US933399A - Dynamo-electric machine. - Google Patents

Description

' W. STANLEY. DYNAMO ELECTRIC MAUHINE.

APPLICATION FILED FEB.2,1905.

2 SHEETS-SEEET 1,

WM-ncaocq @MugM-l od STANLEY. DYNAMO ELEGTRIO MACHINE.

APYLIQATION FILED FEB. 2,1905.

Patented Sept. 7, 1909.

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illmcoocm r srarss ares new WILLIAMSTANI-IEY, GREAT BARRI NGTOLI, MASSACHUSETTS, ASSIGNOR TO EIJECT3IQCOMPANY, A. CQRIQBATION OF NEW YORK.

DYNAIAEO ELEGTBIQ MACHINE.

assume.-

Specification of Letters Patent.

Paten'tedscpt. "2, 19,09.

" Application filed February 2, race. Serial no. 243,842. r Y

'Tocll whom it my conceriii Be it known that I, WILLIAM STANLEY, a citizen of the United States, residing at Great Barrington, county of Berkshire, 5 Massachusetts, have invented certain new and useful Improvements in Dynamo-Electric Machines, of hichthe following is a full, clear, and exact description. I

My invention relates to improvements in [0 alternating current dynamo electric ma chinery, such as alternating-current generators, motors, motor-generators and similar apparatus, employing novel methods for exciting or producing magnetic fields for the A same and generating alternating currents.

I ()ne object of my invention is to provide n machines of the'above-describcd type a magnetic field or fields of constant or nearly constant Value, moving relatively to the V structure producing them (known in the artas moving or rotating magnetic, fields) by exciting currents produced Within the machines themselves.

Afurther object of my invention is the appl cation of moving orkrotary fields upon 40 frequency can be: controlledby other factors than its s eed. r,

, Heretoore in the art, the field or field magnetism of dyn Lino-electric machinery has been produced either by currents of constantvalue and given direct-ionpknown as continuojuscurrents, or by alternating currents'of one or more phases applied in such'manner as to produce a field in a given polar line'or fields periodicallymoving or revolving about the structure. Whenever alternating currents have been cmployeddor such excitation, it has been necessary to generate them by means of auxiliary apparatus, known as cxcitcrs, and in general such apparatus'has consisted of a suitable rotor wound with con- '55 'duotors which pass through a field of constant value and fixed in space. -Thus, it has been necessary to ultimately resort to the use of a magnetic field of constant value and fixed position forthe initial production of 60 all currents of electricity generated dynamically, While in the invention herein disclosed, no such procedure is necessary as the invention provides means for directly gener- .ating' alternating currents bythe passage of suitable conductors through a rotary magnetic field developed by the machine itself independently of any exterior or exciting device. F

In the types of self-exciting}- machines,

such as were developed by (-l-ramme and Pacinotti, the currents induced in the rotor of the machine by the rotation of the armature conductors were so applied to the fieldproducing member of the machine asto rcmforce thefield which generated them,

i In my invention, the currents gencratedby rotation (if the rotor are applied to the stator i f-the machine in suchmanner as to develop I a new field angulurly displaced from the icld generating them, and so-that the total a resulting field, is of constant value but continuously varying in osition. The importance of this mctho of excitation con.-

sists not onl in the roduct'ion of a field of constant value within the machine itself, but? it is also of great value in that the field so produced possesses other dynamic properties than those which would accompany the production of a field produced by continuous currents. The magnetic field produced by" 'themethod herein described can be made to' re-act upon the stator and IOl'OI' C1l(;lX1tS1II which arc-generated the currents producing 4 it at a different frequency than the frequency of rotation of 'thermachine. The circuits, therefore, may be subjected to the dynamic induction of the same 'field at the same'or at different frequencies. v

The characteristics of machines constructed in accordance with my invention differ widely from those of other machines in that these machines the functions of the electromotive force-of the machine may be caused to automatically rise in value with an increase of output of the machine at any power factor and further these machines may be designed and arranged to produce currents of low power factor and given value at a higher potential than is obtained when the power factor of thecircuit is unity.

My invention also involves features of construction which will be hereinafter particularly described in the specification and pointed out in the claims.

The following is a description *ofa dynamo embodying my invention, reference being had to the accompanying drawings which show the simplest form, namely a machine having a single field, by which I mean a inachine having but one north pole and one south pole to be acted upon dynamically by the rotor. It is to be noted, however, that in field and armature as ordinarily understood are po.'

sessed by.both the moving and statipnary windings, for under certain, conditions of operation the machine delivers current to the external circuit from both the rotor and stator circuits both of which thus constitute energy-giving windings by which I mean windings which supply work currents.

In the drawings'Figure 1 is an end View of the dynamo, Fig. 2 is a side elevation of the same showing the stator with the windings removed, F ig. 3 1s a diagram of circuit connections;

*Referringmore particularly to the drawings, A is the stator having the vinding B, which is preferably of the ordinary distributed-winding type and from'which taps G to" C inclusive, are taken at equidistant points for the purpose of connecting them and the mains to the rotpr windings through ,the commutator brushes, as hereinafter described.

I) the rotor rotatably mounted within the stator and driven by the pulley E. The

rotor has the usual closed circuit distributedwinding F connected in the usual manner to a commutator Gr on which bear brushes H H and I I. The rotor winding is also connected to one or more sets of slip rings J J 2 J 3 J" at equidistant points from which alternating currents may be taken, if desired, as hereinafter cxplained. Lying upon the commutator are the four brushes H H and I I placed 90 apart and in a position substantially opposite the taps G'- C C C to which they are respectively connected, the coils connected to the commutator segments on which the brushes bear being opposite to the segments Thus it will be seen each brush is connected to the tap substantially opposite it so that'the rotor and stator circuits consist on the one hand'of a circuit from brush H to tap C through the statoriviuding to the diametrically opposite tap (G and thence to the brush H and-the rotor.

winding, and on the other hand of a circult from the brush I to tap C through the stator-winding to tap C and thence to the brush I and the rotor-windin If the machine be arrangefi as above described, and if there be a magnetic field existing in the machine due to the remanence of previous excltation, as, for instance, if

residual magnetism passes from the stator to the rotor and vertically downward, and if the rotor of the machine be now rotated clockwise at some definite speed, such as, for example, 1000 revolutions per minute, then an ,electromotive force W lll be generated upon tlrecommutator brushes H, H, placed at rightangles to this residual field and consequently a current will begin to flow from these brushes to the taps or intake points of the stator windings in the direct'ion shown by full line arrows, Fig. 3. Such a current will evidently magnetize the stator of the machine at right angles to the direction of the residual magnetism above mentioned and consequently the polar line of the machine will begin to move from the vertical direction, for example, toward the right, or clockwise, for the reason that the, field produced by the generated currents combines with the residual field above mentioned to produce a resultant field in the well-known manner. But this develop- -ment of the field at right angles to the residual field will cause an electromotive force to appear upon the brushes I, I placed vertically upon the commutator and the direction of this electromotive force Will be such as to cause current to flow from the brushes to the intakes or taps C C of the stator winding in the direction of the dotted arrows, Fig. 3, such as to vertical residual magnetism and thus having removed this magnetism will c'ause the magnetism generated by the currents flowing from the horizontal brushes to shift farther 'to the right or clockwise and to do velop a higher electromotive forceupon the vertical brushes I, I. This action continuing will result in the production of an increased current from the vertical brushes and intake taps C G which will produce a magnetic field vertically again, but of opposite polarity to that of the original residual field,.and such vertical field "combining with the horizontal field above mentioned will produce again a resultant field distorted or rotated farther to the right andoccupying a position advanced clockwise beyond that found when the currents from the operative. 'A continuous progression of the polar line thus results, the currents producing it being in this case two alternating currents of hase difierence. It is to be noted that the field which induces a cur destroy the horizontal brushes H, H were alone ce ses rent in the rotor is reinforced by that currentbut another field is built up by that "current which is angularly displaced from the inducing-field,

l havadiscorered that in a machine employing a commutator and embodying my invention the proper connections for the produotion' of sucha rotating field will be found when the connection between the rotor brushes'an'd the stator winding is such as I ;to make the polar line ofthe field displaced from the diameter of commutation for each pair-of brushes by 90 minus the angle of lag of themagnetizing currents. Thus if the machine be constructed tohave magnet i'zing currents iagging=80behmd their clec-- 1" -tro niotiye. forces; the angular displacement of the intake tapsof the stator circuits of the-machine 'to the brushes to which these taps are connectednhould be 90 minus 80 ex-"10. if t'he'ma'gnetizing currents are to lag ncarly'90" the angle between the brushes and the trips to which they are connected should be nearly jzeroias's'hown in Fig. 3.

The reason for dispiac'ing theintake taps V on the-stator winding from theb'rushes on rred' toyand as the "circuits are 'its magnetizatioui From this it will be seen that both 'thc'r'o'tor alid stator circuits of the machine contribute I11a gfi8lf0-mOlLiVE forces to-theproduction of the rotating fieldc' roduced, anditherefore each possess the nail 'roperties of field and armature circuits; #1 he two 'electroxnoti'v'c forces induced upon the rotor and stator "circuits above mentioned have relatlvely opposite lnternal @11- rections, and except for their very sniall phase dieplacement are unable to produce 'a' current'fiowing internally'in the machine.

Thcy,"however, coii'perate to d'eli'vc: work currents" fI'Om bOih the rotor and stator circuits tolthc externaljcircuit ofthe machine and consequently whenever energy currents are required,offtheln achine they are (1e liver'd from both the; rotor and stator circuits which "thus. con

titute' energyrgiving delivered externally circuits. I Such current to: the, mpchinecn ust evidently flow throu the rotorand. statorcircuits in opposite i- H rectionsaandthus eliminate the magnetizm tion that usually. follows when the induced 'circuit of a machine of the usual type delivers energy a an external circuit. The

' each.

windin s. are produced'bythe eifective rotation'ofthe designing that relatively opposite directions of these two that the rotating -1eld progresses, in themachine illustrated, clockwise with reference to the stator circuits and counterclockwise with reference to the rotor circuits, as the rotor revolyes at a greater speed than the electromagnetic rotalionof the field.

I suitably proportioning the, machine, it is not necessary. to introduce energy consiuningdevices into its circuits for controlling the magnetization; that is to say; as

"electroinotive forces is caused by the fact the energy in these circuits is dependent in part upon their resistance such a waste orenergy or loss of energy in magnetizatlon may be greatly reduced by making them of very low resistance as compared with those usually employed in the art, the inductance of. the circuits serying as a controlling factor of the current. i y

The frequency of the currents'in the exciting circuits (statorand rotor) andthe consequent rate' of rotation of'the magnetic field produced thereby depends? upon the ratio of the stator winding to the rotorwindings; that is',' the number of turns in For-a given rate of rotation of the rotor, neglcctingthe resistance of the circuits and their-magnetic leakage, the frequency of the exciting currents "would be such that the eiectromotive forces induced in the statorwindingswill bee unite the rotor electromotive'forces applie to the stator The rotor electromotive ':iorces rotor circuits in the'field produced by the exaction' of the rotating statorupon the stator 'W'indings. Therefore, in ordeuthat these eiectromntive forcesshall be equal the fre citing currents while the stator electromotit e forces are produced by the inductive quency of the exciting currents must be 3 equal to the-frequency of revolution multiplied by the number of turnsf'in th'erotor winding and divided by the sum of the number of turns in both rotor and stator windings, In the construction 'shownin the diagram 'the rotor hast'wice the number of turns of the stator circuit. Tlhefrequency of the exciting currents would therefore be two-thirds ofthe frequency of rotor rotation. If the number of turns of the rotor and stator windings were the same, the-fr'equency of excitation would correspond to one-half the speed of revolution and the commutator would not change the frequency of the currents delivered through it from the 'rotorf lnwpractic'e the resistance and ;mage

'netic leakage can be made so-small byproper be attained.

If external resistance'or seifi-induction is interposed into'* the exciting circuits, the tendency will be in either case toureduce' the frequency, since by such external resistance yery nearly these results can i bination of a stator and windings thereon, a neutral points caused by said recesses, and e rotor and windings thereon, a commutator connected to said rotor windings, brushes bearing on said commutator, connections between said brushes and said stator windings such as to produce a rotating energizing field of definite frequency, said stator h'eing recessed and said brushes being located at Work circuit electrically connected to said 10. windings. v

I WILLIAM STANLEY. Witnesses:

.H. B. BROWNELL,

L. VREELAND.

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