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Publication numberUS516847 A
Publication typeGrant
Publication dateMar 20, 1894
Filing dateJul 1, 1891
Publication numberUS 516847 A, US 516847A, US-A-516847, US516847 A, US516847A
InventorsElihu Thomson
Original AssigneeThe thomson
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Means for regulating alternating currents
US 516847 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)


Patented Mar. 20, 1894.

FIG. 3




SPECIFICATION forming part of Letters Patent No. 516,847, dated March 20, 1894,

Application filed July 1, 1891- Serial No. 398,18'7- (No model.)

To aZZ whom it may concern.-

Be it known that I, ELIHU THOMSON, of Swampscott, in the county of Essex and State of Massachusetts, have invented a certain new and useful Improvement in Means for Regulating Alternating Currents, of which the following is a specification.

My present invention relates to means whereby an automatic regulation of the reactive effects of an alternating current is brought about by the agency of the current itself, for the purpose of securing a practically constant value of such currents in a circuit passing over a working resistance or other portions of circuitin which work is to be done.

In the accompanying drawings Figure 1 is a sectional elevation of a regulator embody ing my invention, showing the circuit connections. Figs. 2, 3 and at show modifications.

Fig. 1 shows a core C which maybe alaminated iron core arranged to constitute a magnetic circuit in whole or in part for the surrounding coils of insulated wire K, K. This core is preferably of the open circuit type to facilitate mounting of the coils in place. These coils are shown as mounted in such manner that one coil balances the other partly, the difference being such that the coil K is able to move toward the coil K except when repelled by the currents in the coils. In a state of rest the coils K, K would lie close together. Cords running over pulleys for counterbalancin g are seen at P, P, P P connecting the two coils so that they may move freely. An electric circuit beginning at a passing through coil K, through switch contacts at F, through coil K, lights Z, Z, to b is shown and may be fed by connection to terminals of a constant potential system with alternating currents. The coils K, K are wound oppositely around the core, so that they are mutually repellant and mutually oppose each others induction on the core to an extent proportional to their proximity. Under these conditions if the coils K, K have a tendency toward each other and the current traversing the circuit due to the potential and resistance does not exceed a certain value, the coils K, K would remain together or remain at rest, and their efiects on the core would so nearly destroy each other, that the magnetizing and consequent reactive effects would be practically null. To render the coils still more nearly coincident as regards inductive relation to the core, one may be made to enter partly within the other as shown. if, however, this current, by the cutting out of resistance or by an increase of potential, should exceed the certain value mentioned the coils would then overcome their tendency to move together and be repelled one from the other to a distance such as would cause their effects upon the core C to increase sufficiently to introduce into the circuit of which they form a part, a reactive kick or self-induction just such as will bring the current to its former value. This increase of inductive effect on the core as the coils are separated is due to the fact that each coil is released or freed to a certain extent from the influence of the other. An indicator may be provided as at 1, showing the amount of separation they attain, a device which is use ful when the coils are boxed up so as to be out of sight. This indicator is shown as a pointer carried by a pulley engaging with the supporting cords. Should it be desired to have the separation or repulsion of the coils finally open the circuit, as when that separation has been extended to its full limit, an automatic switching device may be provided, as at e, 6 consisting of a detent holding up a lever L, which maintains contact at F in circuit with the coils. lVhen the projection from coil K strikes the detent c and unlocks it from under the end of the lever L, the spring S pulls that end down and opens contact at F therefore acting as a safety switch in case the reactive regulation of the coils K K is exhausted due to the removal of too much resistance from its circuit.

My invention is applicable to the case of a series of incandescent lamps fed from constant potential mains, such lamps having provided in them shunting devices for maintaining the circuit closed in case any of them break, or are withdrawn from the circuit, and my invention secures a constant current in the reniaininglamps notwithstanding the constant potential existing at the terminals, simply by its reactive tendency or the self-induotive counter-force exerted against the increase of current due to shunting of lamps. Any modifications in the kind or position of the coils might be used and many modifications in the arrangements or disposition for securing the effects mentioned mayalso be used.

Fig. 2 shows the apparatuswithout the indicator and safety switch, which are only attachments for adapting the apparatus to certain conditions and may under other conditions be dispensed with. The coils K, K in Fig. 2 are both movable and connected by cords over pulleys P, P so as to approach or recede from each other as before. In another part of Fig. 2 similar coils K K are shown mounted so that one only is movable, viz. K said coil being counter-poised in part by a weight W, with cords passing over the pulleys P P The coil K is stationary,and is. connected in series with the lights Z, Z. The coil K? may be wound as a closed circuited hand without any electrical connection with the coil K The amount of the counterpoise weight is adjusted to allow only that tendency toward the coil K which is required to keep the balance of current or keep the value of the current the same. 7

In Fig. 3. the coils K, K are shown. both movable and placed in parallel, such parallel connection being also shown by dotted lines in Fig. 2. i

In Fig. 4 the upper 0011 K which is 1n series with the lower coil K is shown as the only one movable, having counter-weights W, W with pulleys P, P for permitting this motion to overcome the stationary coil K.

In each of.the modifications which my .invention may take the regulation is effected by an automatic production of reactive effects or self-inductive counter-effects to the flow of the current, and the apparatus adapts the amount of these eifects to each case in which they are required ,to exist. The apparatus is also highly eflicient since the magnetization of the core. i very slight unless there is need for considerable regulatio The actual resistance of the coils may be made very small so that they waste but little energy in that way. The apparatus i very 50.

well adapted to maintaining a substantially constant current value,in a circuit of a single light fed from a source of constant potential of alternating currents conveyed from a line of varying potential, providing the variation does not exceed the capacity of the apparatus, hence it is capable of maintaining at practically standard brilliancy a light or a seriesof lights under conditions in which otherwise great fluctuations might take place. It therefore adapted not only to secure uniform lighting but also to save the wear and tear of lamps.

To render the repulsive effect more even and uniform, one of the coilsis made to enter only partially. within the other, by its contracted portion as shown, the coils being preferably made conical for this purpose, so that the coils never reach a position in which'their effects on the core and space areexactly equal and opposite. In this respect'mypresent invention differs from a reactive device wherein one coil may pass entirely over the other, as with the latter, the coil will pass from a posit-ion of inductive coincidence and no repulsion, to a positionof maximum repulsion as the coils are leaving one another, and then to further positions of diminishing repulsion, giving an uneven or irregular variation of force as well as a dead center to start on, with the risk of either sticking fast or moving in the Wrong direction.

- In other regulators devised by me, such for example, as described in the Patent No. 377,217, issued September 27, 1.887, I have shown devices where the coils were arranged to slide over each other; theythereforedid not havea' repulsive action of .uniform strength with a constant current, but had a repulsion which varied according to the position of the coils, being leastwhen the coils were. directly superposed and greatest when one'was about half 01f the other. The, present apparatus differs from this plan, however, in securing a substantial uniformityof' repulsion through the entire range of movement, or limiting, the range of the movement to one in whichasubstantially uniform. repulsion for a constant current is secured; for thisreason acollnterpoise by a constant weight will be found sufii- .cient. In other words, the coils are so made,


or one of them is so relatedto the other, that when traversed by a given current the repulsion will be substantially uniformin allpositions of the coil; and by this means the coil maybe counterpoised by a definite Weightor a spring of definite tension, or its own gravitating tendency may be used, to cause it to take different positions with the same current flowing according to the resistance in thecircuit. The open circuit core isespecially adapted to reactive devices of this class, wherein two opposing coils actoppositely on a common cor'e, for the polarity if any which is developed, is consequent, and the magnetic circuit, even with a closed core is partly through they air. An open circuit core has therefore substantially the same regulating eifect herein as would a closed core, and presents the advantage of easy placing and removal of the coil, a point of special importance wherefthe coil is movable on the core, and, would therefore be difficult to-wind in situ, and bev specially liable to damage requiring repair.

What I claim as new, and desireto secure by Letters Patent, is-

1,. A regulator for alternating currents comprising a core, cq la thereon elat yrlymlou able. under the influence of alternating cur- 2. A regulator for alternating currents comprising a core, coils relatively movable thereon under the influence of alternating currents flowing in them, such coils restricted to a range of motion wherein the mutual repulsion is substantially constant for a constant current, one of said coils having a contracted portion within the other coil, and constant approximating means opposing the repulsion of the coils.

3. A regulator for alternating currents comprising a core, coils upon such core relatively movable under the influence of alternating currents flowing therein,such coils restricted to a range of motion wherein the-mutual repulsion is substantially constant for a constant current and one ofthem entering partly within but engaging with the other ceil when theyare brouglit"together, and constant approximating means opposing the repelling influence of the current in the coils.

4. A regulator for alternating currents comprising coils relatively movable under the influence of alternating currents flowing therein, such coils restricted to a range of motion wherein the mutual repulsion is substantially constant for a constant current, an open circuit iron core surrounded by said coils, and constant approximating means opposing the mutual repulsion of the coils.

5. In an alternate current regulator the combination of mutually inductive coils, one or both being vertically movable and suspended so as to be partly counterbalanced, and subject to a constant gravitating force.

6. In an alternate current regulator, the combination of the mutually inductive coils, mutually repulsive by the action of the currents traversing them, and connected together so as to partly counterbalance one another. t

7. In an alternate current regulator, the ;;combination of the mutually inductive coils,

imutually repulsive by the action of the cur- ,rents traversing them, and cords and pulleys .[connecting said coils together.

In witness whereof I have hereunto set my hand this 23d day of June, 1891.




Referenced by
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US2457372 *Feb 11, 1947Dec 28, 1948Hobart Brothers CoAlternating current vertical welder
US2490354 *Oct 22, 1947Dec 6, 1949Hobart Brothers CoVariable output welding transformer
US2490871 *Aug 31, 1948Dec 13, 1949Hobart Brothers CoAlternating current vertical welder
US7471708 *Mar 31, 2005Dec 30, 2008Cymer, Inc.Gas discharge laser output light beam parameter control
Cooperative ClassificationH01F29/12