US833205A - Electric meter. - Google Patents

Description

PATENTED OCTL16, 1906. T. DUNCAN. ELECTRIC METER.

1901. RENEWED JAN. 7, 1905.

APPLICATION FILED JULY 11 '4 SHEETS-SHEET 1.

HOURS;

. INVENTOR.

ATTORN Y5.

WITNESSES N0. 833,205. PATENTED OCT. 16, 1906. T. DUNCAN.

ELECTRIC METER.

APPLIOATION EILED JULY 11, 19 1. RENEWED JAN. 7, 1905.

4 SHEETS-SHEET 2.

VOLTS W1 TNES 5 ES IN VEN TOR.

m M Q EWM TTORN YS.

'No. 833,205. I PATENTED OCT. 16, 1906. T. DUNCAN. ELECTRIC METER.

APPLICATION FILED JULY 11. 1901. RENEWED JANi'l, 1905.

4 SHEETS-SHEET 3 N0. 833,205. PATENTED OCT. 16, 1906.

' T. DUNCAN.

ELECTRIC METER.

APPLICATION FILED JULY 11, 1901. RENEWED JAN. 7, 1905.

4 SHEETS-SHEET 4 l ,lZ a ,f ar

I w THUMAE jjunuAlL QW BY UNITED STATES PATENT OFFICE.

THOMAS DUNCAN; OF CHICAGO, ILLINOIS, ASSIGNOR TO DUNCAN ELEC- TRIC MANUFACTURING OOMPANY,,OF LA FAYETTE, INDIANA.

ELECTRIC METER.

v Specification of Letters Patent.

Pa.tented Oct. 16, 1906.

To all whom it may concern.-

: Be it known that I, THOMAS DUNCAN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain-new and useful Improvement in Electric Meters, of which the following is a full, clear, concise, and exact description; reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to electric meters, and has for its objects, first, the construction of a meter which may be readily adjusted for accurate operation upon a circuit of any pressure; second, the provision of means. whereby the meter may be adapted to circuits of different frequencies third, the provision of means for compensating for the, diminution of the strength of the drag ordamping magnet without altering itsposition with relation to the disk.

To accomplish the first object of my invention, I provide a portion of magnetic material that is directly associated with the shunt or pressure winding ofthe meter and which immediately cooperates with this winding to produce a' starting torque commensurate with the strength of the pressure-field.

I am aware that portions of magneticmat'erial have been associated inductively with armature-disks for the purpose of overcoming friction; but this torque is furnished by the reaction between the eddy-currents in the armature-disk and the portion of magnetic material. My invention in this respect comprises an element of magnetic material in direct. cooperation with the pressure -field winding, whereby a torque is produced that compensates for the different strengths due to the pressure-winding.

Meters as heretofore constructed were. adapted for given electromotive forces, and when the meters were to be used in circuits of widely-differing pressures they had to be specially constructedtl1at is, no standard meter could be adapted to circuits of widelydiffering pressures.

By means of m inventionI am enabled to construct a stan ard meter and by properly adjusting the cooperative relation between the pressure field-winding and the magnetic torque-adjusting element am .able to adapt the meter to circuits of various electromotive forces. In practicing thls feature ofthe 1nvention the magnetizable element is prefer-- different frequencies, I prefer to provide the or across whic main pressure-winding with an auxiliary winding that serves to modify the phase of the magnetism due to the pressure-winding to bring the same into the desired phase relation with the pressure of the system. I include in circuit withthe main pressure fieldwindin an ad'ustable impedance winding an include in circuit with the auxiliary pressure-winding an adjustable resistance, switches with suitably-marked contact-points being provided "for cuttingout windings, of the adjustable im edancecoil and cutting in the resistance W en the ire uency is increased, the reverse operations eing effected when thefre uency is decreased.

.To accomp ish the third object of m invention, I employ a dampin -magnet w ose poles are brought close toget er. and between is placed a body of magnetizable material which by'an adjustment of its proximity to the poles of the saidma net determines the amount of flux passing etween the poles, whereby the quantity of flux flow ing through the damping-disk (which is also preferably the armature of the meter where the invention is applied to alternating-current meters) is'determined. The dampingmagnet is preferably located over the. armature ordamping-disk, while a body of magnetizable, material, preferably soft lron, is 10- cated beneath .the armature. This body of -magnetizab le material is preferably adjustablelongit'udinall of .the axis of rotation of the armature or isk, being preferably 'rnovably secured upon the damping-magnet The flux flowin through the disk' ma also be adjusted by t e movement of this so t-iron body By providing a meter that isthus adjustable in the respects above specified the'meters may be constructed in large quantities of uniform pattern and size-and readil ada ted to the various service conditions 0 tainmg in commercial practice, so thatya variety of meters need not be carried in stock to suit various working circuits.

,tions between currents and I will explain my invention more fully by reference to the accompanying drawings, in which I Figure 1 illustrates a meter constructed in accordance with my invention, a system of alternating-current distribution being illustrated in combination therewith. Fig. 2 is a detail view showing one of the adjustments for the pressure-field modifier. side view of portions of the apparatus illustrated in Fig. 1. Fig. 4 is a diagrammatic view illustrating the means for adjusting the meter for different frequencies. Fig. 5 isa vector diagram illustrating the phase relapressures in the windings. i r

Like parts, are indicated by similar characters ofreference throughout the different figures.

. I have shown my invention in the embodiment of an alternating-current wattmeter; but there are features of the invention that may be employed in connection with directcurrent systems; and I do not, therefore, desire to be limited to the precise application of the invention.

T have illustrated in Figs. 1 and 4 an alterhating-current generator 1, supplying current over the transmission-mains 2 2 to translati'ng devices 3. The meter is provided with an-armature 4E, that may also constitute the dampi'n disk of themeter, although I do not wish to e limited to a construction wherein the dam ing-disk and armature are in one part. T e currentwinding 5 is included in series with one of the mains 2. The main pressure-winding 6 is included in shunt or the mains andincludes in circuit therewith an adjustablen impedance-winding 7, connections being taken from different parts of this winding to the contact-buttons 8 8, ,l-orresponding to different commercial frequencies, as illustrated in Fig. 4, or to contact-buttons 9 9, Fig. 1, corresponding to the frequencies of one hundred and forty and sixty periods, that usually obtain in commercial practice. Resistance-butto'nslO 10, as illustrated in Fig. 4, or 11 '11, as illustrated in Fig. 1, may be providedfor adjusting the amount of resistance included in circuit with the auxiliary pressure-winding 12, that is provided for the purpose of modif 'ng the phase of the pressure-field. Switc es are associated with the frequency and resistance buttons, which in Fig. 4- are illustrated as separate switches. 13 13 and in Fig. 1 are formed in a centrallypivoted switch-bar 13.

The meter may be readily. adjusted for frequencies of sixty, one hundred, and one hundred and forty periods. When the meter is to be adjusted, for example, to the highest frequency, only the u per portion of impedance-winding 7 should be included in circuit, while the greatest amount of extraneous resistance should be included in circuit Fig. 3 is a with the auxiliary pressure-winding. The pressure-windings may be mounted upon a U-shaped core 14, while the current-winding may be supported by a U-shaped body of magnetic material 15, the armature being interposed between the current and pressure windings.

In adjusting or testing the meter it is preferable to commence with the highest pressure to which it may be operated in practice, so that the pressuie-coils may be properly adjusted to prevent undue heating when operating continuously at the highest pressure for which the meter is designed. Supposing the meter is to be calibrated forthree freguencies-mne hundred and forty, one hunred, and sixty periods per secondwe will take the lowest frequency first. Since this frequency will give the lowest inductance, all the turns of the impedance-winding 7 I should be included in circuit with the pressure-coils 6. This condition is obtained with the connections shown in Fig. 4, where the switch-arm 13 is in contact with the right-hand button 8.

It is well understood by those skilled in the artfthat to enable a meter to accurately measure inductive loads the magnetism of the shunt or ressure core 14 must be in quadrature wit the line electromotive force; but it isimpracticable to lag the current to the extent of ninety degrees, as required, by means of the impedance-coil 7 alone on account of its high resistance. Therefore to obtain this required lag of ninety degrees the secondary circuit-coils 12 are wound upon the core 14 in inductive relation to the pressure-coil 6, and the ma netism resulting from the current through t e secondary coils 12 is combined with the magnetism resulting from the current in the coils 6 to give the desired lag of ninety degrees. To further illustrate this, let the line a b in Fig. 5 represent the current through the shunt-field 6 as lagged by the impedance-coil 7, while a c is the impressed electromotive force. Then current through the coils 12 will be represented by the component line a d, the resultant of a b and a d being a e,'which is in'quadrature with the impressed electromotive force represented hy a 0.

Now if the meter is to be used in conjunction with a system. employing a higher freu'ency -say one hundred cycles per second t en arm 13 should be-placed upon the center button 8, whichcuts out the lower part-offthe impedance-coil 7. This is done for the purpose of keeping the current through the pressure-coils 6 approximately the same on different frequencies, andsince the inductance will be higher on one hundred cycles than on sixty cycles the portion of the impedance already referred to is cut out,zs(;) as to permit approximately the same current to traverse 1t.. To illustrate this in a vector diagram, this current through the pressurecoil 6 may be represented by the line a f, and.

. of a frequency the component a 9 due to the secondary coils 12 gives the same resultant a e as in'the case .of sixty cycles. In this change the arm 13 to the right is connected to the center button 10, whereby additional resistance is included in circuit. This increase in reslstance brings down the magni- This cuts out the two lower portions of the impedance-coil 7, while all of the resistance in series with the coil 12 is thereby included in circuit. This being the highest frequency for which the meter'is calibrated, only the coils 12 the ma upper portion of the impedance coil 7 is used on account of the increased inductance of the pressure-coils, and since the resistance of this portion is less than when the lower frequencieswere used with the other portions in circuit also the lag of the current will be greater, as shown by the line a h, and by putting all of the resistance in circuit with the itude of the' component current in 12 is ecreased, as shown by the line a "l. Thus the same resultant a e is obtained. I

The retarding-magnet 16 is preferably made in the rectilinear shape shown and has between its poles a body of non-ma netic material 17, composed, preferably, of rass,

which separates the poles. The poles of the damping-magnet are drawn into tight engagement with'this body of non-magnetic 'material by tightening the screws 18, that pass through riders 19, movable upon the .sides of the permanent magnet and engaging the bodyof magnetic material 20, composed,

preferably, of soft iron. The portion or bar 20 of magnetizable material is adjustable independentlyof the current-winding and the core portion 15, so that the damping effect upon the armature may be adjusted independently of the windings of the meter, the armature being interposed between the poles of the permanent magnet and the body of magnetizable material 20. The body of nonmagnetic metal 17 serves as a support for a portion of magnetic metal, preferably in' the form of a screw 21, of soft iron.

The keeper 20 serves to drawthe magnetic flux from. the permanent magnet through the disk to complete the circuit for a portion of the lines of force through this keeper rather than directly between the poles of the magnet.

-When the meter is calibrated, the iron screw 21 is screwed down, as shown, and at some future time, if the drag upon the damping-disk should become weakened, the screw is unscrewed a sufficient amount to increase that the tendenc the magnetic reluctance between the poles of the permanent magnet, thereby to force the requisite amount of magnetic flux through the disk. The adjustment may be further compensated for by a movement of the keeper 20. v

To adapt meters of a given type to systems having widely-differing pressures, I employ anadjusting-body of magnetizable material 22, that compensates for the variation in strength of the pressure-field, this body of magnetizable material being preferably in the form of a flat strip ofiron bent at its ends in a plane at right angles to the central portion, which central portion is rotatably secured upon a pin 23 centrally between the pressure-poles, some of the leaves of the magnetic body 15 being removed for the inthe rotary adjustment of the member 22 may be readily effected and secured. The lower portion of the member 22 is in the form of an index that registers with scale-marks 25,in

dicating the various" voltages. When the magnetic member 22 is midway between the, pressure-poles, 1t Wlll have no influence in causing the (118k to move in either direction;

left-hand pole, for example, the disk will but as this member 22 is moved toward the move, say, clockwise or in the proper direc tion, and if moved toward the right-hand pole the disk will move in a contraclockwise direction or backward.

If the meter is to register for a fifty-volt circuit, the strength of the pressure-poles will not be as great as when the pressurewinding is subject to a higher pressure. Hence the iron part 22 will be moved to the index-line corresponding to fifty volts. This brings the iron portion 22 to a position in relation with the left-hand pressure-pole so toward motion imparted to the disk is su 'cient to overcome the friction of the bearings and registering train and at the same time give accurate readings on the low voltage with small loads. This same meter if-placed upon a hundred-volt circuit will have to be only modified in its-adjustment b having the magnetic body 22 moved unti it registers with the scale-mark corresponding to one hundred, which may be accomplished by unscrewing and screwing the screws .24. ther away from the left-hand pole. which is necessary on account of the increased strength of the pressure-field. If the meter is used to register the energy on, say, a two-hundredvolt circuit, the ironpart 22 is moved to a position almost midway between the pressurepoles by having the same register with the corresponding voltscale mark. In this manner the meter is adapted for use on any This brings the part 22 farnumber of pressure-circuits desired, and the readings are direct Without having to use constants or multipliers.

While I have herein shown and particularly described the preferred embodiment of my invention, it is obvious that changes may readily be made without departing from the spirit thereof, and I do not, therefore, wish to be limited to the precise disclosure herein set forth; but,

Having thus described .my invention, I claimas new and desire to secure by Letters Patent-- 1. The combination with a meter provided with a damping-disk, of a permanent magnet within whose field the damping-disk is arranged, and a body of magnetizable material adjustably secured in position be tween the poles of the permanent magnet and to be drawn in and out to vary the amount of the same interposed between the poles 'to govern the magnetic reluctance between the 'oles of the ermanent magnet, substantiall y as describedi 2. The combination with a meter 'provided with a damping-disk, of a permanentmagnet within whose field the damping-disk is arranged, a body of'magnetizable material adjustably secured in position between the poles of the permanent magnet and to be drawn in and out to vary the amount of the same interposed between the poles to govern the magnetic reluctance betweenthe poles of the permanent magnet, and a body of magnetic material upon the other side of the damping-disk, substantially as described.

' 3. The combination with a meter provided with a damping-disk, of a permanent magnet within whose field the damping-disk is arranged, a body of magnetizable material adjustably secured in position between the poles of the permanent magnet and to be drawn in and out to vary the amount of the same interposed between the poles to govern the magnetic reluctance between the poles of the permanent magnet, and a body of soft iron upon the other side of the damping-disk, substantially as described. l

4. The combination with a meter provided with a damping-disk, of a permanent magnet within whose field the dam ing-disk is arranged, a body of magnetiza le material adj ustably secured in position between the poles of the permanent magnet and to be drawn in and out to vary the amount of the same interposed between the poles to govern the magnetic reluctance between the poles of the permanent magnet, a body of magnetic material upon the other side of :the dampingeaaaes disk, and means whereby the latter body of magnetizable material maybe adjusted from and toward the damping-disk, substantially as described.

v 5. The combination-with a meter provided with a damping-disk, of a permanent magnet within whose field the dampingdisk is arranged, a body of magnetizable material adjustably secured in position between the poles of the permanent magnet and to be drawn in and out to vary the amount of the same interposed between the poles to govern the magnetic reluctance between the poles of the permanent magnet, a body of soft iron upon the other side of the dam ing-disk,.

7. The combination with a meter provided with a damping-dislg of a damping-magnet, and a body of magnetizable material located opposite the poles of the damping-magnet, the disk being interposed between the pole portions of the damping-magnet and the special body of magnetizable "material, the said bod of magnetizable material being adjustabl y secured upon the magnet, substantially as described.

8. In an alternating current wattmeter, the combination with the current and pressure windings thereof, of an auxiliary pressure-winding for modifying the phase due to the main pressure-winding, an impedancewinding in circuit with the main pressurewinding, a resistance in circuit with the auxiliary pressure-winding, and switches for adj usting the amount of impedance-winding and resistance, whereby the meter maybe adapted for circuits conveying current at different frequencies, substantially as described.

In witness whereof I hereunto subscribe my name this 23d day of May, A. D. 1901.

THOMAS DUNCAN.

Witnesses:

GEoRcE L. CRAGG, HERBERT EOBERGFELL.

IIC

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