing around a pivot point, and because each lever acts respectively with one of its two free ends on a drive pusher of a switch cell with vacuum, and with its other end respectively free rolls on one of the cam cors respectively, so that depending on the spatial shape of the respective cam cor can act the respective vacuum switching cell. Load selector switch according to one of claims 1, 2, 4 to 6, characterized in that Each load branch is constituted by a concentric bypass contact ring disposed in. the inner wall of the cylinder of insulating material comprising a connection element led to the outside and which can be connected by a bypass contact disposed on the respective contact carrier and which is in electrical contact with the respective vacuum switching cells of this contact carrier . Load selector switch according to one of claims 1, 2, 4 to 7, characterized in that each contact carrier comprises two other rollers that roll on both sides of the corresponding bypass contact ring, so that the respective contact carrier is driven automatically. Load selector switch according to one of claims 1, 2, 4 to 8, characterized in that the control ring y. the bypass contact ring of each phase are combined in each case into a single component.