HK1178678A1 - Switching system - Google Patents

Abstract

The invention relates to a switching system for a transformer, consisting of a plurality of mutually parallel, spaced-apart contact bars (2) which are arranged in a circle around a center longitudinal axis (MLA), a switch shaft (3) extending along the center longitudinal axis (MLA) and a contact arrangement (4) fastened to the switch shaft (3) and having a plurality of contact elements (5) which are arranged such as to be at least radially displaceable in relation to the switch shaft (3). The contact surfaces (6) of the contact elements (5) facing the contact bars (2) are shaped such that the distance (d1) of the contact surface (6) to the center longitudinal axis (MLA) is smaller in the center section (6.1) of the contact elements (5) than in the intermediate sections (6.2) adjoining the center section (6.1) on both sides and/or in the margin sections (6.3, 6.4).

Description

The invention relates to a switch arrangement in accordance with the general concept of claim 1.

The current of the technology has shown that the switchgear of the type is sufficiently well known and is used in transformers, especially step transformers, for powerless switching between different winding contacts of the transformer connected to the transformer.

Such a circuit arrangement consists essentially of several contact rods arranged in a circular manner around a central longitudinal axis and a central, rotatable, storage circuit shaft to which a contact rod is attached.

The contact devices known from the state of the art, such as those of US 4 496 805 A, have roller contacts, i.e. the contact elements connected to the contact rods are rolled or rolled and rotatable and are stored in the contact rod.

The disadvantage of such roller contacts is that the rolling of the roller contacts on the fixed contact rods causes residues, such as carbon residues or electrically poor or non-conductive separation layers, to be trapped on the contact rods or roller contacts by the rolling motion, thereby increasingly worsening the electrical contact.

The present invention is intended to demonstrate a contact system which, when switched, can be easily installed and which can self-clean the contacts.

The essential aspect of the invention is that the contact surface of the contact elements has at least a centre area and adjacent edge areas on either side, which are shaped in such a way that the radial distance of the contact surface to the centre-length axis in the centre-area of the contact elements is less than the radial distance of the contact surface to the centre-length axis in the centre-area of the contact elements. The reduced radial distance of the contact surface to the pivot point of the contact arrangement, namely the centre-length axis, provides a specific exception in the area between the contact points. The devices of the invention, arranged between the contact points, provide a switch switch position in which the contact arrangement is axially located and no electrical switch is placed between the contact elements. A radial protection is made possible by placing a switch position in a circular arrangement opposite the contact space.

The above and the following curvature data always refer to the centre-long axis around which the contact shaft is rotatable. The convex curved areas have a maximum curvature, the distance to the centre-long axis being greater than the distance of contact of the centre-long surface to its centre-long axis, so that the centre-long area is bounded laterally by the maximum wavelength of the adjacent interfaces.

The first edge-section is preferably in a circular arc. The first edge-section is connected to the middle of the switch position by a contact rod. In the middle of the switch position the middle-section's maximum wavelength is at least partially in the space between the electrically contacted contacts. When the contact rod is turned out of the switch position, the contact rod's contact surface must be slid in a three-dimensional direction past the maximum contact rod of the middle-section. This leads to a slight change in the contact rod's contact rod relative to the contact rod, so that the contact rod can be moved radially in the direction opposite to the middle-section of the switch position, leaving behind the contact rod's maximum contact rod.The maximum curvature of the interfaces, which is thus absorbed into the space between the electrically contacted contact rods, prevents, on the one hand, an unwanted twisting of the contact arrangement from the switching position, and, on the other, a self-adjustment of the contact arrangement in the respective switching position is achieved.

The first edge section is preferably joined by a second convex arched edge section. This second edge section may also have a maximum arching which, together with the maximum arching of the intermediate section, limits the first edge section laterally. In particular, in the case of the first edge section with a concave formation, an exception is formed between the intermediate section and the second edge section, which prevents an unintended turn of the contact arrangement from the respective switch position.

Furthermore, it is preferable to provide for rotatable rollers at the second edge-sections, which are extended in front of the second edge-sections, and which, when the contact arrangement is moved in or out of a switch position, reduce the torque to be applied, since after a rolling motion of the first edge-sections at the contact rods, the rollers coming towards the second edge-section reach the system and roll off at the contact rods.

In a preferred embodiment, a housing connected to the switch shaft is arranged in which the contact arrangement is at least partially incorporated. The contact elements of the contact arrangement are implemented as a contact plate package and can be moved individually springing against the housing. Preferably, springs are provided, which are formed as pressure springs and cause a radial pressure pressure pressure effect on the contact elements on the contact rods. The individual displacement of the contact elements can also ensure an electrical contacting, even if the surface consumption of the contact rod or contact elements is increased, for example by wear, since the individual contact elements can adapt to the surface structure.

Preferably, the contact elements shall each have at least two longitudinal holes for the movable attachment of the contact elements in the housing, the longitudinal holes defining a displacement area for the contact elements. When taking a switch position for electrical contacting two adjacent contact rods, the contact elements shall be at least partially pushed back into the housing. When positioning the contact arrangement in the intermediate switch position, with the middle area facing a contact rod, the contact elements shall be pushed out of the housing as far as possible and kept at a limited distance from the contact rod by the longitudinal rods.

The contact elements are particularly preferably shaped as grinding contact elements or grinding contact lamellae, which are characterised by a continuous course of the contact surfaces, so that when the contact arrangement is rotated towards the contact rods, the contact elements make a grinding motion on the contact rods, thus causing a cleaning of the contact surfaces.

The present invention is further explained below by means of examples of the embodiments in connection with the figures. Furthermore, further training, advantages and possibilities of application of the invention are also shown in the following description of the examples and figures.

It is expressly stated, however, that the invention is not to be limited to the examples given:Fig. 1 shows an example of a type-appropriate circuit arrangement in a schematic side view;Fig. 2 shows an example of a first implementation of a type-appropriate circuit arrangement in a winding view;Fig. 3 shows the type-appropriate circuit arrangement as described in Fig.2 in an intermediate switch position;Fig. 4 shows a second implementation of a type-appropriate circuit arrangement in a winding view;Fig. 5 shows an example of a type-appropriate circuit arrangement in a contact-oriented circuit arrangement;Fig. 6 shows an example of a type-appropriate circuit arrangement in a side view;Fig. 8 shows an example of a type-appropriate circuit arrangement with a transverse cross-section of a third-sided circuit;Fig. 5 shows an example of a type-appropriate circuit arrangement in a side view.

The first is a switch arrangement according to the invention, which can be used in particular in an inverter to change the transformation ratio of a transformer.

The switch arrangement 1 consists essentially of several parallel, spaced and circular contact rods 2 arranged around a median longitudinal axis MLA, which are passed through two spaced cage rings 8 and held in predetermined positions above them.

In the area between the two cage rings 8 a contact arrangement 4 with several contact elements 5 is provided, connected to the switch shaft 3 rotatably placed around the MLA centre axis. The contact elements 5 are movable in radial direction to the switch shaft 3 and designed to electrically contact two adjacent contact rods 2. The contact elements 5 are especially spring-loaded movable and are held in a position radially forward in relation to the MLA centre axis by pressure springs pressed towards the contact rod 2.

The switch arrangement 1 shown in the example consists of six contact rods 2. The contact arrangement 4 can thus assume six different switching positions by rotating the switch shaft 3 around the centre length axis MLA, whereby the different switching positions of the switch arrangement 1 allow different transformation ratios of a transformer connected to the switch arrangement 1 to be adjusted.

According to the invention, the contact surface 6 of the contact elements 5 facing the contact rods 2 is so shaped that the radial distance d1 of the contact surface 6 to the median longitudinal axis MLA in the centre area 6.1 of the contact elements 5 is less than the radial distance d3, d4 in the peripheral areas 6.3, 6.3', 6.4, 6.4' adjacent to the centre area 6.1 on each side.

Figures 2 and 3 show a rotatable contact arrangement 4 by means of the switch shaft 3 in a first example, wherein Figure 2 shows the contact arrangement 4 in a switch position where two contact rods 2 are electrically connected via the contact arrangement 4 and Figure 3 shows an intermediate switch position between two possible switch positions wherein the contact arrangement 4 is unlocked from the contact rods 2, i.e. the contact surfaces 6 of the contact elements 5 are not on one or more of the contact rods 2.

The contact arrangement 4 is symmetrically constructed to a symmetry axis SA, preferably mirror symmetrical. The symmetry axis SA passes through the mid-length axis MLA and the mid-range 6.1. In the switching position, i.e. the adjacent contact rods 2 are electrically connected by the contact arrangement 4, the symmetry axis SA approximately divides the space 9 between two contact rods 2 into approximately two equal halves.

The centre area 6.1 of contact surface 6 including the SA axis is concave in a preferred embodiment; this concave indication, like all other concave indications, refers to the MLA centre-long axis of the gear arrangement 1. This concave concave indication gives rise to an exception in the centre area 6.1 where at least a radial distance d1 exists between MLA centre-long axis and contact surface 6 of contact element 5 which is less than the radial distance d2 between the radial spaces 6.2, 6.2' adjacent to the centre area 6.1 on each side and the distances d3, d4', 6.3, 6.4, 6.4' between the first and second radial spaces respectively.

The radial distances d1, d2, d3, d4 are variable due to the displacement of the contact elements 5 relative to the switch shaft 3 running along the median longitudinal axis MLA. However, the individual displacement of the individual contact elements 5 relative to the switch shaft 3 causes a change in each of the distances d1, d2, d3, d4 of a contact element 5 so that the magnitude ratio of the distances d1, d2, d3, d4 to each other is always maintained.

Preferably, the radial distance d1 of the centre area 6.1 to the centre longitudinal axis MLA is chosen so that the contact arrangement 4 can take an intermediate contact position between two switching positions in relation to the contact rods 2 where the SA symmetry axis of the contact arrangement 4 passes through a contact rod 2. In this intermediate contact position the radial distance d1 of the contact surface 6 in the centre area to the centre longitudinal axis MLA assumes a maximum value. However, this maximum value of the distance d1 is less than the radial distance d5 of the outer surfaces of the contact rods 2 to the centre axis MLA, i.e. the contact surface 6 in the centre area 6.1 has a sufficient distance to the contact rod 2 from the centre longitudinal axis. This dimension 3 arrangement allows a simple and smooth contact arrangement to be achieved in relation to the contact rod 1 and the contact rod 2 in the centre area 6.1 and the contact surface 6 to the contact rod 2 from the centre.

The radial distance between the centre 6.1 and the centre 6.2 is constantly increasing, the concave arch of the centre 6.1 passing into a convex arch in the centre 6.2, 6.2' and reaching the radial distance d2 to the centre axis MLA at the maximum arching. The angle α of the arching distance of the two centres 6.2, 6.2' is chosen to be the maximum, so that the arching maxima of the convex arching areas 6.2, 6.2' lie within the interval at least partly or partially between these two centres.

The symmetrical arrangement of the arching maxima results in self-adjustment of the contact arrangement 4 in the switching position, since a twisting of the contact arrangement 4 would result in a push of the contact elements 5.

The first and second edge sections 6.3, 6.4, 6.3', 6.4' are connected to the intermediate area 6.2, 6.2' respectively outwards, the first and second edge sections 6.3, 6.4, 6.3', 6.4' being equally or essentially formed in the example shown in Figures 2 and 3. The first edge section 6.3, 6.3' of the contact area 6 is therefore at least partially connected to the contact rods 2 in the switching position. The flat or essentially flat formation of the first edge section 6.3, 6.3' reduces the radial distance d3 of the first edge section 6.3, 6.3' to the rotational axis MLA in the direction of the second edge section 6.4, 6.4' being continuously rotated, while the maximum rotational axis of the d3' is constantly rotated, 6.2' being a smaller than the maximum rotational axis of the contact rods 4 because the rotational axis between the edge and the contact rod is approximately in the direction of the contact rod 6.2, 6.2' is increased by a rotational axis of approximately 5' between the edge and the contact rod 6.2, 6.2' being a rotational axis of approximately 5' in the direction of the contact rod, and 6.2' being obtained by means of a rotational axis of approximately 6' distance from the contact rod.

Externally, the first edge section 6.3, 6.3' is joined by the second edge section 6.4, 6.4', which is preferably convex and arched relative to the MLA centre axis. These second edge sections 6.4, 6.4' form a lateral rounding of the contact elements 5 so that when the contact arrangement 4 is rotated around the MLA centre axis the contact elements 5 are sliding along the second edge section 6.4, 6.4' on the contact table 2 and the contact arrangement 4 can be moved into the switch position by radial pushing of the contact elements 5 in the direction of the MLA centre axis with low force.

The main difference with the contact surface shown in Figure 2 and Figure 3 is that the first peripheral section 6.3, 6.3' is slightly concave and arched against the central longitudinal axis MLA. This concave arch has a minimum arching in which the first peripheral section 6.3, 6.3' has a radial distance d3 to the central longitudinal axis MLA. The concave arch forms an exception in which the respective peripheral section 2 comes to the plant in a switch position and experiences a defined arrest.

Furthermore, the convex second curved marginal sections 6.4, 6.4' with respect to the median longitudinal axis MLA each have a maximum curvature, in which they have a radial distance d4 to the median longitudinal axis MLA. This radial distance d4 is greater than the radial distance d3, so that at least the maximum curvature is radially superior to the first marginal section 6.3, 6.3'. Thus, the first marginal section 6.3, 6.3' is bounded on the one hand by the maximum curvature of the intermediate section 6.2, 6.2', on the other by the maximum curvature of the second marginal section 6.4, 6.4'.

The contact line 4 consists essentially of a housing 7 with a first housing section 7.1 having a semi-circular exception 7.3 for at least partial reception of the switch shaft 3 and a second housing section 7.2 with an exception 7.4 within which a variety of contact elements 5 are included at a distance from each other.

The contact elements 5 are each mounted spring-wise against the housing 7 by means of springs 10, which are, for example, designed as pressure springs. For the movable fixing of the contact elements 5 to the housing 7, in the stands 7.5, 7.5', which limit the housing 7.4 on the side, are anchored fixing elements 7.6 running in a transverse direction parallel to the switch shaft 3 through the housing 7.4 and through the contact elements 5 by means of a longitudinal hole 5.1.

Figure 6 shows a section by the contact rod 4 at the switch shaft 3 along the line A-A. The contact elements 5 are spring-loaded to move relative to the housing 7, between a forward or reverse end position specified by the longitudinal holes 5.1. When the switch position is taken by the contact rod 4, the contact elements 5 are preferably positioned in a position adjacent to each of these end positions. In order to press them against the contact rod 2 with spring-loaded force, so that an optimal electrical contact is achieved. When the contact rod 4 is removed from a switch position, the convex oil-discharge valves of the intermediate region 6.2 and the secondary region 6.4 must be moved relative to the intersectional area. The contact elements 5 can be moved in the direction of the transverse direction as far as possible, and the contact rods 5 and 5 can be moved in the direction of the transverse direction of the contact rod, so that the contact rods 2 and 5 can be moved relative to the transverse direction of the contact rod, and the contact rods 5 and 6 can be moved in the direction of the transverse direction of the contact rod, so that the contact rods 2 and 5 can be moved in the direction of the transverse direction of the contact rod, and the contact rods 5 can be moved in the transverse direction of the transverse direction of the transverse direction of the transverse.

This rotation of the switch shaft 3 and thus the contact arrangement 4 in relation to the contact rods 2 around the mid-long axis MLA causes a grinding movement of the contact surfaces 6 of the contact elements 5 on the outer edges of the contact rods 2 so that, for example, foreign layers on the contact rods 2 or contact elements 5 resulting from contact contact friction are removed by the grinding movement and thus a self-cleaning of the contacts occurs during the switching process.

In contrast to the previous examples, the centre section 6.1 is flat, the tensioned plane preferably perpendicular to the SA axis of symmetry; furthermore, both the first and second edge sections 6.3, 6.3' and 6.4, 6.4' are preferably circular, the radii and centers of the respective arcs of the first and second edge sections 6.3, 6.3', 6.4, 6.4' being different.

Figure 8 shows a switch arrangement according to the embodiment in Figure 7, wherein in each of the peripheral sections 6.4, 6.4' there are reels 11 which are rotatable against the contact arrangement 4 and slightly protrude with their circumference sides from the contact elements 5. These reels 11 reduce the torque required when the contact arrangement 4 is rotated against the contact rods 2. When a switch position is used where two adjacent contact rods 2 are connected, the reels 11 do not reach the electrical connection to the contact rods 2, so that the first peripheral sections 6.3, 6.3' continue to rub against the contact rods 2 as a self-screwing contact and thereby create a self-screwing effect.

List of reference marks

The first of these is the 'closed' part of the housing, which is the part of the housing which is closed and the other part of the housing which is closed. The first is the 'closed' part of the housing, which is the part of the housing which is closed and the other part of the housing which is closed.

Claims (13)

1. Switching arrangement for a transformer, comprising a plurality of mutually parallel spaced-apart contact rods (2) arranged circularly around a centre longitudinal axis (MLA), a switching shaft (3) extending along the centre longitudinal axis (MLA) and mounted to be rotatable about this, and a contact arrangement (4), which is fastened to the switching shaft (3), with a plurality of contact elements (5) which are arranged to be at least radially displaceable relative to the switching shaft (3) and which have at least one contact surface (6) facing the contact rods (2), characterised in that the contact surface (6) of the contact elements (5) has at least one centre region (6.1) and edge regions (6.3, 6.4, 6.3', 6.4') adjoining thereto on either side, which are so formed that the radial spacing (d₁) of the contact surface (6) from the centre longitudinal axis (MLA) in the centre region (6.1) is smaller than the radial spacing (d₃, d₄) of the contact surface (6) from the centre longitudinal axis (MLA) in the edge regions (6.3, 6.4, 6.3', 6.4').
2. Switching arrangement according to claim 1, characterised in that the contact elements (5) have a concave curvature or are formed to be flat in the centre region (6.1).
3. Switching arrangement according to claim 1 or 2, characterised in that the contact elements (5) each have a convexly formed intermediate region (6.2, 6.2') between the centre region (6.1) and the adjoining edge regions (6.3, 6.4, 6.3', 6.4').
4. Switching arrangement according to any one of the preceding claims, characterised in that the edge regions (6.3, 6.4, 6.3', 6.4') have at least one first edge region section (6.3, 6.3') and second edge region section (6.4, 6.4'), wherein the first edge region section (6.3, 6.3') is formed to be flat or concavely curved.
5. Switching arrangement according to claim 4, characterised in that the second edge region section (6.4, 6.4') adjoining the first edge region section (6.3, 6.3') is formed to be convexly curved.
6. Switching arrangement according to any one of the preceding claims, characterised in that the edge regions (6.3, 6.4, 6.3', 6.4') are each formed to be arcuate.
7. Switching arrangement according to any one of claims 4 to 6, characterised in that the intermediate region (6.2) and/or the second edge region section (6.4) has or have at least in part a radial spacing (d₂, d₄) from the centre longitudinal axis (MLA) which is greater than the radial spacing (d₃) of the first edge region section (6.3) from the centre longitudinal axis (MLA).
8. Switching arrangement according to any one of the preceding claims, characterised in that rollers (11) rotatably mounted on the second edge region sections (6.4, 6.4') are provided.
9. Switching arrangement according to any one of the preceding claims, characterised in that a housing (7) connected with the switching shaft (3) is provided for at least partial reception of the contact arrangement (4).
10. Switching arrangement according to any one of the preceding claims, characterised in that the contact elements (5) are realised in the form of a contact blade, particularly a wiping contact blade.
11. Switching arrangement according to one of claims 9 and 10, characterised in that the contact arrangement (4) comprises a plurality of mutually parallelly arranged contact blades forming a contact blade group, wherein the contact blades (5) are individually resiliently displaceable relative to the housing (7).
12. Switching arrangement according to any one of claims 9 to 11, characterised in that the contact elements (5) each have at least two slots (5.1) for displaceable fastening of the contact elements in the housing (7).
13. Switching arrangement according to any one of the preceding claims, characterised in that the radial spacing (d₁) of the contact surface (6) from the centre longitudinal axis (MLA) in the centre region (6.1) of the contact elements (5) is so selected that the contact arrangement (4) in an intermediate switching lying between two switching settings is free relative to the contact rods (2).