US1216413A - Current-converting device. - Google Patents

Description

A. R. BULLOCK.

CURRENT CONVERTING DEVICE.

APPLICATION FILED JULY 28,1913.

'1 ,216,41 3 Patented Feb. 20, 1917.

W217i 650'60'. 1 1111/6 jiforr JVIL'ZWQQOR Q m4 UNITED STATES PATENT OFFICE.

ARTHUR B. BULLOCK, OF CLEVELAND, OHIO.

CURRENT-CONVERTING DEVICE.

Application filed July 28, 1913.

To all whom it may concern:

Be it known that I, ARTHUR R. BULLOCK, a citizen of the United States, residing at Cleveland, in the county of Guyahoga and State of Ohio, have invented a certain new and useful Improvement in Current-Converting Devices, of which the following is a full, clear, and exact description.

This invention relates to a current converting device for changing alternating current to direct current and vice versa, and more particularly to the type of such devices which employ a rotatable body of segments.

The object of the invention is to provide such a device wherein the current being con verted will be cut off simultaneously witlr the breaking of the circuit through the seg ments.

Generally speaking, the invention comprises the elements and combinations thereof set forth in the accompanying claims.

Reference should be had to the accompanying drawing forming a part of this specification in which Figure 1 is a top plan view of one form of my device; Fig. 2 shows in section the rotating parts, and diagrammatically the electrical connection; Fig. 3 is a top plan view of a modified form of the device; Fig. 4 is a diagrammatic illustration showing the rotating portions of the device and the manner of their electrical connection; Fig. 5 is a perspective View of a modified form of my device, and Fig. 6 is a development of the surface of the rotating body shown in Fig. 5.

The machine herein shown is of the commutator type which employs a rotating body provided with segments which are grouped, to which current is fed and from which current is taken, in such a manner that the sides of the alternating current circuit and the direct current circuit are connected with each other in alternation.

Tn devices of this type, more particularly those for converting an alternating to a direct current, at the time a brush bearing upon the segmented body, passes from a live segment to a portion of the segmented body which is electrically dead, and again to a live portion of the body, there is a tendency for the current to flash over from a live space to an adjacent live space, which flashing Over y P931 in an ar t m quite destructive,

Specification of Letters Patent.

Patented Feb. 20,1917.

Serial No. 781,510.

The possibility of such an occurrence is a weak feature of such a machine, and the purpose of the herein disclosed device is to remove as much as may be the possibility of such occurrences.

In the construction of devices herein em ployed, the current being supplied over the feeding-in ring, is broken at the same time that the current breaks upon the segmented body of the converting device. This breaks the current at two places in series. In this way, the tendency to flash over is minimized and very largely eliminated.

Referring to Fig. 5 of the drawing, 1 and 2 are standards for suporting a shaft 3. Upon the shaft is a rotating body 4, upon the periphery of which are a plurality of conducting elements which are shown in Fig. 6, and are represented by the segments 5, 6, 7 and 8. Each of the segments is con: nected with a portion of a conducting strip. The segment 5 is connected with the portion 9.

The segment 6 is connected with the portion 11 and the segment 8 with a portion 12 of a corresponding strip upon the opposite side of the rotatable body.

The spaces in between the segments and between the sections of the rings are filled with some non-conducting material.

Between the portions 11 and 12 is a conducting strip 12", and between portions 12 and 11 is a conducting strip 11. Similarly portions 10 and 9 are separated by a strip 10", and portions 9 and 10 are separated by a strip 9 These various strips are separated by insulated, electrically dead spaces, indicated at 11 11, 12 9", 9 and 10 The insulated spaces are wider than the brushes passing over them.

The conducting strips 11, 11 12 and 12 are all electrically connected and the conducting strips 9, 9", 10 and 10", are also electrically connected as indicated at 18 in Figs. 5 and 6. These in effect form collector elements. for they may either conduct current to or from the segments, 5, 6, 7 and 8.

A brush 13 is adapted to engage with the strips 9, 9", 10, and 10 while the brush 14- is adapted to engage with the segments 11, 11 and 12 12. These brushes are, as shown, connected with a source of alternating current.

Brushes 15 and 16 are placed so as to engage with the segments 5, 6, 7 and 8, and are so spaced that the brushes will simultaneously engage with segments, which extend toward opposite sides of the body 4:, and to the strips of the collector elements. These brushes are connected with the circuit which carries the rectified direct current.

It will be apparent by reference to Fig. 5 that brushes 13 and 15, as well as brushes 14: and 16, will pass on to non-conducting portions of the rotating body 4; simultaneously, and it is the aim to have them so do. fore the A C circuit is broken simultaneously with the D G circuit between the segments and the brushes 15 and 16. Thus any arc tending to form, due to the breaking of the circuit through the segments, will upon. each side of the circuit be divided between two points of break, and thisgreatly reduces the are at both places of break.

For the purpose of operating the device, a synchronous motor will be employed to rotate the shaft 3. In this manner the rotation of the body 1 will. be in synchronism with the phase reversals of the alternating current. No particular type of synchronous motor is here disclosed for any synchronous motor which runs with suflicient precision, may be used.

In Fig. 1 there is shown a shaft which is mounted in bearings 21 and 22. Upon the shaft is a segmented body 23 which as shown in Fig. 4 is provided with four conducting portions, indicated respectively at 25, 26, 27 and 28. The conducting portions 25, 26, 27 and 28 are shown as segmented merely because it is most feasible to make a rotating body of segments, such as herein employed, according to usual commutator construction. However, these conducting portions may each be of a single unitary conducting material. The portions 25 and 26 are electrically connected, as are the portions 27 and 28.

Upon the shaft 20, there are likewise two annular conducting portions which are indicated at 29 and 30. In the present construction, these form collector elements. These conducting portions 29 and 30 are divided into strips which are separated by insulating portions 31, and the members 29 and 30 are separated from each other by a non-conducting portion 32.

In Fig. 2 we may assume that the conducting body shown is the conducting portion 30, and as will be seen, the same is divided into several segments which are connected with each other by means of suitable conductors, as indicated at 33. The conducting portion. 30 is shown as connected with the segments 25 and 26, while the conducting ring 29 is electrically connected with the segments 27 and 28. The segments of each of the conducting portions are electrically connected Thereand form single conducting portions or segments.

Brushes 3% and bear upon the conducting elements 29 and 30 respectively, while brushes 3G and 37 engage with the segments 25, 2b, 27 and 28, as these segments are ro tating. The brushes which have just been mentioned are carried upon suitable supports which are generally indicated at 38 and As will be noted in Fig. 2, assumin the direction of rotation of the bodies to be as indicated by the arrows, that the brushes 36 and 37 have just passed from conducting portions 28 and 25 respectively, and upon the drawing are shown, as in contact with the insulated spaces which are adjacent these conducting portions. The brush $35 is also seen to be on an insulated portion between, :uljacent segments of the romlurtiug strip 36, and the brush Bl, although not shown in the drawin, is likewise upon an insulated portion which is between adjzurent portions of the conducting strip 29.

The arrangement of the brushes 3t, 35. C36 and 37 should be such that the l) (l circuit is ln'oken simultaneously with the A C circuit.

lVith such an arrangement, it is apparent that there could be no flashing over between contiguous conducting portions upon the rotatable body 23, for the flashing over would only take place as the brushes 37 and 36 were passing from conducting portions upon this body 23. If at this time, the supply of current is also broken, it will be quite c ear that there would be no flaslrover, be cause of the fact that the supply current is not flowing.

The principle of construction which has just been described may be employed in 7 connection with the current converting device which is shown in my pending application, Serial No. 633,027, filed June 14th, 1911.

In Figs. 3 and 4, herein, I have indicated. the manner in which the principle herein disclosed could be applied to the device shown in said application 633,027.

In Fig. 3 there is a shaft 40 which is mounted in bearings ll and Upon the shaft are two conducting portions 1 3 and 44. made up of strips which are separated by insulated portions. the same as indicated in Fig. The conducting portions are electrically connected. as indicated at in Fig. 4t. These portions 43 and l-lform collector elements.

There is also a rotatable segmented body carried by this shaft, which is indicated at d6. As shown in. Fig. -'l, this body is provided with conducting portions or segments 41-7. 48, a9 and 50, the portions 4L7 and 4-8 being electrically connected, as are also the portions 19 and 50. tions 5% may be electrically connected with he l The conducting uerthe portions 47 and 48 upon the rotatable body 46, and the segments of conducting portions 43, may be electrically connected with conducting portions 49 and 50 of the rotatable body 46.

There is a third rotatable body, indicated at 51, which is provided with conducting portions or segments 52, 53, 54 and i he conducting portions 52 and 53 are electrically connected with each other and also with the conducting portions 47 and 48 upon the body 46. The conducting portions 04 and are also electrically connected with each other, and with the conducting portions 49 and 50 upon the body 46.

The conducting portions 52, 53, 54 and 55 are however, of not so great width as the conducting portions upon the body 46, it being the purpose of the construction to have great carrying capacity upon the body 46, whereas the conducting portions upon the body 51 will be utilized nearly at the time ot breaking of the circuit.

Cooperating with the conducting portions 43 and 44 are brushes 5G and. 57, these brushes being connected with the source of supply of alternating current. Upon the rotating body 44 are brushes 58 and 59, these brushes being connected with the external D C circuit. Upon the rotatable body 51 are brushes and G1 which brushes are also connected with the D C circuit.

The conducting portions and their corresponding brushes of the rotatable body 51 are arranged with respect to the conducting portions of the body 46 and their brushes, such that the brushes 58 and 59 will have passed onto insulated portions of the body 46 a little in advance of the passage of the brushes 60 and 61, onto insulated portions of the body 51. In this way, the breaking of the D C circuit is accomplished upon a rotatable body which is distinct from the body which carries the current, thus providing space between the point at which the D C circuit is broken, and the body on which it is carried, and by so much minimizing the likelihood of arcs forming.

, The brushe 56 and 57 are so arranged with respect to the conducting portions 43 and 44, that the brushes 56 and 57 will pass upon insulated portions simultaneously with the passing of the brushes 60 and 61 to insulating portions.

Inasmuch as the shaft 40 will be operated by a synchronous motor, when the deice is used as a rectifier, it will be apparent that the breaking of the circuit by the brushes 60 and 61 takes place at a time when both the alternating current voltage and current waves are subs antially at Zero.

It therefore follows that the conditions at the time of break of the circuits is such as to practically preclude any flash over or arcing between adjacent segments.

It is perfectly within the province of my invention to break each side of the circuit in more than two places if desirable, and thus divide any possible arc, which may form at the points of breaking the circuit, to any group of conducting elements with another circuit, the electrically cooperating conducting elements in each group being connected, both of the above mentioned means for connecting the said conducting elements with the said circuits being arranged to substantially simultaneously break the circuits through the said conducting elements.

2. In a current converting device, the combination with a group of insulated conducting elements, brushes bearing upon said elements whereby the elements are connected with a circuit, a second group of insulated conducting elements, a set of brushes bearing upon said second set of conducting elements by which said elements are connected with a second circuit, the electrically cooperating conducting elements of the two groups being electrically connected, the brushes being arranged to substantially simultaneously break the circuits through the said conducting elements.

3. In a current converting device, the combination with a plurality of collector elements, each collector element being formed with a plurality of strips which are insulated from each other, the strips of each collector element being electrically connected with the other strips of its particular collector element, a group of insulated conducting segments being electrically connected, means for electrically connecting the collector elements with a circuit, means for electrically connecting the conducting segments with a second circuit, both of said means being arranged to substantially simultaneously break the circuits through the collector elements and the groups of the conducting segments.

4. In a current converting device, the combination with a plurality of collector elements, each collector element comprising a 7lurality of conducting strips which are insulated from each other, a group of insulated conducting segments electrically cooperating, the segments and collector elements being electrically connected, brushes bearing upon the collector elements and connected with a circuit, other brushes hearing upon the conducting segments and connected with a second circuit, the brushes being arranged to substantially simultaneously break the circuits through the strips and segments.

5. In a current converting device, the combination with a plurality of collector ele ments, each of said elements comprising a plurality of insulated conducting strips arranged in annular alinement, the strips in each collector element being electrically connected, a plurality of sets of conducting segments, the conducting segments in each set being directly electrically connected with electrically cooperating segments in other sets, said segments also being electrically connected with electrically coop erating strips of the collector elements, brushes cooperat ing with the said collector elements, and brushes cooperating with each of the other sets of segments, the brushes in one set being arranged to remain in Contact with its segments, when the brushes upon the other set of segments have ceased to contact with said segments, the brushes upon the lirst set of segments and the brushes upon the collector elements being arranged to disengage with the strips and segments substantially simultaneously.

6. In a current converting device, the com bination with a pair of annular collector elements, each of said elements comprising a plurality of strips arranged in annular alinement which are electrically insulated, a plurality of annularly disposed conducting segments, cooperating segments being directly electrically connected with the said strips, brushes bearing upon the strips and upon the segments, said brushes being arranged to disengage with the segments and the strips substantially simultaneously.

7. In a current converting machine, the combination with a shaft, a pair of collector elements upon said shaft, each or said ele ments comprising a plurality of insulated conducting strips which are arranged in annular alinement, brushes bearing upon said strips, an annular body mounted upon said shaft, said body being provided with conducting portions which are separated by non-eondncting portions, the said condiuzting portions upon the annular body being directly connected with the said conducting strips with which they electrically cooperate, brushes bearing upon the said annular body, the brushes upon the collector elements and the said body being arranged to disengage with the strips and segments simultaneously.

In testimony whereof, I hereunto a llix my signature in the presence of two witnesses.

ARTH UR ll. BULLO (1K. lVitnesses A. J. Hunsow, L. I. Pon'rnu.

Copies of this patent may be obtained. for five cents each, by addressing the Commissioner of Patents, Washington, D. 0.

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