US841545A - Dynamo-electric machine. - Google Patents

Description

.rb/I0. 841,545.

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MARIUS C. A. LATCUR, 0F li/ilit, FRANCE, ASSIG'NOR 'JRPORATIUN lillliif TO GENERAL YQRK.

Patented Jan. l5, 1907.

Application led June 29,1906. Serial No. 3235975.

o all '107mm' it mfr/y (foncer/1,.'

Beit known that l, Martins t). LATOUR, a citizen of France, residing at Paris, France, have invented certa-in new and useful linprovements in Dynamo-Electric Machines, of which the following is a specii'ication.

My invention relates to dynamo-electric machines of the commutator type, and is particularly applicable to alternatingscurrent motors, although not limited to this particulari plication.

f As is wellhnown in the art commutation in alternating-current machines is attended by diiliculties which are not present in directcurrent machines, since in the iormer type an armature-coil when short-circuited by a brush in commutation is subjected to an alternating llux, which induces short-circuit currents in the coil, which result in sparking and excessive heating. This dilliwty is most pronounced at starting when the liux is at a maximum. ln order to avoid these short circuits in alternating-current niachines of the. commutator type, it has bron pro )osed heretofore to wind the armature with a plurality of ind epondont windings a nd to connect these windings to successive conimutatoesegments. With such an arrangement and with brushes of a certain width no short-circuit .currents are produced. For instance, if three independent windings are employed cach segment is separated from the nearest segments connected to the saine winding by two other segments, so that a brushis used or" a width not O'rc-.atta than two segments the brush can never bear on two segments 'at the same time which are ci nnected to the same winding. lfhile tI is arrangement theoretically improves coz-umutation by avoiding the reduction of short-circuit currents, it lus been found in practice that certain dillieulties arise. in every machine the number ot' slots has certain maximum value7 above which it cannot be carried without reducing the size et the teeth to such an extent as to increase the reluctance of the magnetic circuit unduly. lheI number oi: slots is insu:` jinade as or nearly ais-great, as compa lc with design in order to secure the maximum distribution of the winding, and ctmseouently the mininunn reactance. When a plurality of independentwindings are employed 'it is clearly necessary either to saerilice this distribution or else to distribute each winding in every slot. The latter is the preferable course and the one that has been employed heretofore. lt, however, is subject to the following objection: The coils oit the several windings in a given slot necessarily have induced voltages ol' the same phase since they are in the same position on the armature-core; but these coils are connected to successivo coniniutatorsegments, so that the induced voltages at the commut:ttor-segments do not correspond in phase with the angular positions of the segments. The result, as far as commutation is concerned, is precisely the same as though the brush were shifted back and fort-h every time a slot passes the brush. lt is evident tl at the best conditions lor commutation are not obtained.

ln a former application, Serial No. 242,088, tiled by me'January 2l, 1905, l described an arrangement for two windings by which the above di'i'liculty is avoided. 'The arrangement described in that application consists in making one winding of coils having a width greater by one slot than the coil width or' the other winding. By thus proportioning the coils two coils of the respective windings having one sido in the same slot will have their other sides separated by the distance ol` one slot, so that the median lines of the coils are displaced by hall a. slot. W ith this arrangement the phase of the induced voltage at each commutat(rr-segment corresponds to the angular position of the segment; but it is obvious that this arrangei rent :annot readily extended to more than two windings.

ln later application, Serial No. 275,745, filed by me August 25, i905, l described a second arrangement ol windings a ilicable 1'* i to more than two windings. 'lhe arrangement disclosed in this later application conists in connecting the commutator-leads of one or more oi the windings to intermediate points on the coils oi the winding7 so that the portion of thst winding included between 7iacent connnotatoileads comprises tions of two difiere`- coils in two adjan sets ot slots. By properly connecting the @ads it will be seen that the phase of the i volts-ge at each lead may be made to correspond exactly with the angular position oi the ooinmutator--segment to which itis connected that 'this nietnodmay be ex- ICO los

tended to any number of'windings. It will, however, be noted that in order to extend it to more than two windings it is necessary that each coil should have more than two turns.

My present invention consists in still anv between adjacent commutatordeads, and it is with this meaning that I shall employ the term coil in thc following specifica-tion and in the appended claims.

My invention will best be understood by reference to the accompanying drawings, in whichf' Figures l to 4 show diagrammatically the arrangementsoi four different windings arranged in accordance with my invention.

, Fig. shows the four windings combined.

` mentioned. V6o

Fig. 6 shows a modified arrangement of the winding shown in Fig. V3. Fi 1. 7 shows the combination of the winding of iig. 6 with the windings of Figs,- 1, 2, and 4f; and Fig. 8 shows the same arrangement as Fig. 5, but with the end Aconnections and commutator-leads shown.

in the drawings, A. represents the slotted armature-core. A

c represents a coil of one `winding. This coil is shown as comprising two turns, both arranged in the same slots in the usual manner.

a2 represents a coil oi a second winding. The conductors forming the left-hand' side of this coil are arranged in the same slot, while the conductors formi-ng the right-hand side of the coil are distributed in two adjacent slots. lt will be seen that the phase of the induced voltage in the coil a2 as compared with that oi coil a is displaced by an amount.

corresponding to one-quarter of the distance between adjacent slots. l l l 'ln Fig. 3, aashowsa coil of athird winding. This coil has the conductors of both sides distributedbetween two adjacent slots. The combination of coils a and a3 would give an arrangement precisely the same as was shown for two windings of two-turn coils in my former application, Serial No. 275,745, above It will be` seen that the induced voltage in the coil a? is displaced byV an amount corresponding to one-fourth of a slot with respect to that of coil a2 and Oife-half a slot with respect to coil a.

Fig. 4 shows a coil at of the fourth winding, which is arranged similarly, but oppositely,

senese to the coil a?. The phase of the induced voltage in this coil is displaced by an amount corresponding to three-fourths of the distance between adjacent slots from that of coil a. Consequently if these four coils are connected to lsuccessive commutator-segments the phase'ot the induced voltage of each commutator-segment will correspond to its angilar position.

Fig. 5 shows-the four windings combined in the same slots. In this figure the conductors of the four windings are indicated as in. Figs. 1 to 4 in order to distinguish them by an unshaded square, an unshaded circle, a shaded square, and Aa shaded circle, respectively.

Referring to Fig. 3, it will be seen that the two inner conductors may each be moved out one slot or the two outside conductors moved in one slot without changing the phase of the induced voltage, since the median line of the coil willnot be changed.

Fig. 6 shows the two inside conductors moved nutons slot, and it will be observed that the combination of Figs. 1 and 6 'ves the same winding arrangement as disc osed in my earlier a plication, Serial No. 242,088, above referre to. lf the arrangement of Fig. 6 is employed in place of that of Fig. 3, the four` windings may be combined, as shown in Fi 7.

In 8 have shown4 the end connections and commutator-leads for the windings of Fig. 5. C represents the commutator, to successive segments of which the several windings are connected. B -re resents a commutator-brush which for an a ternating-,

current motor, in order to avoid-shorten cuits, is preferably given 'a width insu@ cient to bridge adjacent segments connect/ed to the same windin that is, for four windQ ings a width somet o less than three segments.

l have spoken of the application of my :inventicn in particular to alternating-census motors; but l desire it to be understood that in its broader aspects it is not 'thus limited. It is sometimes advantageous in digest-current machines to employ e. plurality of winch in sin the same slots. .My invention is appllcable to such machines, and when so applied brushes of the width usual in direct- "current machines would be employed.

I do not desire to limit myself to the particular construction and arrangement of parts here shown, but aim in the a pended claims to cover all modifications w ch are within the scope of vmy invention.

What I claim as new, and desire to secure by Letters Patento the United States, is-

1. In a dynamo-electric' machine of the commutator type, a plurality ot armaturewindings carried in the same slots and connected to successive commutator-se ents, at least oneof said windings having its coils eranged with the conduotois o'ming one side of a, ooii in a single slot and the oon- -duotors forming the other side of the coil distributed in a plurality of slots, whereby the phase of the indueed Voltage at each oom- Inutator-segment eoiresponds to the angulo? position of the segment.

2. in e dynanio-e1eet1ic machine of the oonimutetor type, o piureiity of armatuiewindings eeiied in Jche same siots and oonneoted to successive commuta-of-segments, et ieest one of said windings having its coils arranged with the conductors forming one side of a. coii in e single slot and the oonductos forming 'the other side of the ooii distributed in a piureiiby of slots; whereby the phese of he ind uoed Voiioge :is each coin- 11'nioorsegnient ooresponds to the engw hir position of the segment, and brushes neming on the eoinnmtotor of a Width in-` suiioie iiiy @o hiidge edjlizioen'n segments oonneoted 'to the saine Winding'.

3. in i dynamo-electric machine of" ihe oonnnutator type, foul `enneture-windings; carried in the seme slots and connected io successive oomnmtatobsegments, two of said windings having theii ooiis wronged with the eonduotois foiining one side of o A ooii in single slot and the conductors fome ing the other side of the ooii divided between 3o two adjacent slots, whereby the phase of the induced Voltage at each ooinmutanor-seg- A nient corresponds 'to the angular position' of atei t e four ometure-windin s YP f A oaied in the same slots and connected to successive oonunuteter-segments, seid Winding-"S havin@ thei wibh the oonduo ooii in a single two of ooiis arranged ors iorining one side or?u 4o slot and Jshe conductors forniing` the other eide of the ooi?. divided between two adjacent siots, whereby qhe phase of the induced voitege at each oominutntor-segiresnonde go the :ingnier oositioii oi 45 nent, and biusnes hearing on the `l C n oonnnuinto o' a Width insufficient 11o bridge ,ni segments connes ted to the seine

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