USRE11783E - Electric motor - Google Patents

Description

No. ",783. Beissued Nov. 7, I899.

T. DUNCAN.

ELECTRIC MOTOR.

\ (Application filed. Oct. 12, 1899.)

WITNESSES I I i INVEN c @ATTOZPY field-coils.

UNITED STATES PATENT OFFICE.

THOMAS DUNCANQOF CHICAGO, ILLINOIS.

ELECTRIC MOTOR.

SPECIFICATION forming part of Reissued Letters Patent No. 1 1,783, dated November 7, 1899. Original No. 623,528, dated April 25, 18991 Application for reissue filed Dctoherl2, 1899. Serial No. 733,448-

To all whom it may concern.-

Be it known that I, THOMAS DUNUAN, a

citizen of the United States, formerly residing at Fort Wayne, in the county of Allen, in the State of Indiana, and now residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Electric Motors; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, which form part of the specification.

My invention relates to improvements in induction power-motors, and particularly to that class in which a revoluble closed armature is actuated by means of two magnetic fields differing in phase and supplied from'a single-phase source of alternating currents.

.The' principal object of the present invention is the production of amotor in which the two magnetic fields will be ninety degrees apart, thereby resembling in this feature a two-phase motora'equiring a two-phase system for its successful operation.

It is now recognized in the art that the most efiicient type of induction-motor is the polyphase motor which requires a polyphase systern, of alternating currents for its successful operation; but since there are a great many single-phase plants in which it is impossible to economically or successfully utilize these polyphase motors there is a growing demand for a motor having similar phase relations to those of a quarter-phase motor, but which is adapted to single-phase supply systems instead of quarter-phase.

In the accompanying drawings, forming part of this specification, Figure 1 is a plan view of my invention as applied to a fourpole motor. Fig. 2 is a diagrammatic view of Fig. 1, showing the various windings of the Fig. 3 shows diagrammatically the phase relations of the various currents which actuate the armature, the same to be hereinafter more fully described.

Referring now to the accompanying drawings, a generator 1 is shown for supplying current to the primary mains 2 and-3 for the translating device 5, and a transformer 2 is proved motor.

magnet 16, arranged, as shown, with four pro.

'13 inseries with a condenser 12.

also shown as supplying current to my im- My motor has a suitable field'- jecting pole-pieces of ordinary construction. These pole-piecesare shown as diametric to the armature and at right angles in the present drawings; but-obviously a greater number of poles may be employed, depending upon the size of the motor and the rate of alternations of the system. .Upon the horizon talprojecting poles I employ suitable coils Upon the other diametrically opposite poles are ar-- ranged the coils 7 and 11, the coils 11 having a smaller number. of turns relatively to the The said condenser 12 is so adj usted,v

coils 13. that its capacity just neutralizes the self-imduction of the said coils 11 and 13, or, in other words, untilthe current through the said coils 11 and -13 is in phase with the line electromo tive force of the transformer 2. The magnetism of this current which is in step or phase with its electromotive force is represented in Fig. 3 by the line 13, and a ninety-degree lag is obtained. by my improvement in the mag netism of the poles carrying the-said coils 7 and 11, as follows: There being little or no capacity in the circuit 9, 8, and 6, the pres ence of the iron pole-pieces as cores to the said coils 7 gives the current through these coils a lag which may have such an angle as is shown in Fig. 3 by the line 7, or an angle of about seventy degrees behind the current and magnetism of the coils 13, and to make the magnetism of the coils 7 reach ninety degrees or quadrature I wind upon the same pole piece with them a second coil 11, whose current is in phase with the line-pressure, as hereinbefore set forth. The convolutions of tion to those of the coils 13,and the magnetism produced by the said coils 11 is shown in Fig. 3 by the line, and by completing the par-' allelograin with the two remaining dotted lines the resultant line 17 represents the combined magnetisnf of the coils 7 and 11. This gives a true two-phase field or two magnetizations in quadrature, one being in phase with the electromotive force and the other being. ninety degrees behind it. These magnetizations combine into a rotary magnetic I these coils 11 are wound in an opposite direc- I field adapted to actuate the revoluble arma i,s liown a condenser in series with'thesaidj ture 15; It is not necessary that the current and magnetism of .the coils 13 be in phase with-the electromotive force; but it may be either slightly ahead or behind the same, in

5 which case the turns 01E the coil 11 may be proportione dxo adjust the magnetism of the said coils 7-and11 to uadrature irrespective 'oLthelineelectromoth e force. I

vfl he' coils'13 and li and the condenser 12 are c jojnn-ectedto the circuit with the wires 10 and 1 4:", andthe other magnetizing-circuit is connected withjits coils'7 by the wires 6 and 9. The. drawings represent a motor ex-perimentallyadj usted withouthaving any varie circuitsg but'obviouslyshould any of these auxiliary. adj u'sting. devices be desirable orv necessaryfthey can be used in anywell-un- M r n-manned 9i 581d poles "i g a Phase-laggin .jupo thefother of said pales coils 1 ;1 a'ndl3, the coils 7 mounted upon the .sauiefpo les as the" said can mm codpable-resistance fir-"choke coils'in any of the J "ativ'e relation with the said phasing-coils 11. for the purpose set forth, the magnetism of the said coils 7 and 11 being adapted to form r a resultant that is ninety degrees behind the n magnetism of the said coils 13; and a revoluble armature actuated by the resultantfrotating. magnetic field of the said coils 13,

currentsgtliea. c'onibination= of; a plurality: of r a t 3 t I Fs 9 i n serieswitEthe said coils'lB an I erative relation therewith; and a re'vo'luble closed-circuited armature, arranged in inductive relation to said energizing-coils.

; 2. In a two-phase induction-motor for single-phase alternate currents, the combination of a field-frame provided with a plurality of inwardly projecting peripheral pole pieces;

magnetizing-coi1s 13 wound upon one 'half of the said pole-pieces; the phase-lagging coils '11 connected in series with the'said coils and mounted or wound upon the other half of said pole-pieces; a condenser in series with the said coils l1 and 13 the magnetizing-coils 7--receiyin g curreiit froin the same source as the said coils 11 and 13, and mounted upon the same pole-piecesas shown and in cooperand 11,

- 'In testimony that Iclairn the foregoing as my'invexftion I affix my signature, inthe pres enceof two subscribingwitnesses', this 3d day 60 v-THOlt I AS DUNCAN;

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