US1390050A - Transformer - Google Patents

Description

C. E. LEE.

mmsfonmsa. APPLICATION FILED SEPI- IO. |91?. 1,390,050. PatentdSept. 6,1921.

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Inventor: Curl ISS E.L,

His Attoneg.

UNITED STATES PATENT OFFICE.

CORLISS E. LEE, OF PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.

rRANsFoaMEa Specification of Letters Patent.

Patented Sept. 6, 1921.

Application led September 10, 1917. Serial No. 190,419.

To all whom t may concern.'

Be it known that I, ConLIss E. LEE, a citizen of the United States, residing at Pittsfield, in the county of Berkshire, State of Massachusetts, have invented certain new and useful Improvements in Transformers, of which the following is a specification.

My invention relates to polyphase transformers, reactors and other analogous de vices, and one object of my invention is to provide an imiroved polyphase device of this nature. more particular object of my invention is to provide a polyphase transformer which may be constructed of substantially the same parts as are used in single phase transformers'of the'so-called distributed core type. The so-called distributed core type of single phase transformer is well known and for the present purposes may be defined as a transformer comprising a single inner core leg carrying the winding and a plurality, generally three or four, outer core legs and corresponding yokes completin independent magnetic circuits through t e winding leg. Another more particular object of Vmy invention is to provide a polyphase transformer in which one ormore phases of the system may be opened without affecting the operation of the other phase or phases.

Preferably in carrying out my invention I employ substantially a distributed core single phase transformer for each of the phases of the system on which the transformer is used, omitting one or more of the outer legs of each of the single phase parts or transformers and joining together yokes of different transformers corresponding to omitted legs so as to magnetically couple the different transformers to some extent. Preferably I retain such of the outer legs of each of the single phase transformers as correspond to yokes not required for magnetically coupling the transformers. By thus employing substantially the Same parts, and to some extent the same assembly of parts, as are used for single phase transformers I am able to reduce the costs, and by employing something of the distributed core type of construction I secure in polyphase transformers something of the advantages heretofore secured in single phase 4phases and the: polyphase transformer is better able to operate on a part only of all the ha'ses when the other electrlcal circuit or circuits are disconnected or open; the two vlatter advantages of myinvention can be obtained of course even though the polyphase transformer is not made up of single phase transformer parts. It is possible by my invention to provide a three phase `transformer of substantially balanced magnetic circuits as appears hereinafter.

In the accompanyin drawing and the following description Iiave illustrated and described in some detail the best embodiments of my invention of which I am now aware. Figure l is a perspective view of a preferred form of my invention embodied in a three phase transformer. Fig. 2 is a perspective view of a modification` of the construction of Fig. 1. Fig,y 3 is a plan view of a three phase transformer embodying another form of the distributed type of core commonly found in single hase transformers. Figs. 4and5 are p an views of three phase transformers embodying still another form of single phase distributed core transformer construction; the arrangements of the single phase parts are also d1f ferent from anything villustrated before. Figs. 6 and-7 are elevations of adjacent layers of laminations of the transformer of Fig. 1. Fig. 8 is an elevation of a lamination layer of the transformer of Fig. 3. Figs. 9 to ll are elevations of layers of laminations of transformers resembling that shown in Fig. 3.

The three phase transformer of Fig. 1 is made up, substantially, of three single phase parts or transformers 7, 8 and 9, each of which is substantially like that shown in Fi s. l and 2 of the drawing of the patent to lall #861,029, July 23, 1907, except that the core of each is made up of L-shaped lamination sections instead of U and rectangular shaped 'sections as in that patent.

transformers comprise a number of. eoref sections for each single phase part as appears from thedrawings and as may be more completely understood from the above Hall patent, these sections interlocking to' provide each of these transformers or parts 7. 8 and 9 with a central winding leg 10 and four yoke members 11, 12, 13 and 14 at each end of the winding leg 10. This form of construction is well known and need be no further described. `The winding leUs 10 carry the windings 15. ln thev singe phase part or transformer 7 of F ig. 1 of the drawing of the specification the two yokes 11`are Joined by an outer leg 17; likewise the two yokes 12 are joined by an outer leg 18 and the yokes lby an outer leg 19. The leg normally joining the two yokes 14 of the transformer 7 (that is the leg `that would be found joining the yokes 14 if the part 7 comprised a complete single phase transformer `as may beunderstood from the above Hall patent) has been omitted as appears from` Fig. 1 of the present draw ing; this outer leg has been omitted by ornitf ting or taking away all the L-shaped lamination sections, the leg portions of which normally comprise this outer leg. The omission of these lamination sections results in the creation of spaces in the yoke members 14; these spaces are filled by the interleaved laniinations or lamination sections 25 which are later referred to in more detail. The single phase part 9 of Fig. 1 is similar to the part 7 except that the leg 18 joining the yokes 12 has been omitted and the yokcs 14 are joined by the usual outer leg 20. In the single pbase part 8 of Fig. 1 the two yokes 11 are joined by the usual outer log 17 and the two vokes 13 are lioined by the usual outer leg 19; but both of the legs usually joiningr the yokes 1.2 and the yokcs 14: ha rc been omitted. Thev three single phase parts 7. S and 9 are so assembled together that the outer ends of the yokes correspondingr to each omitted leg of nach transformer are adjacent the outer ends oi' yoke mem bers corresponding to au omitted leg of another transformer; that is, the outer ends of the yokes 12 of the single phase part or transformer 8 are assembled adjacent Vthe outer ends of the yoke members 14 of the single phase part or transformer 7, and likewise the outer ends of the yoke members 12 of the single phase part or transformer 9 are assembled adjacent the outer ends of the yoke member 14 of the single phase part or transformer 8. Further the single phase parts or transformers are so assembled that the spaces in-j the different `adjacent yoke members which occurby reason of the omission or taking away of the L-shaped lamination sectionsbttheomitted .,lcgs,A are dis- Yposed opposite eachother, and these spaces are illed by interleaved laminations or lamination sections 25 of a rectangular shape as before indicated. In order to illustrate this assembly, the laminations of the Vtransformer of Fig. 1 are shownas of much greater-'thicknesses than is usual in practice. ln the transformer of Fig. 1 the L-shaped lamination sections are illustrated as assembled and reversed in pairs, hence the interleaved 'laminations or 'lamination sections 25 are-inserted in pairs. The assembly of the1 lamiriation'vsections of this trans formerof Fig. 1 may oe rn'ere easily under'- stood from a'consideration'of Figsp and 7.

Fig. 6 is a section takenV on theline A-P of Fig.' 1 between two layer-s, looking in the fdirection 'of the'arrow 6; Fig. 7 is falseetion Von line fA'B 'of-F ig. 1 looking in the direction offtl'e arrowf7; hence Figs. G and 7 illustrate adjacent lamination layers. The vertical lined crosslsectioned parts 27 of Figs. 6 and 7 represeifitE in crossse'ction the intermeshing ribsI 27 f (see Fig. 1) of the winding legs corresponding to the 'yoke members'l. Since these 'yoke"members 13 and t'lieii` corresponding outer legs' ltlilke the yoke members 11- and the corresponding onterlegs 17)` are unchanged in the construction of the'three pliase transformer, no

further 'notice 'need be taken 'of them. The remaining parts ofFigs. 6 and 7 illustrate adjacent laminationsand as appears from the location'of the line A-B on Fig. 1. illustrate laminations which are reversed,

ftop and bottomywith respect to each other.

leferring first to thel lamination layer of Fig. 6; an L-shaped section 30'having a wide leg vportion and with its yoke portion 31 nppermost, cooperates with and at its ends butts against another L-shaped lamination section 32 also having a broad vertical leg (formingr a part of the winding log 10 of the part 7) but with its yoke portion at the bottom of the figure. These two lamination sections 3U and 32 complete onev of the lainiY nation layers ofthe section of the single phase transformer T comprising the outer lee' 1S, and this constructionis the same whether the single phase part 7 is used as a single phase transformer (with the addition of the usual leg joining yokcs 14) or whether lthis single phasepart 7 comprises a part of vertical leg (since this single phase section 7 is substantially similar to the construction shown in the above mentioned Hall patent), also forming a part of the Winding legr 10 of the single phase part 7; the yoke portion of the lamination section 33 is at the bottom of the figure. In the lsingle phase transformer or art 8 is a lamination section 34 corresponding to the lamination section 33, that is having a narrow vertical leg and a yoken poition at the bottom of the figure; the two yoke portions of the sections 33 and 34 abut as illustrated in Fig. 6. Between the upper ends of the vertical legs of the sections 33 and 34 is one of the interleaved rectangular laminations or ilamination sections 25. As appears from Fig. 6 this lamination section 25 and the lamination Sections 33 and 34 complete a magnetic circuit through the winding legs 10 of the single phase parts or transformers 7 and 8 so that these two single phase parts or transformers are magnetically interlinked thereby. The usual lamination sections 35 and 36 of the parts 8 and 9 are related in 'the same manner as the lamination sections 33 and 34 and as appears from Fig. 6; that is, the lower yoke portions abut each other and a rectangular lamination section 25 joins the upper ends of the vertical legs 35 and 36. Following the construction described in the Hall patent the lamination sections 35 and 36 have broad verticalleg portions. The outer section of the transformer part 9 comprising the outer leg 20, comprises the usual lamination sections 37 and38 arranged quite like the sections 30 and 32. It should be observed that the lamination sections 25 and the assembly together of the parts 33 and 34 and the parts 35 and 36 not only result in magnetically connecting the winding leg of the transformer part 8 with the winding leg of the transformer part 7 and the winding leg of the transformer part 8 with the winding leg of the transformer part 9, but also the winding leg of the transformer part 7 is magnetically connecte-d with the winding legr of the transformer part 9 thereby. As before mentioned and` for Well-known reasons, such as to secure better magnetic action and greater mechanical strength. the lamination layers of the transformer of Fig. 1 are reversed in pairs, top and bottom. to break the joints; that is, two lamination layers similar to Fig. 6 are located adjacent each other, then against one of these are located two similar layers reversed top and bottom, then two unreversed lamination layers against these latter, etc., as may be observed in Fig. l. A reversed lamination laver is illustrated in Fig. 7. The lamination sections of Fig. 7 bear the same reference numerals as the lamination sections of Fig. 6 and these lamination sections are similarly assembled except for the reversal top and bottom. This reversal will be unYY derstood from a comparison of Figs. 6 and 7. A comparison of these two figures shows that the lower parts of the lamination sections shown in Fig. 6 appear as upper parts in Fig. 7; and likewise the upper parts of the sections of Fig. 6 are the lower parts in Fig. 7. Thus the yoke portions of the lamination sections 33 and 34 abut each other at the bottom of Fig. 6 and at the top of Fig. l7; correspondingly, the lamination sections 25 of Fig. 7 are at the bottom of the figure rather than at the top of the figure as in Fig. 6, It appears from this that when the lamination layers of Fig. 7 is applied against the face of the lamination layer of Fig. 6, each laminationsection 25 lies against and spans the joint between yoke portions of lamination sections 33 and 34, or between 35 and 36.

It thus appears that the three phase transformer of Fig. 1 is substantially made up of parts of and of substantially the same assembly of these parts of, three similar single phase distributed core transformers (7, 8 and 9), these single phase transformers being modified substantially only by omitting the L-shaped lamination sections (similar to 30 and 38 of Figs. 6) corresponding to one outer leg of each of the single phase transformers 7 and 9 and two outer legs of thesingle phase transformer 8, lamination sections 25 being interleaved into the yokes 12 and 14 at the spaces created by the omission of the yoke portions of the omitted lamination sections.

The three phase transformer of Fig. 2 is substantially similar to that of Fig. l except that the two outer single phase parts or transformers 7 and 9 engage the part or transformer 8 at adjacent core sections rather than at opposite core sections as in Fig l; this results in producing a threepliase transformer which has generally a triangular outline rather than the generall)f rectangular outline of the transformer of Fig` 1. The transformer of Fig. 2 further is distinguished `from the transformer of Fig. l in that the lamination layers :irc reversed individually and alternately rather than alternately in pairs :is in the trans former of Fig. l. The adjacent yoke members correspondingr to th(` omitted legs of the different transformers are joined by interleaved lamination sections 25 :is in the con struction of thc transformer of Fig. l. The construction of the transformer of Fig. 2 will be understood without further de Scription.

The three-phase transformer. the plan view of which is shown in Fig. 3. is quite similar to that shown in Fig. l except the three single phase parts or transformers are of a different form. These single phase parts or transformers are of the general Construction disclosed in the patent to Hall #755.766, March 29, 1904, except that the cores are made up of L-shaped pumhiiigs rather than of the U-shaped and rectangular punchings illustrated `in that Hall patent. [is before indicated with respect to the parts of the polyphase transformer of Fig. 1, the construction of these single phase transformers from' L-shaped punching's is well-known. Fig. 8 shows in elevation one lamination layer taken on the line C-D of Fig. 3. 1t will be observed that this lamination layer is composed of L-shaped lamination sections 40 and interleaved rectangular sections 25 which are assembled -in substantially the same Way as in Fig. 6; of course, since the four coreseetions of the core of each single phase part do not intermesh or interlock, ribs 27, such as appear in Fig. (l, do not appear in Fig. 48. The lamination layers are reversed, top and bottom (as the lamination layers 'of Fig.- 6 are reversed individually or in groups) .groups of small members of 4layers as before described. This construction possesses one advantage over the construction of F ig. 1 heretofore described, in that the ma etic flux passing, for example, from the Winding leg of the single phase part 7 to the Winding leg of the single phase part9 is required to traverse a smaller number of joints.

In Figs. 9 and 10 are shown in elevation another construction of the lamination layers by which a better magnetic connection is secured in a three-phase transformer quite closely resembling that of Fig. 3. These lamination layers maybesubstituted in the transformerlof Fig. 3 in the place of those illustrated in that figure and in Fig. 8. These lamination layers arealso made up of L-sbaped sections and rectangular sections but the legs 0f the sections forming the winding legs are of different Widths; thus the lamination section 45 has a larger width of winding legr than the lamination section 4G. The adjacent lamination layers are reversed as before in order to break joints but they are reversed not only top and bottom but also end to end. Thus the lamination layer of Fig. 10 is similar to thc lamination layer of Fig. il except that it is reversed both top and bottom and end and end; in the winding leg of the single phase part or transformer 7. the narrow leg lamination #i6 of the lamination layer of Fig. 9 is found to the left of the broad leg lamination section 45 and the yoke portions of these lamination sections are at the bottom of the figure. while in the lamination layer of Fig. 10 the broad leg lamination section 45 is found at the left of the narrow leg section 46 and their yoke portions are at the top of the figure. It will be apparent that when the long longitudinal portion of the three phase transformer core of Fig. 3 is built up of the lamination layers of Figs. fandyl() alternating either imlividually or in small groups. all the joints of the magnetic circuit are broken or bridged and magnetically the core will function better between the dilferent winding legs.

j A `still furtheiform of laminationlayer 1for substantiaily such a three-phase trans- A,former as is shown .in Fig. .3, is illustrated in elevation in Fig. 11. rlhis lamination layer comprises a plurality of L-shapes 50 assembled substantially7 as before indicated t0 form the winding legs and.yolr es vofthe single` phase parts or transformers'?, Sand 9. j The outer end legs ofthe cores voaf the single phase parts or transformers 7 and 9 are made up of L-shapes`51, the legs of which are longer than thelegs ofthe L-shaped sections 50-,by the Width of l'the yokeA portions of the L-shaped sections. This lamination layer is distinguished from the layers previously described. particularly by the long interleaved lamination sectionA 52. As appears from Fig. 11 this interleaved lamination section 52 extends between the ends ,of the yoke portions of the lamination sections 51 and completely across the ends of the leg. portions ofthejla-minationsections 5() forming the three Winding legs. Thus atone side of the lamination layerthere is an uninterrupted magnetic path connecting the ends of all the Winding legs. Such lamination layers are reversed top and bottoml as more particularlydescribediwith respect to Figs. 6 and 7, these reversals occurring as before either alternately with respect to individual lamination layers or alternately with respect to small groups of lamination layers. By this construction there is a somewhat still better magnetic circuit provided for the magnetic flux passing between the different Winding legs. y M

Figs. 4 and 5 are plans of three-phase transformers embodying other forms of my invention, these polyphase transformers cornprising single phase transformers of the sort disclosed in Patent No. 1,282,086 issued in the name of Sven 11], Johannesen` on October 22, 1918, particularly those illustrated in Figs. 1 and 2 of the drawing of that application. Since this sort of single phase transformer is clearly described in that co-pending application il is not necessary to further describe it here.

These figures illustrate not only the application of my invention to this particular form of the distributed coretype of transformer, but also illustrate how it is possible by mv invention to provide a three-phase trans ormer of substantially balanced magnctic circuits.

Referring first to Fig. 4: In the threephase transformer construction illustrated in this ligure. tivo of the three outer legs of each single phase part or tranformer 50, 5l

and 52 are omitted.. The single phaseV parts or transformersare so disposed with respect to each other that thefwindingilegs are substantially atu the apeXes ofl an-'equilateral triangle and the ends offthev yoke vmembers correspondingto theomitted legs of each Y A ort transformer are dis posed adjacenterds'ffl yoke members of the other tivo single phase parts or transformers as appears from Fig. 4. As described in detail with relation to the construction of Fig. l, interleaved lamination sections 251 are disposed in the spaces of the yoke members of the single phase parts and magnetically connect the Winding legs. These interleaved laminations sections 251 extend from substantially adjacent the outer surface 55 of one winding leg to substantially the outer surface 55 of another winding leg, that is completely fill the spaces created by the omission of the outer leg lamination sections. In consequence of the three section form of the single phase transformers and in further consequence of the relative locations of the single phase transformers with respect to each other, the members 0f each set of interleaved laminations 251, that is, the members of each lot of laminations 251 which join each two certain Winding legs, are of a num ber of different lengths and furthermore are bent at an angle as illustrated at 56; to this extent these interleaved lamination sections 251 differ from the sections 25 of the construction of Fig. l and other constructions before described wherein the interleaved lamination sections 25 are of the uniform length and Without bends. The dotted lines 57 indicate the outer ends of the yoke portions of the L-shaped lamination sections passing through the winding leg of the single phase transformers, at least under the usual single phase conditions.

The single phase parts or transformers of the three phase construction of Fig. 5 are differently disposed. As before, the Winding legs of the three transformers are disposed at the apexes of an equilateral triangle, but in this case only one outer leg of each of the single phase parts 0r transformers 50, 5l and 52 is omitted. The ends of the yoke members corresponding to the omitted legs of the three single phase parts are disposed adjacent each ot er at the center of the tri- As before, interleaved lamination sections 251 are inserted to magnetically join the winding legs. ln a manner somewhat similar to that of the construction of Fig. 4 the lamination sections 251 are bent and of varied lengths. lt will be observed that each yoke member in the construction of Fig. 5 is directly joined to two other yoke members by means of the interleaved lamiv nation sections 251; this is a distinctive fcature of this construction. Various referangle.

ence characters which appear on Fig. 4 also appear 0n Fig. 5 and represent tbc same elements or features.

lt should be understood that While in the above and in the following claims l have referred substantially only to transformers, my invention may be embodied in polyphase reactorsfor other analogous devices, and aim in the appended claims to include such other devices.

While l have described the principle of my invention and the best mode l have c0ntemplated for applying this principle, other modifications will occur to those sliillcdin this art and I aim in the appended claims to cover all modifications which do not involve a departure from the spirit and scopo of my invention.

What ll claim as new and desire to secure by Letters Patent in the United States, is:

l. A polyphase transformer comprising substantially a plurality of distributed core transformer elements, yoke members of each of said transformer elements being joined end to end to yoke members of another of said transformer elements.

2. A polyphase transformer composed of a plurality of distributed core type transformer elements a portion of the core of each of said elements having free yoke members, said yoke members being joined together end to end in the polyphase transformer.

3. A polyphase transformer comprising a plurality of winding legs. `windings on each of said legs, yokes and an outer leg completing an individual magnetic circuit for each of said winding leffs, and yokes joining said winding legs toget ier.

4. A polyphase transformer composed of a plurality of single-phase distributed core type transformer elements, the core of each element being laminated and having a predetermined number of open and closed magnetic circuits, the open circuited core portions providing yokes with free ends; said yokes of different elements being abntted and joined together end to end in the polyphase transformer.

5. A polyphase transformer composed of a plurality of single-phase distributed core type transformer elen'icnts, the core of each element being laminated and having a pre determined number of open and closed mag; netic circuits, the open circuited core portions providingA yolres with free ends; said yokes of differenl elements beingv abutted, and laminated material interleaved therewith whereby said elements are joined togethcr.

6. A three-phase transformer composed of three singenhase distributed core type transformer elements. the core of each element being laminated and having 'n mag iii-tic circuits '@2 only of which in one element ure eleseil, @11H1 only being closed iu the ether elements; said elements being united with magnetic material associated with the open circuits whereby said open eircuits are closed through adjacent elements.

T, A polyphase transformer comprising a plurality of distributed core type transformerelements mid inagneticfmaterial uniting said elements arranged whereby said elements have a plurality of Viimgnetie circuits iti-common.

In witness whereof, I have hereunto set my hand this sixth vday of September, 1917.

eoRLIss E. LEE.

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