US1371994A - Direct-current transformer - Google Patents

Description

mme@ Ma. 15, 1921.

5 SHEETS-sum1."

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f/m L /UQLIJLLJ ("b 3 i "I @gg y I IPJITNESSES A. F. NESBIT.

DIRECT CURRE'NT TRANSFORMER..

APPLlcATloN FILED APR. 25, 19.17.

15mm@ f mm@ Maf., @L

5 SHEETS-SHEET 2.

WITNESSES DIRECT CURHEN? TRANSFORWER.

5 SHEETS-81112514.

A. F. NESBH.

nmsc CURRENT RANsFomnER.

APPLICATIH HLED APR. 25, 1917. A J I 'd @named Mal. @5, WZL

'5 SHEETS-SHEE15.

INUENTOR .4;

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Parana orifice.

ARTHUR F. NESBIT. 0F VLKINSBURG. PENNSYLVANIA.

:DIRECT-CURRENT TRANSFORMER.

Application led April 25,

To all whom t may conce/"n Be it known that l, ARTHUR F. NnsBiT, a citizen of the United States, and resident -of llvilkinsburg, in' the county of Allegheny and State of Pennsylvania, have invented' -certain new and useful rImprovements in determined value, from an alternating.

curient. l

Another object of this invention is thev production of a direct current transformer wherein a stationary stator and a stationary or locked rotor are employed, and whereby a unidirectional current of high potential is obtained from an alternatingcurient of any voltage, frequency oi' phase combina tion.

Another object of my invention is to prvide a transformer wheiein the primary or stator and secondary or rotor core's are integrated and whereby a direct current of any desired voltage is obtainable.

A further object of the invention isto provide a high voltage, direct current transformer having improved means whereby sparkless commutation iseffected, this result being accomplished by means of a commutating field which is angularly adjustable about the axis of a primary core and a secondary core.

A further object of the invention is to provide a high potential direct current transformer wherein the mass and number of the moving parts of the apparatus areA reduced. i'

A still further object of my invention is to provide a transformer having the parts and novel constructions, arrangements, and coinbinations of parts illustratedin the drawings` to be described in detail hereinafter, and to be particularly pointed out in theI appended claims.

As is well known to those skilled in the art, in starting induction motors with the rotor at a standstill, theA rotor acts as a locked rotor at the instant the circuit is .Specication of Letters Patent.

Patented Mar. 15, 1921. i917. serial No. 164,430.

closed on the stator windings, and that the rotating magnetic flux set up by the polyphase .currents energizing the stator coils gives rise to a magnetic field which cuts the rotor coils with the same frequency, that is I to say with the frequency of the E. M. F.

impressed upon the stator coils.

In constructing transformers in accordance with my invention a rotor is provided which is fixed or permanently located with reference to the stator. And to that end the laininae of the coies preferably will be inte-- grally formed and will be provided with a series of rectangular or approximately rec-` tangular openings, the openings in the laminze forming the built up cores registering to form a series of-slots or gaps through which 'the windings of the'stator and rotor coils extend.

Referring now' to the drawings, forming part of this specification, Figure l is an' elevation, partly in section and partly diagrammatic, showing a high potential, direct citrient, vertical transformer, e. a transformer having an axially vertical commutator shaft), constructed and arranged in accordance with my invention.

Fig. 2 is adiagrainmatic plan, on a somewhat larger scale (with the coinmutating field core and its windings omitted for the sake of cleainess), showing a preferred grouping of the series of high voltage coils lon the locked rotor, and showing the connections between the rotor coils and the conimutator, y on the commutator shaft in the particular` construction illustrated in Fig. l,

Fig. 3 is a sectional elevation of the cores v and the windings or coils of the stator and rotor cores (shown in the preceding figures,)

and the coinmutating field cores, the section being taken on the line III-III of Fig. 2.

Fig. 4 is a diagrammatic plan, similar to that of-Fig. 2, show'ng the coinmutating field cores and the win ings and connections to the windings on the axially adjustable primary commutating field core.

Fig. 5 is a plan showing details infthe construction and arrangement of the slip rings and commutator segments and leads therefor as mounted on the commutator shaft and shown diagrammatically in Fig. 2.

Fig. 6 is an elevation, partly in section and partly diagrammatic, like that of Fig. 1, showing a horizontal transformer or transformer modified to have an axially horizontal commutator shaft and having a plurality of stator and rotor cores and commutating field cores constructed and arranged in'accordance with my invention.

Fig, 7 is a detail plan showing a commutator shaft having a multiple groupof commutators, slip rings and bus bars 'arranged -thereon in accordance with my invention as constructed for use with theapparatus of Fie. 6.'

i' n the accompanying drawings the letter vA designates the primary or stator'core and B the secondary or locked rotor core7 of the annular, integrated'structurev forming these cores. By integrated, as used herein, is

meant -a laminated rstructure [having each lamina transversely divided into a series of segmentsv and each segment forming part of the core A and also part of the core B. When yconstructed as shown, the cores have windings thereon forming twelve primary or stator coils al, a2, a3, af, a5, a6, a7, as, a9,-

@10,a, and (L12, and equal number of secondary orlcked rotor coils b1, b2, b3, b4, b5, b, 67, bs, 69,2110, b, and Z112.

Mounted aboveand in axial alinement with the stator andi-rotor cores are the commu-'gv tating ield cores C and C1 of my improved transformer. The angularlyadjustable pri-I mary field core C has windings thereon 01, c, and 0,12. 'The lstationary secondary commutating field core .C1 is embraced orA encircled by the windings forming the coils ,61, b2, 3, etc., of the locked rotor B (as is shown in Figs. 1, 2 and 3.)

Extending vertically through the axiallyY central and. axially alined openings in the cores B and C is a rotary commutator shaft.-

D and positioned on this shaft adjacent to its upper end, is a segmental commutating group or commutator E (Figs;'2 and 5) and coperating group of )slip rings E, to which the segments ofthe 'commutatorE are permanently connected electrically. The lower end of the shaft isconnectedto the armature shaft of a synchronous motor G by which the shaft D is rotated. yThis motor, as shown, is positioned below'the oil tank or container Hin which"the .stator A, lockedY rotor B, and commutating field Icores C'and Clare positioned so as to be submerged in the oil. "It will beobvious ',.however, that the motor G maybe supportedV above the 'tank H ,andj be connected to the oppositefilled Withvoil toabout the level indicated byV the broken line 4, to keep the stator A 'and A tank.

H issecured on a support 2 The i rotor B immersed in the oil and provide for effective insulation of the stator and rotor, and the tank has a tight cover or lid 5 on its upper end. n

' Suitable. supports G are provided above or on top of the-locked iotor core upon which the stationary or secondary core Cl of the commutating field core is positioned, and similar supports T above or on top of the stationary stator core A' provide means for supporting thev angularly adjustable, axially movablefprimary commutating field corev and seriesof windings forming its coils c1, c2', c3, etc.

The primary commutating field core .C is arranged to turn 'angularly relative to the stator and rotor cores A and B and the coils al, a2, etc'.,'and 61,'112, etc., thereon, this field core C turning about the vertical axis of the stator and rotor when being adjusted relaltive thereto and a suitable manually operated adjusting mechanism-being provided for turning the commutating field core. C and for locking the core C in adjusted position (see Fig.'1). j l

. As shown, the adjusting mechanism com'- pri'sesfa segmental gear orcurved rack E secured on the periphery of the core C and having teeth in mesh with those of the pinion 9 on one end of .the vertical shaft 10. 95' The shaft is rotatably secured in the bracket bearings 11 and 12whicli are fastened to the vertical wall of the tank H, and extends upwardly to or above the oil leyel et in the The upper end of the shaft 10 is pro- V.100 vided with a. worm' wheel 13 which meshes with the worm 14. on one. end of the hori-v zontal shaft 15, this shaft also being rotatably mounted in the upper bracket bearing v12.Y The shaft 15 extends through a stuffing 105, box and gland on theside wall of the tank HA and is providedfon its outer .end with a hand wheel 16 forA turning the shafts 10 and 15v to adjust the primary eommutating field core C and its'coils c angularly with respect 11.0

` to the stator A and rotor B and coils a and therefor. As the adjustable commutating` field core must be held in its adjusted positions, the worm wheel 13 and worm laconve'niently serve asa lock therefor in addi- 115v tion to transmitting motion from the shaft 15 to theshaft 10. 1

YThe rotary commutator shaft D, which is shown centeredon the vertical axis of the annulus'formingthe cores A and B for the 120 stator and rotor, (and the axis ofthe tank H), extends through a tube 17 in the tank H and is' provided, adjacent to its upper end,\

with theco'mmutator or segmental commutator groupv E and coperating group F of twelve Slip rings, f1, f2', f3, a f5, a fz a a f1, f11, an'd fu The tube 17 is fastened, by a iange 18 on its lower end to the bottom of the tank'H to form an oil iight joint therebetween and aiiange19 on Aitsupper end is secured to the cover or lid 5 of the tank to rigidly fasten the tube in upright position within the tank. The vertical shaft D is rotatably mounted in bearings 20, 2l, which are secured to the ends of the tank H, and a third bearing 22, on the spider 23 is provided for the upper end of the shaft D. The

'spider 23 is secured in position on the upper a1, 0,2, a3, etc., of the stator A and coils b1, b2, b3, etc., of the locked rotor B, when these coils are assembled in operative position on the cores. T o vfacilitate assembling the parts forming the integrated or unitary cores A and B, each lamina should be slitted and in building up the laminated structure the slits in the laminas xshould be `staggered to form overlapping joints.` Such expedient being old and well known in making laminated cores, need not be further described.

The primary or stator circuit as shown, has a series of twelve polyphase windings a1, a2, etc., these coils preferably being connected in Y or in star and the groups of coils having terminals m1, m2, and m2. (See Fig. 2). The secondary or locked rotor circuit has a series of twelve polyphase windings or coils b1, b2, b3, Zat, b5, b, b1, bs, b2, Z912, 511, and Z 12 which are connected in closed series as in a .closed coil Gramme ring-armature, the series of coils b1, b2, etc., being properly insulated against the potential to be carried thereby. p

Positioned immediately above the primary or stator core A and its coils a1, a2, etc.; so as to be adjustable angularly relative to the coils on the core A, is the primary commutating field core C and its series of twelve windings orcoils c1, c2, c3, c1, c5, c, c7, cs, c2, 01, 011, and 012. which also are connected in Y or in star, and the groups of coils having terminals N1, N2, N3 (Fig. 4) rand immedi- .ately above the secondary or locked rotor core B is the secondary or stationary core C1 of the commutating' field core, this core C1, being embraced or encircled by the windings forming the coils b1, b2, etc., of the locked rotor core IB (Figs. l, 2, and 4).

The terminalsv n1, n2, and n3 of the three groups .of coils forming the primary commutating circuit, however, are not located directly above the similar points m1, m2, and m3, on the main primary circuit, but are displaced forward or backward with reference to them. Arllhis will represent a maximum possible magnetic displacement of approximately 90 degrees. The magnetic iiux produced by the windings c1, c2, c2, etc., will lag or lead according to the extent of adjustment with reference to the main primary magnetic flux.

The terminals of each coil of the electrically adjacent rot'or coils b1 and b2, 62 and 3, Z13 and Zfi, b4 and b5, b5 and o, Z2 and?, Z and bs, o8 and b2, ZJ and Z212, 610 and 51,1, 511 and Z212, 512 and b1 are connected together and have a common lead h1, ft2, h3, Zit, h5, LG, h1, its, it, IL10, h11, or k12, and these leads, as shown, are connected each to its individual ring 1, 2, 3,14, 5, 6, 7, 2, 2, 10, 11, and 12. The group of bus rings 1, 2, etc., which encircles the shaft D and tube 17, is located Within the tank H so as to be immersed in the Oilin this tank. Each of the rings 1, 2, etc., has a' lead jl .7.2, 7.37 .7.4i .7.57 .Zas .'(71 js: .7.97 .7.101 .7.11, and .j12, which extends upwardly through an insulated opening in the tank cover or lid 5 and is connected by a carbon brush k1, k2, 7c3, 7a4, kilo, ZcT, las, 102, 751", 7011,' and k12, to one of the slip rings f1, f2, f3, etc.,`in the group F of slip rings fastened on and rotating with the commutator' shaft D.

Obviously the rings and leads j may be omitted, in such case the leads ZL extending to the brushes 7c for the slip rings f.

The slip rings f1, f2, etc., are permanently connected electrically by leads Z1, Z2, Z3, etc., one to each of the commutator segments c1, e2, e3, etc., forming the commutator E on the rotary commutator shaft D adjacent to the slip rings. (See Fig. 5.)

The commutator segments e1,'e2, e3, etc., are insulated from the shaft D and from each other in any of the various known ways and this insulation may conveniently be utilized to support and insulate the leads Z1, Z2, etc. The necessary number of leakage rings 26 will be provided at the ends of the group F of slip rings and on each side of the commutator F, and preferablya leakage ring. 26a will be supplied onthe commutator shaft D between the adjacent slip rings f1, f2, etc., as shown in Fig. 5.

By splitting up the primary windings into a-plurality of groups of coils, instead of vone group for each phase as shown and described in connection with the apparatus of Figs. l, 2, and 3, a multiplicity of rotary fields will be obtained, instead of a single two pole rotary field, this having the effect of decreasing the secondary voltage and increasing the current carrying capacity of the locked rotor or secondary circuit, by permitting the .parallel grouping of the secondary coils.

The brush I on the commutator-E is connected to the negative leadK and the brush directional current generated bymy improved apparatus.

The 'windings forming the primary or stator-coils al, a2, etc., are connected in three groups of four coils each, the coils (L12, al, a2, and a3 forming one group, the coils a4, a, a, anda?, the secondl group and the other coils as, ae, and al, .the third Vgroup. The coils of each group are connected in series, the leads g1, g2, g3, fromfone terminal of the coils a3, al and all at one end ofeach gro'up being connected instar' and onetersource of alternating current.

Connected -in star by leads o1,'o2,'and o3.

The terminals for the synchronous motor G also are connectedl to the sourceof alternating current. j

y In the modified construction shown in Fig. 6 the grouping of the coils von the primary or stator cores, the secondary or locked rotor cores and the primary commutating field cores, is the same as in Figs. .1, 2, 3,A

and 5.

VThe modified apparatus, however, has

two separate stator cores A, and' A-A, two rotor cores B and B B, two primary ield cores C and CC'andtwo secondaryfield cores Gland CClL yFlach rotor core has its series of cores al, a2, i12/etc., eachv stator core its coils b1, 62,773, etc., and eachv primaryfield core its windings or coils "el, c2,

'03, etc., and each stator and rotorl unit has its complement of slip rinV s f, 7f, et'.4 The commutator shaft being #horizontal, is mountedv at itsendsiin bearingsA 20,

21a which are secured 'on the ends fof the high pressure cover -5a for the commutatore,

thel covervbeing supported on the coi er or'- lid jfor the tank Hf The synchronous rncj tor Gr for driving the oommutator shaft 'D also is `mounted on'the tank cover or lid 5, the commutator shaft' being directly'connected to the armature shaft of the motor G. Each of thejangularly adjustable, .com-

.mutating field cores Gand CC in the ap- 1 .paratus of Fig. 6. preferably is geared to.\

the vertical shaft 10 of asingle adjusting mechanism vused therewith so that the com- 'mutat'ing field cores and coils thereon willbe adjusted in unison, inthemannershown Ain Fig. .5. The vcommutating field cores C may be arranged to .be 'adjusted separately and independently, however, lwhen found y necessary or desirable. -In the' apparatus of Figf two commutators or groups of commutator segments F and F-F will be employed one foreach of the two statiom ygether so'that the plete series similar to a closed Gramme" LeT/1,994.

ary or locked rotor cores', B-B, and ,the brush J2 on one terminal of the commutator- F-F lwill be connected by a lead to'the terminal l of the opposite signl for the com` niutator F while the brush J on thel coniniutator F and brush I2 on one terminal for the ,commutator FF will lead to the apparatus ofv utilization of the generated unidirectional current. j l

' rlhe operation of my improved apparatus wi/ll now be described. A source of alter- 'natingor multi-phase current will be connected by means of suitable conductors to the terminals m1, m2, 4and groups of 'coils a on the stator core A, and to the terminals nl, a2, andn, for the similarly arranged groups of' coils C on the angularly adjustable commutating 'field core m3 for the three aoA C, and also to the terminals for the sy'nchronousmotor G.' Then current is supplied in thisv manner'the three series of primary colis a. on thestator A `are energizedfand thereby causedv to produce a twoi coils of the secondary or locked rotor core Bby means of the magnetic path provided'A by the integrated cores A and B and induces electromotive forces inthe coils b1, b2, etc., of the secondary or locked rotor core B.- The time phase relations of the induced electromotive forces in the coils '61, i, etc. relative to one 4another will be proportionate to the relative angular displacement l .of these coils b1, b2, etc. Y y N These secondary or lockedrotor coilsbl, Z22, etc., are spaced or positioned in regard to one another to have an equal angular displacement andthe terminals ofthe electrically adjacent coils are connected to'- twelve coils form aicomring. l f Y At the same time the multi-phase current is supplied to the terminals/a1, a2, and' a3.

ofthe groups of coilsfc on the primary commutating field core Cyand the coils '01,' c2, etc., alsok are energized and are causedto produce a two-polerotating magnetic field in thecores C and C1.` o ,Y v .The iiuX of .this rotating magnetic field also passes progressively through the secondary or locked rotor coils b1, b2, etc.,

through thev medium ofv the magnetic path provided by the cores C and C1;

The rotary magnetic field Ain the commu# tatingfield cores C, C1, however, is not in 'space phase'relation with the primary rotating magnetic field induced inthe stator coils al, a2, a3, etc, but leads or lagsv behind it by approximately 90' degrees, so that in this way the desired sparklesscommutating conditions are obtained. As the displace-V iso ment of thegroup of commutating fieldy coils c1; c2, c3, etc., is not permanent but may be regulated and controlled angularly with respect to the coils of the stator core A by means of the adjustingl mechanism which -has been described, non-sparking commutating conditions equal tothose of the most modern type of standard direct current apparatus are obtained with my improved transformer. i

When found desirable or necessary secondary field coils may be added to the core C1 which will produce a rotating magnetic field at approximately 90 degrees magnetic displacement relative to the field obtained in the primary coils c on the core C so as to obtain sparkless commutation.

The leads 71,1, 7b2, etc., which are connected at one end to the joined terminals of the electrically adjacent coils 1 and b2, b2 'and b3, etc., extend each to itsv individual slip ring f1, 712, f3, etc., (through its ring z'l, i2, i3, etc., when the rings are employed) and through the slip rings f1, f2, f3, etc., and permanent leads Z1, Z2, etc., to its appropriate commutator segment el, e2, e3, etc., formin the commutatorA or commutating group l chronous motor Gr for driving the commutator shaft is connected to a common source of alternating multi-phase current the commutator will be rotatedsynchronously with the current induced in the coils of the rotor, stator and commutating field cores. The E. M. F.s,induced in the secondary or locked rotorcoils b1, b2, 5 3, etc, when connected in the manner described above, will be superposed one upon the other and be rectified to produce a unidirectional E M. F., the value of which is dependent upon the geometrical sum of the individual E. M. F.s

induced in the secondary or locked rotor coils.

It will, of course, be understood that the synchronous motor is used because it must rotate in step with the generator or transformer supplying current to it and to the coils of my improved transformer.

Modifications in the constructions and arrangements of the parts may be made. Obviously the primary and seconda-ry cores and coils therefonmay be interchanged to position the primary windings on the inside and secondary windings on the outside instead of as shown, and the commutating field cores may be similarly interchanged and als(` other combinations may be formed so long as the same magnetic circuit is embraced by the coils, without departing from my invention as defined in the appended claims.

l claim z-l Y l. A transformer comprising a -main field having integrated primary and secondary cores and a plurality of coils on said primary and secondary cores, a commutating on theshaft D, and as the syn-- field having a core and a plurality of coils` ondary. cores, a commutator group connected to the coils of said secondary core, and collectors for s aid commutator group.

2. A transformer comprising a main field having' integrated primary and secondary cores and a plurality of coils on said primary and secondary `cores, a commutating field having a-core and a plurality of coils on said core, said fields being displaced approximately 90 degrees in phase and said commutating field being angularly adjustable about the axis of said primary and secondary core, a commutator` group connected to the coils of said secondary core, collectors for said commutator group, and means for adjusting said commutating field angularlyrelative to said primary and secondary havingintegrated primary and secondary cores 'With windings on said primary core and on said secondary core, a commutating field having an adjustable core and windings on said adjustable core, said fields being displaced approximately 90 degrees in phase and said adjustable core being axially' alined and being axially movable relative to the main field core in adjusting the commutating field, a rotating commutator group and a synchronous motor for actuating the commutator group, said motor being connected to the source of'current for the windings on said primary core. l

5. A transformer comprising a main field -having cores and coils forming a stator and locked rotor, and an adjustable commutating field having a core and coils, said fields being iaxial alinement and being displaced approximately 90 degrees in phase, a rotat ing commutator group connected to the coils of the locked rotor, means for adjusting said commutating field angularly relative to the main field, and means for actuating said rotating commutator group.

6. A transformercomprising a main field having cores and coils forming a stator and locked rotor, and an adjustable commutating field having a Ore and 0011s, Said fields bemg in axial alinement' and being displaced approximatelyl() degrees in phase, a rotating commutator group connected to the-coils of the locked rotor, means for adjusting said 'eommutating field angularly relative to the^ Amain field anda synchronous vmotor or aetuating saidl rotating commutator group,

said motorhaving terminals connected `in parallel with ythe primary coils of said stator.4 Y

7. A transformer comprising a main field. having integrated primary and secondary cores, and 'apluralityof coils on .said cores,`

y my hand.

a commutatingfield having a core and a plurality of ,ooilsf'thereom said fields being and seoondary'eores of said main field, and each vcorresponding'. group of the primary and stator coils :being similarly connected Y' to a source of power, a eommutator group Connected to the coils of said .secondary core,

and collectors for' said eommutator group.

In testimony-whereof have hereunto set ARTHUR F; N'EsBrrj

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