US1223470A - Current-transforming device. - Google Patents

Description

A. R. BULLOCK.

CURRENT TRANSFORMING DEVICE. APPLICATION FILED JUNE 14, 1911- RENEWED SEPT. 20, 1916.

1,223,470, Patented Apr. 24, 1917.

2 SHEETS-SHEET 1.

A. R. BULLOCK.

CURRENT TRANSFORMING DEVICE. APPLICATION FILED JUNE14, 1911. RENEWED sEPT.20.1-91s.

1,223,470. Patented Apr. 24,1917.

I 2 SHEETS-SHEET 2.

WZfn 666 86 ,In v 6 "To 21 (5 GEM UNITED STATES PATENT onnion.

ARTHUR R. BULLOCK, 0F CLEVELAND, OHIO, ASSIG-NOR TO HENRY C. LEE, TRUSTEE, OF

LOS ANGELES, CALIFORNIA.

CURRENT-TRANSFOILMING DEVICE.

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 Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Current-Transforming Devices, of which the following is a full, clear, and exact description.

This invention relates to a mechanical current transforming device for rectifying alternating currents or changing direct currents into alternating currents. Generally speaking, the invention comprises the elements and the combinations thereof set forth in the accompanying claims.

Reference should be had to the accompanying drawings forming a part of this specification, in which Figure 1 is a top plan view of the machine. Fig. 2 is a vertical sec tional view along line 22 looking in the direction of the arrow. Fig. 3 is a vertical section along the line 33 of Fig. 1 looking in the direction of the arrow; and Fig. 4 is a diagrammatic illustration of the electrical circuits involved in the use of the machine.

The machine is mounted upon a suitable base or floor, which is not shown. by means of journal standards 1 and' 2. These journal standards are provided with bearings at their upper ends which cooperate with caps 3 and 4 in the ordinary manner. These standards 1 and 2 support a shaft 5 upon which is mounted so as to rotate therewith a rotating bod-'y6, the peripheral surface of which carries segments 7 of conducting material, which'are insulated from each other.

The same shaft also carries a rotating member 8, the peripheral surface of which also carries conducting segments insulated from each other. The manner of construc tion of both the members 7 and 8 is the or dinary commutator construction, and further description is not necessary. Beside the rotating member 8 and secured to the shaft, are rings 9 and 10 which are insulated from each other by means of the collar 11, and it will further be understood that the rings 9 and 10, as well as the members 6 and 8 are all insulated from the. shaft 5.

The journal standard 1 is provided with an inwardly extending sleeve 12 which surrounds the shaft 5, and upon this sleeve is rotatably mounted a drum 13 provided with a flange 14 upon which are mounted rings 15 and 16. These rings are split and are se- Specification of Letters Patent.

Patented Apr. 24, 191 '7. Renewed September 20, 1916. Serial No. 121,309.

cured together by means of bolts represented at 17 in Fig. 1. The ring 15 carries the brush holder 18, while the ring 16 supports the brush holder 19, and in each of the brush holders there are a plurality of brushes 20 which are pressed against the segments on the rotating member 6 by means of flexible springs 21.

The drum 13 is rotatable upon the sleeve 12 and by. a movement of this drum the brushes and brush holders maybe adjusted axially with respect. to the rotating member To hold the brush holders in their adjusted positions the drum 13 carrles a lug 22 having an opening through which is threaded an adjusting screw 23, and this set screw bears against a projecting lug 24 formed upon the journal standard 1.

Adjacent to the-standard 2 there is se cured a supportingmember which carries the brushes that bear upon the rings 9 and. 10, and the rotating member 8. .This sup-. port has a base 25 which is secui'ed'to the same floor or base as the journal standards 1 and 2. Secured to the base 25 is anannular member 26 which is provided with an internal groove 27, as indicated in Fig. 1.

Within the groove there is seated a split annular ring 28 which is free to rotate in the groove 27, except when held in the adjusted position by the nut and bolt 29 which draws the two parts of the annular member 26 together and locks the ring 28 against movement. Upon the ring 28 are lugs 30, 31, 32, 33, 34 and 35. Upon each of these lugs extends a rod which at its outer end supports the holder for a brush. From the lugs 30-and 31 extend the rods 30' and 31', and these rods support brush holders that carry the metallic brushes 30 and 31 which, in this instance, are of copper.

From the lugs 32 and 33 extend rods 32' and 33 which at their outer ends support cally connected with connected, and

bear upon the rotating member 8 at points 90 degrees apart. The brush 32 bears on the commutator at a point diametrically opposite the brush 30, while the brush 33 is diametrically opposed to the brush 31. The positioning of the brushes 34"- and 35 upon their respective rings is immaterial.

While the entire surface of the rotating member 6 is provided with a series of segments which are insulated from each other there are only four groups of segments which are actually used, and these four groups are represented at 37, 38, 39 and 40 in Fig. 3, each group com rising five segments. The remainder of t e segments between the respective groups simply act as dead bars and insulation spaces between the groups of live bars. It will be apparent that any suitable insulating material may be used to space the groups of live bars, and further, a single bar of copper or other conducting material of proper width may be used in place of each group of live bars previously described.

The bars of an individual group are all electrically joined together, as indicated at a in Fig. 4, and the group of bars 37 is joined with the group of bars 39, while thegroup of bars 38 is joined with the group of bars 40, by conductors b and 0, respectively.

The segments upon the rotating member 8 cover the peripheral surface, the same as those upon the rotating member 6, and on this member four groups of bars are 'used, but each group comprises four bars, the bars in each individual group being joined together, as indicated at d in Fig. 4, while the bars in the groups 41 and 42 are joined together and the bars in the groups 43 and 44 are joined together by means of the conductors e and f. Further, the group of bars 41 is joined with the group of bars 37 on the rotatin member 6 by a suitable conductor, while t e group of bars 44 is joined to the group of bars 40, the bars 42 to the bars 39, and the bars 43 to the bars 38 by means of conductors g, h, i and 1', respectively.

The brushes 30 and 32 are joined by means of a conductor is, in circuit with which is a variable resistance 1. The brush 31 is likewise joined with the brush 33 by means of a conductor m, and this conductor has in series with it a variable resistance a.

From the foregoing it will be seen that brushes 30, 32 and the brush in the holder 18 are simultaneously bearing upon groups of segments which are electrically the arrangements between these brushes is such that the brush 32 during the rotation of the member 8 makes contact with a given group of segments just in advance of the making of contact by the brush 3O with 'a group of segments electrithe first group, while nected with each wear/o the brush in the holder 18 makes contact with the corresponding group of segments upon the rotating member 6 after the brush 30. Therefore the carbon brush 32 first makes contact to complete the circuit through a group of segments; the brush 30*. being of copper, carries the largest part 0 the current during the time that the given group of segments is in contact with the brushes, while the brush in the holder 18 will break the electrical connection between the brushes and the groups of segments.

It will be remembered that the brushes 39 and 18 areof carbon, while the brush 30 is of copper. And it will further be remembered that the brushes 32 and 30 are conother by means of a resistknown that carbon offers a the passage of the elec- Hence when the ance. It is well greater resistance to tric current than copper.

brush 32 makes contact, the current passing over the brush 32 to the brush 30 encounters some resistance, and in this manner any tendency to sparking is reduced, which sparking sometimes occurs by virtue of a slight residual charge left in the condensers Whose action will be later described.

The current is broken through the carbon brushes in holders 18 and 19. Hence, again, a slight resistance is interposed to the passage of the current, but the real reason for using carbon brushes at the point 18 is because of the fact that the diameter of the rotating member 6 is greater than the diameter of the rotating member 8. Hence the peripheral speed of the member 6 is greater than that of ,the member 8, and the friction between the copper brush and the copper segments at a high rotation is too great to permit of its economical use. Hence the carbon brushes are used.

As has just been explained the peripheral speed of the member 6 is greater than the peripheral speed of the member 8. Hence, when the current is broken between a given set of segments and the brush in the holder 18, it takes place very rapidly, which is a desirable feature, and tends to the reduction of the sparking.

The various electrical connections and operations which have been stated with respect to the brushes 30, 32 and 18 is in kind true of the brushes 31 33 and 19.

In Fig. 4, the various groups of c0nducting bars upon the rotatable members 6 and 8 are conventionally shown, together with the electric connections heretofore described.

The brushes 18 and .30 are connected by means of the conductors 0, p and 70, while the brushes 19 and 31 are connected by the conductors q, 1' and m. The conductors 0 and p are directly connected with direct current mains indicated at D, C.

The rings 9 and 10 simply serve as conductors and receive from or transfer current a closed circuit.

to the brushes 35 and 34 which are connected with alternating current mains designated by A, C.

In Flg. 4, the rings 9 and 10 and their brush connections are diagrammatically represented by conductors s and t, the conductor 8 being joined to the groups of segments 41 and 42, while the conductor 25 is joined to the groups of segments 44 and 43.

In a machine of the character herein described, it is necessary to interpose condensers in certain of the circuits, for the reason that otherwise the sparking upon and the making and breaking of the circuits would be so great as to prohibit the use of the machine. However, by the interposition of condensers in suitable portions of certain of the circuits, the sparking is substantially eliminated, so that the machine is practical and operable.

As one form of condenser arrangementwhich may be used, I have shown the parallelogram or double delta arrangement of condensers 45, 46, 47, and 48, all of these condensers being connected in series and as The adjacent ends of the condensers 48 and 47 are by means of a conductor 20 connected with one of the alternating current mains, while adjacent ends of the condensers 45 and 46 are connected by the conductor '0 with the other of the alternating current mains. The adjacent ends of the condensers 45 and 48 are by means of the conductor w connected with one of the direct current mains, and the adjacent ends of the condensers 46 and 47 are by means of the conductor a: connected with the other of the direct current mains,

. I have found it advantageous to insert as portions of the conductors w and m, a variable resistance represented at V, R,-this resistance serving to modify the rapid action of the condensers in their charge and discharge, and thus produce a more even eiiect in the current flow.

The machine and its connections may be used either to rectify an alternating current or to produce an alternatingcurrent from a direct current. However, for purposes of illustration and disclosure, I will explain the operation of the machine, considering it as usedfor rectifying an alternating current which is supplied over the mains A, C, and producing a direct current which is taken ofl" over the mains D, O.

Considering for the moment that the alternating current is positive in the main A and negative in the main C, then the positive current distributes itself over the segments of the groups 41 and 42, and inasmuch as previously explained, the brush 32 is set slightly in advance of the brush 30, a current from the group of parts 42 will first find its path through the brush 32, the resistance Z, conductor k, conductor p, and

through the direct current main indicated at In the next instant, however, the brush 30 will have come into contact with the group of segments 41 and inasmuch as the brush 30 is a copper brush, a large proportion of the current will flow over this brush from the segments 41, through the conductor is, conductor ;0, to the direct current main D, and so long as the brush 30 is in contact with the segment 41, this condition will hold true because the resistance through the copper brush is much less than the resistance through the carbon brushes 32 and 18. However some current will flow through these carbon brushes, and by means of the intermediate connections flow to the direct current-main D.

As before explained, the brush 18 maintains the contact with the group of segments 37 for, a short interval of time, after the brushes 30 .and 32 have broken with their respective groups of segments. Hence, at this time the current will flow from the groups of segments 41 and 42 to the groups of segments 37 and 39 respectively, and it will be noted that the groups of segments 37 and 39 are connected by the conductor 6, and thence to brush 18. The current passing through the brush 18, finds its path from that brush through the conductor 0 to the direct current main D.

When the circuit is first made by the brush 32 the return circuit from the direct current main is through the conductor r, resistance 71, conductor m, brush 33, segments 44, conductor t, to the alternating current main C,

have left their groups of segments, and the brushes 18 and 19 are carrying the current,

the return circuit from-the main 0 of the direct current is through conductor 9, brush 19, segments 40, which are connected with the segments 38, with the conductor 0, through groups of segments 44 and 43, which are likewise connected with each other and with the groups of segments 40 and 38, through conductor t to the main C of the alternating current mains.

When the copper brushes 30 and 31 are active, the return circuit is through the conductor c of the direct current mains, conductor r, conductor m, to the brush 31, thence through the segments 43 and 44 which are connected by the conductor 7 and back by way of conductor 2% to the main C of the alternating current.

In the next instant of time, the polarity of the alternating currents A, C, will have changed, so that the conductor A will be negative, and the conductor C positive. At the same time, the groups of segments upon the rotatable members 6 and 8 will have changed the relationship illustrated in Fig. 4, and the groups of segments 44 and 43 will have come into contact with the brushes 32" D and C of direct current circuit, conductor and 30 respectively. Likewise, the brushes 18- and 19 will bein contact with the group of segments 10 and 39 respectively.

vUnder these conditions, the positive current will pass to the groups of segments 44: and 43, and this positive current will be delivered to the main D of the direct current mains. In fact, the same cycle of operations which have just been described will be repeated, and the continued operation of the machine will result in always supplying current to the mains D, C, which current always flows in the same direction.

In operating the machine for the purpose of converting alternating into direct current, it is necessary to drive the machine by a motor which operates synchronously with the alternations of the alternating current which is being converted.

Then the various parts of the machine are in the relationship expressed in- Fig. 4,. and the break between the groups of segments 37 and 40 and the brushes 18 and 19 occurs, the current tending to pass across the break, will find a path from main A of the AC mains, conductor 1), condenser 45, conductor w, and to the mains D and C of the direct current mains, returning over conductor w, condenser 17 conductor and main O of the alternating current mains.

lVhen the brushes 18 and 19 are breaking contact with the groups of segments 40 and 39 respectively, and the main 0 is and the main A is of the alternating circuit, then the circuits are as follows: main C, conductor a, condenser 48, conductor w, mains m, condenser 46 and conductor main A.

Attention is called to the fact that there is always a condenser in circuit in parallel with the breaks in the circuit, no matter in which way the current may flow.

Upon a succeeding make after a break in a circuit, the condensers discharge through the direct current mains, and apparently have the efiect of reducing the pulsations of the direct current.

In a machine of the character described, the curve of the resultant current voltage assumes a form which'may be considered as a sine curve wlth all the loops in the curve above the zero voltage line, and the current produced is a pulsating current. However, with the condensers arranged in-the circuit as herein described, the discharges from the condensers have the effect of reducing the pulsations and producing a more continuous and even current than that which would be ordinarily produced in the operation of the machine.

As has before been stated, it is better, although not absolutely necessary to insert a resistance between the conductors which join the condensers with the direct current mains,

both parts of the in this manner producing a slight retardation of the condenser discharges onto the direct current mains.

In using the machine herein described for rectifying alternatin currents, I have been able to run motors 0 various sizes with the direct current produced by the machine,

which in itself is evidence that the pulsations of the current are not very great. Otherwise the 'fields of the motors would become heated by continued running, but I have found that motors running on the direct current produced by the machine, even after several hours of continuous running, develop no more heat in the field than is present when they are run upon the ordinary com- "mercial form of the dlrect current.

condenser arrangen'ient, and the form herein shown is as well adapted for this use of the machine as in the rectification of alternating currents.

The machine is reversible, that is to say, the brushes 18 and 19, and the brushes 30 and 31 may be connected with the direct current or alternating current and the rings 9 and 10 connected with the alternating or the direct current.

Especial attention is called to the feature of making contact with a group of segments through a carbon brush, and resistance, and subsequently carrying the current load through a copper brush, and then breaking the current upon a carbon brush or through some reslstancc, and in addition quickly by means of a second annular body which is rotating with a higher peripheral speed than the first.

Having described my invention, I claim:

1. In a current transforming device, the combination with two rotatable sets ofsegments adapted to rotate together, corresponding segments upon the two sets, be ing electrically connected, a contact making brush and a current carrying brush bearing upon one set of segments, the contact brush being set upon the segments a little in advance of the current carrying brush, said brushes being electrically connected, and a current breaking brush bearing upon the second set of segments, said brush being connected with the current carrying brush.

2. In acurrent transforming device, the combination with two rotatable sets of segments adapted to rotate together, corresponding segments upon the rotating bodies little in advance ing brush of low resistance and a contact making brush of relatively higher resistance bearing upon one of the sets of segments, the contact brush being set upon the segments a little in advance of the current carrying brush, said brushes being electrically connected, and a current breaking brush of higher resistance than the current carrying brush bearing upon the second set of segments and electrically connected with the current carrying brush.

3. In a current transforming device the combination of a rotatable set of segments, a current carrying brush of low resistance and a contact making brush of high resist ance bearing upon said set of segments, said contact brush being set upon the segments a of the current carrying brush, said brushes being electrically connected, a second set of segments, corresponding segments in both sets of segments being connected, the last mentioned segments being adapted to rotate with a higher peripheral speed, a current breaking brush bearing upon the second set of segments, said current breaking brush being of a higher relative resistance with respect to the current carrying brush, the last mentioned brush being electrically connected with the current carrying brush.

4. A current converting device comprising a plurality of sets of conducting means adapted to rotate together, conductors connecting corresponding means of said sets the said sets of conducting means being spaced from each other by an air gap, means adapted to connect said conducting means with an A C circuit, means adapted to connect said conducting means with a D C circuit, and means whereby said set of segments may be rotated.

5. A current converting device comprising a plurality of sets of conducting elements which sets are spaced apart by an air gap, conductors connecting elements in the said sets which electrically cooperate, means for electrically connecting said conducting elements with an A G circuit, means for electrically connecting said conducting elements with a D C circuit, and means for simultaneously moving said sets of conducting elements.

6. A current converting device comprising a plurality of bodies provided with conducting portions adapted to rotate together, said bodies being separated from each other by an air space, conductors connecting corresponding conducting portions upon said bodies, means for electrically connecting the conducting portions with an A O circuit, means for electrically connecting the conducting portions with a D' G circuit, and means for rotating said conducting portions whereby the current to be converted is careach pair,

ried upon a plurality of separated sets of conducting portions.

7, The combination with an A C circuit and a D C circuit of a current converting device comprising two series of sets of conducting elements said sets of conducting elements being separated from each other by an air space, conductors connecting the conducting elements in one series with the corresponding conducting elements in the other series, means for electrically connecting said conducting elements with the A C and D C circuits, and means for moving said conduct ing elements whereby the said conducting elements will connect each side of one of said circuits alternately with the opposite sides of the other circuit.

8. In a current converting device, the combination with a plurality of separated sets of conducting elements adapted to rotate together, said sets of conducting elements being separated by an air space, conductors connecting corresponding conducting elements in each set, means for feeding alternating current to said conducting ele ments, and brushes adapted to cooperate with conducting elements of said sets as the conducting elements rotate, said brushes being adapted to be connected with a direct current circuit.

9. A current converting device comprising a pair of insulated conducting elements which are electrically connected and a second pair of insulated conducting elements which are electrically connected, conductors connecting cooperating conducting elements in means for electrically connecting of conducting elements with an A C circuit, means for simultaneously connecting each pair of conducting elements with a D C circuit, and means for moving said conducting elements.

10. A current converting device consisting of a conducting group comprising a plurality of insulated conducting elements which are electrically connected, and a second conducting group comprising a plurality of insulated conducting elements which each pair are electrically connected, conductors con-.

necting corresponding conducting elements in each of said groups, means for electrically connecting each group with an A C circuit, and means for simultaneously connecting each group with a D C circuit, and means for moving said groups simultaneously.

11. In a current transforming device, the combination with a plurality of sets of conducting elements adapted'to rotate together, the corresponding elements of each set being electrically connected, brushes bearing upon the said conducting elements, each brush upon one set of said elementsbeing electrically connected with the brush of the other set, the brushes bearing upon one set of con- 'segm ducting elements being set to remain momentarily in electricalcontact with one of said conducting elements after the brushes bearing upon the other set of conducting elements have broken. contact. p

1%. In a current transforming device, the combination with a plurality of sets of conducting segments adapted to rotate together the corresponding sets of the two segments being electrically connected, brushes bearing upon said segments, each brush upon one set of segments being electrically connected with the brush upon the other set of segments, means for connecting the said sets of segments with a source of current, said brushes upon one set of segments being arranged to break the circuit after the brushes upon the other set of segments have broken contact.

13. In a current transforming device, the combination with two sets of conducting segments adapted to rotate together, the corresponding segmentsof the two sets being electrically connected, brushes bearing upon said segments, each brush upon one set of segments being electrically connected with a brush upon theother rotatable set, the brushes bearing upon one of said sets of segments being set to remain momentarily in electrical contactwith a segment afterthe brushes bearing upon the other set of segments have broken contact with the corresponding segment.

14. In a current transforming device, the combination with two rotatable sets of segments, one set of which is rotating with a greater peripheral speed than the other, corresponding segments of the two sets being electrically connected, brushes bearing upon said segments, each of the brushes upon one set of segments being electrically connected with a'brush upon the other set, the brushes bearing upon the set of segments with a greater peripheral speed, remaining momentarily in contact with a segment of that set after the brushes bearing upon the other set 4 have broken contact with the corresponding entQ 15. In acurrent transforming device, the combination with two rotatable' sets of segments adapted'to rotate together, one of the sets of segments beingof greater diameter than the other, whereby the peripheral speed of the same is greater than that of the other set, corresponding segments of the sets being electrically connected, brushes bearing upon the said sets, each of the brushes upon one set of segments being connected with the brushes upon the other set, the brushes bearing upon the segment of greatest diameter remaining momentarily in electrical contact with given segments, after the brushes hearing upon the other set have brokencontact with the corresponding segments. I

16. In a current transforming device, the combination with two rotatable bodies adapted to rotate together, one of the bodies being of greater diameter than the other whereby the peripheral speed of the same is greater than that of the other body, each of the bodies being provided with four sets of conductors which are correspondingly arranged upon both bodies, the corresponding conductors being electrically connected, brushes bearing upon the conductors of both bodies, corresponding brushes upon the bodies being electrically connected, the brushes upon the body of larger diameter remaining in contact with the conductors of that body after the brushes upon the other body have broken contact with the corresponding brushes thereon.

17 In a current transforming device, the combination with two rotatable bodies, one of the bodies having a greater peripheral speed than the other, the peripheral surfaces of the bodies being provided with insulated conducting portions, corresponding conducting portions upon the bodies being connected, brushes bearing upon the body of greater peripheral speed, the principal brushes bearing upon the other body, auxiliary brushes also bearing upon the last mentioned body, each auxiliary brush being connected to a principal brush, the said principal brushes being electrically connected with corresponding brushes upon the body of greater peripheral speed, the auxiliary brushes being set to make electrical contact with the conducting portions of that body before the principal brushes contact with the conducting portions, the brushes upon the body of greater peripheral speed being set to maintain contact with the conducting portions upon that body after the other brushes have broken contact with their corresponding conducting portions. 1

18. In a current transforming device, the combination with arotatablebody provided with groups of conductors,.a second-body of greater diameter also provided with similar groups of conductors, corresponding groups upon the body being electrically joined, carbon brushes bearing upon the second body, metallic brushes bearing upon auxiliary carbon brushes bearing upon the first body, each auxiliary brush being electrically connected with a copper brush and having a variable resistance in the said connection, the carbon brushes upon the second body being. electrically connected with the copper. brushes, the relationship being such that the auxiliary carbon brushes may contact with the segments first the metallic brushes may contact thereafter and carry the greater part of the current, and the carbon brushes upon the body of greater diameter break the electrical connection between the brushes and the segments.

19. In a current transforming device, the

the first body,

combination with a rotatable body, provided with conducting portions, brushes bearing upon the conducting portions of said rotatable member, the brushes forming terminals for a circuit and the conducting portions upon the rotatable body forming terminals for another circuit, auxiliary brushes bearing upon the rotatable member, each of which is. connected to one of the principal brushes, the auxiliary brushes being set in advance of the principal brushes to make electrical contact with the conducting portions of the rotatable member in advance of the principal brushes, and a condenser connected with each side of the above mentioned circuits and in parallel with the break in the circuits.

20. In a current transforming device, the combination with two rotatable bodies adapted to revolve together, each of the bodies being provided with conducting portions, corresponding conducting portions upon the two bodies being electrically connected, brushes bearing upon the said rotatable members, each brush upon one body being electrically connected with a brush upon the other rotatable body, the brushes bearing upon one of the bodies being set to remain in electrical contact with the conducting portions of that body after the brushes bearing upon the other body have broken contact with the corresponding conducting portions, anda condenser connected with each side of the said circuits and in parallel with the breaks in the circuits 21. In a current transforming device, the combination with two rotatable sets of segments adapted to rotate together, one ofthe sets of segments being of greater diameter than the other, whereby the peripheral speed of the same is greater than that of the I other set, both the sets being formed with conductlng portions, corresponding segments in the two sets being electrically connected, brushes bearing upon the said segments, each of the brushes upon one set of segments being connected with the brushes upon the other set, the brushes bearing upon the segment of greatest diameter remaining in electrical contact with the segments after the brushes bearing upon the other segments have broken contact with their corresponding segments, the brushes forming terminals for one circuit and the segments forming terminals for another circuit, and a condenser connected with each side of the above mentioned circuits and in parallel with the break in the circuit.

22. In a current transforming device, the combination with a rotatable body provided with conducting portions, brushes bearing upon said rotatable member, the brushes forming terminals for a circuit and the conducting portions upon the rotatable body forming terminals for another circuit, auxiliary brushes bearing upon the rotatable member, each of which is connected to one of the principal brushes, the auxiliary brushes being set in advance of the principal brushes to make electrical contact with the conducting portions upon the rotatable member in advance of the contact of the principal brushes, and a plurality of condensers electrically connected in series and forming a closed circuit, one of the said circuits being connected to the condenser circuit at two points thereon, the other of the circuits being connected to the condenser circuit at two other points upon opposite sides of the condenser circuit and intermediate of the points of connection of the other circuit.

23. In a current transforming device, the combination with two rotatable bodies adapted to rotate together, each of the bodies being formed with conducting portions, the corresponding conducting portions upon the two bodies being electrically connected, brushes bearing upon said rotatable members, each brush upon one rotatable member being electrically connected with a brush upon the other rotatable member, the brushes bearing upon one of said members being set to remain in electrical contact with the conducting portions of that member after the brushes bearing upon the other member have broken contact with the corresponding conducting portions, the brushes forming the terminals for one circuit, and the conducting portionsupon the bodies forming terminals for another circuit, and a plurality of condensers electrically connected in series and forming a closed circuit, one of said circuits being connected to the condenser circuit at two points thereon, the other of the circuits being connected to the condenser circuit at two points upon opposite sides of the condenser circuit and intermediate the points of connection of the other circuit.

24:. In a current transforming device, the

combination with two rotatable bodies adapted to rotate together, one of the bodies being of greater diameter than the other, whereby the peripheral speed of the same is greater than that'of the other body, both the bodies being formed with conducting portions, corresponding conducting portions upon the bodies being electrically connected, brushes bearing upon the said bodies, each of the brushes upon the bodies being connected with the brushes upon the other body, the brushes bearing upon the body of greatest diameter remaining in electrical contact with the conducting portions of that body after the brushes bearing upon the other body have broken contact with their corresponding conducting portions, the brushes forming the terminals for one circuit and the conducting portions upon the bodies forming the terminals for another circuit, and a plurality of condensers electrically connected in series and forming a closed circuit, one of said circuits being connected at two points upon the condenser circuit, the other of the circuits being connected to the condenser cir' cuit at two points which are upon opposite sides of the condenser circuit and intermediate the points of connection of the other circuit.

25. In a device for transforming alternating current to direct current, the combination with a rotatable body provided with conducting portions, brushes bearing upon said conducting portions, said brushes forming terminals of a circuit and the conducting portions forming terminals for a second circuit, condensers connected with corresponding sides of both circuits, said condensers being in parallel with the breaks in the said circuit.

26. In a device for transforming alternating current to direct current, the combination with a rotatable body provided with conducting portions, brushes bearing upon said conductin portions, said brushes forming terminals or a circuit and the conducting portions forming terminals for a second circuit, and a plurality of condensers electrically connected in series for forming a closed circuit, one of the above mentioned circuits being connected to the condenser circuit at two points thereon, the other of the circuits being connected to the condenser circuit at two points upon opposite sides of the condenser circuit, and intermediate the points of connection of the other circuit.

In testimony whereof, I hereunto aifix my signature in the presence of two witnesses. ARTHUR R. BULLOCK.

Witnesses:

R. SULLIVAN, A. J. HUDSON.

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