DE3111100A1 - UMBRELLA BODY FOR JOCHE OF IRON CORES OF TRANSFORMERS AND THROTTLE COILS - Google Patents

Abstract

1. A screening element, consisting of a plurality of insulant layers (9, 12, 13, 14) and a conductive paper insert (10), for yokes (4) of stepwise laminated iron cores, of transformers and inductance coils, for screening the stepped edges of the yoke from end faces, or end screening rings, of windings, characterised in - that the conductive paper insert (10) is completely metallically separated from all neighbouring components (2, 4) which carry opposite voltages, - that the conductive layer (11) in the conductive paper insert (10) is of high resistance and free from voltage-balancing conductors, - that the electrical potential carried by the conductive insert (10) is adjusted in a purely capacitive manner by the relation of the distance from the yoke (4) to the conductive paper insert (10), to the distance from the conductive paper insert (10) to the end face or end screening ring of the winding (2), and - that the edges of the conductive paper insert (10) are set back on all sides with respect to the edges of the remaining insulant layers (9, 12, 13, 14).

Description

TRANSFORMATOREN UNION AG Our mark Stuttgart VPA 81 P 9 1 0 3 DE

Shield body for yokes of iron cores of transformers and reactors

The invention relates to a screen body made of several layers of insulating material with a guide paper insert for yokes of stepped laminated iron cores of transformers and Choke coils for shielding the yoke step edges against end faces or end shield rings of windings.

Corresponding to the screen body described in German patent applications P 30 10 255.7 and P 30 22 070.3 these are usually made up of several layers of insulating material, between which at least one Layer of electrically conductive material provided. is. These electrically conductive layers are at the known arrangements with a low-resistance grid covering them, also made of electrically conductive material connected to thereby prevent the occurrence of voltage differences within the intended for shielding To prevent layer of electrically conductive material.

These grids are usually made of stranded copper or Copper fabric tape made and with a connection conductor out of the actual shielding body and galvanically connected to the component to be shielded .

The disadvantage of these arrangements is the not inconsiderable expense of introducing this low-resistance Grid and in particular the mechanical securing of the connection led out of the screen body

Final conductor. In addition, it is precisely this connecting conductor that causes inhomogeneity in the electrical field and requires due to its comparatively low mechanical strength and its weak anchoring special precautionary measures in the shield body during the assembly of the iron core to be shielded with the associated windings.

The invention is therefore based on the object for transformers and inductors for their windings facing yoke parts to create a screen body that is both easy to manufacture and without complications can be installed and at the same time satisfies the physical requirements placed on it well.

According to the invention, this object is achieved with a screen body of the type mentioned in that the guide paper insert is galvanically completely removed from all adjacent and mutually live parts is separated that the conductive layer in the conductive insert High resistance and free of voltage equalizing conductors is that the electrical lead from the conductive insert Purely capacitive potential due to the ratio of the distance between the yoke iron and the guide paper insert to the Distance guide paper insert - face or end umbrella ring of the windings is set and that the edges of the guide paper insert on all sides opposite the The edges of the remaining layers of insulation stand back.

According to advantageous developments of the invention provided that the insulating material is single-layered between the yoke iron and the guide paper insert and that the guide paper insert coated with electrically conductive material on the side facing away from the yoke iron and is covered on this side by an uncoated paper layer.

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The guide paper insert advantageously covers in the catch direction of the yoke apart from the central laminated core on both sides at least three stages and it is in The longitudinal direction of the yoke is adapted in each case to the line of penetration of the yoke with a core leg.

For secure fixation of the guide paper insert, it is connected to at least one of its adjacent layers of insulating material glued in points and the step-parallel edges of the screen body are bent in the direction of the yoke. The step-parallel edges of the insulating material layers are according to a further development feature of the invention held together by spaced apart caps encompassing the edges.

The screen body designed according to the invention is very advantageous because it is due to its simple structure also easy to manufacture and guarantees an extreme as a result of connecting conductors that are not required great operational safety.

An exemplary embodiment of the invention is based on a Drawing explained in more detail.

Fig. 1 shows the cross section through a yoke of a

Transformer with several wound core legs and
Fig. 2 shows a detail at X in Fig. 1 in very strong form

enlarged scale.
30th

A core leg 1 carries windings 2 with insulation 3 at the end. The core leg 1 is not shown in FIG the manner shown in more detail with a lower yoke 4 interlocked so that the lower yoke 4 and the Hold and support core legs 1 mechanically. The pressing forces required for this are in

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common catfish by bandages and / or press iron and / or Press bolt applied.

Laterally adjoining the two long sides of the lower yoke 4, plates 5 made of insulating material are provided, whose surfaces facing the windings 2 together with the winding-side surface of the lower one Yoke 4 form the winding table on which the windings 2 in a manner not shown down are supported. These plates 5 cover the laminated cores of the further outward in cross section Laminated lower yoke 4 adapted stepwise to a predetermined curve shape.

As a result of the usual grounding of the lower yoke 4 and the windings 2 lying at high voltage potential exist between these two assemblies a considerable amount Potential difference, for its easier and safer control, at least at very high nominal voltages both the windings 2 and the stepped lower yoke 4 with large-area shields are provided. The shielding on the winding side is not shown in detail in the exemplary embodiment Installed in the end-face insulation 3 of the windings.

A shielding body 6, which is located in the space between the plates 5, serves to shield the lower yoke 4 is arranged above the lower yoke 4. To mechanisehen Support of the thin-walled screen body 6 are used filler bodies 7 and 8, which are of the Fill in the steps of the lower yoke 4 and the screen body 6 enclosed step spaces. The packing 7 and 8 are made, for example, of wood, chipboard or wood.

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Fig. 2 shows on a greatly enlarged scale the layered structure of the screen body 6 from layers of insulating material. These layers of insulating material exist beginning on the side of the screen body 6 facing the lower yoke 4 from a layer of about 1 mm thick pressboard 9, followed by a 0.145 mm thick layer of conductive paper 10 with one of the winding 2 facing conductive support 11, which in turn is made of a 0.145 mm thick paper layer is covered. In the exemplary embodiment, above these layers are each 1 mm thick layers of pressboard 13 and 14 provided. To secure the mutual position of the individual layers, at least the paper layers are required 10 and 12 glued together at points.

The conductive support 11 itself is very thin and therefore has a relatively high resistance. Because an essential Part of the conductive support 11 at a distance of 1.145 mm above the main laminated core of the lower yoke 4 lies and the distance between the conductive support 11 and the end face of the windings 2 is much greater, leads the conductive support 11 due to capacitive coupling practically the potential of the lower yoke 4, without to be galvanically connected to it. This makes it possible to use a low-resistance Anlenkgltter for the senior edition 11 to waive.

As tests have also shown, there is a particularly favorable field course when the to the yoke axis parallel longitudinal edges of the screen body 6 are bent by about 90 ° and their edges to a Create the step edge of the lower yoke 4.

2 figures

9 claims

Claims (9)

* · ■ "■ 311 MOO VPA 81 P 9 10 3DE Claims (1; \ Screen body made of several layers of insulating material and one ^ - paper inlay for yokes of tiered laminated Iron cores of transformers and reactors for shielding the yoke step edges against end faces or End shield rings of windings, characterized , - That the Leitpapiereinlage (10) galvanically completely from all neighboring and against each other voltage leading parts (2, 4) is separated, - That the conductive layer (11) in the conductive paper insert (10) has a high resistance and is free of voltage equalization conductors, - That the electrical potential carried by the guide insert (10) is purely capacitive due to the ratio of the distance Yoke (4) - guide paper insert (10) to the distance between guide paper insert (10) - face or end shield ring of the windings (2) is set and - That the edges of the guide paper insert (10) on all Sides opposite the edges of the remaining layers of insulation (9, 12, 13, 14) stand back. 2. umbrella body according to claim 1, characterized in that that the insulating material (9) between the yoke (4) and the guide paper insert (10) is single-layer. 3. umbrella body according to claim 1 and 2, characterized in that the guide paper insert (10) on the side facing away from the yoke (4) coated with electrically conductive material (11) and on this side through an uncoated paper layer (12) 2. - 7 - VPA 81 P 9 1 0 3 DE is covered. 4. umbrella body according to claim 1 to 3, characterized in that the guide paper insert (10) and the paper layer (12) lying on its coated side are each 0.145 mm thick and that all other layers of insulating material (9, 13, 14) of about 1 mm strong paper or pressboard. 5. umbrella body according to claim 1 to 4, characterized in that the guide paper insert (10) in the circumferential direction of the yoke (4) apart from the central laminated core on both sides at least three Covers steps. 6. channel body according to claim 1 to 5, characterized in that the guide paper insert (10) in the longitudinal direction of the yoke (4) in each case to the line of penetration of the yoke (4) with a core leg (1) is adapted. 7. umbrella body according to claim 1 to 6, characterized in that at least the guide paper insert (10) glued pointwise to at least one of its adjacent insulating material layers (9, 12, 13, 14) is. 8. umbrella body according to claim 1 to 7, characterized in that the step-parallels Edges of the screen body (6) are bent in the direction of the yoke (4) by about 90 °. - B - VPA 81 P 9 1 0 3 DE 9. umbrella body according to claim 1 to 8, characterized in that the parallel steps Edges of the layers of insulating material (9, 10, 12, 13, 14) of spaced apart, encompassing the edges Caps are held together.