DE1613746A1 - Process for the production of electrostatic screens - Google Patents

Description

The invention came about with a method for Manufacture of electrostatic screens, in particular, but not exclusively, for ring transformers. She deals furthermore with windings or ring transformers which are provided with a screen produced by the method according to the invention are.

The usual method of applying an electrostatic screen between two windings on a toroidal core in order to prevent the Reducing capacitive coupling between the windings has traditionally been to wrap a single tightly angled layer of wire around to wind the core, with the beginning and the end of this winding not connected. This resulted in the disadvantage that the screen was not quite full-fledged, once due to the gaps between the turns on the outer circumference of the windings,

009843/0673 _copy _ _g _

if the wire was wound close to the inner circumference, on the other hand, by the strong deposition of the wire on the inner circumference when the wire was wound tightly on the outer circumference.

Furthermore, in order to reduce the volume of the screen, small diameter wires had to be used. This led to the fact that high voltages were induced between the ends of the windings, as to cover one Layer a large number of turns was required. These voltages lead to high displacement currents tended to negate the main purpose of the screen. Further" if two or more screens were required in this method, the voltages induced by each screen had to be applied be the same if the noise should be effective. To do that, each screen had to be made from a wire with a different one Diameter, as the winding length, i.e. the inner circumference of the winding, due to the The accumulation of turns changes. In order to ensure that the shield winding always exactly covers the entire winding length, precise control during winding is required. This control is due to normal during production Manufacturing tolerances for cores, tapes and wires difficult to achieve.

It is an object of the invention to provide a more effective single-turn umbrella that is easier to manufacture and less volume than the one produced by

009843/0573 _ *.

Conveniently manufactured screens are required.

The object of the invention is achieved in that by applying a conductive layer to a insulating substrate a turn is formed with an open circuit.

This makes it possible to produce a screen that is fully effective in spite of its small "volume. An expedient embodiment of the invention provides that a layer of an insulating tape is gradually applied a winding is applied, and the tape is covered with a metallic paint film, a narrow one uncovered strip along the entire circumferential length of the Winding remains free, and that tape so on the uncovered Strip is applied so that one edge is within the width of the uncovered strip while the other Edge overlaps the metallic paint film, and then on the remaining uncovered part of the color-free strip a film of paint is applied, the film of paint being continued across the width of the tape far enough to allow the ' Color film overlaps under the tape without creating a short-circuited turn.

Because the screen only has one turn exists, which is also not short-circuited, no high induction voltages can arise.

-4-0 0 9843/0573

Further advantages and details of the invention are illustrated below in an exemplary embodiment explained in more detail by drawings. Here represent:

Pig. 1 is a perspective view

a ring transformer with partially broken layers,

Pig. 2, 5, 4

Sections through a ring transformer showing various manufacturing stages Show,

Pig. 5 a detail of the screen.

It should be noted here that the thicknesses of the various layers or layers are shown in an exaggerated manner, so that they stand out clearly.

-5-

009843/0573

TB 13748

The winding or the windings 1, which lie under the screen, are supplemented and wrapped with a suitable tape 2, for example made of cotton. The winding 1 is then completely impregnated with a suitable lacquer; this is necessary because the screen, when it is completed, is as good as impermeable to impregnation lacquers.

A single, overlapped layer of a non-porous, concordant insulating tape 3 is wound onto the impregnated winding 1, such as, for example, 0.075 mm thick, unsintered, etched Sgglvtetrafluoräthylen, the entire winding 1, with the exception of a narrow strip 6 that surrounds the outer circumference then covered with a conductive paint film 4, which may form the screen. A suitable metallic color is "Aqua Dag Silver Dispersion 915 in MIBK x ^11. " A simple method of applying the paint film is to apply a cover made of a narrow strip of pressure-sensitive tape 5 to the outer circumference before the winding 1 is covered with paint. After the paint has dried, the tape 5 can be removed, leaving a narrow paint-free hanging on the outer circumference.

When the ink film 4 has dried, a length of a self-adhesive polyether tape 7 »such as, for example," Scotsh Boy 56 ", with a suitable width such on the outer circumference of the

-6-

009843/0573

Wrap 1 attached that one edge of the tape halfway across the width of the strip 6 in the color film 4. (Pig. 4 and 5) · The remaining part of strip 6, that of the Polyester tape 7 is not covered, is painted with a metallic paint, the paint film 8 still seeing extends over part of the width of the polyester tape 7, so that the color film 8 the color film 4 under the polyester tape 7 effectively overlaps without creating a short-circuited turn.

The connection to the screen can be made by a suitable conductors held in contact, such as a strip of copper foil 9 wound around the outer circumference (Fig. 1), or by a conductor made from a conductive bonding agent (such as "Aq.ua Dag, Type 16 24").

When the paint is completely dry, which normally requires 15 minutes at 100 ° ß for the paint mentioned, the screen is covered by one or two half-lap layers of suitable tape 10 such as cotton. The winding is then ready for either more screens or the rest of the windings. Where multiple screens are made, can the intermediate layers of the tape require impregnation with a suitable varnish to prevent sponginess.

The above method produces a very effective, low resistance and electrostatic screen very low induction voltage with a maximum thickness on the inner circumference of the ring winding of approximately 0.38 mm.

009843/0573 -7-

That "means that even on small ring windings triple Umbrellas with a thickness of less than 1.6 mm are possible.

The method can be used for all types of electrostatic shielding that are required on ring windings and for layer windings "used" where a very close coupling is required. By using a suitable, permeable, metallic paint, a magnetic Shielding of the entire winding can be achieved. In addition, the application of the invention is not limited to rings, but also shields for other electrical devices can be extended.

- Expectations -

0098 4 3/05 7 3

Claims (9)

Specimen copy May not be changed Claims: 1. A method for producing an electrostatic screen between two windings, characterized in that a turn with an open circuit is formed by applying a conductive layer to an insulating substrate. 2. The method according to claim 1, characterized in that gradually a layer of an insulating tape (3) is applied to a winding (1) and the tape (3) is covered with a metallic paint film (4), a narrow uncovered strip ( 6) remains free along the entire circumferential length of the winding (1). 3. The method according to claim 2, characterized in that the narrow uncovered strip (6) is covered during the application of paint with a narrow strip of a pressure-sensitive tape (5) which is subsequently removed. 4. The method according to claim 2 or 3, characterized in that the insulating tape (3) is non-porous and concordant, and is applied in a single semi-overlapping layer. . - A2 009843/0573 -XJt- 5. The method according to claim 4, characterized in that the winding (1) first wrapped with a textile or porous tape (2) and is impregnated before the non-porous, insulating tape (5) is applied. 6. The method according to any one of claims 2 to 5, characterized in that in further steps a further length of a tape (7) is applied to the uncovered strip (6) in such a way that an edge flies within the width of the uncovered strip (6) , while the other edge overlaps the metallic color film (4) and then on the remaining, uncovered (part of the color-free strip (6) a color film (8) is applied, the color film (8) far enough over the width of the tape (7) is continued so that it overlaps the paint film (4) under the tape (7) without creating a short-circuited turn. 7. The method according to claim 6, characterized in that a conductive strip is applied to the color film (8) to establish the electrical connection with the screen. 8. The method according to claim 6 or 7, characterized in that the paint is dried in further steps and finally a half-overlapped layer of a textile barren - A3 - ■ 009843/0573 other porous tape (10) applied to the paint layer will. 9. The method according to any one of the preceding claims, characterized in that an electrostatic screen produced by the method of one of claims 1 Ms is applied between the superimposed windings of a ring transformer wound onto a toroidal core. ^{BE / kä} 0098A3 / 0573