USRE11250E - Electrical measuring-instrument - Google Patents

Description

r E. WESTON. ELEGTRIGAL MEASURING INSTRUMENT.

Reissned J um 28 INVENTOI? I ATTORNEY.

WIN/58858."

'35 cessedto receive the two bobbins or spools 2 UNITEDFH STATES PATENT OFFICE;

EDWARD N'ES'IlO-N, OF NEWARK,'NEW JERSEY.

ELEGTRICAL MsAsuRINe-iNsTRuM ENT.

SPEGIFIGATION forming part of Reiasued Letters Patent No, 11,250, dated June 28, 1892, @flglnel In 433,837, dated August 5,1890. Application for reissue filed Pcliihery 5, 1892 Bartel No. 42014 I 1'6 all whom it may concern:

Be it known that I, EDWARD W Es'mm of' Newark, Essex county, New Jersey, have invented a, newsnd useful Improvement in Electrical. Measuring-Instruments, of which the followingi's a specification.

My invention relates to an electrical. mess;

uring-instrument intended chiefly for use as an electrordynamometer for the measurement of alternating currents-of electricity.

My invention consists, broadly, in e fixed or' stationary coil ands coil oscillating or vibrating on inclosed pivots in the field of force of said stationary coil, said coils being electrically connected. The vibrating coil on the passage of the current through the circuit, including both coils, assumes an angular position, depending upon the diflfer'encc of poten:

tial between the terminals of the circuit.

The reversals of the currentfin both coils occur simultaneously, and hence an index or pointer connected to the movable coil is always-deflectedin the same direction, thus indicatingthe extent of said angular movement upon a; suitable scale.

' My invention further consists in the constructionand arrangement of the instrument,

as'hereinafter more particularly pointed out.

In the accompanying drawings, Figure 1 is a plan view; Fig. 2, a section on the line X X. of Fig. 1 ;a .nd Fig.3, a'section on the line Y Y,

Fig. 2. v 4 Similar letters and nu rnbers of reference indicate likepnrts. q

1 is the base of the instrument, suitably re- I 3 and'3, which, are placed end to-end and surroundedby coils of fineinsnlat-ed wire connested in series. The bodies of the spools 2 nnd -3 'nrc made of rubber. or other insulating material, they are hollowed out to form a spherical cavity 4, Fig. 3.

5 is acirculnr frame, of insulating 1naterial such-es shells-clued paper-on which is wound a coil. of this wire, the terminals of which are connected to the pivot-pins 6 and t 7, which pins a secured to said frame. The said pins are therefore journaled in the bodies of the spools 2 and 3, and have their hearings in adjustable steps 8 and 9, which aresupported upon the metal arms 10 and 11.

'pivot-pihs 6 and 7 arespiral springs 14; and 15, the inner ends of said springs being connected The arms 7 IO-and ll are secured to an outer cover 12, p

which extends over the outer face of the spool 2 by means of screws 13. Surrounding the to said pivot-pins and the outer ends of said springs being connected to arms 16 and 17,, which are pivoted at the extremities of said arms 10 and '11. By turning the arms 16 and 17 on their pivots the springs 14: and may be contracted or expanded. Supported onthe upper-pivot-pin is a light metallic disk, which carries an indicating-needle 18. The covering-plate 19 on the face of spool 3 carries a. horizontal plate 20, to which is secured. a scale-plate 21; also to the plate 19 is fast-- sued by screws 22 a cross-piece, and through thiscross-piece extend screws 23, which enter the base 1. By-removing'these screws 23 the spools 2 and 3 and associated parts can; be separated from the base.

Within. the ring 5 and filling the space included in it is asheet of inica'24. This sheet passes through an openingin adiephragm 25' of rnbber'or other non-conducting material, which is held between the spools 2 and 3 and extends diumetrically. across the spherical opening or chamber 4. v

26 is an ordinary resistm'ice-coil supported in a recess on the base in any suitable manner. 27 and 28 (dotted lines) are two contacts'prings, the spring 28 being in electrical contact with the binding-post A 29 is apush-bnttonpassing through a sleeve 30, which surrounds an opening in the base:

lplate 1, which button when depressed moves thesprings 27 and 28 into contact, and .so' closes thecircuit. i go The circuit in the instrument proceeds as follo'wsi From the binding-post B by wire a to one of the terminals of the coils on the spools 2 vend 3 and th-rouglrmaid-coils,'the other terminal of which is connectethto the lower spring 15, The cnrrent'then passes by the pivot 7 to and through the 'movable coil on'the frame 5 and thence to the pivot l to, spring 14, to arm 16, to'upper bracket 10, thence by the wire-b through the resistancecoil 26 to the contact-plate 27 by-wirec.te

'contacbplate 28, and so to binding-post A.

It :is intended to use this instrument to measure the 'electro-niotive force otelternatbeinthefform of hollow cylindersand the diaphragmsmay be omitted, the. said conlug currents,or',in other,words,as the several coils are -allconnected in series and as the rcsistance-ooil 26 is made of high resistance, 1 to measurethediflerence of potential between the binding-postsA and B; Inasmuch as the movable coil supported within the fixed coil on the spools 2 and 3 is connected in circuit with the latter itfollows that a reversal of the current in one coil will occur simultaneouslywith the reversal of the current in the other, and hence the needle will always be deflected in the sarne direction, regardless of the alternations oi the current. Of-course the normal or zero position of the frame 5 wheuno current is passing through the-instrument is in a plane passing through the longitudinal axisof the coils on the spools 2 and 3, as shown in the drawings, Figs. 2nd 3, and the .needle is'adjusted so as toniark' zero onthe so scale when the movable coil is in this posttion. The object ofthe mica diaphragm 24 is to deaden the vibrations of the coil upon the frame li-through itsaction as a fan, and this effect is increased by thevpreseuce of thedia- :5 phragm 25, between "which and the movable diaphragm 24 the air-becomes somewhat comprcssed during the movement of the frame, I and henceoflers still g ter resistance to the a motion otthe' latter. i-" 3o -While I here show the spools or bobbins provided with an interior spherical chamber and dia ragm 25 and the frame or ringo provid with the diaphragm 24, it is to be understood that said spoolsorbohbins may structiounot'beiug in any'wise essential.

By the term non-inductive materiai"heret in applied to the spool. or bobbin Imean a 0 spool or bobbin constructed of any material or combination of materials in which induced currents will practically not be produced.

I have already stated that the coils in" the p instrument are to-be made of flnewire. It is 5 also to be understood that the movable coil is to be as light as possible and that the bearings ofits pivots aft are to he jeweled; or, in other-words, the said coil is to be sosnpported that it will move with the minimum of 5c friction and to be so constructed that it will offer the least possible inertia to the actuating force 'of the current. 'By this structural arrangement I am enabled to move the coil to a definite position vwith a current of exceedinglylow strength, and I am therefore .enabledto reduce the eifect of selfinduction in the coils to such an extent that said eflect becomes prscticallyiiuappreciahle and does not interfere to any practical amount with the sensitiveness and accuracy of theappa- I rains. By reducing the size of theconductor in the coils, reducing the weight-and inertia of the-movable coil supporting said coil so as to move with the minimum of friction, and by usingsprings 0t smallest ible force to control the coil I accomplis the important result of practically obviating self-induction.

This was I believe to be art" I I desire next to direct particular attention 7 wholly newin the 1 to the springs 14-and-- 15. The arrangement 1 of these springs is obviously such as to anable them to oppose their resiliency to the retary movementof the pivot-shaft'uniformly at every point of its movement-that is to I say, there is no tendency on. the part of either spring to draw :or push the pivot against one side or other of its bearing, and consequently no irregular wear of either pivot or hearing ensues. In this waythe accuracy of the in- 8b strument-is-notonl enhanced,butconserved The relation of t esprings 14 and 15 tOths coils is of especial importance. It will be manifest that when the current traversesboth coils I havehere two fields mutually reacting upon one another and both variable. The movement of the pivotedcoil will necessarily be duelto thisreaction otthe two fields, but

, the extent of its movement in are will not be necessarily proportional to-the difference in go potential between the terminals ofvthe instrnment, but will simply bear some relation to said potential diiference. For, plainly, iu-- stead ofthe position of the movable coil being due to the reaction-of a variable field. upon a definite constant and fixed field, such as might be produced bya-permanent mag- 7 net, in which case the reacting forcewould act in substantially the same way for all positions of. the coil, its ition is due to the [O0 reaction of two variab e ilelds,'when the rc--- acting forecasts in 'practicallya different we) tor diflerent positions of the coil and the re sultant position of the coil correspondingto any given electro-motive force of current does ins not for all positions. v In my present device, and-actor asI know for the first time in the art, I cause the index of the instrument to'move directly to the no ollcw any one definite known law" true scale-mark, which is tobe read as the indication and there remaini-no bringing back to a sero-readingbeln'g necessary; and also, as I believe for the first time in the art,- I have accomplished this in an instrument where the "r r 5 moving body is, as and for the, reasons already pointed out, controlled by two reactin varia'b e fields-namely, the varying iiel about the movin coil reacting upon the varylug field about t e fixed coil. I have discov-' no ered that I-oan balance a coil of fine wire! thus actuated against an exceedingly delicate coiled springer springs, so that the saidsprings will permit the coil, ang'hence the Iiudex moved by said coil, to move at once to 1:; p

a new position dependent upon-thediflerence in potential between the instrument terminals, and the said springs maybeconstructedas to stren th and elasticiotyandregulated by the means lierein descri so that the indi- ['30 cations of the instrument on direct reading will be accurate for all positions of the said movable coil.

The advautageot the use of two coiled Y tion, which obviously could not be done springs, from what has been said, will be ;apparent. They acf as conductors for the current into and out of the coil, obviating the necessityof mercnry cups jor other form of joint which might olfer resistance to the current and introduce friction, hence become oxidized or worn, and hence become asource of error. in the instrument. 'So, also, the instrument having two springs takes the best portable form, and may be used in any posimercury-cups were employed.

I claim 1. In an electrical m'easilringdnstrument, a stationary coil, a coil movable in the field of said stationary coil, and a spring opposing and counter-balancing the impressedaction of said movable coil, the said coils and spring being connected in circuit.

2. In an electrical measuring-instrument, a stationary coil, a coil pivoted and vibrating in the field of said stationary coil, and a spring opposing and counterbalancing the impressed action of said movable coil, the said coils and spring being in circuit.

3. In an electrical measuring-instrument, a stationary coil, a coil movable in the field of said stationary coil, and two springs opposing and counterbalancing the impressed action of said movable coil, the said coils and springs being in circuit and the said springs being disposed, respectively, to lead the actuating-current into and out of said movable coil.

4:. In an electrical measuring-instrument,a fixed coil, a movable coil in the field of said fixed cell, an index showing the extent of movement of said movable coil,.and a spring opposing and counterbalaneing the move- 40 ment of said movablecoil and in circuit therewith, the said elements being constructed and arranged so that said index willbe moved directly to show theextent of motion of said movable coil and by the counterbalancing effect of said spring be maintained in such position. 5. In an electrical measuring-instrument,a fixed coil, a movable coil in the field of said fixed coil, an index controlled by said movable coil, a scale graduated in definite electricai-units, and a spring opposing and counterbalancing the movement of said movable coil and in circuit therewith, the said elements being constructed and arranged so that by the actuating-current said indr will be moved directly to give a definite reading ori said scale and be maintained at such read-- ing by the counterbalancing eifect of said spring.

6. In an electrical measuring-instrument, the combination'oi' amovable conductor actuated by the current to be measured in a field of force maintained by the said current, and ameans of indicating the extent of movement of said conductor, the said conductor being constructed to offer such electrical resistance and of such light weight and so freely mov able asthat the error due to the disturbing effect of self-induction of the actuaiingcun rent in said conductor shall bear aninlinitesimal ratio to tl ieactual indication and be practically mil.

' 7. In an electrical measuririg-instrument, a stationary coiland acoil oscillating OPIVI- brating on inclosed pivots in the field of force of said stationary coil, said coils beingelectrically con nected; it

8. In an electrical measuring-instrument, a stationary coil, a coil vibrating or oscillating on inclosed pivots in the field of, force of said stationary coil, and a coiled spring connected to a coil-pivot and to an abutment and opposing the motion of said IDOVflblQCOll, said coils being electrically connected;

9. Ii. an electrical measu ring-instrument, a

stationary coil, a coil supported on diamctral inclosed pivots and vibrating or oscillating in the field of force of said stationary cell, a coiled spring concentric with the axis of retation of said vibrating coil having one end connected to said coil and the other end to an abutment, and means for varying the resiliency of said spring, said coils, being electrically connected.

10. In an electrical measuring-instrument,

a stationary coil, a coil vibrating or oscillating in the held of force of said stationary coil, and a spring of conducting material opposing the movement of said vibrating coil, the said coils and spring being electrically connected.

11. In an electrical measuring-instrument,

a spool or bobbin havingan interior'chamber,-

a coil surrounding said spool, a coil supported within said chamber on diametrally-disposed.

pivots extending through oppbsitei sides of said spool, supports outside of saidspool re- ;ceiving said pivots, and-a coiled spring connected at one end toone of said pivots outside of said spool and at the other end to a fixed abutment,- the said cells being electrically connected.

12. In an electrical measuring instrument, a stationary coil, a coil vibrating or oscillatingin the field of force of said stationary coil, two coiled springs of conducting material combined'with said movable coil, and circuit connections, whereby said springs and movable coil are connected in circuit.

13.. In an electrical measuring-instrument, a'stationary coil, a coil vibrating or oscillating in the field of force of said stationary coil,

two springs of conducting material connected,

respectively, to the coil-pivotsand to ,abutments, and circuit connections whereby the current is led first through one spring, then through the coil, and then through the other spring.

14'. In .1 electrical measuring-instrument, the combination of the spool or bobbin of noninductive material, a coil surrounding said spool, a coil supported within said spool on diametral pivots 6 and 7, arms or brackets 10 and 11 outside or said spool and receiving said piVots spiraI springs -14-and 15, surrounding said pins 6 and'7,:a.nd arms 164md 17,-piroted pivots,:spiral springs 14 and 15, surrounding the extremities of said arms 10 ll,the said said p'i'nsfi and 7, and arms 16 and 17, pivoted springs being connected,- res fively, at one at the extremities-of said. arms 10 11, the said I 5 end to said pivotla6 and? an at theotherend springs being connected. respectively, it one- 5 to arms 16 and17, and thessid springsand end to said pivotsB arid-'7 and at the other end .eoila being electrically connected in circuit. 'to-arms ,16 and 17, and a. resistance-coil H, the 15. In sn alectricnliueasuringdnstrument, saidstationary coil, movable coil, springs, and

the combination of-s spoolor bobbin otnon resistance-coil being conneotedin series; inductive materisl -a coil surrounding said J I i' EDWARD WESTON. re spool, a ,coil supported within said spool on Witnesses: j

- dismetrsl' pivots 6 and Karma or brackets 101 M. BOSCH, i and:11outsidecfssidspoolandreceiviugsaid H;;R.' MOLtlR.

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