SK11382000A3 - Switchgear cabinet comprising a protective system against electromagnetic radiation - Google Patents

Abstract

The invention relates to a switchgear cabinet comprising a framing (1) and covering parts (2, 3, 4) provided in the form of lateral walls, a rear wall, a sheet steel top, etc. A protective system provided for suppressing interferences caused by electromagnetic radiation is formed by film pieces (5, 6, 10) which are arranged between the framing (1) and the covering parts (2, 3, 4). The film pieces are electrically conductive and are fastened to the framing using common adhesive tapes before the covering parts are applied. The described construction of a switchgear cabinet permits a high degree of electromagnetic compatibility (EMV) while using few materials and less work time.

Description

electromagnetic radiation

Technical field

BACKGROUND OF THE INVENTION The invention relates to a switchgear cabinet with a chassis and housing parts covering the chassis, as well as a protective device against electromagnetic interference.

BACKGROUND OF THE INVENTION

A cabinet of this type is known by EP 0 529 748 B1 or 0 528 240 A1.

The purpose of the protective device is, firstly, to prevent the emission of electromagnetic radiation from the control cabinet to the environment, in order to avoid interference with other devices or devices. Secondly, interfering electromagnetic radiation existing in the surroundings should also be prevented from entering the enclosure so that the apparatus and equipment contained therein cannot be affected. The interference resistance of the method described is referred to as "electromagnetic compatibility (EMC)." Possible sources of interfering electromagnetic radiation are different: they can be, for example, switching arcs of power switches such as protections or power switches, or devices with power semiconductors, especially when they operate in partial load operation. Other causes of high-frequency disturbances are all operating means that operate anyway in the high or very high frequency range, such as microprocessor devices and transmitters. Radiation emanating from such devices may, in particular, affect neighboring electronic devices. · · Najmä najmä najmä najmä najmä najmä najmä najmä najmä najmä , causing erroneous or undesirable reactions. By themselves, the materials used for the construction of switchboard cabinets, such as 2 mm thick steel sheet, are an effective barrier to the ingress of electromagnetic radiation. For structurally necessary reasons, however, there are numerous locations on the switch cabinets where parts of the housing do not lie directly on the frame or where there are slots in operation, such as on the door. In particular, high and very high frequency radiation (mega and gigahertz region) can penetrate such slits. Up to now, such gaps have been targeted by means of targeted sealing, for example by means of electrically conductive door seals of flexible metal fabric or of conductive compressible plastic or foam. This targeted placement of the sealing material requires careful work and is still associated with the uncertainty that the various possible spots of interfering radiation will be overlooked.

Accordingly, it is an object of the invention to provide a simple and reliable as well as inexpensive protective device against electromagnetic interference.

SUMMARY OF THE INVENTION

According to the invention, this object is achieved by a switchgear with a frame and housing parts covering the structure, as well as with a protective device against electromagnetic interference, the principle being that the protective device has at least one flexible foil member of an electrically conductive plastic film and the member is positioned between the structure and the housing parts.

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The use of a foil has the advantage that a substantially complete EMV screening or sealing of the switch cabinet is achieved. It is therefore ruled out that critical areas or system-related openings, such as screw holes, should be overlooked. However, if holes are needed, e.g. for ventilation grilles or conductor bushings, these can be produced in a simple manner by cutting the foil member. Since foil-like plastics, also in an electrically conductive embodiment, are inexpensive to sell, they are a favorable alternative to the prior art.

Generally, the switchgear has at least one movable part of the casing in the form of a door for access to the interior space. Also, in order to have the desired EMV density, the foil member may be sized for the overall perimeter of the structure, including the door, in such a way that the foil member on the door hinge side extends from the carcass to the door. According to an embodiment of the invention, the EMV seal can be made easier by providing at least one first foil member, which leaves the transfer opening free, in a switchgear with an opening that can be closed by a movable part of the housing, and that at least one separate second opening is provided a film member that is at least locally electrically connected to the first film member.

When locating the foil portions of the casing housing that the members on the distribution frame and / or cannot be excluded locally impairs the required protection against electromagnetic radiation. This possible influence can be counteracted by always damaging which two or more foil members are placed one above the other, especially in the overlapping location.

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In addition, the lower demands on labor in the manufacture of the protective equipment of the switchgear cabinet can be further enhanced by the fact that the foil members consist of a material that shrinks under the influence of heat. Indeed, it is immaterial whether there are folds or similar irregularities when the foil members are placed on the frame or on the housing parts of the switchgear housing, since these can be smoothed out by the subsequent use of heat, e.g. hot air.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail below with reference to the exemplary embodiment shown in the figures.

Figure 1 shows in schematic perspective view the construction of a switchgear cabinet with one foil member and several housing parts.

FIG. 2 is a cross-sectional view of a detail of the access opening area of the control cabinet.

DETAILED DESCRIPTION OF THE INVENTION

The casing 1 of the cabinet shown in Figure 1 may be of any suitable construction, as the invention can be used independently of the features of the casing 1. The casing 1 preferably consists of steel sheet parts with respect to the high suppression of interfering electromagnetic radiation. Unlike conventional switchgear cabinets, the housing parts 2, 3 and 4 indicated in Figure 1 (side walls, rear wall and top plate) are not fixed directly to the frame 1, but instead of the flexible and electrically conductive foil members 5 and 6. it surrounds the foil member 5 of the carcass 1 approximately in a U-like manner, while the foil member 6 it is substantially straight, and is associated with a housing part 4 constructed as a top sheet. The access opening 7 at the front of the carcass 1 is shown in Figure 1 without part of the sheath and without the foil member, since the respective details of this access region are shown in more detail in FIG. Second

The example of Figure 2 assumes that the film material is used with a high-frequency conductive coating. The existing first film member 5 is fastened to the front of the carcass 1 by means of double-sided adhesive tape 8. Due to the dimensions of the film member 5, the overlapping end member 9 is retained on the side surface of the carcass 1. uniformly fastened by means of double-sided adhesive tape 8. The second foil member 10 associated with the access side of the cabinet is overlapping on the end member 9 and is fastened by adhesive tape 11 to the side surface of the carcass. For example, the film member 10 may completely or partially cover the casing member.

As already mentioned, a film having a high-frequency coating is particularly suitable for the purposes of the invention. However, there are films of electrically conductive plastics which are so electrically conductive and thus can be contacted on both sides by contact with other conductive parts.

In the example of Figure 1, it is assumed that foils with a width corresponding to the height of conventional enclosures are available. If the transparencies should be narrower, then the film should be narrower. Two or more of these foil members may be used to cover the carcass.

It is furthermore suitable for the purposes of the invention to produce shrinkable film embodiments. This property allows some smoothing and shut-off after placing the film members on the carcass by means of adhesive tapes using heat, thereby bringing the film members to the carcass.

Claims (5)

PATENT CLAIMS • • • ···· • · • · • • • • • • · • • • · · · • • • • • • • · • · · · · • • · · · • · • · 1. Enclosure with housing (1) housing, interference design and parts (2, (1)) as well as electromagnetic 3, covering the counter device having at least one flexible foil member (5, 6, 10) of a conductive plastic foil and that the foil member by structure (1) and parts 4) by protective radiation, the device electrically (5, 6, 10) is placed between (2, 3, 4) sheaths. The switchgear according to claim 1, characterized in that, in the case of a switchgear with an access opening (7) which can be closed by a movable part of the housing, it is located (7) and that the member (10) is connected in a manner to the first foil member. the at least one first foil member (5) is loosely and the access opening is located at least one separate second foil which is at least locally electrically conductive (5). The switch cabinet according to claim 1, characterized by members 1 or 2, characterized in that two or more foil films are placed one behind the other. 4th sa t way. Cabinet according to claim 3, characterized in that the foil members are located overlapping Housing claims, characterized by heat-shrinkable material. a switchgear according to any one of the preceding claims, wherein the foil members are z