DE2060907A1 - Electrical wound capacitor with a switch-off fuse - Google Patents

Description

Electrical wound capacitor with a safety device

The invention relates to an electrical wound capacitor with a shrinkable dielectric and end contact layers, which connect the assignments with external connection elements, in which as a result of heating by shrinking the dielectric foils in the axial direction, the length of the winding body is reduced and the electrical contact between the assignments and one of the external connection elements is interrupted.

In the case of capacitors with thin coatings which can be regenerated and which are vapor-deposited onto the dielectric risk of fire in the event of thermal overload. This overload can be caused by external influences or by the Capacitor itself.

From the German Auslegeschrift 1 289 584 it is known to provide a switch-off protection in the housing, which by Deformation of the housing is actuated. From the Swiss Patent 324 070 a shutdown fuse is also known, which by deformation of the Housing cover is operated. These known Abechalticherung can only be operated when the active capacitor body is in a tight metal housing is built in.

Also from the German Offenlegungsschrift 1 806 known electrical capacitor must be in a housing be housed so that its protective device

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can work. The dielectric of this known capacitor shrinks when heated and one end face The winding body detaches itself from the front contact, which is anchored on the housing cover. In this way, by shortening the axial length of the winding body, the one occupancy of the capacitor of their associated connection element separated. The case is also involved in this capacitor the actuation of the protective device is necessary.

The object of the invention is that the installation of the capacitor winding in the capacitor illustrated at the beginning in a tight housing is not necessary.

According to the invention, this is achieved in that the contact point of the outer connection element is on the front contact layer and that part of the end contact layer which covers the shrinkable bobbin a weak point in the front contact layer by shrinking the winding body completely apart are separable.

The disconnection fuse according to the invention is based on the fact that the front contact layer, which extends over the entire End face of the capacitor extends at a certain weak point as a result of shrinkage of the wound body rips off. The weak point encloses the contact point of the connection element on the front contact layer. In the case of a round wound capacitor in particular, the weak point surrounds the contact point in a circular manner. The connecting wire is advantageously anchored in the winding core and there with the front contact layer connected either by welding or soldering.

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An embodiment of the invention consists in that the connecting wire is fixed in a plug, which in the winding cavity, which can advantageously be formed by a core tube, is inserted. The frontal area of the plug, the front edge of a core tube on which the shrinkable bobbin is wound, and the end face of the shrinkable wound body lie in a common plane. The entire face (Plug face, core tube face, winding face) is covered with a contact metal layer. The weak point is on the front Contact line between the winding body and the non-shrinking core tube. In the case of impermissibly high The winding body shrinks when heated and the front contact layer tears off at this contact line. Through this the winding body is separated from the connecting element. The weak point does not necessarily have to be reduced by a Thickness of the forehead contact layer be brought about. The weak point is the line of contact between Core tube and winding body also because the core tube and the front contact layer do not shrink is sheared off when the bobbin shrinks at the edge of the core tube.

The sensitivity of the fuse can be controlled in various ways at the vulnerability. An advantageous one The possibility is that the end face of the plug and the end edge of the core tube are opposite the end face of the winding body are arranged increased. The contact layer on the stopper and the front edge of the core tube is opposite the contact layer on the The shrinkable bobbin is raised and both contact layers are connected to one another via a step. The thickness of this stage is less than the thickness of the

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remaining contact layer, d. H. the continuous forehead contact layer has a weak point at the step.

Another embodiment of the invention consists in that the plug protrudes beyond the core tube and rests with a circumferential shoulder on the front edge of the core tube. The outer edge of the part protruding beyond the core tube is beveled and forms a truncated cone. The truncated cone closes with the outer circumference of the core tube at the contact line with the shrinkable winding body away. Also the frustoconical part of the plug is completely covered with a forehead contact layer. This forehead contact layer goes seamlessly into the forehead contact layer of the bobbin over. The front contact layer points at the foot line of the frustoconical part a kink, which represents the weak point in the forehead contact layer.

The fuse according to the invention does not need to be installed in a housing in order to be actuated. Also, their sensitivity can be being controlled. Since the connecting wires are placed in the plug, which is in the core hole is inserted, can be anchored, it does not require a special welding or soldering process for attaching the connecting wires, but these can be used when applying the front contact layers with the Occupancies can be contacted at the same time. This avoids the risk of destruction due to impermissibly high Heat influence of the heat-sensitive end faces of the wound body. Furthermore, when applying the Front contact layers covering the core hole during of the Schoop process. After the fuse has been switched off, the connecting wires remain in their original position. whereby a contact of the same with other parts of the

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Condenser is avoided. The connecting wires are not in their Changed situation.

In order to increase the effectiveness of the fuse, it is advantageous to directly onto the non-shrinking core tube stronger than the dielectric shrinking, capacitively inactive Wind up insulating film. This prevents the winding body from shrinking more than on the outside in the area of the weak point in the forehead contact layer.

On the basis of the figures, the invention is intended to be based on exemplary embodiments and advantages thereof will be explained.

Figure 1 shows .schematically an inventive Capacitor in the area of the front contact layer, which acts as a fuse;

FIG. 2 shows the capacitor according to the invention in the area of FIG. 1 after actuation of the switch-off protection; Figures 3 to 6 show embodiments according to the invention;

FIG. 7 shows the embodiment of FIG. 6 in plan view.

In the figure 1 is a broken view of a section shown by the capacitor according to the invention. On one The core tube 2, which does not shrink, is the wound body 1, the dielectric films of which are preferably in the axial direction shrink, coiled. The plug 6 is inserted into the core tube 2. The connecting wire is in this plug 4 anchored. The entire face of the capacitor is covered with the front contact layer 3. At the stirnsei term Bertihrungslinie between core tube 2 and winding body 1 is the weak point in the Schoop-

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layer 3 · This weak point can be created by the fact that the schoopachicht at this point has a smaller one Has a diameter than the rest of the Schoopschicht; she can also be given that the outer circumferential edge of the core tube in the end face during the Shrinkage of the wound body can act like a cutting tool on the Schoopschicht.

In Figure 2 is the situation after actuation of the switch-off protection shown. The Schoopschicht located on the shrunk wound body 1 is different from that on the α plug face and the core tube face Contact layer at the breaking point or weak point 8 is completely torn or separated. The condenser is switched off in this state. When the fuse is actuated, the connecting wire 4 remains stationary and thus contact with other elements of the circuit cannot occur.

In Figure 3, an embodiment is shown which is suitable for controlling the sensitivity of the fuse is. The weak point 8 consists in a step of the Schoopschicht 3. This step surrounds the connecting wire in a ring shape 4 and the contact point 10 of the connecting wire with W of the end contact layer 3. At the point of the step is the thickness of the Schoopschicht 3 is less than that of the rest of the Schoopschicht. This stage is created in that the end faces of the core tubes and the plug protrude beyond the end face of the winding body. These end faces are offset from one another. The thickness of the metal layer in the weak point results from the Coverage of the contact layers that cover the plug or the winding body. It can be through the thickness of the contact layers be regulated.

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In the embodiment of FIG. 4, the securing plug 6 has an outer part 9 which extends over the end face of the core tube protrudes. This outer part 9 is frustoconical and extends over the face of the Core tube 2 and rests on this with a circumferential shoulder. The foot line of the truncated cone 9 closes with the outer edge of the core tube 2 and meets with the line of contact between the core tube 2 and the winding body 1 in the face. The entire truncated cone 9 and the entire end face of the winding body 1 are with a front contact layer 3 coated. The front contact layer 3 has a ^ at the foot line of the truncated cone 9 Bend 8 and runs on the beveled surfaces with φ a smaller thickness than on the other surfaces. Depending on how steep the angle o (between the base and the side surface of the truncated cone 9 is dimensioned, the thickness of the end contact layer 3 results on the side surface of the truncated cone. This thickness setting is a Measure of the sensitivity of the fuse. The weak point runs in this embodiment at the kink place above the foot line of the truncated cone and on the inclined side surface of the truncated cone.

In the embodiment shown in FIG. 5, strongly shrinking foils 5 are attached directly to the core tube 2 wraps. These foils shrink more than the dielectric foils of the active winding body. This results in the high contact pressure prevailing in the area of the core tube of the inner layers overcome. The plug in the core tube can have the shapes of Figures 1 to 4-. The support shoulder of the truncated cone 9 can extend over the front edge of the core tube 2, the base line of the truncated cone with the front line of contact of the core tube 2 and the strongly shrinking wind

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fertilize or layers 5 coincides. The vulnerability in the forehead contact layer is then at this point. The support shoulder of the truncated cone 9 can also As shown in FIG. 5, it extends over the winding layers of the strongly shrinking insulating films 5. If the core tube 2 consists of a spark-sensitive material, the layers 5 offer spark protection, if they are made of thermally stable material. In addition, the shrinkability is also improved in this embodiment the inner winding layers of the active winding body 1, which rest directly on the more shrinking layers 5, supported. The sufficient shrinkage of the inner winding layers of the active winding body 1 guarantee the perfect puncture of the switch-off protection.

FIG. 6 shows a further advantageous shape of the stopper 6. The part of the stopper which comes from the core tube protrudes, has one or more arms 7 which rest on the end face of the winding body 1. These arms can extend to just under the outer diameter of the end face of the winding body 1. They taper in thickness and width outwards and end with a vertical edge at a low height. The front contact layers 3 are not sprayed so thick that the contact metal only on the plug surface and the surface of the arms 7 and on the end faces of the winding body 1 is calibrated. A connection of the contact metal on the arms 7 and the contact metal on the winding face only takes place on the outer edges of the stopper arms. The connection is made there stepped; vulnerability 8 of the fuse is at this level. If the winding body 1 shrinks, then the contact is interrupted at this point. The advantage of this embodiment is that the Weak point 8 of the contact metal near the outer edge

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of the winding 1 is where the shrinking effect is particularly strong is. Due to the relatively long arms 7, the elastic Bending of the same up to tearing off is particularly large, which means a spring effect and after tearing off the Contact layer 3 of the wound body 1 is even further away from the contact layer on the arms 7. At this Embodiment are also the edges and flanks of the plug 6 and the arms 7 in an advantageous manner beveled inside so that it overhangs on the face of the winding body 1 rest. This avoids that a connection between the contact metal and the winding face and the contact metal on the stopper 6 and the stopper arms 7 arises.

With all types of construction, it is advantageous to use the surface to roughen the plug 6 in order to obtain good anchoring for the contact metal 3.

To get the spring effect, i. H. the sudden opening of the To support vulnerability 8, it is beneficial for the stopper 6 to use an elastic material. When the visual weak spot 8 breaks, the elastically deformed one then snaps Stopper 6 back to its original position.

In the embodiments of Figures 2, 3 and 4 it is It is advantageous to manufacture the core tube and the plug from a thermally stable material. It's supposed to be its insulating ability upon decomposition, e.g. B. by sparking maintained. There are, inter alia, or z. B. polyolefins, Polyamides and polysilanes in question.

In order to achieve good contact between the connecting wire 4 and the contact layer 3, it is advantageous to use this compress at the contact point 10, in a spiral shape

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curl or otherwise widen. The connecting wire 4 is firmly connected to the plug 6 and is sprayed on the contact metal layer 3 is in contact with the coverings of the winding body 1. A special solder or The welding process is therefore unnecessary.

19 claims
7 figures

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Claims (19)

2Q60907 Claims (1.JElectric wound capacitor with a shrinkable Dielectric and end contact layers, which connect the assignments with external connection elements, at which, as a result of heating through shrinkage of the dielectric in the axial direction, increases the length of the rocker body and the electrical contact between the assignments and at least one of the external connection elements is interrupted, characterized in that that the contact point (10) of the outer connection element (4) with the front contact layer (3) and the part of the front contact layer (3)> which covers the front surface of the shrinkable rocker body (1), at a weak point (8) in the forehead contact layer by shrinking the rocker body completely are separable from each other. 2. Capacitor according to claim 1, characterized in that that the weakest (8) circularly encloses the contact point (10) of the connection element (4) with the front contact layer (3). 3. Capacitor according to claim 1 or 2, characterized in that the connecting wire (4) is anchored in the winding core. 4. Capacitor according to claim 3, characterized in that that the connecting wire (4) is fixed in a plug (6) which is inserted into the winding cavity and that the entire The end face of the capacitor is coated with a contact metal layer (3). VPA 9/140/0014 - 12 - 209825/0929 A capacitor as claimed in claim 3 or 4, characterized in that the plug (6) is inserted into the front opening of a notchable core tube (Z) which contains the roughable winding body (1) carries, plugged in and the face of the de§ Plug the end edge of the core tube and the end face of the winding body form a flat surface. 6. Capacitor according to one of claims 1 to 5, characterized in that the Visual weakness (8) along the frontal contact line between the winding body (1) and the core tube (2) runs. 7. Capacitor according to one of claims 1 to 6, characterized in that the End face of the plug (6) and the end edge of the core tube (2) opposite the end face of the winding body (1) are arranged in an elevated position so that the contact layer (3) thereon is opposite to that on the The contact layer located on the winding body is raised and the two located on different levels Contact layers are connected to one another via a step. 8. Capacitor according to one of claims 1 to 6, characterized in that the Plug (6) protrudes beyond the core tube (2) and has a circumferential shoulder on the face of the Core tube rests and that the outer edge of the part protruding beyond the core tube is beveled and the contact layer (3) on the stopper in the shape of a truncated cone from the contact layer on the end surface of the bobbin (1) protrudes. VPA 9 / HO / OO14 - 13 - 209825/0929 9 · capacitor according to one of claims 1 Ms 8, characterized in that on the core tube (2) has a stronger dielectric film than the dielectric film in the capacitively active winding (1) shrinking * capacitively inactive insulating film (5) is wound up 10. Capacitor according to claim 9 »marked thereby t that the plug (6) protrudes from the core tube (2) in the shape of a truncated cone and with a circumferential shoulder on both the face of the core tube as well as on the layers (5) of the more rapidly shrinking, capacitively inactive insulating film rests. 11. Capacitor according to one of claims 1 to 10, characterized in that g e k e η η ze i without t, - that the The plug (6) protrudes from the core tube (2) and has one or more arms (7) which are located on the front side of the bobbin (1) lie on and at the ends in run down a vertical edge of small height. 12. Kohcie ^ 'sator according to claim 11, characterized in that the arms (T) just up to the outer circumference of the end face of the winding body (1) extend. 13. Capacitor according to claim 11 or 12, characterized marked that the width and Thickness of the arms taper towards the outside. 14-. Capacitor according to one of Claims 11 to 13, characterized in that the Front contact layer (3) on the front surfaces of the VPA 9/140/0014 - 14 - 209825/0929 Plug (6) and the arms (7) and the winding body is so strong that only at the end edges of the arms a connection of the contact layers on the Wik kelstirnfläche and the arms comes about. 15. Capacitor according to one of claims 11 to 14, characterized in that except the arm end edges all other edges of the plug (6) and the arms (7) are beveled. 16. Capacitor according to one of claims 1 to 15, characterized in that the Surface of the plug (6) is roughened. 17 · Capacitor according to one of Claims 1 to 16, characterized in that the Plug (6) is designed to be elastic. 18. Capacitor according to one of claims 1 to 17, characterized in that the Core tube (2) and / or the stopper (6) consist of polyolefins or polyamides or polysilanes. 19. Capacitor according to one of claims 1 to 18, characterized in that the Anechlußdraht (4) at the contact point (10) is compressed, spirally curled or otherwise widened. VPA 9/140/0014 209825/0929 is Blank page