US992768A - Electric meter. - Google Patents

Description

J. HARRIS.

ELEGTRIG METER.

urunuzox mum man. 2a, 1906.

Patented May 23, 1911.

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JESSE HARRIS, OF RENSSELAER, NEW YOIHL.

ELECTRIC MET ER.

Patented May'ZIl, 1911.

Application filed September 26, 1906. Serial No. 336.317.

To all whom it may concern: Be. it known that l. JESSE llamu a citizen of the United States. residing at llenssvlaer. in the county of Runs-seiner and. (*tatc of he York. have invented a certain new and useful In'iprovoment in Electric Meters. of which the following is a full, clear. con.

- struments, the provision of improved means whereby a long even scale or a scale of selected graduations may be produced and the instrument may he made dead heat;

I am aware that it, is old to produce even scales, or scales of selected gradation, but this result has been gained at considerable cost, because it has been customary to ma.- chine the pole pieces especially or to add pole pieces so shaped as to produce the result intended. I accomplish this result by so shaping, the magnet metal in forming machines that it inay be used without the necessity of having itmachined. To this end, I desirably form the magnet. into a loop that is ncar v closed. the ends of the magnet lying in dihercnt planes, so that the armature of the meter may occupy a plane intermediate of the polar planes and substantially parallel therewith. The polar faces of the magnet are desirahly separated a distanoe sufficient to permit the passage of the. armature shaft. between the same. which feature of construction avoids the necessity of causing the ends of the magnet to overlap and the provision of shaft holes through ithe overlapping ends of the magnet, though I do not wish to be limited to my preferred construction. In order to reduce the reluc tance between the magnet poles, and to produce the desired operation of the pointer, or index, I interpose a normally stationary soft iron element between said pole-s, whereby an enhancement of the torque upon the armature is secured. This soft iron clement-,by its slums and oosition, may be used in determinin thi-"lmi'artot'oi the scale. it it is desired to have lltl scale uniforunihi soft iron piece may ha re one construction and position. ii. on th other hand. it slmiiltil he desired to have-the normally active portion of the scale very open as com mroil with the balance of the scale. wln-rchy this open portion may be easily read. the position of the iron cl ment maybe changed or the shape of the iron element may he changed. or both change in po ition and shape may he cileetcd for the purpose. l have ]il")(lll('t l a scale whose graduations increase and decrease by making the soft iron element.- in the form of a ring of equal radial cross section throughoutand placing: the portion of the ring control-' ling the open part of the scale near the magnet.

I produce a light moving element for indenting instruments by a peculiar formation of the closed conductor member of the damping device in comhination with an armatnre coil mounted upon the said closed conductor, the arrangementheing such that.

the major portion of the cl sed conductor lies upon one side of the shaft while the moving coil lies upon theother side of the shaft. whereby the weight of the moving element is symmetrically disposed with respect to the shaft. my improved magnetarrangement- CllZlbllllQ' meto make the moving element of very light construction.

The magnet that I employ acts as a dampin; magnet in its operation upon the closed conduct r.

The instrument herein shown and described is dead-heat.

I will explain my invention more fully by reference to the accompanying drawing, showing the preferred embodiment thereof, in which- Fignre 1 is a view in elevation of the instrument. Fig. 2 is a side elevation. Fig. 3 is a view of part of the mechanism as it would appear with the upper pole of the permanentmagnet removed. Fig. 4 indicates one modification. Fig. 5 indicates another modification.

Like parts are indicated by similar characters of reference throughout the differentfigures.

I have not deemed itneccssary to show the meter easing nor the circuit connections of the meter.

The meter illustrated happens to be :2 voltmeter, thougl. the invention is not to he Q v sea-gee mediate of these planes and substantiallyparallel therewith. In the embodiment of the invention shown, the moving elementin- .cludes a closed conductor e and an armature .cbil f, desirably mounted upon a continuation g of the closed conductor, which continuation, with the balance of the conductor, constitutes a damping device. The coil f thus has a metallic foundation or mounting,

which also acts as a damping element. The armature shaft or arbor d supports the coil and the closed conductor, the continuation g and the coil f upon one side of the shaft approximatinp in weirht a sector-shaped nortion of the closed conductor upon the other side of the shaft, whereby a balanced construction is secured. C

- It will be seen that the pole c is adapted to generate one set of eddy currents and the other pole Z) is adapted to generate another set of'eddy currents. because these poles are not superposed or sulliciently coincident to' produce but one set of eddy currents.

I desirably interpose a normally stationary ring segment it, made of soft iron, between the poles of the permanent magnet. this ring of soft iron lying in a plane parallel to the polar planes. The armature winding f surrounds the ring 71. which preferably passes through the bore of said winding. T he ring h thus tends to close the magnetic circuit of the permanent magnet. thereby strengthening the field in which the armature coil may move.

The ring piece h of soft iron acts as a path for the magnetic flux and conducts said flux in proportion to its cross-section and proximity to the polar faces of the permanent poles of the permanent magnet offers a re sistance to the magnetic flux. The ring being inserted in this space, lessens this re sistance and defiectsand guides said flute, as predetermined by its shape and the position in which it is placed.

The torque is the product of the flux produced in the moving coil and that of the permanent magnet cut by said moving coil for each position it takes. -With a regular increase of current in the moving coil and an even magnetic flux from the permanent;

magnet. The air gap between themagnet, throughout the range of movement of said moving coil, :1 regular and evenly spaced scale would result.

The ob cct of the tongue enlargement; of ring h, when employed; is to lessen the magtion of the swing of the moving coil, thus increasing the flux at that point, and by so doing increasing the torque and widening the spaces in the scale for each regular increase of current in the moving coil. Two ways are thus provided for defining the permanent magnet flux, in certain portions of the swing of. the movi g coil. Bot-h ways hhve to do with modii I the air gap be tween the poles and ring. In Fig. 4 the tongue is provided upon ring 72, and in Fig. 5 the air gap is shortened by tilting the ring h toward the pole of the magnet. Both methods result in increased scale spaces corresponding to the bunching of the magnetic flux. In Fig. 4 the changes would be more abrupt, while in Fig. 5 the change from close to wider lines or spaces would be gradual.

If it is desired to have the scale evenly graduated throiighont, the ring may be of uniform radial cross-section throughout and allel with the planes of the poles of the permanent magnet.- If it is desired to have the scale gradually increase and then gradually decrease, this same ring, instead of lying in a plane parallel with the polar planes of the permanent magnet, may be inclined as indicated in Fig. 5, the portion of the ring controlling' the open part of the scale being nearest the permanent magnet. If it is desired to have the first and last Sections'of the scale with closer graduations than an intermediate. portion of the scale, the' iron ring may be providcdwith the projection f as indicated in Fig. 4 extending between the radii that mark the limits of the central portion of'the scale. Of course. if some other portion of the scale is to be more open than the balance, the projection upon the ring is correspondingly disposed. In other words, I make the ring of such an area, per unit of length that is traversed by the moving coil, that the portions uttered to the magnetic flux are. so to speak. a duplicate of or proportional to the scale desired. The scale as illustrated in Fig. 4 is of use in relation to volt meters employed in connection with 11 volt circuits. as the portion of the scale scale) may be made very prominent, so that. any changes may be easily manifested in the normally active part of the scale.

It will be seen that by means of the non superposed pole arrangement and the in clusion of the ring It in the magnetic circuit between the poles the reluctance of th magnetic circuit is due almost entirely to netic resistance of the air gap at that pormay be placed in a plane substantially par-- be! U061. 90 volts and volts (in a volt l desirably of such section that it will carry freely substantially all the lines of force i in the permanent magne the lines of force where they thread the air gaps being alone available for the operation of the instrument.

* By means of m new construction, no

machine work or slaping of pole pieces is necessary, the permanent magnet being merely bent into its shape by a shaping machine, it not being necessary to machine it thereafter, as it IS capable of ctlecting v Y an equal distribution of magnetic flux in the shape in which it leaves the forming machine.

In other instruments hitherto devised, it

;' is necessary to have specially shaped pole pieces to get the desired scale arrangement.

In my invention the instrument winding is preferably placed in one gap and the damping element is preferably placed in the other gap, whereby the damping effect is increased. In the device of'my invention suhstam tially the entire damping element. is threaded by the magnetic flux and the damping E circuit is very short, whereby weight is not only eliminated, but the effectiveness of the i eddy currents is increased.

In the device of my invention, the instrument may be non-symmetrically arranged with respect to its axis of rotation, whereby an increased leverage is secured without an 5 increase of weight, the pointer or index and i the winding being balanced by means of the damping plate, a characteristic of considerable importance in connection with an in strument designed to answer quickly to any 0 changes of load in the electrical circuit.

In the case of indicating instruments, a suitable coil spring construction 2' may be employed-for swinging the index to zero (0) and against which the torque of the instrument isexerted, in order that the index I or pointer may indicate the value being measured.

'the air gaps. The soft iron element It is- The clip 3 is added merely for adjusting the balance of the structure, comprising the closed conductor and the pointer.

It is obvious that changes may readily be made in the device of my invention as shown in its preferred embodiment, without departing from the spirit of the invention, and I do not, therefore, wish to be limited to the precise construction shown, but,

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. An electric meter including a magnet having polar portions which lie in ditierent planes that are substantially parallel with the plane of movement of the moving element of the meter, an iron clement inter posed between the polar planes and located opposite the poles, the moving element being disposed in a plane between the polar planes and including a winding located. substantially upon one side of the axis of movement of the movable element, and a closed conduct-or located substantially upon another sidc'of the axis of movement of-the movable element.

2. An electric meter including a magnet having polar portions which lie in difleren't planes that are substantially parallel with the plane of movement of the moving element of the meter, an iron element interposed between the polar planes and located opposite the poles, the moving element being disposed in a plane between the polar planes and including a winding encircling the iron element and located substantially upon one side of the axis of movement of the movable element, and a closed conductor located substantially upon another side of the axis of movement of the movable element.

In witness whereof, I hereunto subscribe my name this 18th day of Sept. A. D., 1906.

I JESSE HARRIS.

Vlitnesses: V

BENJ. K. Tarrou, Anmnoss Marroons.

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