Title of Invention

A MECHANICAL SWITCH CONTACT FOR BIPOLAR SWITCHNG OVER

Abstract

A mechanical switch contact for bipolar switching over, particularly in an on- load changeover switch of a tap changer, comprising: an insulating material support (1) at which fixed contacts (4, 5; 6, 7) disposed in pairs adjacent to one another and in addition in pairs opposite one another are arranged, a contact carrier (2), which has a pivot arm (2.2) at one of its two free ends and an actuation profile (2.6) at its other free end and which is rotatably mounted at the insulating material support (1) to be pivotable between two stationary states, an electrically conductive contact member (8) arranged at the pivot arm (2.2) in such a manner that depending on the respective possible end setting of the contact carrier (2) in the stationary state it conductively interconnects the fixed contacts (4 and 5 or 6 and 7) arranged adjacent to one another Iin pairs on one of the two sides, and telescopic guides (9, 10) which are disposed on either side of the pivot arm (2.2) and which are each provided with a respective compression spring (11, 12), each telescopic guide being supported at one of the free ends thereof at the contact carrier (2) and at the other free end thereof at the insulating material support (1) in such a manner that the contact carrier (2) is subjected to a snap action and in the case of force action on the actuation profile (2.6) is abruptly pivotable from one stationary state to the other stationary state. -

Full Text

Mechanical Switch Contact The invention relates to a mechanical switch contact for bipolar switching over, particularly in an on-load changeover switch of a tap changer. There is known from WO 95/24724 a switching-over arrangement for an on-load changeover switch of a tap changer which comprises a mechanical main switch contact and a similarly mechanical resistance switch contact. In that case not only the main switch contact, but also the resistance switch contact each consist of two intercoupled, actuable individual interrupter contacts, wherein each instance one individual interrupter contact of both the main switch contact and the resistance switch contact is electrically connected with the first on-load changeover switch side and the respective other individual interrupter contact of both the main switch contact and the resistance switch contact is electrically connected with the second on-load changeover switch side. In this arrangement the individual interrupter contacts of the main switch contact are electrically connectible by a first three-way switch and the individual interrupter contacts of the resistance switch contact are connectible by a second three-way switch. There thus takes place in each instance a bipolar switching-over by means of two three-way switches. An on-load changeover switch for a tap changer is known from WO 96/30922, in which, as a technical possibility realisation of such a bipolar switching-over, lever-like mechanical contacts pivotable about a fulcrum are provided. In addition, spring-loaded toggle levers are provided, which act on the rotatably mounted mechanical contacts in such a manner that these can adopt two switch settings beyond a dead centre. The two movable contacts are, for each phase, separately arranged in the same horizontal plane in the outer region of the on-load changeover switch. This known construction of the mechanical switch contacts for bipolar interruption is, however, complicated and technically costly, requires a precise adjustment of the mounting and, in addition, needs a relatively large amount of space. The object of the invention is therefore to indicate a mechanical switch contact for bipolar switching over, which is simple in construction and consists of as few as possible components which are easy to mount, is in that case constructed to be modular and as an independent subassembly, which can be installed without further adjusting or adapting operations in, for example, an on-load changeover switch and, moreover, demands least possible space there. This object is met by a mechanical switch contact with the features of the first patent claim. The subclaims relate to particularly advantageous developments of the invention. A significant advantage of the mechanical switch contact according to the invention consists in its particularly compact, simple mode of construction. Not only the mechanical main switch contact, but also the mechanical resistance switch contact can be prefabricated with few parts as identical, modular subassemblies. Thus, the same modular mechanical switch contacts are usable for both the main switch contact and the resistance switch contact; the main switch contact and resistance switch contact of each phase can be realised in simple manner as a common subassembly of two identical, interconnected modular switch contacts according to the invention. The invention will be explained in more detail by way of example in the following on the basis of drawings, in which: Fig. 1 shows a mechanical switch contact according to the invention, in perspective illustration, Fig. 2 shows a contact carrier of the switch contact, which is illustrated in Fig. 1, by itself, Fig. 3 shows a combination of two switch contacts according to the invention in accordance with Fig. 1 as a standardised, single-phase subassembly for main switch contact and resistance switch contact and Fig. 4 shows a circuit of an on-load changeover switch of a tap changer, as can be realised by mechanical switch contacts according to the invention. Initially the mechanical switch contact, which is illustrated in Figure 1, according to the invention will be explained in more detail. It comprises an insulating material support 1 which receives the further components described in the following. The insulating material support 1 is provided with parallelly extending longitudinal guides 1.1 ... 1.4 in the form of continuous bores, which are discussed in more detail further below. In addition, it comprises two bearing points 1.5 and 1.6, in which a contact carrier 2 is rotatably mounted by means of a bearing pin 3. Lateral spherical receptacles 1.7 and 1.8, which will similarly be discussed in more detail, are provided in the regions of the two bearing points 1.5 and 1.6. Moreover, the insulating material support has integrally formed contact mounts 1.9 ... 1.12 in which fixed contacts 4 ... 7 are arranged. The contact carrier 2, which is shown by itself once again in Figure 2, is rotatably mounted in the insulating material support 1 by means of a bearing 2.1 and the already mentioned bearing pin 3. The carrier comprises a pivot arm 2.2, which is pivotable about the bearing 2.1 and has in turn a contact mount 2.3 at its free end. This contact mount 2.3 consists of a continuous bore which extends parallel to the longitudinal axis of the bearing 2.1 or of the bearing pin 3. A respective counter-bearing mount 2.4 or 2.5 is similarly integrally formed in spherical shape in the region of the contact mount 2.3. The contact carrier 2 has an actuation profile 2.6 at its other, opposite free end. Arranged in the contact mount 2.3 is an electrically conductive contact member 8 which has contact rollers 8.1 and 8.2 at the two free ends, respectively. These contact rollers 8.1, 8.2 respectively correspond either with the fixed contacts 4 and 5 on one side of the insulating material support 1 or with the fixed contacts 6 and 7 on the other side of the insulating material support 1 depending in which direction the contact carrier 2 is pivoted about the bearing 2.1. Two telescopic guides 9 and 10 are, in addition, arranged at both sides between the contact carrier 2 and the insulating material support 1. These telescopic guides 9, 10 consist of two tubular members displaceable one in the other. They have at one free end thereof a spherical portion 9.1 or 10.1 by which they are respectively supported in a spherical mount 1.7 or 1.8 of the insulating material support. At the respective other free end thereof the telescopic guides 9, 10 each have a spherical counter-bearing by which they are in turn supported in a respective one of the two counter-bearing mounts 2.4, 2.5 at both sides at the contact carrier 2. In addition, a biased compression spring 11, which is similarly supported between the spherical mount 1.7 and the counter-bearing mount 2.4 at the contact carrier 2, is disposed around the first telescopic guide 9. A further biased compression spring 12, which in turn is supported between the spherical mount 1.8 and the other counter-bearing 2.5 at the contact carrier 2, is arranged in entirely analogous manner around the second telescopic guide 10. In the setting shown in Figure 1 the two fixed contacts 4 and 5 are thus connected together by way of the contact rollers 8.1 and 8.2 which are disposed in electrical connection by means of the contact member 8. If on actuation of the on-load changeover switch a roller or the like is now guided in the actuation profile 2.6 and runs thereon, the entire contact carrier is then pivoted downwardly about its bearing 2.1 against the force of the biased compression springs 11 and 12. As a consequence, the two contact rollers 8.1 and 8.2 then connect the opposite fixed contacts 6 and 7. Due to the telescopic guides 9 and 10 at both sides in conjunction with the explained springs 11 and 12 a snap mechanism is in that case realised in simple manner which on the one hand prevents the contact carrier 2 from being able to adopt an undefined intermediate setting and on the other hand ensures a sufficient contact pressure of the contact rollers 8.1 and 8.2 on the respective fixed contacts. The lateral spherical portions 9.1 and 9.2 of these telescopic guides 9 and 10, which are respectively mounted in the spherical mounts 1.7 and 1.8 of the insulating material support 1, in that case act as spatial, three-dimensional mounting. The telescopic guides 9 and 10 on switching over, i.e. pivotation of the contact carrier 2, change not only their length - due to the telescopic construction - but also their spatial position. Two of these switch contacts according to the invention, which are combined into a complete mechanical switch unit for one phase of an on-load changeover switch, are shown in Figure 3. In that case one switch contact I acts as main switch contact and the other switch contact II acts as resistance switch contact. The same parts are provided with the same reference numerals - it can be recognised that both modules have completely identical construction. For reasons of clarity not all of the explained details have been provided with reference numerals in this illustration. In Figure 3, just as shown in Figure 1 for an individual switch contact, an asymmetrical construction of the actuation profile 2.6 of the contact arm 2 has been selected. Here the two switch contacts I and II have been installed to be offset relative to one another by 180 degrees so that the two actuation profiles are faced towards one another. However, this is only one of many possible forms of embodiment. The connection of the two switch contacts I and II is effected by common connecting pins 13 ... 16, which are guided through the respective longitudinal guides 1.1 ... 1.4 and screw-connected at both sides. In addition, it can be seen in Figure 3 that the respectively opposite fixed contacts 4 and 6 of each switch contact I and II are disposed in electrical connection with one another in each instance by a connecting cable 17 or 18. Moreover, it can be recognised that the adjacent contacts 5 and 7 of each switch contact are electrically connected together on the one side by a first conductive connection 19 and correspondingly the adjacent fixed contacts 7 and 5 are electrically connected together on the other side by a further conductive connection 20. Thus, a bipolar switching over can be realised in the case of an on-load changeover switch at a tap changer. This is illustrated again in Figure 4: in the upper region of the circuit, there is schematically illustrated the selector of the tap changer, which undertakes a power-free preselection of the new winding tap n + 1 of the tap changer which is to be changed over to, whilst the previous winding tap n is still electrically connected. The two sides A and B of the on-load changeover switch, between which in sequence an uninterrupted switching-over shall take place under load, are shown thereunder. Also shown thereunder are the mechanical switch contacts and, in particular in the lefthand branch, i.e. the main switch branch, the main switch contacts SK. The indices A and B denote the respective association of the corresponding individual contact with the side A or B of the on-load changeover switch. In the righthand branch, i.e. the resistance branch, the resistance switch contacts HKM are shown in entirely analogous manner; the same applies for the indices. The broken line shows the part of the circuit which is technically realised by the two mechanical switch contacts I and II according to the invention. Below that, the first vacuum switching cell SKV, which is connected in series, for the load shunt is in addition shown in the main switch branch and in the resistance branch the series circuit of a transition resistance and a second vacuum switching cell HKV for the load shunt L is illustrated. Reference Numeral List: insulating material support longitudinal guide longitudinal guide longitudinal guide longitudinal guide bearing point bearing point spherical mount spherical mount contact mount contact mount contatt mount contact mount contact carrier bearing pivot arm contact mount counter-bearing mount counter-bearing mount actuation profile bearing pin fixed contact fixed contact fixed contact fixed contact contact member contact roller contact roller telescopic guide spherical portion telescopic guide spherical portion spring spring connecting pin connecting pin connecting pin connecting pin connecting cable connecting cable conductive connection conductive connection Patent Claims: 1. Mechanical switch contact for bipolar switching over, particularly in an on-load changeover switch of a tap changer, comprising the following features: it comprises an insulating material support (1) at which fixed contacts (4, 5; 6, 7) disposed in pairs adjacent to one another and in addition in pairs opposite one another are arranged, a contact carrier (2), which has a pivot arm (2.2) at one of its two free ends and an actuation profile (2.6) at its other free end, is rotatably mounted at the insulating material support (1), an electrically conductive contact member (8) is arranged at the pivot arm (2.2) in such a manner that depending on the respective possible end setting of the contact carrier (2) in the stationary state it conductively interconnects the fixed contacts (4 and 5 or 6 and 7) arranged adjacent to one another in pairs on one of the two sides, and at both sides of the pivot arm (2.2) there are provided telescopic guides (9, 10) each with a respective compression spring (11, 12), which are each supported at one of the free ends thereof at the contact carrier (2) and at the other free end at the insulating material support (1) in such a manner that the contact carrier (2) is subjected to a snap action and in the case of force action on the actuation profile (2.6) is abruptly pivotable from one stationary state into the other stationary state. 2. Mechanical switch contact according to claim 1, characterised in that the telescopic guides (9, 10) are each supported at one of the free ends thereof at a counter-bearing mount (2.4, 2,5) at the contact carrier (2) and at the other free end thereof at a spherical mount (1.7, 1.8) at the insulating material support (1) in such a manner that a three-dimensional, spatial mounting at the support points is achievable. 3. Mechanical switch contact according to claim 1 and 2, characterised in that the insulating material support has longitudinal guides (1.1 ... 1.4) in such a manner that at least two identical mechanical switch contacts are connectible together in modular manner. 4. Mechanical switch contact according to the preceding claims 1 to 3, characterised in that the contact member (8) is locked in the centre region in a contact mount (2.3) at the pivot arm (2.2) and has at each of its two free ends a respective contact roller (8.1, 8.2) which co-operates with a respective one of the fixed contacts (4 ... 7). 4. Mechanical switch contact for bipolar switching over substantially as herein described with reference to the accompanying drawings.

Documents:

512-chenp-2003-abstract.pdf

512-chenp-2003-claims duplicate.pdf

512-chenp-2003-claims original.pdf

512-chenp-2003-correspondnece-others.pdf

512-chenp-2003-correspondnece-po.pdf

512-chenp-2003-description(complete) duplicate.pdf

512-chenp-2003-description(complete) original.pdf

512-chenp-2003-drawings.pdf

512-chenp-2003-form 1.pdf

512-chenp-2003-form 18.pdf

512-chenp-2003-form 26.pdf

512-chenp-2003-form 3.pdf

512-chenp-2003-form 5.pdf

512-chenp-2003-pct.pdf