US2090360A - Electrical condenser - Google Patents

Description

Aug. 17, 1937. J. K. SPRAGUE ELECTRICAL CONDENSER Filed June 28, 1932 JUZZAZVK $24612" 1 NVE N TOR.

Patented Aug. 17, 1937 UNITED Ls'rATEs PATENT OFFICE- ELECTRICAL CONDENSER chnsetts Application June 28, 1932, Serial No. 619,787

3 Claims.

My invention relates to the construction of electric condensers and to a method and means for providing connections between the metal foils and the outer terminals of the condenser.

In condensers of the types most generally used there are provided two metal foils separated from each other by layers of insulating material; the metal foils and the insulating layers being wound together into a compact roll of cylindrical or rectangular shape. For electrical connection with the metal foils there are to be provided leading-out or terminal wires and while a great number of constructions. have been suggested and used for this connection, these constructions are either not fully satisfactory or are complicated and expensive.

The object of the present invention-is therefore to provide an eiiicient electrical connection between the metal foils of the condenser and the terminal leads, which is simple and easy to manufacture.

Another object is to provide means to mechanically strengthen the whole condenser assembly, which means at the same time assist to maintain proper electrical connection between the terminals and their respective foils.

A still further object is to provide means, whereby the terminals of the condenser are reenforced at the point of egress from the condenser assembly andare mechanically connected to the assembly independently of their connection with their respective foils.

A further object of the invention is to relieve the connecting point between the terminals and the metal foils from any mechanical stress which may be exerted on the free end of the terminal.

A further object of the invention is to provide a novel construction for a compact electrical condenser.

Further objects will appear as the description progresses. a

My invention willbe explained on hand of impregnated paper condensers, but it should be well understood that it is not limited to such condensers.

' vertical plane through the lines 3-3 of Fig. 1.

Fig. 4 shows another construction of a conprotective outer shell for the condenser.

In the drawing forming part of this specificadenser of my invention, with a different method of securing the terminal wires to the condenser.

The condenser Hi illustrated in the drawing, comprises two. strips li-ll of aluminum or other suitable metal foil having interposed one or more layers of paper or other insulating material l2-l2 (two layers being shown in the drawing). The insulating layers are preferably impregnated with a suitable di-electric material, for instance paraffin. The metal foils with the interposed insulating layers are wound into a roll.

The metal foils il-ll are displaced with respect to their corresponding edges (see Fig. 3) so that the outer edge of one foil extends beyond the insulating strips to the left as at H, and the outer edge of the other foil extends similarly to the right as at l5. There is thus provided at each end of the condenser an uninsulated edge of each of the foils. While the sheets of the insulating layers l2-l2 are wider than the foils forming the condenser, they do not extend beyond the edges I4 and i5, but the several sheets i2-l2 align with each other edge for edge.

The outside terminals of the condenser are formed of wires 2l-2l which may be for instance copper wires or tin-coated copper wires and are'cut to convenient lengths. The wires 2l-2I are shaped at one end to form circular loops 22-22 (see Figs. 1 and 3). These loops are connected to' theedges l4 and 15 respectively by means of soldering 23-23. Thereby the loop surrounds the projecting edges l4 and I5 respectively, which together with the solder fill out the whole loop thereby contacting with the terminal wires 2l-2l on a large area.

The condenser roll is then surrounded by a wrapper i8, preferably of thin fibre or other similar insulating material, which forms a strong The width of the wrapper'lii exceeds that of the condenser roll and forms on each end thereof hollow tubular extensions l8-l8.

The extensions l8-I8 surround the loops 22-22; holes l9-I9 being provided in the T wrapper through which the terminal wires 2l-2l pass.

The tubular extension l8-i8 is filled out with a suitable compound 25 in plastic or molten state, which upon hardening, substantially contribute to the mechanical strengthening of the condenser and also seals the condenser against moisture. Furthermore, the compound 25 also greatly strengthens the connection between the metal foils ll-H and the loops 22-22.

On the outer side of the wrapper i9 and surrounding the wires 2i-2l are provided eyelets 28--2@ which are pressed against the wrapper l6 and the compound 25 and the wires 2l-2i are 5 soldered to the eyelets at the point of egress 213-4 1, whereby mechanical connection of great strength is established between the terminal wires 2l2i and the condenser assembly.

It should be noted that any mechanical stress 10 or pull exerted on the wires 2 I-2i will be taken up by the whole condenser assembly at the I point 24 without any stress being transmitted to the soldered contact between the foils Ii-li and the loops 22-22.

Another form of relieving the joints between the wires 2l-2i and the foils from mechanical stress, consists of the provision of an auxiliary wrapper l6, as shown in Fig. 4. The wrapper l6 surrounds the condenser proper and is pro- 0 vided near to each end with small holes 20', through which the wires 2l-2l are passed. The holes 20-20' are placed inwardly of the connections between the loops 22-22 and the respective foils of the condenser, whereby the 2 wires 2|--2l are bent inwardly and securely held by said auxiliary wrapper, after which they pass through the main wrapper l6, which is then wound and sealed about the condenser assembly. From the foregoing it should be noted that my invention provides for an inexpensive, simipie and compact condenser construction of great mechanical strength. Furthermore, it provides for a reliable connection between the metal foils and the outside terminals, which connection is altogether relieved of mechanical stress exerted on the free end of the terminal wire, and at the same time provides for a reliable low resistance electrical contact between the metal foil and the terminal wire.

aoe sco soldered to the extending ends of the metal foils,

and a wrapper of insulating material surrounding said roll and said looped ends, holes on said wrapper for the egress of the free ends of said wires, and eyelets surrounding said wires, said eyelets being soldered to said terminal wire and being in intimate contact with said wrapper.

2. An electrical condenser comprising two metal foils and interposed layers of insulating material wound together to form a roll, said metal foils having edges extending beyond the insulating layers, terminal wires soldered to said extending edges, and a wrappersurrounding said condenser roll and provided with holes for the passage of said wires, and means to fasten said wires to the wrapper at their points of egress.

3. An electrical condenser comprising two metalfoils and interposed layers of insulating material wound to form. a. roll, each metal foil extending with one edge beyond the insulating layers, and terminal wires having looped ends soldered to the extending ends of the foils, a wrapper surrounding said roll and extending beyond its two ends, a compound hardened in situ in said extensions and pressing against said loops, holes in said wrapper for the passage of the terminal wires and eyelets surrounding said wires at their point of egress from the wrapper, said eyelets being in intimate contact with said wrapper and pressing against said compound and being soldered to said wires.

JULIAN K. SPRAGUE.

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