DD214481A1 - CONTACT ARRANGEMENT FOR LOAD PROPERTIES OF LEVEL TRANSFORMERS - Google Patents

Abstract

The invention relates to a contact arrangement for load selectors with on the inside of an insulating cylinder arranged in a circle fixed contacts and with swinging around in a circle formed as contact rollers movable switch contacts. The aim of the invention is to provide a not affected by the pollution of controls in their switching properties contact arrangement. Here, the task was to solve the design of the control of the roller contacts so that a well-defined contact separation takes place. According to the invention the object is achieved in that the contact rollers are fixed to a common, movably mounted and pressed by spring elements radially against the fixed contacts on the outer cylinder insulating material, wherein the distance of the contact rollers with the distance of the fixed contacts is tuned so that at any time the switching at least one contact roller of the switching contact with the corresponding stationary mating contact is in contact. The invention can be used in all load selectors o.a. Type can be used for tapped transformers.

Description

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Field of application of the invention ;

The invention relates to a contact arrangement for load selectors of tapped transformers with circularly arranged on the inner wall of a cylindrical housing fixed stepped contacts with additional Abbrandkontakten.

Characteristic of "known technical solutions:

There are already a variety of designs of Lastwählern known in which the fixed contacts on the inner wall of a cylindrical housing are circular, arranged. (DE-QS 2021157 "load selector" ·, DE-OS 2215094 "load selector for transformers ¹¹ ; DE-AS 2845463" load selector for tapped transformers ") Furthermore, load selectors are known in which the existing in the form of several roller contacts power switching contacts per phase at The rotational movement of the switching shaft from the respective contact of the stage run and then turn the next stage contact 'turn on (DE-OS 2219220 "diverter switch οο, θϊ load selector".) In such load selectors so switch mainly three trained as rollers and driven by a centrally disposed switching shaft switching contacts step-to-step the current by jumping abruptly from one fixed contact to the next to an insulating cylinder,

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In this case, arcs are drawn in each case, in addition to contact erosion also insulator parts of the outer cylinder, in which the step contacts are arranged, damage.

In known Lastwählern the three switching rollers are individually movably mounted and are pressed by Pederθlerne nt a radially against the mating contacts. In order to prevent the rollers from approaching the insulating cylinder radially outwards during the switching operation when leaving the mating contact and damaging the latter by the influence of arcing, it is necessary to steal the course of the roller movement in a sensible manner.

To prevent burns of the plastic outer cylinder, the irregular burning of the edges and contact rollers as well as to achieve a well-defined contact separation load selectors are already known, the fixed stages contacts control cams are assigned. (DE-OS 2914928 "contact arrangement for load selectors of tapped transformers"). The control cams consisting of insulating material are designed as control cams, which cause a radial movement of the roller contact away from the outer cylinder during the Abschaltablauf. However, this arrangement has the disadvantage that the control cams are gradually turned on by arc residues and thus the isolation distance is reduced to adjacent stages on the circumference. Furthermore, since such cam pairs are required for each contact on the circumference, the technical complexity is considerable. Another disadvantage of such a cam control is to be seen in the fault of the arc extinguishing, since the roller contact actuating cam are arranged directly and directly on the fixed contact.

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That is, by the immediately below and above the fixed contacts arranged cam, the deletion process of the arc positively affecting oil flow is disturbed.

Furthermore, it has also been proposed to form the control curve from a control ring arranged on the inner wall of the cylindrical housing made of insulating material to the potential of the slip ring.

and via the control roller and lever to provide a mechanical connection to the stage η power switching shift lever (WP H 01 F 2462874 "contact arrangement for load selector of tapped transformers"). However, this arrangement is still liable for all technical advantages of the disadvantage of a z.T. unacceptable high economic, constructive and technological effort.

Object of the invention:

The object of the invention is to eliminate the deficiencies inherent in the prior art and to provide a contact arrangement for load selectors with fixed contacts arranged on the inner wall of an insulating cylinder in which an impairment of the switching characteristics due to the contamination of control elements by conductive residues is avoided unobstructed oil flow achieved and the technical-economic effort to produce such an arrangement is reduced to a minimum.

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Explanation of the essence of the invention:

The invention has for its object to design the control of the movement of the existing of multiple contact rollers movable switch contacts constructively so that with minimal contact erosion a well-defined contact separation takes place.

According to the invention, this object is achieved in that the movable switch contacts preferably consist of three contact rollers, which are arranged tangentially and radially rigidly against each other together on a preferably consisting of insulating contact carrier. 029ϊ contact carrier is movably mounted on the centrally arranged switching shaft and is pressed by spring elements radially against the fixed contacts on the outer cylinder. The distance of the contact rollers of each movable switching contact to each other is matched with the distance of the associated fixed contacts so that at any time of switching at least one of the three contact rollers is in contact with a fixed contact. By the common attachment of the three contact rollers on a contact carrier is achieved that the contact rollers control each other in their radial movement. By suitable design of the shape of the fixed contacts, for example "convex running surface, it is achieved that the contact rollers perform with their common contact carrier during the switch a racfiale movement. Rolls from standing and curve shape of the tread of the fixed contacts are tuned so that the time of the largest radial deflection coincides with the time of arc extinguishing.

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Since the contact rollers feel each other at the fixed contacts, no insulation sections between the fixed contacts negatively influencing guide parts are necessary.

Äusführungsbeispiel:

In the embodiment shown in the accompanying drawings, the invention will be explained in more detail below.

In the accompanying drawing show:

Figo 1: Individual switching phases during a switchover in a basic representation;

2 shows a longitudinal section through the arrangement of a contact with continuous current contact;

Fig. 3 ί the top view of a switching contact in the neck.

At the existing of insulating outer cylinder 1 are distributed uniformly on the circumference, the fixed Abbrandkontakte 2 are arranged. Centric about the center axis of the Lastwählers moves by the spring 11 under radially outwardly directed spring pressure and also movably guided in this direction contact carrier 3 »in the middle of the main contact roller 4 and right and left next to the Vorkontaktrollen 5? 6 are arranged.

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The two Vorkontaktrollen 5 »6 are electrically connected via a respective switching resistor 7 with the main contact roller 4. From the switching phases shown in Fig. 1 a ... f can be seen that always at least one role of the switching contact with a consumable contact 2 is in contact. As a result of the mechanical coupling of all three rollers of the switching contact and the guidance of the contact carrier 3 provided in the radial direction, all three contact rollers 4j 5j 6 always execute the same radial movement. In an assumed switching movement in the clockwise direction assumes in Fig. 1 b, the Vorkontaktrolle 6 the leadership. Thus, the main contact roller 4 lifts off the Abbrandkontakt 2 and it burns according to FIG. 1 c between the two contacts an arc. Due to the spherical design of the fixed Abbrandkontaktes 2 takes place with progressive switching movement, a simultaneous radial movement of the contact rollers towards the center, which on the one hand pulled the arc from the outer cylinder 1 and on the other hand, the arc extinction is improved by increasing the arc length. The switching position with the largest radial deflection is shown in Fig. 1 c. With progressive shifting movement, the analog movement is repeated, when the arc on the Vorkontaktrolle 6 burns and VorTsontaktrolle 5 accepts FIG. E Λ the lead. In Fig. 2 and 3, a corresponding construction example of the contact arrangement of the load selector is shown, wherein in the movement phase shown in Fig. 3 · during the clockwise switching of preferably designed as Isolierstoffteil contact carrier 3 has reached its greatest radial deflection, which favorable extinguishing conditions for the Arc at the main contact roller 4 prevail.

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Da Daistiomkontakt 8 leads the Stiom while del rest of Lastwählis from Daueiatiomkontakt 9 to Stiomableitungsiing 10th

Claims (1)

TRO 4700 Erfindunp; sanspruch Contact arrangement for load selectors of tapped transformers with on the inner wall of a cylindrical housing arranged in a circle fixed stepped contacts with additional Abbiandkontakten and with
gradually swiveled around in a circle, consisting of several contact rollers, movable switch contacts, characterized in that the switch contacts are preferably formed of three contact rollers, the tangential and radially rigidly against each other together on a preferably consisting of insulating contact carrier movably mounted on the centrally arranged shift shaft is arranged and is pressed by spring elements radially against the fixed contacts on the outer cylinder, are arranged, that the running surface of the movable
Switch contacts associated fixed contacts
on the outer cylinder has a spherical curve shape and that the distance of the contact rollers of each movable
Switching contact with each other is dimensioned so that
the time of the largest radial deflection of the contact carrier coincides with the arc quenching. For this 3-sheet drawings!