US285691A - sheehy - Google Patents

Description

(No Model.) 4 Sheets-Sheet 1.

R. J. SHEEHY.

DYNAMO ELECTRIC MACHINE.

No. 285,691. Patented Sept. 25, 1883.

WI TJVESSES I-NVENTOR y his fittomew 130150;! J Sizes/y N. PETIRS, Pmwumu lm. Washmgton, D c.

(No Model.)

4 SheetsSheet 2. R. J. SHEEHY.

DYNAMO ELECTRIC MACHINE.

No. 285,691. Patented Sept. 25, 1883.

Min

i mum IJVV'EJV TOT? Hubert J. Shady,

WI '[iN/JSSES n. PETERS. PhMo-Lvlhognpfm. Waminflnn, n. c.

(No Model.)

' R. J. SHEEHY.

DYNAMO BLEGTRIG MACHINE. No. 285,691. Patented'Sept. 25, 1883.

4 Sheets-Sheet '3.

WITNESSES IJV VEJVTOR By his flitm'neys lzo&erilksyledfyy 4 Sheets-Sheet 4.

(No Model.)

B, J. SHEEHY.

DYNAMO ELECTRIC MACHINE.

No. 285,691. Patented Sept. 25, 1883.

Wl T/VESSES UNITED STATES PATENT OFFICE.

ROBERT J. SHEEHY, OF NEIV YORK, N. Y.

DYNAMO-ELECTRlC MACHINE.

SPECIFICATION forming part of Letters Patent N0. 285,691, dated September 25, 1883..

I Application filed November 22, 1882. (X0 model.)

To to whom it may concern:

Be it known that 1', ROBERT J. SHEEHY, a citizen of the United States, residing in the city, county, and State of NewYork, have invented certain new and useful Improvements in Dynamo-Electric Machines, of which the following is a specification.

My invention relates to the art and practice of economically converting mechanical into electrical energy.

It has for its object to increase the efficiency of the so-called dynamo-electric machine, especially such forms as are employed in the production ofcur rents ot'large volume and high intensity. It concerns, in this connection, the methods of utilizing the magnetic field, of economically maintaining the magnetic intensity, of applying the power to rotate the armatures, of adapting the armature-conductors to the requirements of the external. circuit, of maintaining a uniform current throughout any given circuit, and to other matters of less importance.

In general the more important improvements herein set forth may be described as follows: First, for the purpose of generating currents economically I have constructed my machine with a number of field pole-pieces, arranged in aseries of alternating polarities, and have provided intermediate armatures between adjacent pole-pieces and exterior armatures against the outer faces of exterior polepieces; secondly, I maintain the fields of the several armatures by means ofthe currentsgenerated in said outer armatures, employingone or both, as may be required; thirdly, I eommunicate the power from a main shaft to the independent armature-shafts through the medium of frictioirgearings, which may be independently operated; fourthl y, I provide mechanism whereby the length of the conductors in each of the several bobbins of any armature may be simultaneously increased or reduced to conmensate for changes in the conditions of the external circuit; and, fifthly, I provide means for automatically operating said mechanism for varying the length of the conductors in the armaturebobbins when the normal strength o'tcurrent is disturbed thereby, so altering the electro-motive force and internal resistance of said armature as to rcgenerators. Fig. 0

drawings, Figure 1 is 2 a plan, of my comis a longitudinal view,

partially in section, of one of the arn'latures,

showing the commutator mechanism, the mechanism for varying the length of arm ature-conductors, and the motor for automatically actuating the same. Fig. 4 is a section, and Fig. 5 a face view, of the connnutat-or employed in conjunction with each armature. Fig. 6 is an end view of the apparatus for varying the length of said armature-conductors. Fig. 7 is a modification of my improvements, consisting of a combination of a commutator with the mechanism for varying the length of armatureconductors; and Fig. Sisadetachedview of one of the cores of the armatui'e-bobbins.

Similar letters of reference are applied in the several figures to the same parts.

, Referring to the drawings, A A represent two electro-magnets, with yokes B and B re spectively. The pole-pieces of these electromagnets are shown at C, 0, C and C, re spectively. Each of the pole-pieces 0 consists of a block of iron having a longitudinal semicir iular recess, 0, formed in each side thereof. The helices of the cleetromagnets are connected together in one electric circuit, the winding being in such directions that un der the infiuence of the current the polarization of the alternate pole-pieces will be opposite. Thus, for example, that of C will be north, that of C" south, &c.

XVithin each of the cylindrical openings formed by the confronting recesses 0, made in the extensions 0, CF, 0'", and C, as also within each of the recesses formed in the outer surfaces of the two extreme polc-pieces C and O, is placed a cylindrical armature, D. The outer armatures, D and D, are each provided with a field of force created by the pole-piece 0 upon one side only, whereas the three intermediate armatures D D", and D are each provided with fields of force created by a pole generator or bank of 60 -0 low rectangular core, M, of soft 11011, and these cores are, for convenience, constructed of four piece upon each side. The former therefore Against the extremities of each pole-piece O is secured an iron plate, E, which serves to extend the magneticfield over the ends of the armature-bobbins as they are revolved in proximity to that extension. A standard, F,'preferably ,of non magnetic metal, is secured to each of the plates E, at the ends of each armature, and within said standards are formed suitable j ournal-boxes, f, for receiving the respective ends of the armature-shaft d.

The armatures D are independently connected through their shafts d with a horizon tal shaft, G, extending in a direction at right angles therewith. The horizontal shaft G car ries a pulley, g, by means of which a rotary motion may be communicated thereto from any suitable source of power. The rotary movement of the shaft G is communicated to the armatures D, respectively, by means of beveled friction-wheels H and I, of compressed paper, mounted upon the shaft G and the in-" dividual armature-shafts d. I prefer, also, to so construct the frictionwheels H that they may be independently disengaged from their respective armature-wheels I at will. This I accomplish by connecting each of the wheels H to the shaft G by a convenient spline-andfeather attachment, which permits a horizontal movement of the same to and from the friction-wheels I. In the sleeve h of each of the friction-wheels H is formed an annular groove, 71 for receiving the two semicircular prongs j j of a forked lever, J. Thelevers J are each pivoted at a point, j, in a manner allowing the extremities of the prongs j j to be moved longitudinally along the shaft G, carrying there with the friction-wheel H. At the remote extremityof each lever J is formed a slot, k, for receiving a pin, k, carried upon a cam-lever, K. By means of this system any desired nu mber of armatures may be actuated.

The construction of the. armature which I prefer to employ in this connection consists of an annular series of coils, L to L, of insulated wire, surrounding the armature-shaft d. Each of the coils L is constructed with a holsections, m, M, m and m". The sections m are constructed to fit together in the manner shown inFig. 8, with their edges projecting slightly beyond the opposite sides of the coils, and forming tenons a, which fit into corresponding apertures, a, formed in a series of horizontal girders, N. The girdersN are supported at their respective extremities by means of two soft-iron cylinder-heads, O and O, affixed to the armature-shaft (l in the manner described in an application for Letters Patent filed by me November 7, 1882. Suitable radial lugs, 0, are formed upon the inner surface of each cylinder-head O and O, to'which the also formed in the inner face'of the heads 0,

and O. A sufficient space is preferably left between the surfaces of the coils L, adjacent to the heads 0 and O, 'as also between the coils and the longitudinal plates 1?, to allow a free circulation of air for the purpose of cooling the machine.

-The inner terminal of each coil L of each armature is connected with the inner terminal of the diametrically-opposite coil, in a manner to be hereinafter described. The outer terminal of each coil is connected with an individual segment r 1- to r r of a commutator, R, carried at one, end of each armatureshaft d and revolving therewith. The eommutators R each consists of a metallic disk, S, secured to the armature shaft (1, and faced upon one side with compressed paper or other suitable insulatingmaterial,asshown at8. Thecurved segments 1' r, &c.", are secured to the iron supportingdisk S by suitable studs. 8', which serve to separate the segments from the disk and allow air to circulate between the two, and prevent false connections from being estab lished between adjacent plates through the accumulation of metallic dust from the commutator. The segments 1' r, &.c., are thus arranged upon the lateral face of the commutator, and forming rings concentric with the axis of the shaft (1, as shown in Fig. 5. In

each ring there are two segments placed dia- V they are respectively connected. The posi-- tion of the commutator with reference to the polar extensions 0 is such that during the period in its revolution when a current of a given direction is being generated in any given in ductive coil-'as,' for example, L of the armature-the outer terminal of that coil will be connected through its commutator-segment r with one of the collecting-brushes T. The inner terminal, as before mentioned, is con- 1 nected with the inner terminal of the diametrically-opposite coil, L, and the outer terminal of the latter to the diametricallyopposite segment, 0'', of the commutator and collectingbrush T At the moment, however, that the current ceases to be generated in the coils L and L or becomes too weak to be of service, the connections with the brushes T and T are severed by the intervention of the non-conducting segments s At the instant, or immediately before, the connections of any given coil are severed, the connections of the next succeeding coil are completed with the same contact-brushes. The current is thus at all times collected from a constant amount of inductive wire. The commuta'torbrushes T an d T are supported at the respective extremi ties of an arm, 8, which is supported at its center upon a collar, surrounding the shaft (1, and constituting a journal in which the arm may be rocked. A clamp, s, is fastened to, but insulated from, each extremity of the arm 8, and in these clamps the contact-brushes are held in their required positions by means of set-screws S The angular position of the arm may be manually adjusted, as required, for the purpose of bringing the brushes in the proper positions relative to the commutatorscgments.

For the purpose of preventing the occurrence of electric discharges or sparks between the brushes T and T and the successive commutator-segments when the circuit between the same is interrupted, I employ a series of contactsegments, 1 to 1;, and independent contact-brushes T and T, for short-circuiting the successive coils innnediately before or at the ta ct with the brush T or T.

instant their connections with the brushes T and T are severed. The segments t to i are preferably arranged in an annular series at the back of the disk S, and are supported by lugs extending therefrom. The outer terminal of the armature-coil L is connected with the segment t, the corresponding terminal of coil L with segment 1 and so on in regular succession.

The two contact-brushes T and T are respectively carried in brackets forming extensions of the clamps 8. These brushes are in direct electrical connection with each other through a conductor, 1., and a resistance-coil, T", may be included for the purpose of diminishing the strength of current traversing said eonductor. The positions of the respective segment '6 and segment 9', to which any given ter minal is connected, are so arranged relatively to their respective contact-brushes that imme diately upon or before the segment 1' passes from beneath the brush T or T the corresponding segment, 1,will be brought into con- The force of the residual current in the armature-coil will thereupon be expended in the circuit of the conductor 1.

For the purpose of regulating the volume or strength of the current generated in each armature independently of the remainder, I construct the coils of each armature in such a manner that a greater or less portion of the wire constituting the same may be employed at will, thus varying the total amount of active inductive wire in the circuit. The means whereby I accomplish this end consists in placing upon each armature-shaft d, at the end of the armature D, away from the commutator R, a disk, U, of non-conducting materialsuch, for example, as compressed papercar ried upon the face of a metallic supportingplatc, U", and in mounting thereon eight ra- 7o dial series of contactpoints, a. Any requisite number of individual contact-points a may be contained in the radial series; but each series is preferably constructed with the same numher, and the consecutive contact-points are ar 7 5 ranged at equidistant intervals from each other, and the inner ones of all the series the same dist-anecdrom the center of the disk U. The successive contact-pointsaare electrically connected by conductors a with the successive layers or groups of layers of the insulated wire constituting the bobbins L of the armature D. Thus, beginning at the center of the bobbin, the inner contact-point, a, of any given radial series is connected with the inner group of convolutions of that armaturebobbin which is in the same axial plane therewith, the second contact-point from the center is connected with a second group of con volutions in the same a1'mature-bobbin, the 0 third contact point likewise with a-- third group, and so on. The same construction is followed out with reference to each bobbin and its radial series of contact-points.

For the purpose of automatically determin- 5 ing the amount of wire which shall be rendered operative at any given time, and thus con trolling the strength of the current transmit ted to theexternal circuit, 1 have devised the following means for simultaneously placing any of the contact-points a in all the series in electrical connection with the corresponding contact-point of the diametrically-opposite series, and determining which set of contact points shall thus be connected by means of the arranged to revolve a shaft, '0, in the direction I 10 indicated by the arrow, underthe influence of an electric current of increasing strength, and to allow the same to be revolved in the opposite direction through the intluence of a weight,

'v,whcn the current traversing the coils of the I I 5 motor decreases in strength.

Upon the shaft 1) is formed a continuous thread, along which a corresponding threaded traveler, '0 is caused to move in one direction or the other, according to the direction we of revolution of the shaft. The two prongs w of a forked lever, XV, extend upon opposite sides of the traveler t and are loosely jointed thereto by means of the transverse studs n, projecting from the traveler through elongated slots w,-f rmed in the extremities of the respective prongs. The lever W is pivoted at a point, a and is forked at the ex tremity remote from the shaft 1) in a manner similar to that described with reference to the I 50 lever J, as shown at in w. The prongs w and w embrace a collar, X, surrounding the arma- NV. The extremity of the collar X remote from the groove 00 engages the short arms of a series of eight levers, Y, which serve to close the circuits between the diametrically-opposite contact-points u, in a manner hereinafter described. The levers Y. are respectively pivoted at points equidistant from each other to annular lugs 1 formed upon a collar, y, which collar surrounds the shaft and is rigidly attached thereto. Each of the levers is, increover, so constructed that the extremity of its long arm 1 which is preferably insulated from the lever itself by an intervening block, 1 of compressed paper or other suitable insulating material, may be swung outward from the center of the shaft (1 in the plane of the radial the disk U by arms at, extending through the metallic supporting plate U but insulated therefrom. Each guide-rail a is provided with a movable collar or traveler, a, upon which is carried a circuit-closer, a, hereinafter described. A slot, y, is formed in the extremity of each arm 3 of the levers Y, through which slot'extends a stud, a formed upon each of the travelers a. The circuit-closers U each consists of a wheel, a having four teeth or projections, two of which, diametrically opposite each other, are of slate or other suitable nonconducting and non-inflammable material. This four-armed wheel is pivoted at its center to a resilient arm, a, of conducting material, rigidly supported from and in electrical connection with the carrier at. The conducting teeth or prongs of the wheel u have their extremities rounded, and are constructed to fit intorecesses u formed'in the faces of each. of the contact-points u. The insulating teeth or prongs enter between adjacent contactpoints, and serve to prevent an electric discharge from taking placebetweenthe adj acentpoints when-the contact between one of the conducting-armsand one of said points is suddenly broken during the passageof the wheel.

It will now be evident that when the collar X is moved forward toward the lug to which the levers Y are pivoted, the short arms of the levers will be pressed outward, and the long arms forced toward the center of the shaft, thereby bringing the circuit-closers into 0011- tact with. theinner contact-points, u. \Vhen, on the other hand, the collar X is moved in the opposite direction, the long arms ofthe levers will be carried outward by means of the force exerted by the springs Y, combined with the centrifugal force occasioned by the rapid revolution of the armatureshaft. As the arms.

y are carried outward the circuit-closers U make connections between the successive contact-points u and the guide-rails u. The rails a, which correspond with the diametricallyopposite armature-coils, are electrically connected with each other by conductors 2. The object of this regulating mechanism is to maintain a constant uniformity in the strength of current traversing the external circuit.

The operation of the device is as follows: As shown in the figure, the circuit-closers U are in contact with the inner circular range of contact-points a, which, as already described, are connected withthe inner terminals of the innermost groups of conductors of the respective bobbins to which they correspond. This is the condition best suited to the development of currents of high'electro-motive force. If, now, for any reason the resistance of the external circuit is diminished, the strength of current in the circuit will be proportionally increased. This will operate the motor V to withdraw the collar X and allow the outward movement of thelevers Y. The circuit-closers U, on leaving the inner circular series of contactpoints a and making connections with the second series, eliminate from the main circuit the inner group of conductors, as already explained. This simultaneously reduces the electro-motive forceof the current generated and the internal resistanceof the machine. If the strength of current is still excessive, the circuit-closers are still farther advanced, and the length of wire in the armature still fartherdecreased. Ultimately the condition is reached in which the original strength of current is again established throughout the circuit. 011 the other hand, if the strength of the current generated falls below the predetermined point,-

the motor-shaft v is rotated in the opposite direction by means of the weight 1) and the convolutions are reintroduced.

For the purpose of adjusting the motor to respond to currents of any required strength, I prefer to attach the cord supporting the weight to a-conical drum, Z, in such a manner that the weight will exert :a greater retarding influence upon the shaft 1; at the start than thereafter, to prevent action of the regulatorin response to slight diminutions of resistance or variations of speed of the machine.

' It is desirable that the time intervening between the breaking of the circuit with one contact-point u and the closingof the circuit with the next succeeding point should be as small as possible. For the purpose of effecting this result, and to prevent the circuit-closers from remaining at positions intermediate between two contact-points a, I mount upon the shaft 0 an arm, 2, carrying at its extremity a pyramidal wedge, z, and place in the path of its revolution an adjustable tension-clutch, 2 consisting of two resilient arms or springs, z normally so far separated as to allow the Uri cam z to enter the space between them, but not to allow it to pass between without separating them still farther. This renders the movement intermittent.

The respective parts of the machine are so adjusted that one revolution of the shaft 1) will cause the circuit-closer U tobe moved from one contact point a into contact with the succeeding point. The resilience of the springs 2 will be sufficient to normally hold the pyramidal wedge z and prevent the operation of the motor. IVhen, however, the current increases sufficiently to force the wedge through the springs, the shaft will immediately complete one entire revolution and the circuit will be completed through the succeeding contact-point a. This operation is repeated with every increase in the strength of the current which is adequate to effect the operation. For the purpose of allowing the shaft 0) to be revolved freely in the reverse direction, I prefer to mount the springs :4 upon a hinged support, z, which is normally held in an upright position by the spring 2 but which will be thrown backward and temporarily carry the springs out of the path of the wedge a when the latter strikes the springs upon the opposite side.

In Fig. 7 I have shown a modification in the construction of the device employed for cutting the successive layers of bobbin-wire out of circuit. The object of this modification is to combine a commutator with the device for varying the length of the armature-conductors, and thereby dispense with the commutator placed at the opposite extremity of the armatures. It consists in constituting each lever Y a conductor, and pivoting them in a non-c011- ducting support. An annular series of metallic contactsegments, t" to t, surrounds the levers Y, one of which is adjacent to and in in electrical connection with each of said segments. The brushes T and T will then at any time be in electrical connection with the outer terminals of opposite bobbins. Assuming that the inner terminals are connected to gether directly, and that the connections between opposite guide-arms have in this i11- stance been severed, currents will be collected by said brushes, which will depend in strength upon the positions of the circuit-closers U. This combined collector and governor maybe advantageously employed in conjunction with many of the well-known forms of machine.

The bank of generators thus described may be regarded as a collection of separate generrators, or as a single instrument, and the individual armatures may be operated in series multiple arcor may be independently em ployed on separate circuits.

I am aware that the coils or convolutions of field-magnet helices have been introduced into and withdrawn from the circuit of a dynamoelectric generator for the purpose of varying the intensity of the field of force, and thereby indirectly modifying the strength of current generated; but the plan of regu ation presented herein is essentially different from this, inasmuch as it aims to directly modify the intensity of the current generated by varying the length of wire subject to inductive action in the bobbins of the armature.

I claim as my invention 1. The combination, substantially as hereinbefore set forth, of an electroanagnet, its pole- 7 5 pieces, an armature moving within the field of magnetic force created between the inner faces of said pole-pieces, and independent armatures moving within the exterior field or fields created by the outer faces of said pole-pieces.

2. The combination, substantially as hereinbefore set forth, of two or more electro-mag nets, four or more pole-pieces thereof arranged consecutively with alternating polarities, armatures moved within the field of magnetic force created between the confronting faces of the pole-pieces of the same or of adjacent elec tro-magnets, and armatures moved within the fields created by the external faces of the outermost pole-pieces. 9

3. The combination, substantially as hereint before set forth, of two or more electro-magnets, their pole-pieces arranged consecutively with alternating polarities, armatures moved within the intermediate fields between adjacent pole-pieccs, armatures moved within the exterior fields created by the outer faces of said pole-pieces, and a magnetizing-circuit the current within which is supplied by one or both of the armatures moving within said exterior fields for maintaining the fields ofall of said armatures.

4. In combination with the armatures of a battery of dynamoelectric machines, a shaft for each armature, a friction-wheel on each armature-shaft, an independent driving-shaft, and mechanism for independently engaging the friction-whecls on the independent shaft with those on the armature-shafts.

5. In combination with the armatures of a battery of two or more dynamo-electric machines, two or more separate armature-shafts, friction-wheels mounted on said armatureshafts, an independent shaft, friction-wheels on said independent shaft, a forked lever for II 5 independently sliding each of said friction wheels on said independent shaft, and a camlever for locking said friction-wheels upon said independent shaft into and out of engagement with the friction-wheels on the ar- 12o matureshafts respectively.

6. The combination, substantially as hereinbefore set forth, of an armaturebobbin, a conductor disposed thereupon in several convolutions or layers of covolutions, a series of I25 contact points respectively connected with the terminals of each of said convolutions or layers of convolutions, and an automatic traveling circuit-closer making contact with said contact-points, for the purpose of introducing one or more of said convolutions or layers of convolutions into a circuit of conductors.

7. The combination, substantially as hereinbefore set forth, of two bobbins carried on either side of a central shaft, a radial series of contact-points; for each bobbin respectively connected to the conductors of said bobbins at difierent points in their lengths, and traveling circuit-closers electrically connected together and simultaneously making contact with corresponding contact-points in the respective radial series for the purpose of connecting the conductors of one bobbin with those of the other, and for simultaneously and equally varying the length of the conductor in each.

8. The combination, substantially asherein- I 5 before set forth, of an annular series of bobbins, a commutator provided with conductingsegments corresponding to said bobbins and in electrical connection respectively with their outer terminals, a radial series of contactpo-ints for each bobbin, said contact-points beingrespectively connected with each of the conductors of said bobbins at corresponding points throughout their lengths, and traveling circuit-closers for connecting diametricallyopposite bobbins through corresponding contact-points.

9. The combination, substantially as hereinbefore set forth, of an annular series of bobbins, a radial series of contact-points for each bobbin, the contact-points of each series being respectively connected with the conductors of said bobbins at corresponding points in their lengths, and traveling circuit-closers for connecting diametricallyopposite bobbins through the medium of said contact-points.

10.- The combination, substantially as hereinbefore set forth, of an annular series of bobbins, commutatorsections connected to the outer terminals of said bobbins, and means whereby the inner terminals or corresponding points along the lengths of the conductors constituting the diametrically-opposite bobbins may be connected together.

11. The combination, substantially as hereinbefore set forth, of an annular series of bobbins, a main line maintained in electrical connection with the outer terminals of said bobbins through commutator mechanism, and means whereby equal and corresponding fractions of the coils of such of said bobbins as are in action may beintroduced into or withdrawn from said main line correlatively with the changes in the strength of current traversing the same.

12. The combination, substantially as hereiubefore set forth, of an annular series of bobbins, mechanism for varying the lengths of the armature-conductors in action, and a motor whose movements are controlled bychanges in the strength of current for actuating said mechanism.

13. The combination, substantially as hereinbeforc set forth, of an annular series of bobbins, contact-points arranged in circular and radial series and revolving simultaneously with said bobbins, traveling circuitclosers for each of said radial series, and a motor operating under changes in the strength of current traversing the main line for simultaneously actuating all of said circuit-closers.

14. The combination, substantially as hereinbefore set forth, of an annular series of bobbins, a radial series of contact-points for each of said bobbins, traveling circuit-closers for -each radial series, the diametrically-opposite circuit-closers being in electrical connection, a wedge-collar for simultaneously actuating said circuit-closers each to travel radially and 'make successive engagements with said conmature-bobbin, a motor whose movements are controlled by variations in the strength of current generated in said workingconductor, and mechanism for rendering the action of said motor intermittent. Q

17. The combination, substantially as hereinbefore set forth, of mechanism for varying the length of working-conductors in two or more armature-bobbins, a motor whose movements are controlled by changes of strength in the current generated by said bobbins, and mechanism for rendering the action of said motor intermittent when said variation is caused by an increase.

18. The combination, substantially as hereinbefore set forth, of mechanism for varying the length of working-conductors in diametricallyopposite armature-bobbins, a motor whose movements are determined by increases in the strength of current generated in said bobbins to actuate said mechanism to intermittently diminish the length of said conductors, but to increase them uniformly in accordan cewith I said variation.

19. The combination, substantially as hereinbefore set forth, of mechanism for varying the length of active conductor upon an armature, a motor actuated by changes of strength of the current generated by said armature, a

motorshaft, a pyramidal wedge carried by said shaft, and mechanism for retarding the passage of said wedge in one direction only.

20. The combination, substantially as hereinbefore set forth, of an armature, a motor for varying the length of the active conductor upon said armature, a motor-shaft and pyramidal wedge carried by said shaft, springs permitting the passage of said wedge between them in one direction, but with retarding in- IQQ lluence, and a shouldered lever carrying said springs, said lever being depressed by said wedge when moving in the opposite direction for the purpose of allowing its free passage.

21. The combination, substantially as hereinbefore set forth, of an armature generating electrical currents, a motor operating in opposition to a weight for controlling through intermediate mechanism the strength of current generated by said armature, a drum upon which the supporting-c011l of said weight is l wound, having a part of its surface conical for increasing the leverage necessary to wind said weight for the purpose of opposing the action of the motor at certain times.

In testimony whereof I have hereunto subscribed my name this 21st day of November, A. D. 1882.

ROBERT J. SHEEHY. lVitnesses:

DANIEL W. Enonconn, MILLER G. EARL.

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