US444552A - Electric indicator - Google Patents

Description

(No Model.) 2 Sheets-Sheet 1. J HOPKINSON ELECTRIC INDICATOR.

Patented Jan 13 WITNESSES:

INVENTOR.

N D 5 m K P n. H N H G JV (No Model?) 2 Sheets-Sheet 2.

. J. HOPKINSON.

ELECTRIC INDICATOR.

No. 444,552. Pa te nted Jan. 13, 1891.

a if: [QQI c 0 Q WITNESSES: INVENTOR,

1 dm-m HEIPKINSDN. QWM 1 w Att'y.

UNTTED STATES PATENT OFFICE. f

JOHN HOPKINSON, OF HOLMVOOD, ENGLAND, ASSIGNOR, BY MESNE ASSIGN- MEN TS, TO THE VVESTIN GI-IOUSE ELECTRIC AND MANUFACTURING COM- PANY, OF PITTSBURG, PENNSYLVANIA.

ELECTRIC INDICATOR.

SPECIFICATIOH forming part of Letters Patent No. 444,552, dated January 13, 189-1.

Application filed February 23, 1889. Serial No. 300,846, (No model.) Patented in England July 27, 1882, No, 3,576.

To all whom, it may concern: pensating for the drop or loss may be deter- Be it known that 1, JOHN I'IOPKINSON, a mined by properly adjusting the relative ofsuloject of the Queen of Great Britain, residfects of the two coils of the indicator.

ingin Holmwood,Wimbledon Common, S.\V., In the accompanying drawings there is \Vestnnnster Chambers, England, have in shown in diagram in Fignrel an organization vented a new and useful Improvement in of apparatus for carrying out the invention.

Electric Indicators, (Case No. 279,) (for which Fig. 2 is a diagram showing the application Letters Patent of Great Britain No. 3,576, of the coils to an indicator.

bearing date of July 27, 1882, have been Referring to the figures, A representsady- [O granted to me,) of which the following is a namo-electric machine, and N lamps or other specification. translating devices of any suitable character My invention relates especially to apparaconnected in multiple are between the contus for determining the difference of potential ductors L L leading from the terminals of existing at a given point in a system of electhe machine.

I 5 tric circuits supplying translating devices, the The indicating apparatus is represent-ed at special object being to provide an indicator C. It is constructed with two coils c c opposin which the varying drop or loss of potential ing each other. The one coil 0 is connected upon a circuit may be readily compensated across the poles of the generatorAor between for at all times. the lines L L at the points E and F. This 20 When current is supplied by means of main coil is of line wire and has a comparatively 7o conductors to points more or less distant from large number of convolutions. The second a central station, there is a fall of potential, coil 0 is of thick wire, having comparatively due to the resistance of the conductors, and few convolutions. It is connected either dias the current flowing increases the fall of rectly in one of the conductors L or L orin a 25 potential also increases, so that if it is desired circuitderived therefrom, so that either the to maintain a constant difference of potential whole current or a proportional part thereof at the distant points special means must be will pass through it from the point G to the employed for determining the loss under any point H. The current passing through the given load. To accomplish this I employ an coilc opposes in effect that throughthe shunt- 0 indicator wound with two opposing coils, one coil 0. I usually prefer to use a proportional of comparatively high resistance and conpart of the currentrather than all the current nected across the terminals of the source'of passing through the lineL It is then easy by electricity and the other of low resistance, so properly adjusting the relative resistance of connected as to be traversed by all or a deterthe two circuits including the two coils to in- 3 5 minateproportionalpartoftheourrent flowing dicate the compensation required for any tothe translatingdevices. If, now, the current given value of resistance of themain lines flowing to theworkcircuiti11crcases,theeifect and thus secure a constant difference of poof the series coil increases correspondingly. tential between the two conductors at the dis 1f the difference of potential at the terminals taut point. The shunt-coil 0 may be made 40 of the source bemaintained atanormal value, of German silver for the purpose of preventthe dili'erence of potential at the terminals of ing it from varying materially in its resist the translating devices will not be as great as ance; but this is not necessary. before, because of the greater loss or drop The differential apparatus may assume upon the circuit which accompanies the various different forms without departing 4 5 transmission of the increased current, so'that from the essential features of the invention. in order to maintain the proper difference of It may be arranged to indicate directly to the potential upon the work-circuit it is necessary eye when the value of the difierence of po to increase the difference of potential at the tential upon the work-circuit requires regu terminals of the source. The increase in diflation.

5o ference of potential thus required for com- It will be evident that an increase of our rent flowing to the mainline will increase the effect of the coil 0' of the indicator, thereby tending to correspondingly operate the indicator. If no change takes place in the difference of potential at E F, then the indicator will be thrown out of balance. The increased effect of the series coil 0" in theindicator may be balanced by increasing the difference of potential between the points E and F. By properly ad justing the relative effects of the two coils, therefore, the additional difference of potential required to bring the indicator to its normal position may be made to exactly compensate for the increased drop upon the line, sothat the difference of potential at the terminals of the translating devices will be maintained approximately constant if the index of the indicator is kept in a normal position.

I claim as my invention- 1. In an indicator, differentially-wonnd conductors, one designed to be connected in shunt upon the work-circuit and the other in series therewith, substantially as described.

2. The combination, with a source of electricity and a work-circuit supplied therefrom, of an indicator having two opposing coils, one connected in shunt upon the work-circuit and the other in series therewith, substantially as described.

The combination of a source of electricity, translating devices supplied therefrom, and an indicating apparatus for determining the difference of potential upon the work-circuit, consisting of two opposing coils, one receiving currents proportional to the difference of potential at the terminals and the source and the other receiving currents proportional to the current delivered to the work-circuit, and an indicatoroperated by the resultant effects of the currents traversing the two coils.

In testimony whereof I have hereuntosubscribed my name this 9th day of February, A. D. 1889.

JOHN .IIOPKINSON.

Witnesses:

CRANSON, E. A. HALL, Clerks to JlIessrs. John Newton (12' Sons-,9 B irchin Lane, London, Public Notaries.

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