US815729A - Transformer. - Google Patents

Description

W. S. MOODY.

PATENTED MAR. 20.1906.

TRANSFORMEB..

PLIOATION FILED DBO.13, 1901.

2 SHEETS-SHEET 1.

W'nesses;

H PSC Si PATENTE!) MAR. 2G, 1906.

W. S. MOODY.

TRANSFORMBR.

APPLIUATION FILED 1150.111901.

2 SHEETS-SHEET 24 y Invenof; D Waler .Mooclfb NFFFL gritElllll" FFQF.

WALTER S. MOODY, F SCHENEUFADY, NEW YORK,`ASSlGNOR T() GEN- n L ELECTRIC COMPANY, A CORPORATON OF .NEW YORK.

remmer-'ostina l No. 815,729. Specification of Letters Patent. iatented March 20, 1906. l

Application led December 13, 1901i Eeriel No. 85,787.

To all whom t may concern: u casing surrounding` the transformer. .ln Be it-lrnown that I, YWALTER S. MOODY, a practice the apparatus shown 'in Fi 3 is 5 5 citizen of theUnited States, residing at Schen usually immersed in a body of suitablg -pre y ectady, county 01"' Schenectady, State of New pared oil contained in the cast-iron casing York, have invented certain new and uset'ul C of Figs. l and 2, the oil serving to insu- Improvements in Transformers, of which the late the windings from each other and from following is a specification the core and casing and to absorb the' heat 6o This invention relates toimprovements in generated in the windings and convey it to electrical apparatus for transforming 'from the cast-iron casing, whence it is dissipated io high to low potential, and vice versa. into the outside atmosphere. The inside The improvements consist in the peculiar cylinder is separated from the legs F of the construction and arrangement oi the high core A by an annular space Q, Fig. fl, formed and low potential windings whereby imporby the spacing-pieces B, Figs. 3 and 4, of intant advantages are obtainedgboth in elecsulation-iinpregnated wood or. other suitable I 5 trical operation and in mechanical structure. material. The oil or other cooling fluid thus 0f the drawings, Figure /1 is an elevation of has tree access to all parts of the core and to the transformer-casing,,partly in section, to the inner surface of the inside cylinder and 7o show the transformer itself inside the casing, serves to insulate the latter from the core. a part of the transformer itself being also in Each cylinder comprises a high and a low po- -zo section to show the construction and arrangetential coil, so that there are two high-potenment ot the windings to which the invention tial windings and two low-potential windings relates. Fig. 2 is a top plan view ot the casconcentrically arranged on a given part of 75 ing with the cover removed to show the top the core. V5] hen as formerly there were only of the transformer and the conducting-leads two windings-one of high Voltage and one of 2 5 to both the high and low potential windings. low voltage-arranged concentrically on a Fig. 3 is an elevation of a core of one type of given part ofthe core,it was necessary to cmtranstormer to which the invention may be tploy thick insulation between them, owing to 8o applied, the windings being shown in crossthe great difference in potential between the lsection on the core. Fig.- 4 is a bottom View last turns, and this thick insulation not only 3o of the core and windings ot' Fig. 3, showing occupied valuabley winding space, but by the bottom conductingeads. FigisavercansinCr the distance between the high and e tical longitudinal section of a primary coil. low potential coils to bc considerable pro- Fig. l6 is a similar section of a secondary coil, duced considerable reactance. W' ith longer and Fig. v7 is a plan'of an insulating part. coils, where the total amount of copper in one lhe various features of theY invention can `coil could be closel associated with-the total .3S

. be applied advantageonslyto the core-type amount ot copper in the other coil, there is transformers shown in the drawings, in which less reactance between the windings; but even 9o type the core constitutes a single magnetic `when the practical limit of length is reached circuit, and these features may also be emtheA amount of insulation required to protect 4o ploycd with transtormers'ot other types. the low-potential winding from the high-po- The windings are arranged. as most clearly tential. winding is so great as to separate the shown in Figs. 3 and 4, the inside cylinwindin sto such an extent as to produce con- 95 der comprising two coils, being separated siderab e reactance, besides occupying Valufrom the outside cylinder, also comprisable winding space. Ey the arrangement 45 ing two coils, by an annular space O, Fig. shown thereactance is much reduced, as the Li, formed by the spacing-pieces l?, Figs. 3 necessary insulation between the high and and et, oli insulation-imprevnated wood lor low potential coils comprising each cylinder me other suitable material.' T is space serves is much less. The low-potential coil or secto insulate the outer surface of the inside cylondary S t the inside cylinder lies nearer the 5o inder from the inner surface oi the outside core` than the high-potential coil or primary cylinder and exposes a large'extent of the .Pf'of the same cylinder, thus requiring,T less surfaces of both cylinders to the cooling or? insulation (solid Yor fluid.) between itselil .rnd fects of' air or oil or other cooling fluid in the the core than it'. the high-potential winding tential winding.- outside cylinder lies nearer the iron casing C,

' half Aof the total primary winding to the cooli ing action lof the oil or other luid. A most .a secondary coil. between the two parts of the primary permits each primary andsec'ondary coil to be located .and outside of the primary,

The secondary S2 of the were located nearer the core than the low-poi' l thus requiring less insulation (solid or fluid) between itself and the casing than if the highpotential winding were nearer the casing than the low potential winding. The arrangement brings the two primary coils P P2 next to each other, but lseparated'from each other by the space O. This space is, in fact, a duct through the center ofy the high potential winding and accomplishes the important result of providing insulation between parts of I the primary which may have a great difference of potential. The space O also exposes importantfeature of this arrangement is that the space-O produces the above benecial results without increasing the reactance, which itgwould do if itwerebetween a primary and I The location'ofl the space close together, separated onlyby the minimum amount of material required for adequate insulation. There aretwo'important results attending the locationr of the two coils of the primary between the secondary'coils. The rst result -is the lack of the necessity of placing thick insulation on both the inside which would take up valuable winding-space. The primary if placed next the core would have to be heavily insulated from both the .core and secondary; but with the arrangement described it is necessary only to insulate the insideof the primary of the inner cylinder and the outside of the primary of the outer cylinder, since the space O serves to insulate the two primary coils from each other. The second impor- 'tant result is that the casing C can be made smaller, with a less'space between it and the if the high-potential primary were nearest the casing. The construction of the coils is such as to obtain I greatly-improved results both as to electrical operation and mechanical strength. Y

.1t has been customary to wind transformercoils ofinsulated copper wires of circular crosssection, either winding the wire directly on the core in cases where the single-circuit core f was composed of four bundles ofsheet-metal.

laminations or winding the wire separately and slipping the coil over the core. The coils in the present case are constructed of a flat p strip of copper or other suitable conductor, as lshown in Figs. 5 and 6, which strip is formed into abarrel or cylindrical winding, as described, by winding the 'strip edgewise by means ofthe apparatus disclosed in the patent to John Frank, No. 771,902, October 1l, 1904, orbyany other winding apparatus suitable for the purpose.I Such awinding has suil serves to insulate the l coil from each other, but also o insulate the ic parts in its cient mechanical strength and rigidity to resist strains from handling during manufacturing, &c., which formerly changed the shape of the old-style coils, so that it was necessary in order to make possible the assembly of one coil over another to allow considerable difference in diameter between the two coils. The edgewoundcoil is thus' economical in radial transformer-space. It is also very economical in longitudinal winding-space, and it has been found that a much larger effective amount of copper can be, wound in a given space b winding a strip on edge than by the old-style winding. The edge-wound coil also tends to reduce eddy-currents andv leaves a large part' of the coil exposed for ventilation.

The windings shown in Fig. 3 are made in practice inthe following manner, taking, for example, the outside cylinder,"cJomprising the coils P2 and S2: The coil .P2 is first wound on 'the mandrel of the proper winding apparatus. When this coil is to be the high-potential and low-current winding, it is composed as shown in Fig. 5, of a single edgewound copper strip 1. This strip is preferably covered before winding edgewise with ordinary cotton isulation 2, which not only 4 turns of the wound edges of the turns from metal proximity. The spaces thus formed between the turns serve to reduce eddy-currents. It is preferable that the edges of the turns of this high-potential coil be insulated, although i t may not be absolutely essential in all casesas, for example,'if the coil be separated a sufiicient distance from other metallic parts. The use of insulation possible a closer approximation of thehig'h and low potential coils, thus not only economizing space, 'but reducing reactance and increasing the eificiency of the apparatus. The next step is the placing of the insulation X, Fig. 3, around the outside of the coil P2, which is done without removing the coil from the mandrel of the winding apparatus! Thus insulation need not be as thick in proportion to the thickness of the coils as is indicated in the drawings, where it is exaggerated for clearness, and it need bevonly thick enough to properly insulate the high from the Alow potential winding. The insulation may consist of press-board, or one or two sheets of oilsilk, vor of any other suitable material. In some cases the insulation may be sufficient, so that the insulation 2, Fig. 5, on the edges of the high-potential turns may be dispensed with but even in this case the turns of the coil must be suitably insulated from each other. After the insulation X has been properly secured in place, as by Ataping in the the well-known manner, the coil S2, composed, as shown in Fig. 6, of a plurality of copper strips in multiple with eachother IOO over the edges makes IIO when it is to be the low-potential and high-current winding, is wound over the insulation X and the coil P2 without removing the latter from the mandrel. The coil S2 is woun d over the coil P2 so tightly that both coils, with the interposed insulation X, constitute a single .Tigid mechanical structure, which is not only very convenient to handle during the process of constructing the transformer, but also enables the high and low potential coils to he located so closely together that their mutual reactance is reduced to a minimum.

The bunches oi" parallel strips l of the coil S2 are separated from each other by insulation in a novel manner. Rings 3, Fig. 7, of flat horn fiber or other suitable material are split, as shown at 4, and. these rings are disposed yseries along the length of the bunches, the

end of one split ring adjoining the end of another split ring, so that, as shown in Fig. 6, the series of rings l'orm a substantially continuous helix, which completely insulates the bunches of strips from each other.

Another important advantage of the edgewoundcoil is that, owing to its smooth periphery, the insulation X, such as press-board, between the coils is not creased, as was formerly d one by the wires or irregular insulation of the old-style coils. This is important.because the creasing ofthe press-board or other insulation seriously impairs its insulating qualities, while i'fit is not creased it may be of much less thickness, and valuable space can consequently be saved.

The copper strips of the low-potential coil S2 are preferably covered with a cotton or other suitable insulation 2 before winding them on edge; but if they are wound bare the turns of the completed coil may be separated by independent insulating-strips, or byan applied varnish, or by an insulating glaze or enamel if the latter can be successfully placed on the strip so that it will not crack oli' when the strip is wound edgewise. The cotton covering of the several strips which compose one bunch is not essential as insulation, but serves to reduce eddy-currents. The inner cylinder, consisting of the primary P and secondary S,with interposed insulation, is constructed in the same manner as the outer cylinder above described, except that the lowpotential' coil S is wound rst, and this cyli der may be slipped in place over a core-leg l?" without any enveloping insulation, if desired, as the low-potential winding S will be suliciently insulated from the core by the spacing-pieces B and by the oil or other fluid in i the space Q Jformed by these pieces. l prefer, however, to wind each cylinder with cotton tape T, mainly -for the purpose oi holding` the copper strips in alinement, although, o1Ll course, such tape will serve to a degreeas an insulation. It will be noted that the insulation X extends down beyond the edges of the l coils and that the space between this -insulation and the spacing-pieces B and D is iilled with wooden blocks Y. This construction is i'or the purpose of preventing leakage to the secondary from the high-potential primary and at the same time strengthening the projecting parts of the insulation X. Each leg F of the primary shown is similarly equipped with two cylinders. lt will be noted that owing to the edgewise winding of the strip and to the peculiar arrangement of the coils each turn of all the coils is directly exposed, save for the cotton insulation 2 and the thin winding oi tape T, to the cooling action of the oil or other cooling fluid in the casing. y

The transformer shown in the drawings is especially adapted to three-wire service, and to this end I .have shown the coil connections in accordance with my Patent No. 595,403, granted December 14, 1897, which discloses a means of obtaining automatic regulation when the loads on the two sides of the threewire circuit are unbalanced. ther means may, however, be employed.

ln accordance with my patent above noted the primary coils are all connected in series, as shown in Figs. 2 and 4 oiC the drawings. The circuit is from the main Pm of Fig. 2 down through the right-hand coil P of Figs. 3 and 4, (the latter of which is a bottom view,) out through the end M3 of the copper strip comprising said coil to the end M of the copper strip com rising the left-hand coil F2, up through t e latter coil to the top cross-con'- to the end M2 of the strip composing said coil t'o the end M ofthe strip which composes the left-hand coil P, the main Pn, Fig

The'secondary line-terminals are shown in Fig. 2, 'G and H being the outside lines of the three-wire circuit and N the neutral. The secondary coil S on one leg of the core is connected in series with the secondary coil S2 on the other leg of the core across one side 032 the three-wire circuit, and the secondary coil S2 on the former leg is connected in series with the secondary coil S on the latter leg across the other side of the circuit. In Fig. 4 are shown the cross connection VV, which joins the bottom leads Sx SY and the connection W, which joins the bottom leads SX SY. The circuits may be traced as follows: from the line-terminal G, F ig. 2, to the top lead SX of the right-hand inside coil S, down through this coil, F ig. 4, to the bottom leadS", across the bottom connection W to the bottom lead SY, up through the' left-hand outside coil S2, Fig. 4, to the to lead Sy', and thence to the neutral termina N. The other side of 'the circuit leads from the line-terminal H, Fig. 2,

ductor M4 of Fig. 2, across to the right-handl coil P2, Figs. 3 and 4, down through the latter' IOO and up through the latter to IIO to the top lead Sx of the left-hand inside coil tom lead Sy of the right-hand outside coil S2, up through this c'oil, Fig. 2, to the top lead SY, and thence to the neutral terminal N.

.The vcasing C may be of cast-iron and may have the wave shape E, as shown. The cover V is removably Asecured to the casing by suitable bolts, and when the cover is removed the entire apparatus, .together with the supporting-clamps U andV L, canbe lifted out of the casing. The term cylindrical employed yherein is not intendedv to limit the shape of the coils to-a tr'ue annular cross-section, but is intended to indicate merely the general barrel shape thereof. i Y

What I claim as new, and desire to secure vby Letters Patent of the United States, is-

"'1. Ina transformer, the combination with the core', of a winding comprising a high and a low potential coil and arrangedon the core, and a second winding also comprising a high and a low potential coil, said second winding being arranged outside the first, and sepa rated therefrom by a cooling and insulating space'.

2. lIn a transformer, the combinationvwith the core, of a winding comprising a low and a high potential coil, said winding being arranged on the core and separated therefrom 3o by a cooling and insulating space; and a second winding also comprising a low and a highpotential coil,said second winding being arranged outside the first and concentric therewith.

the core, of a cylindrical winding comprising a low and a high potential coil, said winding being arranged on the core .and separated therefrom by a cooling and insulating space and a second cylindrical winding also comprisinga high and a low potential coil, said second Winding being arranged outside the first, and separated therefrom by a cooling and insulating space.

4. In a transformer, the combination with the core, of a cylindrical winding comprising a high and a low potential coil, said winding being arranged on the core 5 and a second cylindrical winding also comprising a high and a low potential coil, said second winding being arranged outside the first and concentric therewith.

5. In a transformer, the combination with the core, of high and low potential windings consistingof cylindrical coils arranged one outside the other, one of the windings being subdivided into mechanically separate adja cent coils separated by an annular cooling and. insulating space.

6. In a transformer, the combination with the core, of high and low potential windings consisting of cylindrical coils. arranged one outside the other, the high-potential winding being subdivided into two separate coils 3. In a transformer, the combination with` which are separated by anannular-coolingv 5 and insulating space.4

7. AIn a transformer, the combination with the core, of a cylindrical low-potential coil arranged on the core, a cylindrical high-potenlpotential coil surrounding the second highpotential coil.

8. In a transformer, the combination with the core, ofa cylindrical low-potentialcoil separated from the core by a cooling and insu ating space, a cylindrical high-potential coil surrounding said secondary, a second cylindrical high-potential coil'surrounding the first high-potential coil and separated there? from by a cooling and insulating space; and a second low-potential coil surrounding said second high-potential coil.

9. In a transformer, the combination with the core, of av cylindrical windingmounted thereon and consisting of two cylindrical coils each composed of one or more edge-wound conducting-strips, said coils fitting one within the other to provide a single structure, and a second cylindrical winding constructed 'like the first, and separated therefrom by a cooling and insulating s ace.

' 10. In a trans ormer, the combination,

with the core, of a cylindrical winding mount; ed thereon consisting of an inside low-potential and an outside high-potential coil,

each coil consisting of lone or more edgewound conducting-strips; and a second cyllndrical winding surrounding 'the first and IOO separated therefrom by a cooling and insulating space, said second winding consisting of an inside high-potential coiland an outside low-potential coil, each of which consists of Y one or more edge-wound conducting-strips.

h 11. In a core-type transformer, the combination with the core constituting a single, magnetic circuit, of cylindrical windings disposed on different parts of said core, each winding comprising a low-potential coil and a high-potential coil; and other cylindrical windings a'lso ,comprising each a low-potential coil and a high-potential coil, and arranged respectivelyoutside the first windings.

12. In a core-type transformer, the combination with the core constituting a single magnetic circuit of cylindrical windings disposed on different parts of said core,each wind-- ing comprising an inside low-potential coil and lan outside high-potential coil; and other cylindrical windings comprising. each an insideI highotential coil and an outside lowpotential coi ,and arranged respectively outside the first'windings, the two high-potential coils of each set of cylindrical windings being separated by a cooling'and insulating space.

yprises a cylindrical 13. A transformer winding which comcoil consisting of an ed ewound flat strip, an' insulation covering or the exterior of the coil, and a second coil consisting of a lat stri wound edgewise over said insulation and fldrming therewith a unitary structure.

14. In a transformer, the combination,

with the core, of a cylindrical lowotential winding arranged next the core an consisting of one or more edge-wound flat strips, and a cylindrical high-potential .winding consisting of one or more ilat strips tightly wound edgeWise over said secondary winding and forming therewith a unitary structure.

15.. In a transformer, the combination with the core, of a Winding comprising a cylindrical coil consisting of a single edge-wound strip, and a cooperating winding comprising a cylindrical coi consisting of a plurality of interconnected edge-Wound strips.

` 16. In a transformer, the combination `withthe core, of a cylindrical low-potential winding arranged nearest the core, a cylindrical high-potential winding arranged outside of and concentric with said low-potential Winding, the highotential winding beirlgl divided into two coi s separated by an ann ar space; and a low-potential winding arranged outside of and concentric with the high-potential winding.

17 A cylindrical coil composed of a plurality of insulated conducting-strips arranged side by side in a bunch and wound on edge.

18. In a stationary induction apparatus, the combination with the core, of a Winding subdivided by an intermediate annular s ace, and a second Winding divided into coi s located inside and outside the irst winding.

19. A coil for stationary induction apparatus which comprises one or more conductingstrips wound on edge, and a continuous insulating-helix comprising a series of split rings arranged end to end.

20. A plurality of insulated strip conductors arranged side by side and wound `on edge so as to form a coil.

`21. Aplurality of stri I side by side and woun I between the strips, and heavier insulation between the turns of the coil.

Witness whereof I have hereunto set my this 11th day of December, 1901.

WALTER S. MOODY.

conductors arranged into a coil, insulation hand Witnesses BENJAMIN B. HULL, MARGARET E. WOOLLEY.

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