US901498A - Condenser. - Google Patents

Description

WITNESSES H Y .lHVE/l'ifOR-f I f v Elihu Thomson, MA/M UNITED STATES PATENT OFFICE.

ELIHU THOMSON, OF SWAMPSGOTT, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

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Specification of Letters Patent.

Patented Oct. 20, 1908.

Application filed. Kay 5, 1904. Serial No. 206,479.

To all whom it mayconcem:

Be it known that I, ELIHU THoMsoN, a. citizen of the United States, residing at Swampscott, in the county of Essex and State of Massachusetts, have invented certain new and useful Improvements in Gondensers, of which the following is a speci tication.

In working with high voltage condensers in which adjacent metal conducting plates of opposite polarity are separated by a comparativelythick layer of dielectric, there is a concentration of the dielectric stress upon the edges of the conducting plates, while be-' tween the plates the stress is nearly uniform through the layer of dielectric. By reason of this difference in the stress due to the charge, the tendency to break down the insulation between the edges of the conducting plates is much greater than between the bodies of the plates. This excess of stress on the edges of a conducting plate is not so marked where the voltage between adjacent working platesis not so great and the layer of dielectric material is thinner.

I have found that the liability of break down in high voltage condensers may be greatly diminished by placing a number of intermediate conducting plates between the main or active plates of a condenser. Each of the intermediate plates is separated from adjacent conducting strips or plates by thin layers of dielectric. The intermediate plates are not electrically connected to each other or to either of the main plates. In arranging the conducting plates in high voltage condensers I prefer to displace adjacent main conducting plates with respect to each other so that the distance between corresponding edges is considerably greater than the distance between the bodies of the plates. The intermediate unconnected conducting plates may be arranged so that their edges terminate in the sloping planes connecting the corresponding edges of adjacent main plates. 1

By the construction described thestrains between adjacent main plates are equalized in a way which would not be the case if the intermediate unconnected plates were not employed. These intermediate plates distribute the stress over separate dielectric layers between them and prevent the existence of extended weak areas between the main plates, suchas might otherwise-exist.-

Moreover as the distance between the edges of the main conducting plates is considerably greater than the distance between the bodies of the plates, the inequality in distribution of the charge upon the plates is less objectionable than would otherwise be the case.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to ipnd forming a part of this specification. or a better understanding of my invention, however, reference may be had to the accompanying drawings and description in which I have illustrated and described one embodiment of my invention. 4

Of the drawings, Figure 1 is a perspective view showing the arrangement of conducting plates in the condenser; Fig. 2 is a sectional side elevation; and Fig. 3 is a view taken at right angles to Fig. 2 on a large scale showing the arrangement of the plates in a portion of the condenser. I

Referring to the drawings, five similar and parallel plates or sheets A of conducting material such as tinfoil are shown as connected together at one end by a conducting strip or sheet B which may also be made of tinfoil. Between each adjacent pair of these plates is located a similar plate C. The plates C are connected by a strip or sheet D. The plates A are displaced laterally with respect to C. Between adjacent plates A and C are located a number of intermediate metal plates or conductors E. These are shown best in Figs. 2 and 3 and may alsolbe in the form of sheets of tinfoil. At each side of each of the intermediate plates E is placed a suitable layer of dielectric.- This may consist of a number of sheets of paraftined paper F. p

In the construction'shown plates A and C are prolonged in undiminished widths to the connecting sheets B and D. The portion of the top'plate A to the left of the line 1 1 in Fig. 1 may, however, be regarded as the terminal portion of the plate or conductor, and the portion of the plate to the right of the line 1 1 may be regarded as the body or working portion of the plate. Each ofthe plates A and C shown may similarly be regarded as composed of a terminal portion and a body or working portion. The terminal portion of the plate may well, in many cases, be made of a width much less than that of the body of the plate or may indeed be inthe form of a wire or rod or the like.

In the construction illustrated the body portions of each pair of adjacent plates A and 0 form the parallel sides of a parallelepiped, none of the plane angles of which are right angles. The edges of the intermediate equalizing conductors all terminate in the planes forming the side walls of this parallelepiped. The surfaces in which they terminate are, however, not necessarily plane, but may be curved to a considerable degree, provided they approximate in arrangement that described above The paper sheets may extend as usual beyond the edges of the metal sheets. The assembled condenser plates and separating layers of paper are thus embodied in a block G of paraflin or the like as shown in Fig. 2. The plates A and C form the active conductors of the condenser, the plates A all being of one polarity and the plates C of the opposite polarity.

The stress-equalizing plates or conductors E are not electrically connected to each otheror to the active conductors. They serve, however, to equalize the forces tending to break down the dielectric between adjacent active conductors. This is due, I believe, to the fact that they prevent the existence of coincident weak spots under abnormal stress extending through any considerable thickness of what would, otherwise be a single dielectric layer between the main plates.

The form of my invention which I have illustrated and described in'detail has given excellent results under severe conditions of service. 'I do not, however, intend that the claims hereinafter made shall be limited to the particular construction described and. illustrated as it is obvious to those skilled in the art that changes may be made in the form and arrangement of the condenser without departing invention.

What I claim as new and desire to secure by Letters Patentof the United States, is,

1. In a condenser, a pairof active conductors of opposite polarities, and one or more stress-equalizing conductors between iiid active conductors and insulated therefrom the spirit of my 2. In a condenser, a set of active conduct ing sheets electrically connected together, a second set of active conducting sheets also electrically connected together, adjacent sheets of each set having interposed between them one sheet of the other set, and a number of conducting members located between each sheet of one set and the adjacent sheets of the other set, said conducting members being insulated from each other and from said sheets.

3. In a condenser, a pair of parallel active conductors or sheets of different polarities, and one or more parallel stress-equalizing conductors or sheets located between said active conductors and insulated therefrom.

4. In a condenser, a pair of parallel active plates of opposite polarities displaced laterally with respect to each other, and an equalizing conductor between and parallel to said active conductors, the edges of said equalizing conductor terminating in the surface connecting corresponding edges of the active conductors.

i 5. In a condenser, a pair of parallel and similar active conductors of diiierent polarities, one or more intermediate equalizing conductors, the edges of the working portions of the active conductors and of the equalizing conductors terminating in the plane forming the sides of a parallelepiped, none of the plane angles of which are right angles.

6. In a condenser, a pair of active conducting sheets or plates of opposite polarities, and one or more insulated conductors located between them. 7. In a condenser, a pair of active conductors of opposite polarities placed side by side, and an Insulated conductor placed between them.

8. In a condenser, a pair of conductors. in inductive relation with each other. and arranged to be connected to a source of electricity so that a difference of potential exists between said plates, and an isolated conductor interposed between and in inductive relation with each of the first mentioned conductors.

In witness whereof, I have hereunto set my hand this third day of May, 1904.

ELIHU THOMSON.

Witnesses:

DUGALD McK. MGKILLOP, J OHN J. WALKER.

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