US923614A - Armature construction. - Google Patents

Description

B. .A.- BEHREND.

ARMATURE CONSTRUCTION. APPLIGATION FILED SEPT. 19, 1904.

Patented June 1, 1909.

2 SHEETS-SHEET 1.

WQ & V y 6 W [torn e 1m: NnRRls pzrcRs ca, wAsnnvsYcN. 12 c B. A. BEHREND.

AEMATURE GONSTRUGTION.

APPLICATION FILED SEPT. 19, 1904.

923,614. Patented June 1, 1909.

2 SHEETS-SHEET 2.

In wen tor.- Witnesses fiern ard A-Befirenzi L7. I fliiorney TO THE BULLOCK ELECTRIC HANU:

' OR, BY MESNE ASSIGNhlENTS, Ci MPANY, A CORPORATION OF OHIO,

AND ALLIS-OHALI\IERS COMPANY, A CORPOPA'.FIO\ (F NEW JE BE CCNSTRUOTION.

My invention relates to dyname-electric above enumerated.

0 this end, 1 employ means tor increasn e reluctance of the my invention Bniinnlvn, citizen of the oniteo States, re 3 magnetic path thron 1e iron cl" the armasiding at Norwood, in the county o Hamil- T; ture near the periphery of the d magnet in ten and State 0 1 Ohio, have inyented certa n such manner to lstantially a new and useful Itinprevemenin Armature l unilorm densit llur; between Oonstruction, of which the tollow'ng is a full, the held noles diror t .e iron of said clear, and exact specification. l 1 "e machines, and more particularly to the coin struction ano arrangementot the armatures of such machines.

It has been customary in constructing armatures of dynamo-electric machines, espe cially the armatu es of large alternaters, to build the core of segmental lan'iiiue, fastened. to a fixed frame it a rotating iield is used, or fastened to a shaft or spider it a rotating armature is employed. These laininze are ar ranged with the adjacent ed e of the so merits oi each layer either in contact separated a short distzn e, th joint between adjacent se men layer being of uniform width length. The laminze in adjacen shifted or staggered so as t rigidity of the armature structu 'e and break L the joint between the armatur r In such a construction as just describe especially in high speed. in: chines, 1 i alternators in which a small number of are employed on tne field magnet, i lack of uniformity in the density t t. magnetic flux through the arinatni sort In fact, it may be aid that the magnetic flux in passing through the armature core between the field magnet poles, i'ollmvs tr paths, one being short and of hi h "t and the other being long and low density. The former pr thi low reluctance and is close to t Winding While the latter is of high rel and remote from said winding. T l I netic material of the armature core tends toward saturation near the armature winding While the parts away from said winding are far from saturation. This condition is undesirable as it augments the core loss due to hysteresis and eddy currents in the ar mature, thus reducing the efficiency of the machine.

The object of my invention is to increase the efliciency of a dynamo-electric machine by overcoming the objectionable feature sot r call considered,

airiature of a dynamoercctric machine having ere built up ot segmental laminte in rich the space or breal' between adjacent segments in the an r is e )1 ihery of the tiom said invnitioii formed alo part dynamo-elec tri o my inven armature illustrat' seginen V inatie v nnroved armature coni ti'uction face view of a stationary armature segment punched in accord.- ance with my invcntior ngs, 6 represents the shaft r magnet l he laininze 7 mounted uph sai'l shatt are slotted at 8 to receive the iz'indings 9, which are held in the slots by the 'ed s The windings are n'eferably so connected 1 north pole is produced at N and a sent 1 pole at S. The core of the armature it. is built or the segmental laininie ll, fastened to the supporting frame if in any desired nanner, here i The segments in adshow 4 do e-tailed.

1. r .r yaeent layers are he dotted lines indicating the segments in the next layer belowsegments 11. Thesegments 11 are slotted at 13 to receive the windings 1 which are held in position in the slots by means ofwedges 15. Thesegments 11 are preferably so punched that when assembled in a single layer in theframe 12, the space or break 16 between adjacent segments is greater or wider at 17 near the periphery of the field magnet l, or near theslots 18 containing the armature l l, than at 18 a point at a distance from the periphery of the field magnet 3, or remote from the slotted edge of the armature segment.

In igs. and 4:, l have illustrated dia grammatically a two-pole rotatable field magnet l3, having poles N and S, and a stationary armature A built up of laminze, each lamina or layer being divided into foursegments 11. 3 represents the customary construction in which the segments in a single layer are spaced apart a slight distance, the space or joint between adjacent segments being of constant width throughout its length. in such a construction it may be assumed that the magnetic flux between the poles of the field magnet i follows two paths through the iron of the armature on either side of the field magnet axis, one path indicated diagrammatically by line G, being short, of small reluctance and high density, the other path indicated by line D being long, of great reluctance and low density. It will thus be seen that the iron of the armature A near the periphery of the field magnet F and along the path C tends toward saturation, while the iron along path D is far from saturation. Furthermore the mass of iron composing the armature core is not being efiiciently employed. In l I have shown a similar machine with the armature constructed in accordance with my invention. To produce a path of substantially uniform reluctance and permit a substantially uniform llUX density between poles I increase the reluctance of the path C in any desired manner preferably by so designing the break, orgap 16 between adjacent segments that it is wider at 17 near the periphery of the field magnet F and diminishes in width gradually along the line of said break or gap in a direction away from said periphcry. The path of uniform reluctance thus produced is indicated diagrammatically by he E. This construction reduces the tendency toward saturation near the field magnet periphery, reduces the core loss due to hysteresis and eddy currents in the ar1na ture, and increases the efiiciency of the machine. By permitting the iron of the armature to be worked more efifectively, the machine may be built with less iron in the armature for a given capacity than with the construction shown in 3.

In Fig. 5 l have illustrated on an enlarged r l r I i I J i 1 scale one of thearmature segments 11 of the machine shown in Fig. 1. The broken lines ab represent radial lines from the center of the rotating field it will be clearly seen that the edges of said segment are not allel to the radial lines throughout their length, but make an appreciable angle with said radial lines adjacent to the slotted edge of the segment.

Although this invention is here shown as applied to machines which have approximately radial joints or gaps between adjacent segments, it must be understood that it is equally applicable to machines of other types and constructions and the magnetic reluctance of the path of the flux through the armature core may be increased in any de sirable practical manner. My invention is also equally applicable to machines having fined field magnets and rotating armatures as may be readily seen from Fig. 2, in which thearmature segments 11 are shown as mounted on the arms of aspider 20. The armature coils are indicated as before by 14, and are shown held in theslots 13 by means of thewedges 15.

I aim in the appended claims to cover all modifications of my invention which do not depart from its spirit and scope.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. In a dynamo-electric machine, a field magnet, an armature, said armature providing for the flux passing through the armature between any two field poles, paths of difierent lengths but of equal reluctances so that a substantially uniform flux density in the armature is obtained.

2. In a dynamo-electric machine, a field magnet, an armature having its core built up of laminae, said core providing for the flux passin through the armature between any wo field poles, paths of different lengths and having spaces which equalize the reluctances i of said paths and cause a substantially uniform flux density.

3. In a dynamo-electric machine, a field magnet, and an armature, having its core built up of segmental laminae having portions of the adjacent edges of the segments of a single layer cut-away in such a manner that the magnetic path for the fiuX between the field magnet poles has substantially uniform reluctance through the armature core.

4. In a dynamo-electric machine, a field magnet, and an armature having its core built up of segmental laminae and in which the space or break between adjacent segments in the same layer is of gradually de creasing width from the periphery of the field magnet inward.

5. In a dynamo-electric machine, a field magnet, an armature having its core built of laminae and providing for the flux passing through the armature between any two field poles, paths which are of different lengths and extend into the armature different distances remote from the periphery of the field magnet but are of equal reluctances, so that the flux density in the armature at different distances remote from the field magnet is substantially the same as adjacent the field magnet.

6. In a dynamo-electric machine, a field magnet, an armature having its core built of laminm, said armature providing for the flux passing through the armature between any two field poles, paths which extend into the I armature different distances remote from the periphery of the field magnet, and having slots which equalize the reluctances of said paths so that the fluX density in the armature at different distances remote from the field magnet is substantially the same as adjacent the field magnet.

7. As an article of manufacture, a punched armature segment having two edges forming arcs of concentric circles, one of which is provided with slots forming teeth, and one of said arcs subtending a smaller angle than the other.

In testimony whereof I affm: my signature, in the presence of two witnesses.

BERNARD ARTHUR BEHREND. YVitnesses:

LILLIAN J. BmTToN, FRED. J. KINsEY.

Images