US1473862A

US1473862A - Three-phase reactance coil

Info

Publication number: US1473862A
Authority: US
Inventors: Nyman Alexander
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1916-06-19
Filing date: 1916-06-19
Publication date: 1923-11-13
Anticipated expiration: 1940-11-13

Description

Nov. 13 1923.

A. NYMAN THREE-PHASE REACTANCE COIL' Filed June 19, 1918 2 Sheets-Sheet 1 WITNESSES: y'fiwwf AT'T ORNEY Patented Nov. 13,

UNITED STATES PATENT OFFICEQ;

ALEXANDER NYHAN, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOB TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL VANIA.

THREE-PHASE REACTANCE COIL.

Application filed June 19, 1918. Serial No. 240,835.

To all whom it may concern:

Be it known that I, ALEXANDER NYMAN, a citizen of Finland, and a resident of \Vilki'nsburg, in the count of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Three-Phase Reactance Coils, of which the following is a Specification. 1

My invention relates to current-limiting reactance coils and it has special relation to coils which are adapted to be inserted in polyphase circuits to limit to safe values the abnormal current flow therein that may be occasioned by short circuits or by other unusual conditions conducive to the flow of ab-' normally high currents.

Heretofore, in polyphase power systems and particularly in'3-phase systems, it has been customary to insert, in each line of the polyphase system, acurrent-limiting reactance coil. Such schemes have given rise to large and unwieldy coil units which are especially undesirable where economy of floor space is desired. It has frequently been" necessary, moreover, to space the coils of the separate phases far enough apart to eliminate the inductive interference which may be occasioned b the flux generated by one or more of the 0011s acting upon the other coils.

Furthermore, when it is desired to install 3-phase reactors which shall carry heavy currents, the usual type of construction, in which the coils are placed one above another, has sometimes failed. to give entire satisfaction because of the circulating currents which may beset up in the parallel cables of which each coil is composed: It is, of course, well understood that, forgcurrents exceeding a certain value, two or more cables in parallel are generally used to give sufficient currentcarrying capacity for such a reactor. g

In 3-phase reactance coils, as at present constructed, there has always been more or less of a phase distortion occasioned by the method of placing these coils in position. This has been inevitable since no method has heretofore been developed of so disposing polyphase coils carrying currents which are out of phase with res ect to each other, that the fluxes generated y such currents shall not act inductively upon the associated coil units of the .reactor in an undesirable manner.

Finally, it is often necessary to arrange even direct-current circuits, which contain coils, in such manner that totally independent currents may be carried b such associated coils without any change msuch currents producing an undesirable inductive effect upon associated coils in proximity thereto. 7

It is, therefore, an object of my invention to so dispose a plurality of coil units, either with or without a frame for bracing. the same, in such manner that absolute symmetry shall be maintained between said coil units. This s mmetry will, in turn, cause any undesirab e fluxes which may thread the associated coil units to be perfectly neutralized and, therefore, perfect phase relationship will be maintained between the fluxes generated by the several cbil units. 7

Moreover, by so disposing a plurality of coil units in universal symmetry, the space required for a given current ca acity will be greatly decreased, on account 0 the fact that all of the space, which it is desired shall be occupied by said reactance coils, will be taken up without, in any way, producing inductive interference between closely associated coil units.

Moreover, by so disposing the coils in the above-mentioned arrangement, very heavy currents may be carried'by a number of coils in parallel without said parallel coils being subjected .to the initiation therein of circu+ lating currents which, as has been heretofore noted, are quite undesirable.

Finally, it is an object of myfinvention to provide an arrangement of a plurality-of coil units whereby a number 0 direct-current circuits, which contain coils in proximity to each other and which carry totally independent currents, may be maintained in said desirable proximity without any one of the coils being affected inductively by a change of current condition which may take place in any of the associated coils.

For a better understanding of my invention, reference may be had to the accompanyin drawing in which:

Fig. 1 is a diagram illustrating the mannet in which a reactance coil of my improved construction may be inserted in a polyphase distribution system; Fig. 2 is a plan view of the coil indicated in Fig. 1; Figs. 3 and 4 are elevational sectional views taken on the line 1-1 of Fig. 2 and illustrate the manner in which the coil units are secured in place through the use of vertically extending and horizontall diagram s owin fluxes in four the associated coil units; while Fig. 6 is a vector diagram illustrating the manner in which the fluxes threading the various coil units of Fig. 5 are added vectorially to obtain substantial neutralization.

Referrin now to Fig. 1, a poly-axial reactance coi 1 is shown connected in circuit with the

polyphase lines

2, 3 and 4, said lines carrying current supplied by an alternatingcurrent source 5, here shown as a polyphase alternator.

The reactance coil is composed of a plurality of airs of coil units 6 and 7 8 and 9 and 10 an 11, and it will be observed that the coil units of each pair are oppositely disposed, with their axes in alinement, and that the coil units of the respective pairs are connected in series in the line conductors-2, 3 and 4-.

The coil units 6 7 8, 9, 10 and 11 are supported within a slieleton frame, each of the six sides of which comprises two members disposed at right angles to each other, and at angles of forty-five degrees with reference to the adjacent side planes of the frame. For a more detailed description of the frame, reference may be had to Fig. 2 wherein members 12 are shown as two bars disposed at right angles to each other and each having its ends twisted into a plane at right angles to that of the body portion.

The frame members which constitute the side of the frame that is opposite to the side shown in Fig. 2 are duplicates of those shown and each of the remaining four sides of the frame comprises two bar members 13 that are disposed at right angles to reach other and at forty-five degree angles with reference to the planes of the sides comprising the bar members 12. The ends of each member 13 are bent outwardly into planes that are substantially parallel to the adjacent ends of the bars 12 and the three adjacent bar ends of each set are fastened tother by bolts 14 and are suitably insuated from each other and from the bolts, as indicated.

Cleat-securing members 15, of which there are four for each coil, are secured to the

bar members

12 and 13 by bolts 16-16, and

extending cleats; Fig. 5 is a.

the relationship of the within these retaining members are placed cleats 17 which are provided with recesses 18 in which the coil units are wound and by means of which the coil units, after being wound, are braced against strains which may be imposed thereupon by short circuits occurring on the s stem.

It will be observed that, y constructing a frame in the manner indicated, a minimum amount of material is used and, at the same time, a strong cubical frame is built up upon the interior of which the coil units may be mounted in universal symmetry.

The operation of winding the coil units within the frame to constitute my reactance coil is as follows 2-- The Wire or cable, 4, for instance, is led through an insulator 19, which is located at the intersection of the heretofore described bar members 13, and is then wound aboutthe cleats 17, in turns of successively decreasing diameters, until the desired length of wire or cable has been wound. For purposes of illustration, I have shown three layers of cable so wound as to constitute one of my coil units and while I have shown in Figs. 2 and 3 the cable as wound upon cleat members that are disposed transversely, with refer ence to the coil turns, it will be understood that an alternative construction, com rising cleat members disposed turns, may be employe if desired, such cleat members being shown in Fig. 4.

Furthermore, it will be observed that my coil units are so wound that they are substantially in the form of frustums of pyramids or-cones and, having such form, it possible to dispose six of them within a cubical frame in such manner that practically the entire space within the frame is utilized to its maximum extent. After one coil unit, for instance, unit 11, has been wound in the manner above indicated, the cable is carried across to the four cleats attached to the directly opposing interior face of the frame and the process of Winding is there repeated, with the difference that the conical mructure is reversed, and the diameters of the succeeding turns are now successively increased until the desired length of cable has been wound. The cable is then carried out through an insulator 20 inserted at the intersection of the two cross pieces, as indieated. It will be observed, therefore, that my invention contemplates the use of a plurality of coil units which are arranged in sections by pairs, one of each pair being secured to directly opposing interior faces of a polyhedral frame, and each section thus formed bein inserted in series circuit relationship with one phase of the polyphase system.

Referring to Fig. 5, the manner in which such a poly-axial reactance coil will accom arallel to t e coil 6 threadin 1,47a,ae2

plish the com lete maintenance of phase rementioned

coils

10 and 11, will also have fluxes initiated therein as indicated at 23 and 24, 'respectivel onsidering now the flux of any one coil and remembering that such consideration applies to all of the coil units eqlually, since they are arranged in universa symmetry, it will be observed that flux from coil 10, as well as passing directly across and through its companion coil 11, will also branch out into space in all direc tions, and portions thereof will thread through the coils 8 and 9. Let us desi ate these portions by 25 and 26. It wi l, of

course, be understood that, in the coils which are mutually perpendicular to the four coils shown, a like threading of flux will be produced. In short, each and every coil unit of my poly-axial reactance coil wi l have fluxes therethrough from every other associate coil, the flux coming from its companion coil, which is disposed directly opposite, and the four equal fluxes, which are constrained to thread; therethrough, and which are initiated in, the four coils situated perpendicular thereto.

Referring now to Fig. 6, the manner in which these various fluxes combine to produce a constant mutual inductive effect on each other is illustrated. Similar vectors denote similar fluxes, as noted in Fig. 5. Considering, for instance, the vector indicating the flux 23 which is produced by the coil 8. The flux 25 emanating from coil 10, will thread through the coil 8 and, it will be observed, is in a direction opposite to that of the flux initiated in said coil. Further more, a flux 26 initiated in coil 10 will thread through the coil 9 and there add to the flux 24 from the latter coil. It is obvious, of course, that the

fluxes

25 and 26, since they are initiated by the same current, are in phase with each other and we may, therefore, represent the direction and amount of the same by

vectors

25 and 26. If now, vector 23 is combined with vector 25 the resultant will be vector 27. It will be observed that, in such addition, the vector 25 is, in reality, subtracted vectorially from vector 23.

On the other hand, the vector 26, which represents a flux tending to act in the same direction as flux 24, will be vectorially added thereto and a resultant 28 be obtained by such combination. By the proper vectorial addition of the

fluxes

27 and 28, the combined vector 23-24 is obtained and it will be observed that this is the same flux which we assumed was present in the two oppositely disposed coils 8 and 9, without a consideration of the effect thereupon of fluxes initiated in associated coils.

It will be apparent, therefore, that, by the use of a reactor, as hereinbefore described, polyphase currents may be passed through a plurality of coil units which are disposed in close roximity without, in any way, producing inductive interference between the several coils.

a reactor havin a hexahedral frame to which are secure six coils, I desire that my invention shall not be limited to the specific number of coils or to the specific number of phases which are indicated for urposes of illustration. It isentirely possible that it may be desirable to construct a polyhedral coil which shall be capable of insertion in more than three phases and, since such a coil would require more than the number of coil units which I have used for purposes of illustration, I desire that the broadest possible interpretation be placed upon the appended claims.

While I have herein shown and described Again, I have designated my coils as frusto-conical in form. However, since a cone, genericall speaking, is nothing more than a pyrami havin an infinite number of sides, I wish it to understood that a cone having the form of a pyramid may be used if it is desired to allot the necessary space which such a form of coil would occupy. Moreover, while ,the coils, as shown in the hereinbefore described reactor, are substantially short frustums, it will be furthermore understood that such description does not preclude the use of a coil which may be perfectly conical in shape, since such a coil is nothing more than a frustum of a cone, the upper base of which is of zero area.

Moreover, I desire that the use of the arrangement of a plurality of coils which I have shown shall not be limited to alternating-current practice. There has been frequent demand for an arran ement of coils which are carrying indepen ent direct currents, whereby the circuits and coils carrying such currentscould be disposed in proximity to each other and have no inductive interference occasioned therebetween, and I therefore wish it to be understood that the arrangement of coils herein described and claimed may be readily applied in directcurrent practice.

Furthermore, while I have shown my coil units as comprising equal terms, I have not limited the appended claims to such an arrangement, since it is quite possible that some special designs of coils may demand more or less turns in one unit than in others tion with a and, under such conditions, the only limitin feature would-be the t pe of frame whic would be used; that is, it might be desirable '?ap licable to several situations, I desire that 'on y such limitations shall be placed upon my invention as are imposed by the prior art or are specifically pended claims.

I claim as my invention:

set forth in the apinter- 1. A tri-axial reactance coil having sectin axes.

2. reactor comprising a plurahty of coils mounted on rectilinear, intersecting axes.

3. A reactor, comprising a plurality of coil units, the axes of said coil units being so disposed as to intersect.

4. A reactor, comprising a plurality of coils, having symmetrically disposed, intersecting axes.

5. A reactor comprising a plurality of coil units of substantially frusto-conical shape having independent axes and symmetrically mounted on a cubical frame.

6. A reactor'comprising a plurality of multi-sectioned reactance coils, said sections being symmetrically mounted on a polyhedral frame.

7. A muti-sectioned reactance coil, said sections being mounted on a polyhedral frame, and being attached to faces of said polyhedral frame disposed in relative angularrelation. L

'8. A- multi-sectioned reactance coil comprising equal .sections,-one of said sections being attached to each face of a polyhedral frame. 1

9. In a polyphase reactor, the combination with a plurality of single-phase coils, of a polyhedral frame, each of said coils being so disposed on said frame with respect to the remainder of the coils that the reactance of each coil is independent of the flux generated by every other coil.

10. In a polyphase reactor, the combination-with a plurality of coil units, of a polyhedral frame, one of said coil units bemg attached to each face of said polyhedralfi frame.

11. In a polyphase reactor, the combinalurality of single-phase coils, of a polyhe ral frame, said coil being so disposed with respect to the remainder of the coils on the interior of said frame that the reactance of each coil is independent of the flux generated by every other coil.

12. In a polyphase reactor, the cornbition with a plurality of coil units, of a polyhedral frame, one of said coil units being attached to each face of said polyhedral frame, and said coil units being substantially similar and of such shape that they occupy substantial] the entire available space within said rame,

13. In a polyphase reactor, the combination with aplurality of coil units, of a polyhedral frame, one of said coil units be ing attached to'each face of said polyhedral frame andpsaid coil units being substantially frusto-conical in form.

14. In a polyphase reactor, the combinat1on with a plurality of coil units, of a polyhedral frame, said coil units being arranged on intersecting axes within said frame.

15. In a polyphase reactor, the combination with a plurality of coil units, of a polyhedral frame, said coil units being so arranged on intersecting axes within said frame that they are mutually perpendicular to each other.

16. In a polyphase reactor, the-combination with a plurality of coil units, of a polyhedral frame, said coil units being symmetrically arranged on intersecting axes around a point within said frame.

17. In a polyphase reactor, the combination with a plurality of coil units, of a polyhedral frame, said coil units being disposed on intersecting rectilinear axes and arranged symmetrically around a central point Within said frame.

18. In a polyphase reactor, the combination with a plurality of coil units, of a hexahedral frame, one of said coil units being attached to each face of said hexahedral frame.

19. In a polyphase reactor, the combination with a plurality of coil units, of a hexahedral frame,- said-coil units being disposed Within said frame and one of said coil units being secured to each face of said frame.

20. In a polyphase reactor, the combination with a plurality of coil units, of a hexahedral frame, said coil units being disposed within said frame and one of said coil units being secured to each face of said frame, the coil units attached to directly opposite faces being connectedin series.

21. In a polyphase reactor, the'combination with a plurality of coil units, of.a hexahedral frame, said coil units being disposed within said frame and .one of said coil units being secured to each face of said frame, the coil units attached to directly oppositefaces being connected in series to form sections mutually perpendicular to each other.

- 22. In a polyphase reactor, the combination with a plurality of coil units, of a hexahedral frame, said coil units being dis.- posed within said frame and one of said coil units being secured to each face of said frame, the coil units attached to directly opposite faces being connected in series to form sections mutually perpendicular to each other, each of said sections being adapted for connection in one phase of a polyphase distribution system.

23. The combination with a. plurality of conductors comprising a polyphase system, of a set of n reactance coil units, said set of m 0011 unlts being arranged in sectlons, each of a set of n reactance coil units, said set of coil units being arranged in 5 sections,

and a polyhedral frame having n sides, each of said sections being adapted for connection in one phase of said polyphase system and one of said coil units being secured to each side of said n-sided frame.

25. The combination with a plurality of conductors comprising a polyphase system, of a set of n reactance coil units, said set of coil units being arranged in sections, and

ALEXANDER N YMAN.