US313546A - Frank j - Google Patents

Description

(No Model.)

I. J.- SPRAGUE.

ELECTRO DYNAMIC MOTOR.

Patented Mar. 10, 1885 0 0 61 6 cud a6 Jags. 1719.4 1 7155 W6 UNITED STATES PATENT @rrrcn.

FRANK J. SPRAGUE, OF NEIV YORK, N. Y.

ELECTRO-DYNAMIQ MOTOR.

EiPECIPICATION forming part of Letters Patent No. 313,546, dated March 10, 1885.

Application 'filed November 4, 1884.

' New York, in the county and State of New York, have invented a certain new and useful Improvement in Electro-Dynamic Motors, of which the following is a specification.

In an application for Letters Patent filed February 20, 1884, of which this application is a division, I have set forth a method of regulating the speed and power of electro-dynamic motors by the inverse varying of the magnetizing effect of the field-magnet coils of the motor.

The present application relates to the construction and apparatus set forth in the prior one just referred to, but which were not claimed therein, the claims being confined to the method of operation alone. \Vhile the invention herein set forth was designed espe cially for the regulation of motors, it is adapted as well to the regulation of dynamo-electric generators by varying the magnetizing effect of their field-coils.

In carrying out my invention, I wind the field-magnet of a machinepreferably a shunt wound motor-in sections of coils, and make connections therefrom to a suitable commutator in such manner that the sections may be progressively thrown into or out of multiplearc relation with each other. By throwing a greater number of sections from a series relation into multiple arc the magnetizing effect of the fieldcoils is increased, the field is strengthened, and the mechanical effects in the armature are reduced, as is set forth in the application above referred to. The armature being in shunt relation with the fieldcoils, the armature-current is also incidentally effected by the change in resistance of the field. I may, however, employ other means for varying the armature-current, and, preferably, those set forth in my Patent No. 295,454, dated March 18, 1884. Here the relation between the field-sections in series and those in shunt relation to the armature is varied. In that patent is set forth a method of field regulation by the use of adjustable independent fieldcoils; but I prefer the method herein set forth.

To arrange the field-coils so that they may be changed from series to multiple arc with each other, I prefer to have the sections divided into two sets orv ranges, each connected (X0 model.)

with the supplying-circuit at one end and having the other free. By connecting the free end of each range to different points of the opposite range, more or less of the coils are placed in parallel circuit. If I employ together with this regulation the armature-regulation just referred to, the same coummutator may be used for both purposes. The field regulation or regulation of both field and armature maybe accomplished automatically by devices controlled by variations in the speed of the motor. Thus a constant speed is maintained.

The figures of the accompanying drawings are diagrams illustrative of the principles and features of my invention, and I will describe the same in detail.

Figures 1 and 2 represent the arrangement set forth in the application referred to.

O G are main conductorsj a a is the fieldcircuit, and a a a the armature-shunt. In Fig. 2 the armature is shunted around a less number of field-coils, the difference of potential atits circuit terminals is lessened, and it receives less current, and the speed or power is diminished.

The field regulation is illustrated in Figs. 3 and 4.. The fieldeoils are broken at terminals 7) b, and by a suitable commutator, which will be presently described, greater or less portions of the coils are progressively thrown into multiple arc with each other, to decrease the resistance, strengthen the field, and diminish the speed, and progressively removed from such relation to produce a contrary effect. In this arrangement the armature-terminals are considered as fixed;

Figs. 5 and 6 show the same arrangement of field, with the armature capable of being shunted around a greater or less number of the field-coils, illustrating the fact that the,

present mode of regulation may be used in connection with that set forth in the application referred to. Incidentally the regulation of the field has an increased effect, by the increase or diminution of the armature current due to the increase or diminution of the resistance around which it is shunted; but by us ing the field and armature regulation together an enormous effect may be produced on the speed of the armature. By a very slight change'the racing of the armature, even if the whole load is suddenly thrown off, is prevented.

Fig. 7 illustrates the commutator and connections employed with the new method of regulating the field.

O O are the main conductors, and c, c, 0 &c., are sections of field-coils.

The commutator is composed of a circle of metal blocks (Z d d d, 850., two of which are extended into the arcs e e. The connections from the field-sections are made the first and last to single and opposite blocks (1 of the commutator, and each of the others to two blocks, d, d (1 and cl".

The pivoted commutator-arm consists of an insulating central portion, B, and metal extensions f f These ends each bear on one of the arcs and upon the range of contacts. The field-current from 0 passes to h, where (in the present position of the arm) it divides. part passing to contact d extension f, arc c, and coils 0, to the reuniting-point h. The rest passes through coils c to contacts (2, arc 6, extension f, and contacts d cl" to 72 It will be seen that coils c and c are thus placed in multiple are to each other. By moving the commutator-arm in one direction or the'other more or less of the sections of field-coils in which the magnet is wound are multiple-awed upon each other, and the strength of the magnet is increased or diminished. Fig. 8 shows this arrangement in connection with that for changing the relation between the sections of field-coils in series and those in shunt relation to the armature set forth in the patent referred to. Here the additional arms Z Z, insulated from each other, bearing on the contact-blocks and passing under the arm B, are employed. The terminals of the armature M are connected, respectively, with these arms. As the armsZ Z are moved, the armature is shunted around a greater or less number of the field-coils, remaining in series with the remainder. The arms B and Z Z may work simultaneously, if desired. By the use of the commutator shown in Fig. 8, the armature current or the strength of the field, or both, may be regulated, the circuits never being broken, no adjustable resistances being employed, and all the field-coils being constantly in circuit and producing their magnetizing effect.

Fig. 9 illustrates an automatic arrangement which may be employed for moving the arm B to maintain a constant speed. A centrifu gal governor, F, is connected with the motorshaft, so as to be affected by variations in speed. Its moving collar carries two contactarms, m m, insulated from each other, and connected, respectively, with the conductors O 0. These arms enter between the three armsnn a, which also are insulated from one another. G is a small electric motor one of whose terminals is connected with the two arms a n", the other with arm n. The motorshaft is connected by a worm-gearing or other slowing-down gearing with the arm B. The

connecting-spindle is for convenience ofillustration broken off and laid out in dottedlines. An adjustable weight, H, is employed, so that the governor can be set to hold the contactarms centrally at the normal speed of the I110- tor to be regulated for its proper efficiency. Should a variation in the load cause the speed to slightly decrease, the governor-balls fall, and the arms make their lower contacts, closing circuit to motor G, and causing it to revolve in a direction to shift the arm B to decrease the field strength, and so keep the speed at its normal point. When, on the contrary. the speed slightly increases, circuit is closed to the motor G in the opposite direction, and the movement of the arm B causes an increase in the field strength, which keeps the speed still at the normal.

It is evident that the field regulation hereinbefore described is applicable to the field magnets of dynamo-electric generators, and also that the apparatus set forth may be used with series motors or generators when it is desired to throw their field-coils into or out of multiple-arc with one another.

WVhat I claim is- 1. The combination, with an electro dynamic motor having field magnet coils wound in sections, and in shunt relation to the armature, of a commutator and connections, whereby the sections may be progressively thrown into or out of multiple-arc relation with one another, substantially as set forth.

2. A field-magnet having two ranges of sectionally-wound coils, each having one end connecting with the supplying-circuit, in combination with a commutator, connections from the bights of the sections to contact-blocks of said commutator, and movable arms making contact with said blocks, and forming the free ends of the ranges, substantially as set forth.

3. The combination, with an electro-dynamic motor having its field -magnet wound in sections, of means for changing the relation between the number of sections in series with the armature and the number in shunt relation thereto, and means for varying thestrength of the field-magnet, substantially as set forth.

l. The combination, with a fieldmagnet having sectionally-wound coils, of the commutator consisting of the circular range of contact-blocks, the two contact-arcs, movable conductors connecting said arcs with said blocks, and connections, such as shown and described, with the sections of field-magnet coils, substantially as set forth.

5. The combination of the circular range of contact-blocks, the contact-arcs, and the pivoted arm consisting of an insulating center and metallic extensions bearing on the arc and blocks, substantially as set forth.

6., The combination, with an electro-dynamic motor having its field-coils in sections and its armature in a shunt around a variable number thereof, of the commutator consisting of the circular range of contacts, the two arcs, the arm having metallic extensions bridging IIO the arcs and contacts, the two arms bearing increased when the load is decreased and de- 011 the contacts, and the armature and field creased when the load is increased, to mainconnections, such as described and shown, tain a practically constant speed, substansubstantially as set forth. tially as set forth.

5 7. The combination, with an electro-dynam- This specification signed and witnessed this ic motor, of circuit-controlling devices for 21st day of August, 1884:. varying the magnetizing effect of the fieldmagnet coils, and apparatus connected with FRANK SPRAGUE' said motor, whose speed varies with the load, WVitnesses: 10 and which affects said circuit-controlling de- WVM. H. 1VIEADO\VOROFT,

vices, whereby the said magnetizing effect is T. G. GREENE, Jr.

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