US845997A - Electrical resistance. - Google Patents

Description

No. 845,997. PATENTED MAR. 5, 1907. A. O. BENEGKB.

ELEGTRIGAL RESISTANCE. APPLICATION FILED 11mm, 1906.

WITNESSES. IIVVENTOR AWOR/VEYS.

UNITED STATES PATENT OFFICE.

ADELBERT 0. BENEOKE, OF NEWARK, NEW JERSEY, ASSIGNOR TO THE AMERICAN INSTRUMENT COMPANY, OF NEWARK, NEW JERSEY, A COR- PORATION OF NEW JERSEY.

ELECTRICAL RESISTANCE.

Specification of Letters Patent.

Patented March 5, 1907.

Application filed June 1,1906- Serial No. 319,697.

To (all whom it may concern:

Be it known that I, ADELBERT 0. BE- NECKE, a resident of Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Electrical Resistances, of which the following is a specification My invention relates to improvements in resistances which are intended to carry comparativcly large currents, and especially to shunts for electrical measuring instruments.

The object of my invention is to reduce the mechanical size of such resistances 'to a minimum, which is particularly important in electrical measuring instruments, shunts which have to be inserted in the conductors carrying the current to be measured. If such resistances were given a sullicient cross section not to become overheated b the amount of electrical ener y consumed in the same by conversion into Iieat, they would be so enormously large that their use would become prohibitive.

There have been made several attempts in the art to desi n such resistances in such a manner that the dissipation of the heat generated in the same is aided by the cooling effect of the air-currents or by th8 radiation from large surfaces. The most successful attempt in this direction is disclosed in Unite States Patent No. 497,482, granted to Edward Weston, dated May 16, 1893. In the specification of this patent the inventor states that he has been able to send a current of one thousand amperes through each square inch of cross-section of German silver without overheating.

My invention has enabled me to pass a current of ten thousand or even thirty thousand amperes to each s uare inch cross-section of a similar materia without overheating the same. I have accomplished this result by making the terminal plates of my resistances of a material of hi h electrical conductivity, as copper with amp e cross-section and mass to carry the current for which the resistance is intended without being heated to any appreciable amount, and by reducing the cross-section of the resistance material inserted between these terminals to such an extent that the necessary lengths to make up a resistance of required value becomes so small that any heat generated in the same will be rapidly conducted away and absorbed by the large and massive terminals.

In carrying out my invention I make use of the structure hereinafter described, and illustrated by the accompanying drawings, in which-- Figure 1 is a side view of my improvement. Fig. 2 is a plan view of the same, and Fig. 3 illustrates a slight modification.

Like letters of reference refer to similar parts throughout the specification and drawings.

The device consists, essentially, of the massive terminals o and I), made of a material of high electrical coruluctivity, connceted together by the resistance material 0 of small cross -section and corresponding short lengths. In practice lfind it convenient to fix the resistance material into the ends of the terminals a and b by slotting the adjacent ends of the terminals, as illustrated in Fig. 1, and then inserting the edges of the resistance material into such slots and soldering the same into position. However, any convenient method may be employed for uniting the resistance material with the terminals in intimate metallic contact.

In the selection of suitable resistance material it often happens that such material when heated by the passage of an electrical current in the open atmosphere will oxidize, and thereby deteriorate. To prevent this oxidation and keep the resistance material from direct contact with the atmosphere, I find it convenient to serrate or glovetail adjacent ends of the terminals, as illustrated in Fig. 1, and to iill the space su1= rounding the resistance material with some non-conductin fireproof substance 71. For

example, pow ered glass held to ether b .some suitable binder, or mica, asbestos, or

any other material will answer the purpose, so long as it will kec the resistance material from contact with tie atmosphere and will form an electrical insulator. L

As a convenient means of connecting such a resistance into an electrical circuit provide bolts and nuts (I, by which the ordinary bus-bars may be connected to the ends of the device.

In case the device is used as a shunt for electrical measuring instruments I provide employed b main connection'with the massconductivity, and a conductor 0 tenths of an inch. It is evident that the unit or standard,when they the furthermore, the binding screws 6, to which the electrical measuring instrument 9 1s connected by means of conductor-wires f.

The resistance material 0 may be in the 3 form of a single thin sheet, as shown in Fig. 1, or in the form of a number of sheets arranged side by side ,or one on top of the other or m the form of a single wire or a number of wires, as substantiall illustrated in Fig. 3.

I have foun by experiments that the crosssection of the resistance material can be reduced almost indefinitely; but in practice I find that in order to produce a number of such devices of uniform resistance the length of the resistance material should best be not reduced to more than a length of about twoshorter these lengths are chosen the more difficult it will be to keep the same exactly within desired limits. I

Inoperation when such a resistance is connected' in a circuit the current will pass from the terminal a to the terminal I) through the resistance material 0. A certain amount of electrical energy will be consumed in the resistance material and converted into heat. This amount is directly proportional to the resistance and to the square of current passing through thesame. The heat developed in the resistance material in case. the density of the current is as large as I have mentioned above would under ordin circumstances be .sufi'cicnt to fuse the resistance material and therewith to render the device inoperative. The extreme short 'le he of the resistance material thereby bfingin the terminals into such close'proxi'r'nity, oweveL-as ive termin s prevent any overheating of the resistance material, as all'heat'generated in e same is. rapidly conducted-away} by the, terminals whose masses are sufficientjto 'ab sorb the heat without becomi g zhemselves overheated. 1 It frequently happens in practicathat it is desirable to have a resistance of; greater can rying capacitythan is found in a structure made in accordance with Figs. 1 and-2; Un der such conditions it is only-necessaryto couple up several units of this tgp'e inpa'rallhi in t e circuit or,.better still, top ace several of. the same one upon the other and connect".- them all togetherb means of the connecting bolts and nuts d. n this manneri'tispossi-- ble to construct the resistances ,after'a single coup ed together, as described, to pro co. the requlred-resistance."

I claim:- V v 31 An electrical rfiistance device, consisting of-two blocks'of metal of hifgh s ecific s. sp r cific resistance and-short length connecting saidblocks of. metal the free length-of sa'i conductor being such that the'heat gener- -ing1 of two, blocks ofmetal of hi h spfcific ated therein by the passage of a current there-' through, is conducted to and absorbed b Y said blocks of metal as rapidly as such heat is enerated, whereby said conductor will nothe overheated.

An electrical resistance device, consisting of a short conductor of high specific resistance, connecting two masses or blocks of metal of high specific conductivity, the free length of said conductor being such that the heat generated by the passage of an electric current therethrou h will be absorbed b said blocks of metal as rapidly as generated, whereby said conductor will not become overheated.

3. An electrical, resistance device, comprisin two blocks or masses of metal of high speci 0 conductivit separated by a short space, a conductor of i h specific resistance connected to said blocEs and spanning said space, the length of said conductor being such that the heat generated by the passage of a current therethrou' h, is conducted to and absorbed by said looks or masses of metal as rapidlyas generated, whereby said conductor wi 1 not become overheated.

4. A resistance device for electric circuit, comprising two blocks or masses of metal of highs ecific conductivity',.and a conductor of big specific resistance connecting said blocks or masses of metal, said conductor being of such small cross-section. as to produce the desired resistance within such a short length thereof,-that the heat generated by the, passage of an electric current there- 'through Wlll be conducted to and absorbed by the said blocks or masses of metal as rapidl as generated, whereby said conductorwi 1 not becomeoverheated.

5-, An electrical resistance device, consistconductivity, and a conductor 0 hig spe- ,cific-resistance and short length connecting satdblocks of metal, the free length of. said eonductor bcing such that the heat generated] therein by :the passage of a current therc'through, is conducted to; and absorbed by said-blocks of metal as rapidly as generstedvwhereby said conductor will not be overheated; ands fire-proof insulating materdiatinclosing the free surface of sa d conubtOil 'ing of afs'hort conductor .of high specific resistanceconnectingtw'o masses or blocks of metal oi'high specific conductivity, the free length of. saidco'nductor being such that the.

.heatgenerated by the passageof an electric current therethro h will be absorbed b said blocksof'met as rapidl as generate whereby said *conductorwil not be overheated, anda fireproof insulating material inclosing thefi'eesurface of said conductor.

7. Anelectrical resistance device comprising' two blocks or masses of metal oi high spe- '6. 'An eIectrical resistance device, consistsaid resistance device in an electric circuit.

cific conductivit separated by a. short space, a conductor of i h specific resistance connected to said bloc s and spanning said space, the length of said'conductor being such that the heat generated by the passage of a current therethrou h, is conducted to and absorbed by said locks or masses of metal as rapidly as generated, whereby said conductor Wlll not be overheated, and a fireproof insulating material inclosing the free surface of said conductor.

8. A resistance device for electric circuits, comprising twoblocks or masses of metal of high specific conductivity, and a conductor of high specific resistance connecting said blocks or masses of metal, said conductor being of such small cross-section as to produce the desired resistance within such a short length thereof, that the heat generated by the passage of an electric current therethrough will be conducted to and absorbed by the said blocks or masses of metal as rapidly as enerated, whereby said conductor will not ecome overheated, and a fireproof insulating material inclosing the free surface of said conductor.

9. An electrical resistance device, consisting of two blocks of metal of hi h specific conductivity, and a conductor 0 high specific resistance and short length connectin said blocks of metal, the free length of Sci conductor being such that the heat generated therein by the passage of a current therethrough, is conducted to and absorbed by said blocks of metal as rapidly as generated, whereby said conductor will not be overheated, and means for connecting up 10. An electrical resistance device, conl sisting at two blocks of metal of high specific conductivity, and a conductor of high specific resistance and short length connecting said blocks of metal, the free length of said conductor being such that the heat generated therein by the passage of a current therethrough, is conducted to and absorbed by said blocks of metal as rapidly as generi ated, whereby said conductor will not be overheated, and a shunt-circiiit leading around said conductor.

11. An electrical resistance device, consisting of a shortconductor of high ecific resistance, connecting two masses or looks of metal of high specific conductivit the free length of said conductor being suc that the heat generated by the passe e of an electric current therethrough will e absorbed by said blocks of metal as rapidly as generated, whereby said conductor will not be overheatedya shunt-circuit leading around said conductor and means for connecting up said resistance device in an electric circuit.

12. Anelectrical resistance device, comprising two blocks or masses of metal of high specific .conductivity located in close toximit to each other and a conductor 0 high specific resistance and short length having s of meta its ends embedded into said bloc respectively, thereby leaving a short free length of conductor between said blocks of metal.

13. An electrical resistance device, comrising two massive terminals, com osed of locks of metal of high specific con uctivity located in close proximity, and a conductorof high specific resistance having its ends embedded into said blocks of metal res actively, to leave a short free length of meta between said tcrminals.

14. An electrical resistance device, consisting of two blocks of metal of high specific conductivity and a hi h-resistance conductor connectin said bloc s of metal, said conductor being of such short free length that the heat generated therein by the passage of a current therethrough is absorbed and dissipated by said blocks of metal as rapidly as generate This specification signed and witnessed this 18th day of Ma 1906.

ADELl ERT O. BENECKE. Witnesses:

Louis M. SANDERS, FREDK. O. Freeman.

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