US2274011A

US2274011A - Electrical condenser

Info

Publication number: US2274011A
Application number: US156023A
Authority: US
Inventors: Strab Hermann
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1936-08-05
Filing date: 1937-07-27
Publication date: 1942-02-24
Anticipated expiration: 1959-02-24

Description

Feb. 24,1942. -rRK 2,274,011

ELECTRICAL CONDENSER Filed July 27, 1937 Patented Feb. 24, 1 942 UNITED STATES. PATENT, OFFICE ELECTRICAL CONDENSER Hermann Strib, Stuttgart, Germany, assignmto Robert Bosch Gesellschaft mit beschrinkter Haftung, Stuttgart, Germany Application July 27, 1937, Serial No. 156,023 In Germany August 5, 1936 6 Claims.

The invention relates to improvements inflat pack or pressed electrostatic wound condensers,

particularly to those having a very thin metal denser in such a way that the metal coating of the condenser is allowed to project up to the front of the wound condenser or beyond it and a metal layer-is applied to the front, for instance, by spraying by the Schoop spraying process. A connecting wire can be soldered on to this metal layer. In order to obtained a good adhesion of the current connecting layer on to the metal coating of the condenser, it is useful to apply the current connection layers before impregnating the wound condenser. In order that after applying the metal layer, the impregnating medium may penetrate into the condenser, it is advantageous not to provide the whole front of the condenser with a metal layer, but only one or several parts of its front side.

Now it has been discovered that a flat pressed wound condenser the current connections of which are produced in the manner indicated may under certain circumstance have a greatly reduced puncture strength when the metal layer is applied to those parts of the inner condenser windings that have been bent during pressing. This is explained by the fact that the impregnating agent cannot penetrate into those parts of the. front of the condenser to which the metal layer is applied; Therefore the parts of the condenser under the metal layers applied to the front sides are not as fully provided with the impregnating agent as the other parts, since there is a longer way for the impregnating agent to .reach these parts than if it could penetrate di- The.

rectly on the front side of the condenser. parts of the condenser situated under the metal layer have consequently a somewhatsmaller v puncture strength than the other points.

In order to keep the reduction of the disrup tive strength so produced as small as possiole, according to this invention the parts of the wound bands bent during the flat pressing of the wound condenser are kept free from the current connection layer at least within the first inner third of the winding bands on the front of the condenser.

These bent parts are, of course, con

siderabiy stressed by the mechanical .tensile stresses which have occurred during the fiat pressing. It is consequently'doubly important that these parts should be adequately impregnated. I

The invention is more particularly described with reference to the accompanying drawing,. in which:

Figure 1 is an elevation of one form of con- .struction.

0, d, and f, metal layers are sprayed on, ,on to which a current connection wire g is soldered. The regions a and b are left free from the metal layers.

The metal layers 0 and d are situated on the front faces of the outer condenser windings, and

these, on being pressed flat are not so sharply bent as the inner windings. In order to provide a current lead for the inner windings from the front faces of the condenser, a further metal layer 1 is provided between the two bent places It and i of the innermost winding; this metal layer here covers the front faces of the inner windings which have been left free from the layers 0 and d at the bent parts.

Instead of the metal layers c and d being applied at the rounded ofi parts of the condenser they may also be arranged between the points h and i'and united with the metal layer 1. How- .ever, this arrangement has the dis-advantage,

puncture disappears in a region which is'larger than the hole in the dielectric, whereby the short circuit current is by itself interrupted. In this process there occur very small quantities of gas which cause a slight swelling of the condenser. This swelling occurs particularly in those regions of the wound condenser where the windings lie flat. with this swelling there is a certain possibility that the sprayed-on metal layers will burst.

By the arrangement described this danger is reduced to the lowest possible degree.

I declare that what I claim is:

1. An electric wound condenser of the fiat type comprising flat strip winding coiled upon them-.

. themselves, a dielectric separating the conducting metal coatings of the condenser, said metal coatings of different potential vice versa projecting one on each front side of the condenser and one or more coherent layers of metal applied on the front sides electrically connected to the projecting edges of the coatings whereby at least the first inner thirds of the bent parts of the windings are kept free from said metal layers.

3. An electric wound condenser of the flat type comprising flat strip windings coiled upon themselves, a dielectric separating the conducting metal coatings of the condenser, said metal coatings of different potential vice versa projecting one on each front side of the condenser and. one or more coherent layers of metal applied on the front sides electrically connected to the projecting edges of the coatings whereby at least the first inner thirds of the bent parts of the windings are kept free from saidmetal layers and a metal wire conductor soldered to said applied metal layers, each conductor electrically connecting all of the applied metal layers on each side of said condenser, but being spaced from said windings.

4. An electric wound condenser of the flat type comprising fiat strip windings coiled upon themselves, a dielectric separating the conducting metal coatings of the condenser, said metal coatings of difierent potential vice versa. projecting one on each front side of the condenser and at least three coherent layers of metal applied on the front sides electrically connected to the projecting edges of the coatings whereby the contact metal layers of the inner windings of the condenser are applied between the two bending points of theinnermost winding and those of the outer windings on one or on each rounded part of the front sides of ,the condenser, the inner bent parts of the windings being free from said metal layers.

5. An electric wound condenser of the fiattype comprising flat strip windings coiled upon themselves, a dielectric separating the conducting metal coatings of the condenser, said metal coatings of different potential vice versa projecting one on each front side of the condenser and at least three coherent layers of metal applied on the front sides electrically connected to the projecting edges of the coatings whereby the contact metal layers of the inner windings of the condenser are applied between the two bending points of the innermost winding and those of the outer windings'on one or each rounded part of the front sides of the condenser and a metal wire conductor soldered to said applied metal layers, the inner bent parts of the windings being free from said metal layers, each conductor electrically connecting all of the applied metal layers on each side of said condenser, but being spaced from said windings.

6. An electric wound condenser of the flat type comprising fiat strip windings of metal and-insulating material coiled upon themselves to provide successive layers of metal and insulating material, alternate layers of metal being exposed at opposite sides, respectively, of said condenser. and a layer of metal applied to the edges of said windings at each side of said condenser to electrically connect metal layers of like polarity, the inner bent edges of said windings being free from said applied metal layers.

HERMANN sTRAB.