US 1784815 A
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Description (OCR text may contain errors)
Dec. 16, 1930. v, 3, APPLE 1,784,815
I DYNAHO ELECTRIC MACHINE ELEMENT Filed June 14, 1928 2 Sheets-Sheet l J W :7 im/W05.
' I Dec. 16, 1930. i v. e. APPLE I 3 MINVQ TOR.
Patented Dec; 16, 1930 PATENT v OFFICE vmcmwr G. APPLE, or DAYTON, OHIO DYNAMO-ELECTRIC-MACHINE ELEMENT Application filed June 14,
My invention relates to improvements in windings of induction motor secondaries and specifically to that class wherein each turn of the winding is a closed loop forming its own independent circuit; and some of the objects of my improvements are, first, to provide a construction wherein inductors of maximum size for agiven core-slot may be used; second, to so form the closed loops that they may be endwise entered through partially closed core slots; third, to form each ,closed loop of a single piece so that there will be no joints any-.
where in its circuit; fourth, to form each closed loop complete prior to assembly with a core so that no further joining or bending is required after assembly therewith; fifth, to
provide a winding which may not be readily removed from the core, but which may in its entirety be endwise entered or removed from the core at will.
Other objects will become apparent to those skilled in the art as my invention is described in detail and reference is made to the drawings wherein- Figs. 1 and 3 are detailed views in perspective of portions of cores having slots such as are commonly used in dynamo electric machine elements;
Figs. 2, 4 and 6 are detailed views in perspective of closed loops which may be endwise entered in the slots of cores as shown in Figs.
. 1 and 3.
Fig. 5 is an outline of a blank which may be cut from sheet stock and from which the loop Fig. 6 may be formed.
. Fig. 7 shows a cross section of the loop taken on line 7-7 Fig. 6.
Fig. 8 isa perspective view of a winding as it appears when stacked in cylindrical formation prior to entry thru the core slots.
Fig. 9 is a perspective view of a completed rotor.
Heretofore in winding induction motor secondaries wherein the winding comprises a 5 plurality of closed loops, it has been the custom to use loops having one end open and to endwise enter such loops into closed or partially closed core slots until the open ends of the loops project thru and beyond the core, then bending and joining the projecting ends 1928. Serial 1113. 285,361.
in appropriate pairs to form a single closed turn of each loo'p.
I am aware that it has been proposed t form closed loops for induction motor secondaries by slitting and spreading a single piece of stock from a point near one end to a point near the other, but the proposed loops are of such form as may be used only in open core slots and must be radially entered therein.
The electrical and mechanical advantages :0 of partially closed core slots are well known in the art and my invention comprises closed loops of such form as are adapted to entry therein.
In Fig. 1 the apertures 20, 20 etc., are of a form frequently used when each contains but a single inductor, an open portion 21 being about half the width of a portion 20, tho this proportion need not necessarily be maintained in the instant case.
In Fig. 2 I show a closed loop having inductor bars 22 and 23 of a size and form adaptable to endwise entry thru apertures 20, the upward extending connecting ends 24and 25 being of a thickness to pass thru the open portion 21 and of a width to provide the desired cross sectional area. The downwardly extending connecting ends 26 and 27 are shown as of involute form tho they may be of any form that will connect the bars 22 and 23 without interference with similar connecting ends of other bars in the winding. In a complete element comprising a core Fig. 1 and half the number of loops Fig. 2 as there are apertures in the core, alternate slots would contain, one a bar 22 and the next a bar 23', etc., the winding consisting of but a single layer. 'The apertures 20 and bars 22 and 23 may be square as shown, or they may be round, oval or of other form.
In Fig. 3 the apertures 28, 28 etc., are of a form usually used when two inductor bars are to occupy positions one above the other in the same' slot in a two layer winding. Open portions 21 are similar to those in Fig. 1.
In Fig. 4 I show two closed loops adapted to be used in connection with core Fig. 3. The loops are so formed that inductor bars 29 will occupy the inner half while inductor bars 30 occupy the outer half of the apertures I 28, the upwardly extending connecting ends 31 and 32 are similar to those in Fig. 2 and the assembled bars 30 and 29 arranged one over the other as shown are entered thru apertures 28,.the ends 31 and 32 passing one following the other thru the open portion 21. Loops as shown in Figs. 2 and 4 may be forged, cast or otherwise made to their finished form before assembly with the cores.
Another form of loop applicable to a core, such as I show in Fig. 3, may be made, as in Fig. 6, wherein an inductor bar 33 and an inductor bar 34 may occupy circumferentially adjacent positions in each aperture 28 to compose a winding in a single cylindrical layer, and the upwardly extending connecting ends 35 and 36 therefore have offsets as at 37 and 38 so that when bars 33 and 34 are passing side by side thru an aperture 28 said ofisets will cause the ends 36 and 37 to extend upwardly from the middle portion of the aperture 28 thru the open portion 21 where they may pass one following the other thru the core. The cross section of the loop shown in Fig. 7 taken on the line 77 Fig. 6 shows more clearly how the offset 38 brings the connecting end 36 to a middle position as required. For clearness slot 28 here contains but the onebar 34. In a complete winding the remaining open portion of the slot 28 would be occupied by a bar 33 which would of course be offset in the opposite direction.
A loop, such as is shown in Fig. 6 may be forged or cast or otherwise made, but is preferably made from sheet stock and in Fig. 5 I show a blank or suitable outline cut from sheet stock and if such blanks are taken in a somewhat diagonal direction crosswise of a sheet of stock, as shown, they may be cut one after the other throughout the length of the sheet with very little waste. The broken line 41 indicates where the blank is to be slit to form the ends 35 and 36 and the connecting ends of a specific form, any form of end connection which extends first upwardly from the inductor bars sufiiciently to pass thru the partially closed portion of the slot is considered within the scope of my invention. A winding comprising loops of the character shown is not readily assembled with a core one loop at a time and I therefore proceed as in Fig. 8 where an entire winding composed of loops as shown in Fig. 6 is stacked in cylindrical formation prior to assembly with a core. The loops may be brought to the arrangement shown by stacking in a suitable fixture or they may be stacked by entering the ends of the loops slightly into the slots of the core with which they are to be assembled. When the loops are thus stacked they may be simultaneously endwise entered thru the core slots, bars 33 and 34 forming pairs which pass thru apertures, as at 28 Fig. 7 side by side and ends 35 and 36 forming pairs which pass thru the open portions 21 one following the other.
When the winding has been assembled with a core 42 in the manner described a means of retaining it in place may be provided, by molding a band of insulating material thru and around the bars, as at 44 Fig. 9, by driving Wedges thru the slots, or by any other means desired. The band of insulating material has the advantage of bracing the bars where they extend beyond the core against centrifugal force, while if wedges or other removable retaining means are provided the entire winding may be endwise entered or removed from the core at will.
A rotor, as shown in Fig. 9, may of course be entered only small end first into the stator within which it runs. The upwardly extending ends 36 will be at sufiicient distance from the core of the stator to clear the winding thereof, and the ends 43 will provide without additional mechanism a fan to keep the motor cool.
While I have herein shown my improved winding applied to a core whereof the periphery is the active surface, it is obvious that by slightly modifying the form of the loops so that the connecting ends, which must pass thru the open portion 21 of the cores, extend inwardly instead of outwardly and the other connecting ends vice versa, the winding may be assembled with hollow cores whereof the inner diameter is the active surface as where the stator is the induction motor secondary. The loops may also be applied to elements of synchronous motors where induction starting is employed.
Such other variations in the details, methods, and uses of my invention as do not depart from the spirit thereof I aim to cover in the following wherein I claim 1. In a winding for a. dynamo electric machine element having a core with partially closed slots, a closed loop integrally comprising two spaced apart inductor bars and connecting ends, a bar being of a cross section which will fit and which may be endwise entered thru the wider portion of one of the core slots, the connecting ends at one end of said bar being of such cross section and extending from the bar in such direction as may be endwise passed thru the narrow or open of the loops when paired with the opposite bar of another of the loops one radially above the other forming a composite cross section which will fit and which may be endwise entered thru the wider portion of one of the core slots, the connecting ends at one end of said pair of bars being of such cross section and extending from the bars in such direction as may be endwise passed, one following the other, thru the narrow or open part of the same slot.
3. As a winding for a dynamo electric machine element having a core with partially closed slots, a plurality of closed loops, each integrally comprising two spaced apart inductor bars and connecting ends, a bar of one of the loops when paired with the opposite bar of another of the loops one circumferent-ially ad acent to the other forming a composite cross section which will fit and which may be endwise entered thru the wider portion of one of the core slots, the connecting ends at one end of said pair of bars being of such cross-section and extending from the bars in such direction as may be endwise passed, one following the other, thru the narrow or open part of the same core slot.
4:. As a dynamo electric machine element, a core having partially closed slots and a winding comprising inductors which substantially fill the wider portion of said slots so that they may not be radically removed thru the narrower portion thereof, spaced apart bars being joined by means of end connecting portions to provide a plurality of closed loops, each end connecting portion at one end of the winding extending radially from an edge of an inductor to a point beyond the tops of the core teeth before proceeding to join the other inductor of the loop, said part of an end connecting portion extending from an inductor to a point beyond the tops of the core teeth being of a cross section which may pass thru the narrower or open portion of a core slot so that the entire winding may be endwise entered or removed from the core at will.
5. 'lhe combination in a dynamo electric machine element of a core having partially closed slots and a plurality of inductor bars contained therein of a size and form which may not be radially removed from the slots, spaced apart bars being joined at both ends by connecting portions to form closed loops, the connecting portions at one end being of such cross section and extending from the bars in such direction as will pass endwise thru the narrow or open portion of the slots when the bars are passed endwise thru the wider portion of the slots.
6. In a dynamo electric machine element, a unit of the winding comprising two paralle l angularly spaced apart inductor bars jomed at both ends by involute end turns to compose, a completely closed loop, said involute end turns at one end of the loop extending inwardly toward the axis of the said element and at the other end outwardly away from the axis of the said element.
7 In a dynamo electric machine element, a core having a plurality of winding apertures, a winding in said apertures, restricted openings in said apertures adapted to prevent radial removal of bars of the winding from said apertures, and end turns proceeding radially outward from the said bars and adapted to be drawn endwise through the said restricted openings when said winding is withdrawn endwise from said apertures.
8. In a dynamo electric machine element, a core having partly closed winding apertures, and a winding comprising a plurality of longitudinally disposed conductor bars arranged in cylindrical formation with end connecting turns which extend radially from said bars, said bars being, adapted to be end- Wise entered only through the wider portion of said apertures and said radially extending end connecting turns being adapted to be passed through the narrower part of said apertures.
In testimony whereof I hereunto-set my hand.
VINCENT G. APPLE.