US1390064A - Winding for dynamo-electric machines - Google Patents

Description

H. W. TAYLOR AND F. H. CLOUGH.

WINDING FOR DYNAMO ELECTRIC MACHINES.

' APPLICATION FILE!) DEC- 9,1920.

Hen.

der'ICk Clou th, M M

Their Attovney.

PatentedSept. 6,1921.

I I I Inventors.

\W. Teylov,

UNITED STATES PATENT OFFICE.

HENRY WILLIAM TAYLOR, OF BILTON, AND FREDERICK HORTON CLOUGH, OF RUGBY,

ENGLAND, ASSIGNORS T0 GENERAL ELECTRIC COMPANY, A CORPORATION NEW YORK.

WINDING FOR DYNAMO-ELECTRIC MACHINES.

Patented Sept. 6, 1921.

Application filed December 9, 1920. Serial No. 429,500.

To allwkom it may concern:

Be it known that we, HENRY WILLIAM TAYLOR and FREDEnrcK HORTON CLoUcH, subjects of the King of Great Britain, residing, respectively, at Bilton, county of Warwickshire, England, and at Rugby, county of Warwickshire, England, have invented certain new and useful Improvements in Windings for DynamdElectric Machines, (for which I have filed an application in England, Dec. 2, 1919, No. 30,063,) of which the following is a specification.

The present invention relates to dynamo electric machines and more particularly to armature windings for alternating-current machines.

In large alternating-current generators in which the windings dis osed in the armature slots consist of'con uctors of considerable depth, magnetic flux across the slot resulting from the current in the conductors gives rise to a parasitic voltage within the conductors which is liable to cause local currents and thereby produce heating of the conductors and an inefficient use of the copper in the armature.

It has hitherto been proposed to limit the current which will flow as a result of these parasitic voltages first, by dividing the con ductor into a number of separate multiple bars or sections and secondly, by continuing these laminations of the complete conductor throughout an entire coil or winding and so connecting the ends that the order of sec tions in the'conductors in the upper portion of the coil is the reverse of the order of the sections in the lower portion of the coil.

It will be understood that such an arrangement limits only the parasitic currents which flow between the various sections and not parasitic currents which flow locally in each section owing to its own thickness. It will also be understood that the maximum possible number of sections is limited by the number of turns in the complete winding. It is found therefore that on large machines with very deep conductors, the local currents which flow even when these provisions are made are still excessive and impose limitations on the design of the machine.

One object of the present invention is to the'sections in turn being formed of a pluupon the current in the units below the one in question. The flux across such a unit may therefore be considered as consisting of a variable element due to the current in the unit and also of a number of constant elements which depend upon the. number of units below the unit in question, as, for example, the second unit is subjected to the influence of one constant element of flux, the third unit is subjected to the influence of two constant elements of flux, the fourth unit to three constant elements of flux, etc. By the'term constant I mean that the flux due to the current in the units below is uniformly distributed throughout the unit in question. A variable element of flux, however, is not uniformly distributed but, as above stated, increases in density from the bottom of the unit. It is to be noted that from time to time as the current changes the value of both the constant and variable elements also changes. At the time of maximum current the total quantity of flux existing in any unit, that is, the sum of the constant and variable elements is a'maxiinum and this is the flux which upon the rise of current has cut the bottom of the conducting unit but not the top of the unit. Regardless of the total quantity of flux which is moved upward through the unit it is this flux only which causes the voltage to be set up tending to cause the parasitic current to flow between the topand bottom of the unit. A further object of the present invention is to provide a dyna'moelectric machine constructed as above set forth, wherein the sections and laminations are so connected that the voltage due to these flux elements shall be opposed to one another and the eddy currents which flow as a result of these voltages reduced to a minimum.

, With these and other objects in View, reference will be had to the accompanying drawings wherein Figure 1 represents diagrammatically a plurality oi armature slots which are adapted to receive a winding of four turns per phase, the conductor being divided into four sections, each of which sections is composed of three laminations; Fig. 2 is a full development of the winding illustrated in Fig. 1.

Referring to Figs. 1 and 2, A to H represent a series of armature slots, Jr to D being located beneath one field poleand slots E to H being located beneath a pole of the opposite sign. Thefour sections of the conductor as illustrated in Fig. 2 are located in the lower halves of slots A to D, occupying positions 1 to i therein and in the upper halves of slots E to H, occupying positions 5 to S. It will be noted from Fig. 1, which shows the positions occupied by one section, that this section passes from position 1 in slot A to position 8 in slot E, hence back to position 2 inslot B, to position 7 in slot F and so on until position 5 in slot H is reached. This section therefore occupies successive positions. in each group of slots A to D and to H and on completion of the winding has occupied all of the positions 1 to S. The section which lies in position 2 in slot A passes from that position to position 7 in slot E, back to position 3 of slot '13 and continuing likewise occupies successive positions until all positions 1 to 8 have been occupied. Each of the remaining sec tions occupy successive positions in like manner. It will be noted that the order of the sections in each of slots E to H is the reverse of the order in the corresponding slots A. to D.

Each of the sections is composed of three laminations, a, 7) and c, and it may be ob served that the laminations of the section which is shown in Fig. 1 appear in the reverse order in positions 2, 3, 6 and 7 from the order in which they appear in positions 1, 4, 5 and 8. It is likewise true of the laminations of all sections that occupy a reverse order in positions 2, 3, 6 and 7 from the order in which they occur in positions 1, 4t, 5 and 8. All sections and laminations are directly connected togetherin multiple at the ends of the winding.

Considering the flux elements as above defined, acting upon the section shown in Fig. 1, it will be observed that for positions 1, 1-, 5 and 8 the constant flux elements are 0+3+t+7zls and for positions 2, 3, 6 and 7 they are -125-6:14E. The

variable flux elements, that is, the elements of flux existing within the section by reason of the current within that section, are for positions 1, 1, 5 and 8 1+1|1+1: i and for positions 2, 3, 6 and 7 1l11:4.

The constant flux elements therefore neutralize each other as do the variable flux elements, with the result that the eddy cur rents which tend to flow within sections are practically eliminated.

lVhile we have termed the members represented by a, Z) and 0 laminations, it is apparent that they may be considered merely as conducting units which in themselves may be composedof yet smaller subdivisions of the conductor.

What we claim as new and desire to secure by Letters Patent of the United States, is,

1. An armature provided with slots and a winding located therein, said winding comprising a plurality of sections, each of which is composed of a group of laminations, said sections and laminations being each insulated from one another throughout the winding and connected at their ends in multiple, each section from one end to the other of said winding occupying successively all positions within a slot and the order of the laminations within each section being reversed in certain of the half turns from their order in the remaining half turns of the section, whereby the total number of flux elements linking the laminations of each section in one direction is equal and opposite to the total number of flux elements linking the laminations of each section in the opposite direction.

2, An armature provided with slots and a winding located therein, said winding comprising a plurality of sections, each of which is composed of a group of laminations corresponding in number to the turns of the winding, said sections and laminations being insulated from one another throughout the winding and connected at their ends in multiple, said sections occupying different relative positions in successive turns of the winding and said laminations occupying different relative positions within the several halt turns so that the total number of constant flux elements linking the laminations of each section in one direction is equal and opposite to the totalnumber of constant flux elements linking laminations of each section in the opposite direction.

In witness whereof, we have hereunto set our hands this seventeenth day of November, 1920.

' HENRY WILLIAM TAYLOR.

FREDERICK HORTON CLOUGH.

itnesses to the signature of Henry Villiam Taylor:

M. E. TAYLOR, V. M. SHARLAND.

Vitnesses to the signature of Frederick Horton Clough:

J. A. Fosrnn, D. VVHITE.

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