US623525A - Electric meter - Google Patents

Description

` Patented Apr. 25, |899. T'. DUNCAN. LEcTmc METER. (Applieation led May 23, 189B.)

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No. 623,525. Patent-empf. 25, |899.

. T. DUNCAN. Y

ELEJTHI()v METER.

(Applicatiun mod May 28, 1898.) (No Model.) 2 Sheets-Sheet 2.

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ELECTRIC METER.

SPECIFICATION forming part of Letters :Patent No. 623,525, dated April 25, 1899.

Application filed May 23, 1898. Serial No. 681,403.

T0 all whom t may concern:

Be it known that I, THOMAS DUNCAN, a citizen of the United States, residing at Fort Vayne, in the county of Allen and State of Indiana, have invented certain new and useful Improvements in Electric Meters, of which the following is a specification.

lWly invention relates to improvements in alternating-current induction-motor meters in which a closed revoluble metallic disk armature is operated by the influence of a shifting magnetic field produced by the resultant magnetic effect of two or more magnetic fields differing in phase from each other and operating in mutual cooperation.

One of the objects of the present invention is to reduce the cost of manufacture of meters of this class by making them simple and of very few parts.

Another object of the invention is to-so arrange the-actuating-coils that they will all be upon the same side of the armature, thereby reducing to a minimum the cost of assembling or putting together and rendering the cleaning and repairing easily accomplished by any ordinary central-station employee.

A third object is to enable a change in the speed to be made When checking or adjusting without having to alter or change any of the coils or windings or Vary the retardation.

In carrying out the foregoing objects I employ the following'elements in my improvement: a source of alternating electric currents, supply-mains, a series field-coil through which passes the current supplying the translating devices, a shunt eld-coil Wound with smaller wire and receiving its currents from the terminals of the said series field-coil or from the said supply-mains, an iron core provided with a plurality of projecting polepieces, some of which support the said series and shunt field-coils and become magnetic cores for them, a revoluble aluminium disk armature mounted upon a suitable spindle and operated by the inductive iniiuence of the said series and shunt ield-coils, an adjustable iron part or keeper arranged adjacent to the upper and opposite face of the disk armature from the series and shunt fieldcoils and also from the iron core upon which said series and shunt coils are mounted, means for producing the necessary retardation in- (No model.)

cident to all forms of motor-meters, which consists in employing a winged fan if the torque varies as the square of the current in amperes through the meter or the usual form of magneto-electric drag if the torque of the meter varies directly or proportional to the energy consumed, and a suitable registering mechanism.

It has been the practice in the construction of motor-meters of this type to operate the disk armature by arranging the energizing coil or coils of one phase adjacent to its upper face or surface and the energizing Vcoil or coils of a different phase adjacent to its lower face, and the resultant magnetic action of these two sets of coils produced rotation of the intervening disk. In the present improvement the actuatingcoils of different phase are located adjacent to one side of the disk, and the resultant field produced by these energizing-coils is caused to act inductively upon the disk armature and set it in rotation. For the purpose of regulating and adjusting the torque and speed of the disk I employ an iron keeper suitably arranged adjacent to the opposite surface of the disk armature from which the energizing-coils are located. rlhe function of this keeper is to assist in attracting or drawing the magnetism of the energizing-coils through the disk armature, thereby adding to the efficiency of operation of the meter.

In the accompanying drawings, which form part of this specification, Figure l is an elevation showing the energizing-coils in section. Fig. 2 is also an elevation showing the energizing-coils in section and the speed-regulating core l5 adjustable. Fig. 3 differs from Fig. 2 in being wired up or connected to measure the watts. Fig. 4L shows a modified form of core carrying the energizing-coils with speed-regulating core horizontally adjustable. Fig. 5 shows still another modification of the core which supports the energizingcoils and arranged as a Coulomb-meter. Fig.

6 is similar to Fig. 5 with the exception of its being connected to register the watts.

The operation of the arrangement shown in Fig. l is as follows: When an impulse of current from the transformer 2 passes through the series iield-coil 6, it magnetizes the polar projection or limb of the iron core 7, upon IOO which the said coil is mounted. If the translating devices are non-inductive, the current traversing the coil 6 will be approximately in phase with the pressure or electromotive force of the mains 3 and 4, with the exception, possibly, of whatever lag is introduced into this circuit by the reaction of the core 7, but which in the present instance may be altogether omitted. Another coil S, wound with finer wire and having a greater number of turns than the series field-coil G and herein referred to as the shunt field-coil, is mounted upon the other projecting pole-piece of the iron core 7. The terminals 9 and 10 of this shunt iieldcoil S are connected in parallel to or shunted around the terminals of the said series fieldcoil, and since the coil S has a greater number of turns than the coil G the current passing through the former will lag perceptibly behind that passing through the latter or coil G. This difference in time period between the currents in the two coils is accompanied by a corresponding difference of phase between the magnetisms of the two coils. These two magnetic fields, however, combine into a resultant shifting magnetic field in a manner now well understood by those skilled in the art and which sets the disk armature 14 in rotation. The disk armature is mounted upon a spindle 22, which also carries a worm 17 and which meshes with and operates a suitable registering mechanism 16. To make the rate of speed proportional to the current through the coil G, I have secured upon the circumference of the disk armature a number of aluminium vanes 13. For adjusting the speed of the armature I use the iron portion or keeper 15, placed adjacent to the upper surface of said armature, and by raising or lowering it more or less of the lines of force of the shifting iield are caused to eut the disk or armature. I can also employ the resistance 11 for adjusting the speed. Said resistance may also be used to adjust or vary the phase of the current through the coils 8 in a well-understood manner. In supporting the iron core 7 suitable screws 12, as shown, may be used.

Fig. 2 is also a front elevation of the present improvement, showing the field- coil 6 and 3 in section. A secondary coil 20 is also shown wound upon the same core with the coil 8 and having a resistance 21 connected in series with it. rlhe function of this coil 2O is to retard or lag the magnetism of the polar projection upon which the said coils S and 2O are mounted. The iron keeper 15 in this Iigure shows a slot 19 and set-screw 18 for adjusting its position or distance from the surface of the disk.

Fig. 3 differs from Fig. 2 in that it shows the terminals 9 and 10 of the shunt field-coil connected to the main leads 3 and 4 instead of the terminals of the series Held-coil, and also by the addition of the impedance-coil 24 in series with the shunt-coil S. This arrangement of the connections permits of the instrument measuring the energy or watts instead of the current in amperes only, as in the case of Figs. 1 and 2. A change in the retardating is also necessary with these counections, and to secure the proper relation between torque and speed I have shown the usual permanent magnets 23 embracing the disk armature 14. The impedance-coil 24 and resistance 2l are for adjusting the magnetism of the coils S and 2O to quadrature with the electromotive force of the mains 3 and 4.

In Figs. 1, 2, and 3 I have described my improvement in its simplest form and that in which only two projecting pole-pieces on the core 7 are shown. I prefer, however, to employ more than two, as is shown in Figs. 3, 4, and 5. By so doing I obtain greater accuracy and eliminate to a perceptible degree any trace of mutual induction between the two field- coils 6 and 8. In Fig. 4 the core 7 has a third polar projection 25 midway the coils 6 and 8 and the projecting pole-pieces supporting them. This becomes a leakage-path for the magnetism of both coils 0 and S. Fig. 5 shows a core 7 having four polar extensions, of which the two end or outer ones support the field-coils and the two inner are leakage- poles 25 and 25. Said figure also shows a resistance 2G in series with the coil 8, the purpose of which is to vary the lag or phase of the current, also the strength of said current in the coil S. Fig. 6 is similar to Fig. 5 as regards the core 7, but the connections of the field-coils are arranged to measure the watts, as in Fig. 3. They differ, however, from Fig. 3 in that the secondary coil 2O of Fig. 3 is omitted and a resistance 11 is connected across the terminals of the coil 8, as shown. By suitably proportioning the resistance 11 the current through the coil 8 is retarded until it is in quadrature with or ninety degrees behind the circuit-leads 3 and 4, which enables the meter to measure with accuracy inductive loads.

I do not wish to be understood as limiting myself to the exact number of poles shown 011 the core 7, as other modifications might readily suggest themselves to those skilled in the art-such, for instance, as the addition of two more poles-t'. e. by putting one at each end of the core 7-and which would bound the coils G and S upon their outer sides.

Having described myinvention, what I desire to secure by Letters Patent is- 1. The combination in an induction-motor meter of a revoluble metallic disk armature, a laminated iron core 7 having a plurality of poles adjacent to one side of said armature, a laminated iron core 15 adjacent to the opposite side of said armature and having its adjacent surface parallel to the surface of said disk armature in its revolution, coils for magnetizing the said iron core 7, and a suitable means for retarding the revolutions of said armature.

2. The combination in an induction-motor meter of a revoluble metallic disk armature,

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an adjustable iron core 15 having a portion of its surface adjacent to and parallel with the said disk armature, an iron core 7 adjacent to the opposite side of said disk armature, coils for magnetizing the said core 7, and means for retarding the revolutions of said disk armature.

3. The combination in an induction-motor meter of a revoluble metallic disk armature, retarding-fans attached to and revoluble with said disk armature, an unwound iron core 15 adjacent to the upper surface of said disk armature, means for Varying the distance between the adjacent surfaces of the said iron core 15 and the said disk armature,an iron core 7 adjacent to the lower surface of said disk armature, coils for magnetizing said iron core 7, and a suitable registering mechanism.

4. The combination in an induction-motor meter of a revoluble aluminium disk armature, means for retarding the revolutions of said armature, an unwound iron core 15 having its lower surface parallel with and adjaf cent to the upper surface of said armature, means for Varying the distance between the adjacent surfaces of the said iron core 15 and the said disk armature as set forth, au iron core 7 adjacent to the lower surface of the said disk armature, coils for magnetizing the said iron core 7, a spindle 22, and a suitable registering mechanism.

In testimony that I claim the foregoing as my invention I have signed my name, in the presence of two witnesses, this 20th daj1 of May, 1898.

fr'HoMAs DUNoAN.

Witnesses:

EDWARD A. BARNES, M. GRACE WEBBER.

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