US832353A - Commutator. - Google Patents

Description

No. 832,353. PATENTED OCT. 2, 1906.

R. S. WHITE.

COMMUTATOR.

APPLICATION FILED 0011.14. 1902.

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Inventor.

Roger S.White, MM-

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No. 832,353. PATENTED OCT. 2; 1906,

R. S. WHITE.-

GOMMUTATOR.

APPLICATION TILED 001'. 14. 1902.

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. UNITED STATES PATENT OFFICE.

ROGER S. WHITE, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO.

GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK. I

COMMUTATOR.

Specification of Letters Patent.

Patented Oct. 2, 1906.

Application filed October 14, 1902. Serial No. 12'7,229.

T0 aZZ whmn it may concern:

Be it known that I, ROGER S. WVHITE, a citizen of the United States, residing at Philadelphia, county of Philadelphia, State of Pennsylvania, have invented certain new and useful Improvements in Commutators, of which the following is a specification.

My invention relates to new and useful improvements in the construction of commu tators and of roller-collectors for electric-motor meters, and is especially adapted to those having an armature mounted on a horizontal shaft supported by roller-bearings which also cooperate with the commutator and act as current-collectors. Heretofore in motors of this type commutators have been used having the usual straight-edge segment, rendering it necessary to make the gaps or airspaces between the segments as small as possible, as each gap, forming, in effect, a flattened surface, breaks the continuity of the true circular path of contact on the commutator-surface of the roller-bearings and allows the armature to settle a minute distance as each gap passes a roll. This is more particularly noticeable with a very small load and introduces an error which, while almost negligible when a very light armature is employed and when the commutatorsegments are very near together, becomes serious when an armature of heavier construction is used, as in wattmeters or large-capacity instruments, and when higher differences of potential between adjoining segments having an increased air-gap is desired. Now in order to eliminate this source of error I employ anew and improved commutator and roll by means of which I secure and maintain an even, true, and constant condition of contact of commutator and collecting device. I provide two pairs of rollers on which the commutator of the meter-motor bears, each pair being connected to one side of the line and taking the place of a single brush, and I so construct the parts that one roller of each pair is slightly ahead of the other roller of that pair relatively to the segments of the commutator. I accomplish this by mounting the two rollers of each pair on the same shaft and forming the commutatonsegments so that they extend around the cylindrical surface of the commutator enough to make each segment overlap the next. For this purpose the segments may be curved helically commutator.

throughout their length, or, as I prefer to make them, one-half of each segment may be ofi'set relatively to the other half so as to be slightly in advance of it on the surface of the As thus constructed the commutator rests on the two pairs of rollers which constitute the antifrictionbearing for one end of the shaft, the two rollers of each pair being of the same size and mounted to engage the commutator on opposite sides of the ofl'set in the segments. If segments'are used which are curved throughout their length, the rollers of each pair are mounted a sufficient distance apart to have the same effect. It will thus be seen that one roller of each pair is slightly in advance of the other roller of that pair relatively to the commutatorsegments, and I so arrange the parts that this advance is sufficient to bring one roller into contact with a segment as the commutator is turned on its axis just before the other roller of that pair breaks contact with the adjacent segment. As the two rollers of each pair are electrically connected, a coil of the armature is thus short-circuited momentarily when the current therein is reversed. Also the slight drop or lateral movement of the shaft and armature when a segment leaves the roller is prevented, as one roller of each pair is always in engagement with a segment, and thus supporting the shaft in proper position. "Moreover, there are two paths for the current entering and leaving the commutator, thus affording better electrical connections to the coils of the armature.

The features of novelty of my invention will be definitely indicated in the appended claims.

The details of construction and the mode of operation will be better understood by reference to the accompanying drawings, which show one embodiment "of my invention.

In the accompanying drawings, Figure 1 is an end view of a commutator embodying my invention. Fig. 2 is a side elevation of the same, showing a single commutator and set of rolls. Fig. 3 is an end view of a modi fication.

View of the preferred shape of commutatorsegment. Fig. 8 is an end view of the same.

Fig. 4 is a side elevation of the, same, showing two commutators each with' Fig. 9- is an end view of the same bent to the desired curvature. Fig. 10 shows the assembled commutator. Fig. 11 is an end view thereof. roll in proximity to the commutator. Figs. 13, 14, and 15 illustrate various modified forms of segments, and Fig. 16 shows a roll in which the contact portions are insulated from the shaft;

Let 1 represent the armature-shaft of the motor-meter, preferably supported in a horizontal position either on a conical bearing 2 at one end and a roller-commutator 3 at the other, as'shown in Fig. 2, or on roller-commutators at both ends, as shown in Fig. 4. The preferred shape of commutator-segment is shown in Figs. 2, 4, 7, and 10, where the ortion a. b of one edge of the segment 4 overaps a slight distance beyond the theoretical line of commutation X Y, while the remain- .ing portion 0 d of the same edge does not eX- tend to said line. The opposite edge of said segment is similarly stepped, the portion 0 f, corresponding to and parallel with the pore tion a b, stopping short of the line of commutation- X Y, while the portion 9 h, correspondin to and parallel with the portion a (1, over aps said line by the same amount as the ortion a b overlaps the line X Y. It is rea y necessary that these edges a b, g h shou d extend only to the theoretical line of commutation; but by overlapping them a little less accuracy isreguisite in shaping the segments and in assemb ing the commutator.

The segments are preferably punched from sheet metal and arethen curved, as shown in Fig. 9, to fit the periphery of the body or spool 5 of insulation. The heads of the spools have equispaced notches 6 to receive tongues 7 on the segments, which are then clam ed in place by rings 8.

The ro s which support the commutator and serve to convey current to the armature the disk 9 only.

each comprise two parallel metal disks 9 9" of the same diameter mounted on a shaft 10. Ordinarily both disks support the commutator, being so'arranged that the edges a b, e f pass over one disk and the portions 0 d, g h over the other. Suppose the commutator shown in Fig. 10 to be rotating. It is evident that when the gaps adjoining the edges 0 d, g it pass the disk 9' the other disk 9 alone sup:

ports the commutator, and when in turn the gaps adjoining the edges a b, e f reach the disk 9 the commutator will be supported by In each instance the supporting-disk will engage a cylindrical portion of a segment, so that there will be no jolt as V the gaps pass the other disk.

It is obvious that many other shapes of commutator-segment may be used. Thus in Fi 13 there are two steps, in Fig. 14 a plura it of small steps having square edges, and in ig. 15 a plurality of V-shaped steps.

12 shows a double-disk With segments of such shapes the number and relative position of the disks must be modified to correspond. Indeed, with Figs. 14 and 15 a cylindrical roller extending the full length of the commutator may be used. It is obvious, also, that flat brushes may be used in conjunction with my improved meter-commutator with marked advantage. In the case of brush and commutator contact as in ordinary use it is found that it constitutes by far the largest frictionfactor in meters, especially marked as a ap-is passing a brush, for the receding edge 0 one segment a llowsthe brush in contact with it to drop until the approaching edge of the next segment comes in contact with and raises it to its normal position. In doing this, however, it

not only lifts the brush against the force of- I its spring, but it does so with its more or The armature-shaft may have more than one armature, and they may be arrangedjn several diflerent ways and connected up in different electrical circuits, as will be apparent to. any one skilled in the art. If it is desired to use an insulated roller-bearing, I

the disks may be insulated from the shaftby an insulating-sleeve 11, as shown. in .Fig. 16. 'i What I claimasnew, and desireto secure by Letters Patent of the United States, is'

1. An electrical instrument comprising an armature-shaft, a commutator having overlapping segments carried thereby, and pairs of current-carrying rollers supporting said commutator.

2. In an electrical instrument, a shaft, an armature and commutator carried thereby, and two pairs of coaxial rollers on which said commutator bears, said commutator being so constructed and arranged that one roller of each pair is in advance of the other of that pair relatively to the segments of the commutator.

3. An electrical instrument comprising a shaft and armature, a commutator having overlapping segments carried by said shaft, and a pair of current-carrying rollers arranged so that one of the rollers passes the gap between adjacent segments before the other roller.

4. In an electrical instrument, a shaft, an

' armature and commutator carried thereby,

and pairs of concentric rollers on which said commutator bears, said commutator and rollers beingarranged to short-circult coils of the armature successively and to prevent jarring of the shaft as the segments of the commutator leave the rollers.

5. In an electrical instrument, a shaft, an armature carried thereby, a commutator on said shaft having segments which overlap longitudinally of the commutator, and current-carrying bearing-rollers for supporting said commutator.

6. In an electrical instrument, a shaft, an armature carried thereby, a commutator on said shaft, a portion of each segment of the commutator being in advance of the remainder of the segment circumferentially of the commutator, and current-carrying bearing-rollers for supporting said commutator.

7. In an electrical instrument, a shaft, an armature and commutator carried thereby, each segment of said commutator having an offset therein advancing a part of the segment ahead of the remainder circumferentially of the commutator, and a pair of rollers mounted to make electrical contact with and support the segments of the commutator on opposite sides of said ofisets.

8. In an electrical instrument, a shaft, an

armature and commutator carried thereby, each segment of said commutator having an offset therein advancing a part of the segment ahead of the remainder circumferentially of the commutator, and two pairs of rollers on which the commutator bears, the rollers of each pair being arranged to contact with the several segments of the commutator on opposite sides of the offsets.

9. In an electrical instrument, a shaft, an armature and commutator carried thereby, each segment of said commutator having an ofiset therein advancing a part of the segment ahead of the remainder circumferentially of the commutator, and two pairs of rollers on which said commutator bears, the rollers of each pair being electrically con nected and arranged to contact with the commutator-segments on opposite sides of said offsets.

In witness whereof I have hereunto set my hand this 11th day of October, 1902.

ROGER S. WHITE. [L. s.] WVitnesses:

EDMUND JoNEs, A. STANLEY PETERSON.

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