FI79631B - MEDELST VAERMESAEKRING SKYDDAD SJAELVREGENERERAD KONDENSATOR OCH FOERFARANDE FOER DESS FRAMSTAELLNING. - Google Patents

Description

1 79631 Thermally fused self-regenerating capacitor and method of manufacturing the same

The invention relates to a method of manufacturing self-regenerating capacitors consisting of one or more rolls, in which a metal layer is applied to strips of insulating material, the thickness of which at each point may vary depending on the distance of the strip from the side edges of the strip, the metallized strips are wound contact electrodes are pressed onto the side surfaces of the roller and the contact electrodes are connected to the terminals (EP-A1-109100). The invention also relates to a self-regenerating capacitor.

15 The automatic regeneration of a capacitor manufactured in this way after a momentary short circuit between opposite electrodes is due to the evaporation of the metal of the electrodes at the fault point. An irreparable short circuit in the electrodes marks the end of the life of such a capacitor-20. If the short-circuit current is strong, it can melt any fuse wire in its circuit. In some cases, a short circuit may cause the capacitor to explode. The short-circuit current may also be so weak that it does not melt the fuse wire. 25 In the latter case, strong heating occurs at the breakthrough point, causing damage to the capacitor.

In the past, efforts have been made to protect against the devastating consequences of such deficiencies by enclosing the condensate roller in a hermetic housing, the shape of which may change under the effect of internal pressure. When the condensation coil damage is usually accompanied by a gas discharge, this phenomenon has been used in the past to cause a deformation of a part of the housing to which the end of a 35 cut-off conductor is attached.

Similarly, fuse devices that are activated at the fuse device by ambient air, so-called thermal fuses, have been used in the past. Such thermal fuses are placed in containers in which the heating devices or elements are immersed in oil. The natural convection provided by the oil in the vessel keeps the temperature constant. The inventor has attempted to fit such thermal fuses inside capacitor vessels into air, oil with natural convection impeded or to non-liquid coating compositions. Such arrangements have proven ineffective because the short circuit usually occurs too far from the point of failure.

The object of the invention is a self-regenerating capacitor effectively protected by a thermal fuse and a method of manufacturing the same.

The method of manufacturing a capacitor according to the invention is characterized in that a thermal fuse is arranged on the shaft of each coil, in a zone with a high degree of metallization, which is connected in series with the conductor of the coil and that the contact electrodes are connected to the conductors.

The capacitor according to the invention is characterized in that a thermal fuse is arranged on the shaft of each coil, in the zone with a high degree of lowering, which is connected in series with the connection conductor of the coil, and that the contact electrodes are connected to the connection conductors.

Due to the thickly metallized strip, the deterioration of the condensate-30 market roll is localized to this strip because the electrical resistance of the conductive layer is lower there. The reasons for the deterioration of this point are further accentuated if this band is located near the center of the roll, where normal operating heating is strongest.

35 By appropriately selecting the width and position of this strip relative to the edges of the insulating tape, the occurrence of a dangerous defect of 3 79631 can be limited to this well-defined point on the roll shaft. By fitting a thermal fuse to the coil shaft at this point, any thermal damage to the capacitor coil immediately activates the thermal fuse 5 and cuts off power to the condenser coil, even when the faulty heating is not sufficient to melt the normal fuse wire.

The invention will now be described in connection with two embodiments with reference to the accompanying drawings. Figures 1 and 2 of the drawings are schematic sectional views of various pairs of strips forming capacitor rollers.

Figures 3 and 4 are cross-sectional views of capacitors according to the invention 15.

In Figures 1 and 2, a capacitor roll is formed ·: ·. by winding on a roll a pair of metallized dielectric strips, i.e. insulating strips 3, 4. The metallization of these strips 3 and 4 is not uniform, but its average thickness is substantially less on both sides of strip 5, the center line of which rotates on the roll in a plane perpendicular to the roll axis , especially in a plane of symmetry perpendicular to the axis of the roller, for example.

According to Figure 1, the metal layer 6 of each strip 3 and 4 has a protrusion 7 at the strip 5. However, such an arrangement is not the only possible one, since it is sufficient for the average thickness of all the layers on the strip to increase in the vicinity of the strip 5. This result can also be achieved with the metallization according to Fig. 2, i.e. with metal layers having a small thickness 8 on one side of the strip 5 and a large thickness 9 on the strip 5 itself and on the other side. The large thickness is preferably on the side on which the metallization extends to the edge 35 of the insulating strip on which the contact electrode, for example zinc, has been printed, for example by the Schoop method.

4,79631

It is clear that the strip 5 does not necessarily have to roll at a plane of symmetry of the roll perpendicular to the axis of the roll, but can roll at a point lateral to this plane of symmetry. In this case, the heat-5 rake must be on the roller shaft at the point on this page.

Fig. 3 is a sectional view of a capacitor consisting of two capacitor rollers 10 and 11 or two rows of rollers 10 10 and 11 in a housing 12. The two rollers are arranged in parallel. Each of them consists of metallized strips according to Figure 1 or 2. The thickly metallized strip point is between the two dashed lines 5. A thermal fuse 14 is arranged inside the plug 13 on the shaft of each capacitor. In the latter case, there may be a jacket or sleeve around the fuse 14. The housing • 12 can be filled with one of the hardened insulating compounds 15.

► 20 The melting temperature of the thermal fuses is slightly higher than the operating temperature of the capacitors, eg 10 ° C, or if the coating and impregnation of the capacitor rolls requires a temperature slightly higher than the operating temperature, the melting temperature is slightly higher than this temperature. If the heat treatment temperature of the capacitor rollers is relatively high, this treatment is preferably performed before the thermal fuses are placed on the plug shaft.

According to its preferred embodiment, the invention 30 is implemented by fitting a single capacitor roll to each housing.

The capacitors according to the invention, made of conventional insulators, paper, polypropylene, etc., are provided with thermal fuses, the melting temperature of which is selected between 90 ° C and 180 ° C. The fuses in this case are relatively thick and thus easy to handle, made of wires or strips made of alloys that melt at these temperatures. Such alloys consist of at least two of the following metals: Sn, Pb, Cd, Bi and Hg. Examples of alloys with a melting point between 90 ° C and 180 ° C are: 80% Hg, 20%

Bi (90 ° C); 53% Bi, 33% Pb, 14% Sn (96 ° C); 54% Bi, 26% Sn, 20% Cd (103 ° C); 40% Bi, 40% Pb, 20% Sn (111 ° C); 50% Sn, 32% Pb, 18% Cd (145 ° C); 67% Sn, 33% Pb (180 ° C); 68% Sn, 32% Cd (180 ° C). The wires or strips forming the thermal fuses are preferably protected by a sheath or sleeve wide enough to be sure to cut off the circuit when the wire or strip melts. Such a sheath is necessary when the fuse is surrounded by some hardened mass.

Figure 4 is a perspective view of a cross-section of a capacitor according to the invention formed by one of the rollers 10 in the housing 12.

The capacitor roll 10 has an axial hole 13. This axial hole may be a shrinkage of the seat 20 around which the capacitor roll is wound, or it may be a shaft hole of a hollow insulating socket belonging to the capacitor roll 10.

The capacitor roll 10 is coated with two side electrodes 15 and 16, which are obtained, for example, by spraying tiny droplets of metal according to the Schoop method. The connecting conductor 17 passing through the cover 18 is soldered to the upper electrode 16. A strip of fusible conductive metal, for example a lead-tin alloy, is in this case pressed to have a narrower part 19 which acts as a fuse, two normal plate parts 20 and 21 between. The end of the part 20 is bent at a right angle and this assembly is inserted into the hole 13 in the shaft of the capacitor roll 10 so deep that the bent end 35 of the part 20 comes into contact with the electrode 15 to which it is soldered. The narrower part 19 should be at the point of the roller, 6 79631 where the thickness of the metal layer is greater. The head 21 may act directly as a connecting conductor or may be soldered to an insulated connecting conductor 22, as shown in the drawing. The capacitor roll provided in this way can be impregnated with a suitable insulator simply by wetting it with it or by vacuum impregnation.

Once the capacitor has been inserted into the housing 12, which is preferably an insulating material, the free spaces between the capacitor and the housing can be filled with a suitable filler, for example a solidifying or thermosetting solid at normal temperature. This filler can form a relatively thick layer around the capacitor roll and thus replace the cover 18.

When a filler such as oil does not cause the fuse vir-15 to melt as it melts, it is not necessary to coat the strip portion 19 just in case. Otherwise, the strip part 19 can be protected by sleeves (not shown) which prevent the filler from coming into contact with the metal of the part 19.

20, *

Claims (6)

A method of producing a self-generating capacitor comprising one or more rollers (10, 5), wherein a strip of metal material (6,8,9) is applied to strips (3,4) of which a metal layer (6,8,9) is applied. average thickness decreases on both sides of a zone (5) which has a high degree of metal annealing and is located at a certain distance from the side edges of all strips, whereby contact electrodes (15, 16) are applied to the side surfaces of the roller, characterized in that on each side a shaft fuse (14) is connected in series with the roller connection line (22) and the contact electrodes (15, 16) are connected to connection lines (22,17). . A self-regenerating capacitor comprising one or more strips (3,4) of resistant rolls (10,11), which strips are of dielectric material, on which is applied a metal layer (6,8,9), the average of which is 20 thickness decreases on both sides of a zone (5) which has a high degree of metallization and which is at a certain distance from the side edges of all strips, whereby contact electrodes (15,16) are arranged on the side surfaces of the roll, characterized in that on each roll shaft, at the zone (5) having a high degree of metallization, is provided a fuse (14) which is connected in series with the connection line (22) of the roller and that the contact electrodes (15,16) are connected to the connection line (22,17). . 3. A capacitor according to claim 2, characterized in that it consists of a capacitor roller (10) located in a housing (12). Capacitor according to Claim 3, characterized in that the housing (12) contains several capacitor rolls (10, 11) placed one above the other.