US489065A - Alternating-current dynamo - Google Patents

Description

2 Sheets-Sheet. 1.

(No Model.)

\ J. J. WOOD. QALTBRNATING CURRENT DYNAMO. No. 489,065.

" Patented Jan. 3, 1893.

FIG. I.

WITNESSES:

(No Model.) 2 Sheets-Sheet 2.

' J. J. WOOD.

ALTERNATING CURRENT DYNAMO.

No. 489,065. 4 PatentedJan.3,1893.-

INVENTOR:

WITNESSES: I v ml I 6;44164 71 M 2 77s.! By lus iomeys,

To all whom it may concem:

, UNITED STATES PATENT O ICE,

JAMESYJ. wooD,'oF FORT waY-nn-innmna.

ALTERNATING-CURRENT DAYNAMVO.

SPECIFICATION forming part of Letters Patent No. 489,065, dated January 3, 1898.

Application illed July 22, 1892- Be it known thatl, JAMES J. W001), a citizen of the United States, residing at Fort Wayne,- in the county of Allen and State of Indiana, have invented certain new and usefull mprovements in Alternating-Current Dynamos, of which the following is a specification.

This invention relates to dynamo electric machines for generating alternating currents,

or by the addition of a current rectifying commutator, for generating pulsatory currentsof uniform direction It relates especially to dynamos of that class wherein the armature is a stationary ring, and

the field-magnet is mounted to revolve with' in this ring, and-has outwardly turned polar armsof. successively alternated polarities terminating closely adjacent to the inner'fac'e of the armature core.

My present invention provides an improved construction of revolving field-magnet for dynames of this class.

Figure 1 of the accompanying drawings is an end elevation of a dynamo constructed according to my invention partly in section on the line 1-1 in Fig. 2; Fig. 2 is a side elevation thereof, the field-magnet and armature being in diametrical mid-section on the line 2-2 in Fig. 1; Fig. 3-is a vertical transverse section through the armature and field-magnet on theline 3-3 in Fig. 2.

LetF designate the field-magnet as awhole, A the armature, a a the armature coils, E E.

the exciting coils of the field-magnet, and O.

; clamped between annular frames 1) I) having feet I) which rest on and are bolted to the standard B. The frames or rings b may be made of cast iron, the laminated armature core 0 being embraced between them and as toned by insulated bolts It passed through them from side to side. The core is formed Serial No- 440,92 1t (Ho model-l ring 'shaped core, as illustrated in my applicationSerial No. 369,823,filed'0ctober 30, 1890.

The field-magnet F is mounted on the retative shaft D of the dynamo, which shaft turns in bearings formed on brackets B B which are fastened to thebase B. The fieldv preferably of steel, through which the shaft D passes, and from which.-it is preferably magnetically separated by sleeves-dd of gun metal or other non-magnetizable material.

placed caps or disks g g, preferably of steel, which ,are formed respectively with polar arms N N and-S S branching from them. The arms of the two disks are of equal number branching from one disk being of north polarity, and the arms S S branching from the other disk of south polarity. When the two disks are applied, the arms of one disk are alternated with those of the other, forming polar ends projecting between polar ends of the other disk with like intervening spaces. The arms branch from, the disk first in outward direction, then backwardly toward the middle of the core, and then are-gradually core, terminating in exterior polar faces which being turned off in a lathe constitute seg ments of a cylinderof such diameter as to fit freely but closely within the armature so that the field-magnet may be rotated therein. The field-magnet is wound with one or more we citing coils which are applied around the exterior of thecore 1 between the opposite disks g g and within the polar arms N S. Two coils are shown, a main coil E and a regulatmagnet is constructed with a tubular core f,

Against the opposite ends of this core are,

and are uniformly spaced, the arms N N turned outward and project away from the 5 tened against the continuous inner face of a ing coil E; These coils receive continuous or pulsatory currents of uniform direction from any suitable source. The field-magnet being in place within the armature,-the polar faces of its arms N S revolve closely adjacent to the armature projections and coils. Each armature coil receives consequently the inductive action of alternately north and south poles in rapid succession, thereby generating alternating currents in the armature coils in the manner well understood.

Dynamo machines have before been made wherein afield magnet consisting of a core having polar arms branching from its opposite ends and terminating i1 external polar faces of alternately contrary polarities, has revolved within a ring-shaped armature. In such machines, however, the armature and field-magnet have been made of equal width, and the polar arms of the fieldmagnet have been simply turned back at the ends and extended across the exterior of the exciting coil thereof, instead of projecting outwardly away therefrom, and presenting merely theiroutturned polar ends toa narrow armature, as in my improved construction. The constructions heretofore made have involved a serious loss of efiiciency by reason of the leakage of lines of magnetic force between the polar arms, and from arm to arm through the armature core without cutting the armature coils, with the result that the defect is avoided.

efficiency of such machines has been so low as to render them commercially impracticable in competition with other alternating machines. Myinvention provides an improved construction whereby this serious practical The polar arms instead of being laid backwardly close against the exterior of the exciting coil,are turned outwardly away therefrom at or near the middle thereof, and terminate in outwardly radiating polar ends. 4 The armature core is reduced from the entire width of the field-magnetto a width of approximately only one quarter thereof,

and the polar ends or faces of the arms N- S are made of the same restricted width as the armat nre core. In this manner the lines of force are confined and concentrated, being forced to pass from the armsN N to the arms S S by entering the armature core, and consequently passing through and cutting the armature coils, so that very nearly all of the lines of force are made effective in the generation of electric potential. The field-magnet is further strengthened by constructing it with the disksg g, which are turned inwardly or toward the medial plane of the field-magnet, so that these disks are cupped, as best shown in Fig. 2, so that they partly inclose the end portions of the exciting coil or coils. The cupping of the disks is effected by the formation of webs w to between the successive arms N N on one disk and S S on the other, these webs being turned inwardly following the direction of the arms, and thereby constituting the cupped portions of the disks, and being also formed with their outlines joining the arms by easy curves, as shown in Figs.1 and 3, so as to distribute the lines of magnetic-force to the arms. The inductive effect of the coil sets npli'nes of magnetic force extending longitudinallythrough the coref,and radially through the disks 1g and by the cupping of these disks to partly embrace the ends of the coils, the exterior portion of the coil is made effective to add to the magnetization of the polar arms by setting up lines of magnetic force in the cupped portions of the disks, which lines are distributed to the respective arms. The fieldmagnet is thus made stronger than it would be without the disks, and without the cup ping of the disks. w

I claim as my invention the followlug dofined novel features substantially as hereinbefore specified, namely:-

1. The combination of a revolving multipolar field magnet with a stationary ring armature within which it rotates, said armature consistingof an annular core much narrower than the field magnet, and successive coils applied to said core, and said field magnet consisting of an axial core, an exciting coil around said core, and alternated: polar arms radiating from the opposite ends of said core, bending back around said coil toward the middle of the core, and having their end portions turned outwardly and terminating in poles facing and closely adjacent to said armature.

2. The combination with an exterior stationary ring armature having successive coils applied to the inner side of its core, of a re: volving field magnet consisting of an axial core of greater length than the width of the armature, an exciting coil around said core, and polar arms radiating from the opposite ends of said core, extended inwardly past the ends of the coil toward the middle thereof, each arm entering between two of those of 0pposite polarity, and the polar ends of the arms turned outwardly away from the exciting coil and terminating in polar faces within and closely adjacent to the armature, whereby the polar ends approach the armature abruptly on its inner side, and the loss by leakage of IIO lines of force between the polar arms and armature core without cutting the armature coils is reduced to the minimum.

3. A field magnet consisting of an axial core, an exciting coil around said core, laterally-expanded heads or disks at the opposite ends of said core, cupped toward the middle thereof so as to partially inclose the ends of I site ends of said core, bending back around said coil toward the middle of the oore, each arm entering between two of those of opposite polarity, and having their end portions turned outwardly to form radiating poles, and webs w w formed integrally with said arms between them at the ends of the coil, partly inclosing the end portionsthereof, and joining the arms with curves sweeping toward the re arms, so that the lines of force induced in said .webs are divided and diverted into the arms.

In witness whereof I have hereunto signed my name in the presence of two subscribing CHAS. J ONES.

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