HU223171B1 - Selector switch - Google Patents

Abstract

BACKGROUND OF THE INVENTION The present invention relates to load selectable stage transformers for continuous switching between the taps of a partial control coil. The fixed level switches (16) are arranged in a horizontal plane on the inside of the insulating material cylinder (1) for all phases. This insulating material roller (1) has an inwardly rotatable coupling shaft (2) having a contact holder (3) for each phase to be coupled which is pivotally mounted on the coupling shaft. The contact holders are provided with two stationary vacuum switch cells (27, 28). ŕ

Description

FIELD OF THE INVENTION The present invention relates to load selectable stage transformers for continuous switching between the taps of a stage transformer control coil. The load selector housing is provided with an insulating material cylinder, where fixed stage contacts, which are electrically connected to the ducts, are arranged in a horizontal plane, circular, for each phase inside the insulating material pipe. On the axis of the insulating material cylinder, there is a switching shaft which also has a rotatable contact holder for each horizontal plane of the fixed gear contacts. Each of the contact holders is provided with at least two mechanical contacts formed in contact with the fixed stage contacts in the corresponding horizontal plane. At least one of the contacts in each contact holder is electrically connected to a first vacuum switch cell and at least one further contact on each contact holder to an intermediate switch resistor via a second vacuum switch cell where the other side of each vacuum switch cell is separately loaded on each contact holder. electrical connection.

Such a load selector is known from DE 38 33 126 C2.

The load selectors, in conjunction with transformers, are used to switch the drips of the transformer control coils under load, thereby specifically compensating for voltage changes.

It is possible to produce and operate load separators with less effort, without the usual separation of the selector and load switches.

When switching, different contacts are drawn in the load selector. To avoid this, the aforementioned DE 38 33 126 C2 discloses a load selector in which, in each phase to be switched, there are two simultaneously rotatable mechanical switch contacts arranged on a common contact holder, one for each movable mechanical switch contact arranged on the contact holder. is assigned.

By means of a pivotable mechanical switch contact, the switch contacts of the load selector, which can be brought into position, are concentricly arranged on a wall of an insulating material cylinder.

The vacuum switch cells lie horizontally on the contact holder and are controlled and actuated concentricly by an additional cam located axially between the fixed gear switch circuit and an additional slip ring.

This known load selector has several disadvantages.

One disadvantage is that the horizontal arrangement of the vacuum switch cells on the contact holder requires an undesirable large diameter for the insulating material cylinder and thus for the entire load selector. The smallest dimensions of the vacuum switching cells, depending on the switching power, are determined, and this particularly affects their longitudinal expansion. In the longitudinal direction, even the actuating rods extend from the vacuum switch cells. Therefore, it is obvious that the common contact holder must have a defined radial extension due to the dimensions of the vacuum switch cells and due to the actuators, which defines the diameter of the load selector.

Apart from this general size problem, the special disadvantage is that due to the horizontal installation of the vacuum switching cells in the prior art, loading of the load switching oil with the upper part of the bellows of the vacuum cells cannot be completely displaced by the oil filling. This results in uneven loading of the accordion jacket of the respective vacuum cell when operating the vacuum switch cells, which entails the risk of rupture. Such a retention of residual air in the region of the vacuum cell's accordion shell can only be reliably excluded by the loading of the load selector under vacuum; however, such a vacuum charge can only be carried out on site, for example after verification, at extremely high costs.

It should also be borne in mind that the load selectors generally have a large axial longitudinal deflection, i.e. extremely high structural height. Each phase to be coupled is arranged in a fixed stage contact circuit, arranged on top of each other, rotatable means for actuating the coupling shaft holding the phase contact carriers inside the load selector, the load selector head, and the bearing of the coupling shaft - the load selector has an extremely long elongation. As a result, said coupling shaft inside the load selector is also extremely long.

Such coupling shafts are generally made of fiberglass-reinforced insulating material or other insulating material, however, metal coupling shafts have also been proposed.

In the known load selectors, the contact holders are fastened to the coupling shaft by means of fixing screws.

DE-44 14 951 C1 discloses a further mounting of a contact holder on the coupling shaft where a clamping flange is used.

Known load selectors, due to different tolerances and deflections of thermal expansion, oil tanks, and coupling shafts, may experience problems in the interaction of structural members, in particular vacuum switch cells, with circular actuators, in particular because of the vacuum coupling they have a linear path.

HU 223 171 Bl

It is an object of the present invention to eliminate these disadvantages and to provide a load selector that enables the space-saving arrangement of the vacuum switching cells and their safe and reliable operation in all operating conditions.

SUMMARY OF THE INVENTION The object of the present invention is to provide load selectable stage transformers for continuous switching between the taps of a regulator coil of a stage transformer. The load selector housing is provided with an insulating material cylinder. The fixed stage contacts, which are electrically connected to the taps, are arranged in a horizontal plane, circular, for each phase inside the insulating material pipe. On the axis of the insulating material cylinder, there is a switching shaft which also has a rotatable contact holder for each horizontal plane of the fixed gear contacts. Each of the contact holders is provided with at least two mechanical contacts formed in contact with the fixed stage contacts in the corresponding horizontal plane. At least one of the contacts is electrically connected to a first vacuum switch cell on each contact holder and the at least one further contact on each contact holder is connected electrically to a second vacuum switch cell via an intermediate switching resistor. The other side of each vacuum switching cell is electrically connected to each load carrier separately by a load discharge, wherein each contact carrier is independently pivotally connected to the switching shaft, both vacuum switching cells are positioned on the contact holder and their operating rods are axially disposed.

In the load selector according to the invention, the vacuum switching cells are arranged upright on the contact holders. The contact holders have sliding contacts, which are guided precisely by rollers on a guide ring. The cams in this drain ring control the vacuum switch cells.

Knife contacts, which are embedded in the contact holder, conduct current through the drain ring.

Additional blade contacts on the contact holder allow current to be supplied.

It is a further feature of the invention that the contact holders are movably disposed on the coupling shaft.

A particular advantage of the load selector according to the invention, apart from its small dimensions, is that all forces for actuating the vacuum switch cells and the contact forces through the discharge ring and fixed contacts are applied axially in the stable oil tank. This avoids radial loading of the coupling shaft, particularly with respect to deflection, and the resulting change in control time of the vacuum coupling cells and reduction of contact forces.

By means of a rotatably and axially displaceable bearing holder guided axially by the discharge ring, the switching process is assured even with the height displacement due to different tolerances of the oil tank and the coupling shaft due to thermal expansion.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to the drawings. The attached drawings show

1 is a detail view of a first embodiment of a load switch according to the invention, in a side view, in section;

Figure 2 is a sectional plan view of a portion of the load selector contact holder of Figure 1,

Figure 3 is a side elevational view of another embodiment of the load selector of the present invention,

Figure 4 is a schematic diagram illustrating a schematic diagram of a load selector according to the invention

Figure 5 is a modified version of the circuit of Figure 4, a

Figure 6 is a typical switching sequence of the load selector of the present invention.

The load selector illustrated in Figure 1 illustrates an embodiment of the present invention with a rotatable contact holder 3 mounted on a coupling shaft 2 and vacuum switching cells 27,28 arranged in an upright position.

The load selector consists of an insulating material cylinder 1 in which a coupling shaft 2 is formed centrally and extending over the length of the insulating material cylinder, preferably made of insulating material. The connecting shaft 2 can be rotated in a known manner; Maltese cross gears, not shown, are usually used for this purpose. Also, the bearing of the coupling shaft 2 on the bottom of the insulating material cylinder 1 is not shown.

The coupling shaft 2 holds, in each plane of the fixed gear switches 16 to be actuated, described below, a contact holder 3 which is pivotally mounted on a coupling shaft 2 in a bearing bracket. The 4 bearing brackets 4.1,

4.2 screws are fixed to the coupling shaft 2.

The contact holder 3 consists of a bearing part 5, a support housing 6 and a contact housing 7. Each of the structural parts of the contact holder 3 is interconnected by screws 8, 9. In the illustrated embodiment, the contact housing 7 comprises an upper contact housing portion 10 and a lower contact housing portion 11. The two parts are connected to each other by 12 screws. The contact housing 7 may be made in one piece. In the bearing part 5, a pin 14 is provided for connection to the bearing bracket 4, which allows rotary movement. The position of the pin 14 is secured by a cross pin 15.

As a whole, the entire contact holder 3 can thus be pivoted as a complete assembly around the pin 14 and thus with respect to the fixed coupling shaft 2.

In the wall of the insulating material cylinder 1 there are arranged, in planes, separate switches 16 for each phase to be connected, which regulate the regulating coils of the stage transformer3.

They are electrically connected to the taps of Bl. The fixed level switches can be brought into position by means of contacts 17, 18. These contacts 17,18 are arranged side by side on the contact holder horizontally so that when rotating the switch shaft 2 and thus the contact holder 3, one of the contacts 17,18 reaches the next next fixed gear switch 16 before the other of these contacts the gear selector switch. Thus, the contact acts as a switch contact and the other contact acts as an auxiliary contact.

Figure 2 illustrates the arrangement of the two contacts 17, 18 on the contact holder 3 side by side in plan view. Each of the contacts 17 and 18 contacts the top and bottom of the degree switch 16, respectively, the upper contact portions 17.1 and 18.1 and the lower contact portions 17.2 and 18.2. In the embodiment illustrated in Fig. 2, the contact 17 acting as a switch contact is a top 17.1 and

The lower contact portions 17.2 are doubled due to the potential for high current transfer, wherein the upper contact portion 17.1 is formed of contact elements 17.1a and 17.1b

The lower contact portion 17.2 comprises contact elements 17.2a and 17.2b. Such a dual configuration of the contact 17 acting as a switch contact is advantageous for the various embodiments, but is not a requirement of the invention. The upper contact portions 17.1, 18.1 of both contacts 17, 18,

The lower contact portions 18.2 are pivotally mounted on the housing 7 around the pivot points 19, 20, 21, 22. The contacts 17,18 are pressed against each other by the springs 23, 24, 25, 26, that is, in the direction of the fixed limit switches 16 in between and engaged.

In other words, the respective upper contact portions 17.1,18.1, as well as the associated lower contact portions 17.2,18.2, exert a certain contact force on the coupling fixed rocker switch 16. With the described bearings, a safe run-up on the fixed gear switches 16 is possible around the pivot points 19, 20, 21, 22. Figures 1 and 2 illustrate only the front and top contact portions, pivot points, and springs.

Further, each of the contact holders 3 is provided with two vacuum switching cells 27,28 secured by upper and lower clamps 29, 30, 31, 32 such that the bellows 33, 34 and the operating rods 35, 36 of the vacuum switching cells 27, 28 extend vertically upwards. . These are the structural parts described

Figure 1 shows only those in the forward direction. The actuating rods 35, 36 of the vacuum switching cells 27, 28 are actuated by two levers 37, 38 having at each free end a roller pin 41, 42 with a guide roller 39, 40. The other free ends of the levers 37,38 act on the operating rods 35, 36 already described. Both levers 37, 38 are pivotally mounted about pivots 43,44, but it is also possible that they are arranged with a common pivot point. The guide rollers 39, 40 of each lever 37, 38 cooperate with a guide ring 45 having an upper guide track 46 and a lower guide track 47. The guide ring 45 is located radially on the inner wall of the insulating material cylinder 1. As shown in Figure 1, the first guide roller 39 is connected to, i.e. runs on, the lower guide track 47, while the second guide roller 40 rolls on the upper guide track 46. Each of the guide tracks 46, 47 serves to actuate the vacuum switching cells 27, 28, whereby, when the respective control rollers 39, 40 run on a cam, their respective levers 37,38 pivot about the pivot point 43,44, and thus the vacuum switching cells 27, 28 , 36 operating rods.

The insulating material cylinder 1 also has on its inside a drain ring 48 which has an outlet connector 49 and is used for load discharge. In a particularly simple manner, the guide ring 45 and the outlet contact ring 48 may be formed from a conductive material as a single structural member, as illustrated in FIG. The discharge contact ring 48 is further connected to a mechanical discharge contact 50 arranged on the contact holder 3 and, similarly to the contacts 17, 18 described above, also comprises an upper discharge contact portion 50.1 and a lower discharge contact portion 50.2. Each of the lead-in contact portions 50.1, 50.2 is pivotally mounted about each pivot point 53, 54 and pressed against each other by additional springs 51, 52 so as to encircle the lead-in contact ring 48 at a defined contact pressure.

Finally, the contact holder 3 has two other rollers 55, 56 which roll down on both sides of the lead-out contact ring 48, thereby guiding the entire contact holder 3.

By the described arrangement, it is possible to compensate for any tolerance, thermal expansion, and especially to compensate for the deflection of the long coupling shaft 2. In each case, the pivotable contact holder 3 is pivotally guided around the switching axis 2, so that despite the tolerances, the control rollers 39, 40 can be controlled and thus the vacuum switching cells 27, 28 can be actuated, even if only a small travel path.

Figure 3 illustrates a further embodiment of the load selector according to the invention. In this embodiment, unlike the example described above, the contact holder 103 is not rotatable but is displaceable longitudinally. Inside the insulating material cylinder 101, also on its common axis, is a coupling shaft 102 which holds a longitudinally displaceable contact carrier 103. Longitudinal displacement is accomplished by means of a wire 104. Again, two stationary vacuum switch cells are provided, of which only the front vacuum switch cell 105 is depicted. In this embodiment, in each of the planes, the step contacts 106 are arranged in a circular shape in the wall of the insulating material cylinder 101, which again can be provided by means of a switch contact and an auxiliary contact.

EN 223 171 Bl pipes in position. Of these, only the upper contact portion 107.1 and the associated lower contact portion 107.2 are shown. Similarly, within the insulating material cylinder 101, a lead-in contact ring 108 is enclosed by a lead-in contact, which lead-in contact consists of an upper lead-in contact part 109.1 and a lower lead-in contact member 109.2.

In this case, the guide of the complete contact holder 103 is provided by a roller 110 running on the path of the lead-out contact ring 108. The vacuum switching cells are again controlled by means of two levers 115,116 having at their free ends a control roller 113,114, which also runs on a lower control track 111 and an upper control track 112, thereby actuating the actuating rods of the vacuum switching cells. Of the actuating rods, only the actuating rod 117 of the vacuum switching cell 105 in the forward direction is illustrated.

Fig. 4 is a schematic diagram of a circuit that can be implemented with a load selector according to the present invention. The electrical connections between the contacts 17, 18 and the vacuum switch cells 27, 28, and from there to the discharge contact 50 and thus the discharge contact ring 48, are not shown in Figure 1.

Figure 5 illustrates a circuit in which, as shown in Figure 2, the contact 17 serving as the switch contact comprises two adjacent contacts 17a, 17b. The electrical connections are not shown in Figure 2 corresponding to this wiring diagram. It can be seen that the principle mode of operation is no different, i.e., the same switching process is achieved with both the circuit shown in Figure 4 and that illustrated in Figure 5.

Such an exemplary switching process is illustrated in Figure 6, which illustrates a load selector with different switching steps. Such a load selector having switching steps n-2, n-1, n, n + 1, n + 2 is in principle known from EP 0 160 125. Here, the average distance between the fixed stage contact on the base coil and both adjacent fixed stage contacts is greater than the other fixed stage contacts. This allows the use of a load selector for transformers with higher rated voltages, thus providing a higher shock voltage. Fixed stage contacts suitable for such a load selector are already described in this document, which are configured in different ways.

Nevertheless, it is particularly advantageous if the fixed level switches 16 are not arcuate, i.e. parallel to the arc of the insulating material cylinder 1, but are straight-line as shown in Figure 2. While the prior art 17.1,18.1 upper contact portions and 17.2,18.2 lower contact portions are continuously running on the same path of the fixed gear switches 16, it is straightforward to achieve contact with a different point on the surface of the fixed gear switches 16, which reduces wear.

Claims (9)

PATENT CLAIMS 1. For load selectors for transformers for continuously switching between the taps of a regulator coil of a transformer, wherein the load select housing has an insulating material cylinder, with fixed gear contacts which are electrically connected to the ducts for each part of the insulating material, arranged with a switching axle common to the axis of the insulating material cylinder having a rotatable contact holder for each horizontal plane of the fixed degree contacts, each of the contact holders having at least two mechanical contacts which are in contact with the fixed degree switches in the corresponding horizontal plane configured wherein at least one of the contacts is provided on each contact holder and a second vacuum switching cell, and wherein the other side of each vacuum switching cell is electrically connected to each of the contact holders, characterized in that each of said contactors is electrically connected to said second contactor. the contact holder (3) is independently movably connected to the coupling shaft (2), both vacuum switching cells (27, 28) are arranged upright on the contact holder (3) and their actuating rods (35, 36) are located axially. Load selector according to Claim 1, characterized in that each contact holder (3) is mounted on the coupling shaft (2) pivotally about a pivot point. Load selector according to Claim 1, characterized in that each contact holder (103) is disposed axially and longitudinally displaceable on the coupling shaft (102). Load selector according to claim 1 or 2, characterized in that each of the contacts (17, 18) comprises at least one upper contact portion (17.1, 18.1) and at least one lower contact portion (17.2,18.2), wherein the contact portions are at least one spring. (23,24,25,26) are pressed against each other and, when coupled to a fixed selector switch (16), engages it on both sides to provide an electrical connection. 5. Load selector according to any one of Claims 1 to 3, characterized in that the fixed level switches (16) have a horizontal dimension in the insulating material cylinder (1) which has a different shape from the inner contour of the insulating material cylinder (1), in particular a straight line. Load selector according to one of Claims 1, 2, 4, 5, characterized in that a control ring (45) is arranged on the inner wall of the insulating material cylinder (1) in the horizontal plane of each phase to be connected and thereby of each fixed gear switch (16). having an upper guide track (46) and a lower guide track 5 It has a shooting path (47) and a lever (37, 38) pivotally mounted to each of the vacuum switch cells (27, 28) on each contact holder (3), rotatably mounted around a pivot point (43,44), and the lever arms (37, 38). 38) with one free end connected to the actuating rod (35, 36) of a vacuum switching cell (27, 5 28) and the other free end via a control path (46, 36). 47), which control tracks (46, 47) are formed on the actuator of the vacuum switching cells (27, 28). 7. Figures 1, 2, 4 to 6. Load selector according to any one of claims 1 to 3, characterized in that each load discharge consists of a concentric drainage contact ring (48) arranged on the inner wall of the insulating material cylinder (1) having a discharge connection (49) and a drainage contact (3) on the contact holder (3). 50), which is electrically connected to the respective vacuum switching cell (27, 28) on this contact holder (3) is configured to be in contact. 8. Figures 1, 2, 4 to 7. Load selector according to any one of claims 1 to 4, characterized in that each contact holder (3) is provided with two additional roller contacts (3) which are rolled down on both sides of the associated drainage contact ring (48). It has 10 forced steering rollers (55, 56). 9, 1, 2, 4 to 8. Load selector according to any one of claims 1 to 3, characterized in that the control ring (45) and the discharge contact ring (48) of each phase are combined as a structural element.