US1382257A - Variable-speed constant-voltage generator - Google Patents

Description

W. A. TURBAYNE.

VARIABLE SPEED CONSTANT VOLTAGE GENERATOR.

APPLICATION FILED NOV. 6.19I6.

Patented June 21, 1921.

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UNITED STATES PATENT o F cE.

FALLS, NEWYORK, ASSIGNOR TO U. S. LIGHT FALLS, NEW YORK, A CORPORATION OF NEW VARIABLE-SPEED CONSTANT-VOLTAGE GENERATOR.

Specification of Letters Patent.

Patented June 21, 1921.

Application filed .November 6, 1916. Serial No. 129,669

To all whom. it may concern:

Be it known that I, WILLIAM A. TUR- BAYNE, a citizen of the United States, residing at Nia ara Falls, in. the county of Niagara and state of New York, have invented new and useful Improvements in Variable-Speed Constant-Voltage Generators, of which'the following is a specification.

' The present invention relates to variable speed constant voltage generators.

Many devices are in use for maintainlng substantially constantthe voltage developed at the terminals of a generator which is subjected to wide'variations in speed. The present invention relates to generators which are inherently capable of delivering a substantially constant voltage, no extraneous devices being necessary. a

An object of the present invention is to provide a novel dynamo-electric machine which, when operated as a generator, will inherently develop a substantially constant voltage.

A further object is to provide a dynamoelectric machine of the kind referred to, which will be simple in construction and cheap to manufacture.

Further objects will be apparent as the Referring-to the drawings Figure 1 represents diagrammatically one embodiment of the invention.

Fig. 2 represents a development of the armature windings showing the field poles, the brushes and the field windings cooperating therewith.

igs. 3 and 4 represent details.

The field frame of the dynamo-electric machine which forms the subject-matter of the present invention, is indicated as a whole by the numeral 1. This field frame 1 is represented as the stator of the machine.

In the embodiment illustrated, the arma ture is designed to rotate; This armature is indicated as a whole by the numeral 2. The field frame, as illustrated, is rovided with six pole pieces, 3, 4, 5, 6, Thesepole pieces are provided with field windings 3, 4, 5, 6, 7 and 8 respectively. Located adjacent to each ot the pole pieces 3 to ,8 inclusive are auxiliary pole pieces 9, 10, 11, 12,13 and 14. Theseauxihary pole pieces 9 to 14 inclusive, are dlsposed a short di'tance from the main pole pieces 3 to 8 in clusive, in the direction. of rotation of the mutator at and 8. in the armature-conductors.

armature 2. The auxiliary pole pieces are provided with windings 9, 10, 11, 12, 13, and 14 respectively.

he armature 2 is provided with a commutator 15. Bearing on the commutator 15 are six brushes 16, 17, 18, 19, 20 and 21. Of these brushes 16 and 20 bear on the compoints of equal potential. Said brushes 16 and 20 are connected together and to the lead 22 of the generator. Brushes 17 and 19 points of equal potential and are connected together and to the lead 23 of the generator. Brushes 16 and 20 on the one hand and brushes 17 and 19 on the other hand, constitute the main brushes of the machine. Using a series two-path armature with symmetrical end connections, considering on] the flux from.the main poles and disregard ing armature cross flux, the points of maximum differenceof potential will come opposite the main pole pieces. Therefore, brushes l6 and 20 will the centers of pole pieces 5 and 7, while brushes 17 and19 will be located 0 posite the centers of pole pieces 4 and 8. l rushes 18 and 21 are auxiliary brushes locatedat points displaced from the center line through the pole pieces 3 and 6 by an amount equal to the angle X which will be chosen of a magnitude best suited for the regllation desired. eferring to Fig. 1, it will be noted that the field windings 3, 4, 5 are connected across the main positive brushes 16 and 20 and the auxiliary brush 18. Field windings are connected across negative brushes 17 and 19 and auxiliary brush '21. The auxiliary windings 9, 10, 11, 12, 13, and 14 are preferably connected to the auxiliary brushes 18 and 21 as indicated. The field rheostat 24 may be provided in series with the field windings 9 to 14 inclusive. The complete circuit arrangements of the dynamo electric machine are illustrated in Fig. 2,.which shows the direction of current The lowermost arrows illustrate the presence and direction of field exciting current. The uppermost arrows indicate the presence and direction of load current in the armature conductors when circuit is completed across leads 22 have been indicated as a single coil marked A. Windings 6, 7, and 8 have been indibe located opposite and 23. In Fig. 2, windings 3, 4, and 5 designed to maintain 65 volts at its terminals.

The main brushes 16 and 20 and 17 and 19 are at points of maximum potentialdifl'erence when the main poles only are excited and, as will be noted in Fig. 2, are located to commutate armature conductors located substantially midway between adjacent main poles. Under this condition, a difierenoe of potential of some 15 volts exists across brushes 16 and 18 and brushes 19 and 21,

across which the main field windings are connected, so that current through the/left hand main field windings will flow from brush 16 to 18, while current in the left hand main field windings will flow from brush 21 to brush 19, the direction of this current around the various field poles giving them the polarity indicated on the drawings. Under this condition 1 also, the auxiliary shunt field winding connected across brushes 18 and 21 will be subjected to a difference of potential of some 35 volts, current flowing in the direction from positive brush 18 to negative brush 21 and giving the auxiliary poles 9 to 14 inclusive the polarities indicated on the drawing. The excitation of these auxiliary poles, however, will tend to alter the distribution of voltage around the commutator, shifting the curve to the right. This shifting tendency will increase as the voltage across brushes 18 and 21 increases,- following speed increases, for instance.

Under the conditions illustrated by the broken line curve in Fig. 2, it will be noted that the difference of potential existing across brushes 16 and 18 and 21 and 19, has become reduced, so that substantially only 3 volts exists across these brushes, which.

means a very decided reduction in the current through the main field windings. Under this condition also, the voltage across brushes 18 and 21 will have risen to some 55 volts. It is obvious from the diagram that the voltage across brushes 18 and 21 could not greatly exceed this value, as otherwise the current through the main field windings would drop to zero and the machine would be incapable of producing the desired E. M. F. The most advantageous position for the auxiliary brushes 18 and 21 will be determined in practice. The maximum value of the voltage developed would be determined by adjustment of the field rheostat 24 connected in circuit withthe auxiliary windtemplates means whereby the effects of the j armature current shall be compensated for so that the shifting of the field flux will be uninfiuenced by this armature current, the flux distortion being brought about wholly by the action of the auxiliary poles. It is well known, of course, that the effects of the armature current can be absolutely com nsatedsfor by means of com ensating windings of the well known yan type distributed around the pole faces and connected in series with the external circuit. compensating windings exert a magneto-motive force exactly equal to the M. M. F. imparted by the armature winding. The particular construction of field frame illustrated in connection with the described embodiment of this invention, adapts itself readily to a less expensive means for compensating for the affects of the armature current. Such meansare illustrated in the detail views, Figs. 3 and 4. In Fig. 3, main pole 3 is illustrated having in addition to the main exciting winding 3, the series windings 25, which are adapted to be connected in the external circuit. Thewindings 25 will. be given such a value that any tendency of the armature current to distort the flux and thereby raise the voltage on brushes 18 and 21, will be offset by the increased excitation applied to the main poles.

A similar result may be obtained by the means illustrated in Fig. 4:. In this figure the series windings 25, also adapted to be connected in the external load' circuit, are applied to the auxiliary poles, the current in this case poles in a direction opposite to that flowing in the shunt winding. The current around these auxiliary poles, therefore, exert a M. M. F. opposed to that developed by the current in the armaturewindings.

The embodiments of the present invenflowing around these auxiliary These tion which have been described, are chosen What I claim as new and desire to secure by Letters Patent of the UnitedStates is '1. In a variable speed generator, means for providing field flux, an armature, main brushes cooperating with said armature, auxiliary brushes cooperating with said main brushes to supply current for energiz-r ing said means, and means responsive to the brush, and means responsive to the E. M. F. voltage across said auxiliary brushes for disacross said auxiliary brushes for distorting torting the flux due to said first mentioned said field flux. means. 7. In a variable speed generator, field 2. In a variable speed generator, means poles for providing field flux, an armature, for providing field flux, an armature, main main brushes commutating armature conbrushes cooperating with said armature, ductors located substantially midway beauxiliary brushes cooperating with said tween said field poles auxiliary brushes offmain brushes to supply current for enerset from said main brushes, a set of field gizing said means, means for opposing arwindings for exciting said poles connected mature cross flux and voltage responsive between each main brush and an auxiliar means for distorting the fiux'of said field brush, and means responsive to the E. M. F.

fluxroviding means. acros said auxiliary brushes for shifting the 3. n a variable speed generator, field flux due to said poles. poles and anarmature, main brushes co- 8 In a variable speed generator, an aroperating with said armatureto commutate mature, a main brush and an auxiliary armature conductors placed substantially brush, field windings connected between said midway between adjacent poles, a pair of brushes, a second main brush and a second auxiliary brushes, each cooperating with a auxiliary brush, other field windings conmain brush to provide excitation for said nected' between said second brushes, and

field poles, and means responsive to the means responsive to the E. M. F. across said E. M. F. across said auxiliary brushes for auxiliary brushes for distorting the flux shifting the points of maximum potential. due to said field windings to vary the poten- In a variable speed generator, field tial difference between each main brush and poles and an armature, main brushes 00- its cooperating auxiliary brush. operating with said armature, a, pair of 9. In a varlable speed generator, inhomauxiliary brushes each cooperating with a bination, means for providing field? flux, main brush to provide excitation for said an armature, main brushes, auxiliary field poles, and means responsive to the brushes, said means beingresponsive to the M. F. across said auxiliary brushes forpotential difference between said main and distorting the flux due to said field poles. auxiliary brushes, and means connected 5. In a variable speed generator, field across said auxiliary brushes for distorting poles and an armature, main brushes .cothe flux due to said first mentioned means.

operating with said armature, a pair of 10. In a variable speed generator, means auxiliary brushes each cooperating with a for providing field flux, an armature, main main brush to provide excltation ,for said brushes cooperating with said armature,

field poles, means for opposing armature auxiliary brushes, two sets of field windings,

cross flux, and means responsive to the each set being connected between an auxil- E. M. F. across said auxiliary brushes for iary brush and a main brush, means for opdistorting the flux due to said field poles. posing armature cross-flux and means re-' In avariable speed generator, field sponsive to thevoltage across said auxiliary poles for providing field flux, an armature, brushes for distorting the flux due to said main brushes commutating armature confield windings to vary the difi'erence of poductors placed substantially midway betential between each main brush and its cortween adjacent poles, auxiliary brushes oifresponding auxiliary brus set from said main brushes, aset of field In witness whereof, I have hereunto subwindings for exciting said poles connected scribed my name.

,between each main brushand an auxiliary WILLIAM A. TURBAYNE.

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