US714157A

US714157A - Regenerative system.

Info

Publication number: US714157A
Application number: US10057302A
Authority: US
Inventors: Albert G Davis
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1902-03-29
Filing date: 1902-03-29
Publication date: 1902-11-25
Anticipated expiration: 1919-11-25

Description

Patented Nov. 25,` |902.'- A. E. DAVIS, K BEGENEBATIVE SYSTEM.

A {Applicationled Mar. 29, 190B.)

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Invenor? Patented Nov. 25, |902. A. G. DAVIS. v REGENERATIVE SYSTEM. [Applicat'im med Mar. 29, 1902.)

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Patented Nov. 25, |902. A. E. DAVIS.

HEGENEBATIVE SYSTEM.

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REGENERATIVE SYSTEM.

(Application filed Mar. 29, 1902.)

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UNITED STATES VPATENT OEEICE.

ALBERT G. DAVIS, OF SCHENECTADY, NEW fYORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

REGENERATIVE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 714,157', dated November 25, 1902.

Application filed March 29, 1902. Serial No. 100,573. (No modehl To @ZZ whom, t may concern: tromotive force impressed upon the motor- Beit known that I, ALBERT G. DAVIS, aciticircuit. zen of the United States, residing at Schen- In the preferred manner of carrying my inectady, in the county of Schenectady, State vention into effect I combine with the operof New York, haveinvented certain new and ating system a combination dynamo-electric 55 useful Improvements in Regenerative Sysmachine located at a station on aline of railtems, of which the following isaspeciiication. way or at a fixed point distant from the line My invention relates to a system of conof travel of the moving bodyor vehicle, so control especially adapted for restoring energy structed that it will transform the constantly- 1o to the source of supply in the braking of elecdiminishing electromotive force generated by 6o trically-operated bodies of considerable mass, the motors of the moving vehicle,acting as gensuch as railwaytrains, elevators, hauling erators, into apractically-constantelectromeplants, and the like. tive force counter to and greater than that of In braking by means of ordinary brakes the line, so that a current will continue to the kinetic energy whichisstoredin the movflow from the generators on the cars to the 65 ing body is uselessly destroyed. A large perline until the car is brought almost to a full centage of the energy which is thus ordinastop. This is accomplished by so connecting rily wasted maybe recovered and returned to the fields of the individual machines or elethe line or source of power by the use of the ments constituting the combination set to a 2o invention herein described. rheostat operated by means controlled by the 7o The system which I have now devised peroperator on the car that the field of one mamits of the location of the translating device chine or element is increased as the field of at a fixed point distant from or adjacent to the other machine or element is decreased. the line of travel of the moving body-such, The armatures of these machines are mechanfor instance, as at a station on the line of ically connected together and also mechan- 75 railway instead of on the vehicle-and also ically connected to a third armature operatdispenses with storage batteries and overinginapractically-constant field. The funccomes the difficulties which have been extion of -the last-mentioned machine of the perienced by their use. combination is to maintain the fields of the 3o My invention as herein described and illusmotors on the car practically constant, inde- 8o trated relates to the operation of electric mopendent ot' the line-voltage, while said motors tor cars or trains, and is particularly adaptare acting as generators; and my invention ed for use with the modern high-speed equipfurther consists of means for so connecting ments, in which a number of electric motors said machine with the iields of the said moare employed. It has for its principal object tors that such a constant iield as. above de- 85 the return to the supply-line of a part of the scribed will be maintained. energy taken up by the car or train in its or- In a modified system embodying myinvendinary operationthat is, when the car has tion I make use of a motor-generator set loattained its normal running speed and it becated at a fixed point or station, the motor 4o comes necessary to stop at a station. This being an alternating-current motor, taking 9o slowing down or braking is accomplished current either directly from the main line or without the operation of the mechanical brakthrough a transformer. The tield of the diing device usually carried by the car and is rect-current generator is varied by electricmaintained until the car has been brought ally-operated means located at the fixed point almost to a full stop, at which time the said and controlled from the moving vehicle. The 95 mechanical braking device may be operated. means for maintaining a constant field for the Afurther application of my invention is in car-motors when acting as generators comstarting a train from a station without the prises a'shnnt-Wound generator mechanically use of the resistance ordinarily carried by coupled to the motor-generator. A storage 5o the car for the purpose of varying the elecbattery located either at the station or on the roo car or an independent dynamo-electric machine might be used for this purpose.

A further modified system embodying my invention comprises means for varying the ratio of transformation of the transformer supplying current from the line to a rotary converter. In this system the fields of the motors carried by the moving vehicle are maintained practically constant, as is also the field of the rotary converter, by means of a smaller auxiliary rotary converter taking cnrrent through an independent transformer directlyl from the line.

My invention may also be used in starting a car or train. When thus used, it comprises means for so varying the fields of two of the machines constituting the combination set, or for varying the field of the direct-current side of the motor-generator, or for varying the ratio of transformation of the transformer supplying current from the line to the rotary converter that a gradually-increasing electromotive force Will be impressed across the armatures of the motors carried by the car,which motor-armatures are operating in practicallyconstant fields maintained by either the third machine of the combination set above referred to, or by an auxiliary machine located at the same point at which the translating device is located, or by a battery carried by the car. In this manner the said motors may be brought up to speed without the use of resistances or other starting devices carried by the car, thus accomplishinga great saving in the energy supplied by the line.

My invention will be better understood from the following description, taken in connection with the accompanying drawings, while its scope will be pointed out in the appended claims.

Referring to the drawings, Figurelisadiagram matic representation of one embodiment of my invention as applied to a train system in which the motors carried by the cars are arranged to restore energy to the line through `the agency of a translating device located at the station as the train is being brought to rest at said station. Fig. 2 is a diagram of a modification in Which means are provided for starting the train from the station through the agency of the translating device at the station. Fig. 3 is a vertical sectional View of one form of magnetic clutch which may be used in connection with my invention. Figs. 4 and 5 are diagram matic representations of cars and motor connections. Fig. 6 is a diagrammatic representation of one system of station distribution and connections thereto. Fig. 7 represents an arrangement of contacts which may be used on the controlling-switch which controls the connections between the translating device at the station and the propelling-motors in the system shown in Fig. l. Fig. 8 is a diagrammatic representation of a modified system in which a motor-generator is used and in which means are provided for varying the field of the direct-current side of said motor-generator, and Fig. 9 represents diagrammatically another modified system. In this case the ratio of transformation of the transformer supplying current from the line to a rotary converter is varied by electricallyoperated means controlled from the moving vehicle.

Referring now to Fig. l, A represents the main source of supply of a polyphase current to the line L. T is a transformer, and B a rotary converter of ordinary construction located at any suitable point or points along the line, preferably at the stations. From the direct-current side of the rotary converter leads the feeder F, which is connected at intervals through the conductors F to the third rail or trolley-wire R', from which the current used by the cars, which are operating on the track R R, is collected in the ordinary manner. The system ofground or rail return is here shown, but acomplete metallic circuit might be used as well. The motors carried by the cars may be operated by the usual method of series-parallel control or any other Well-known method. The motors M M2 are shown at X on the right of Figs. l and 2, connected in their normal running connection for maximum speed-that is, in parallel to the third rail R/ through the conductor 4a. At each station E (indicated by dotted lines) and connected between the positive brush of the direct-current side of the rotary converter and ground is a composite machine C, comprising three armatures as a4 c5 and three field-magnet systems f3f4f5. The field-windings of the upper two of these machines or elements are inversely controlled by means of a controlling-switch Rh, which is operated by the motor M.

As shown in Fig. l, additionalcontact-rails l, 2, and 3 are provided at each of the sta tions. Trolley-shoes adapted to engage these conductors or contact-rails are carried by the cars. When the car or train reaches the station, so that the shoes engage with these conductors, the connections are made such that the elds f and f2 of the motors M and M2 will be separately excited from the lower machine of the combination C and such that the armatures a and Co2 Will be connected in multiple across the terminals of the middle machine of the combination C. This arrangement is indicated diagram matically at Y, Figs. l and 2. By means of a switch on the car*such, for instance, as s on the car V, (shown in dotted lines in Fig. 4t, in which figure the Wheels of the car are represented by @LO-current may be supplied to the motorM through the conductor 3. In practice these connections may be readily made by the controller carried by the car in such a manner as shown in Fig. 7, which will be described farther on.

In the system shown in Fig. I the motorM is so connected electrically that it will run in one direction only and is connected With the controlling switch-arm b by means of a worm IOO IIO

and gear or other mechanical connection and a magnetic clutch D, one form of which is shown in Fig. 3 and which will now be described. Loosely mounted on the spindle g and capable of rotary movement, but incapable ot vertical movementthereon, is a magnet h, which carries the coil m and is rigidly attached to the handle h. Splined to the spindle g and capable of vertical movement thereon is the armature h, which is normally kept away from the magnet h by means of the spring d. Upon the energization of the magnet la the armature h is attracted andthe arm h is constrained to move with the spindle g. The arm b is limited in its movement by the stop s and returns to its normal position aided by the spring d, as soon as the magnet is denergized.

If as the train comes into the station the switch or controller is properly placed, current 4will ow from the source of supply through the rail 3, conductor 16, field f, and armature d of motor M, conductor 17, coil m of magnetic clutch D, and conductor 1S to ground. The magnetic clutch will operate and the motor M will start and run the controlling-switch Rh in such a direction as to continually decrease the iieldf4 ot the middle machine of the combination C and increase the field f2 of the upper machine of the combination C.

The operation of the system shown in Fig. 1 will now be described. Normally when no car is at the station current is received by the combination machine C from B through feeder F, conductor 9, and the armatures a3, d4, and a5 in series to ground. The field windings f2, f4, audf5 are also connected between F and ground, as shown. Each machine of the combination is running light as a motor, and the sum of the counter electromotive forces generated by the armatures d4 and d5 nearly equals the impressed electromotive force of the line. Vhen the car arrives at the braking distance from the station, so that the shoes carried by the car engage the rails shown between the track-rails, if the proper connections are made at the controller the motor M operates to reduce the iield f4 and increase the ieldj"3 at such a rate that the counter electromotive force produced by a4 running asa motor always remains just a little less than the electromotive force impressed upon it by motors M' and M2 running as generators. The middle machine then drives the upper and lower machines of the combination C as generators, and the field f2 is increased at such a rate that the electromotive force across the terminals of the three machines is slightly greater than that of the line. In this manner current is forced through conductor 9, feeder F, back through the rotary converter B, which now runs as an inverted rotary and supplies current through the transformer T to line L. The current generated by the armatures a' and d2 of the car-motors acting as generators iiows through the conductor rail l, conductor 7 armature a4, conductor 8, rail 2, conductor 5 to negative terminal of motor-armatures. Part of the current generated by the lower machine of the combination C flows through the armaturesa4 and a2, conductor 9 to line, and the remainder flows through the conductor 8, rail 2, conductor 5, ields f and f2 to ground at G, thus maintaining the field strength of M and M2 practically constant. By properly regulating the speed of the motor M and the divisions ofthe lield-windingsf3 ai1df4,which are connected to the controlling-switch Rh, the above condition of the system maybe maintained until the train comes nearly to a full stop, at which time the hand or air brakes may be applied.

In the system shown in Figs. 2 and 5 the motor M is so wound and connected that it may be reversed at the will of the operator on the car through the agency of a reversingswitch, such as is shown at S2 in Fig. 5. This switch may be embodied as .part of the controller or may be a separate switch located anywhere on the car or train. As will be seen, it is unnecessary in this system to use the magnetic clutch D, previously described in connection with the controlling-switch Rh, as the arm b is so connected as to be moved in either direction by the motor M. In this system an additional rail 4 is required, as is also an additional contact-shoe on the car. Current flowing through the rail 3 from the contact-.shoe carried by the car through the conductor 16, eldf, conductor 17, armature a to ground will cause the motor M to rotate in one direction. To reverse the motor M, a circuit is completed through the rail 4 from the additional contact-shoe carried by the car, conductor 19, field f in the opposite direction, conductorl', armature d to ground.' The operation of this system while the car is being brought to rest in front of a station is substantially the same as that of the system shown in Fig. 1, it being necessary to rotate the motor in the proper direction to reduce the field of the middle machine and increase the iield of the upper machine of the combination C.

The system shown in Fig. 2 is also applicable as means for starting a car or train from a station and for bringing it up to such a speed that the motors on the car can be connected directly in their parallel position to the third rail or trolley R' Without the use of a starting-resistance or intermediate series position of the controller. lt will be remembered that when the car was brought to rest at the station the arm h of the controllingswitch Rh Wasin such a position that the field f4 of the combination C was at its minimum strength, while the field f2 was at its maximum strength. It now the motor M is reversed, so as to turn the arm b in the opposite direction, the field f2 will be gradually diminished and the field j"L gradually increased. The gradually-increasing electro- IOO IIO

&

motive force of CL4, running as a generator, will be impressed upon the armatures a' and a2 of motors M' and M2, while the fields f' and f2 are constantly excited by a5, as before. In this manner the motors M and M2 are gradually speeded up until the arm b strikes its stop s or the contact-shoes carried by the car leave the

rails

1, 2, 3, and 4, at which time the motors are connected in parallel to the third rail R'.

In Fig. 6 I have illustrated one system of distributing the stations E along the line L, using but one rotary converter for every three stations, the feeder F connecting these three stations together. Of course any other combination of stations could be made, depending mainly upon the distance between stations. Such a system as here illustrated tends to more evenly distribute the current, which has been fed back to the line of the cars, slowing down at the various stations by feeding it directly to cars which may be running at speed between stations instead of forcing it back through the rotary converter and through a considerable length of line-wire.

In Fig. 7 I have shown a development of a controller G which may be used in connection with the system shown in Fig. 1 and the connections therefor. 3a to 13a represent the movable contacts commonly used in the series-parallel method of control. 1c to 18c represent the fixed contacts, and their connections With the motors M' and M2 and the shoes if, t', t2, and t3 may be readily traced. 1d to 18d represent a set of movable contacts, which are to be brought into communication with the fixed contacts above referred to in order to connect the motors M' and M2in such a relation as shown in Figs. 1 and 4 and furnish power to the motor M. This last-named set `of movable contacts may be mounted on the same cylinder on which the contacts 3u to 13 are mounted or may be separately and independently mounted. It must be understood that I do not limit myself to the form of controller herein shown, for any set of switches which would act to make the connection required to carry out my invention would do just as Well.

In the system shown in Fig. 8 instead of using the combination-machine C above described I employ a motorgenerator comprising the alternating-current motor M4 and the direct-current generator G2. The motor M4 takes current directly from the main generator A through the line L and transformer T. Mounted on the same shaft which carries nishes current for the field f7 of the generator G2 and for the motor M, which is used to operate the arm b of the controlling-switch Rh, which in turn controls the field f2 of the generator G2. The controlling-switch Rh is so connected tothe field f7 and the resistance 1" that as the field is gradually cut out a corresponding amount of the resistance r' is cut into the eld-circuit, and vice versa when the field f7 is gradually increased. The motor M is controlled by a switch S2, carried by the car or train and may constitute part of the motor-controller or may be a separate switch located anywhere on the car or train. The track-rails are represented by R R, the trolley or third rail by R', and the auxiliary rails in front of the station by 2, 3, and 4, as before. The operation of this system is as follows: The current generated by the generator G2 under normal conditions flows through the feeder F, conductor F', to sectional third rail R', through the motors in series or multiple connection to ground, and the auxiliary machine G' merely acts to assist the generator G2 and maintain the field f7 practically constant. WVhen the car or train arrives at braking distance from the station-that is, when contact-shoes carried by the car engage the fixed

rails

2, 3, and 4-the connection to the motors lV and M2 are made as shown in Fig. 8 and the switch S3 is thrown to connect the motor M, so that it will operate to gradually reduce the field f7 of the machine G2. The motors M' and M2 are therefore run as generators, driven by the momentum of the car. The machine G2 will run as a direct-current motor with a gradually-diminishing counter electromotive force maintained just a little below that impressed upon it by the motors M and M2, acting as generators, and the machine M4 will run as a generator, feeding current into the line L through the transformer T. The circuit through the motors M' and M2 and the machine G2 may be traced as follows: motor-armatures a' and a2, conductor 42, trolley or third rail R', conductor F', feeder F, armature of G2,

conductors

20 and 25, auxiliary rail 2, conductor 5 to armature a' and a2. The generator G', one side of which is grounded, furnishes current to the fields of the car-motors through the following circuit:

conductors

30, 20, and 25, auxiliary rail 2, conductor 5, fieldsf andf2 to ground. The generator G' also furnishes current for the field]L17 through the following circuit: conductors 30 and 20, field f7, conductor 21, arm Z? of controlling-switch Rh, conductor 22 to ground When the maximum field f7 is in circuit and through conductors 30, 20, and 23, arm b, conductor 24, and resistance r when field f7 is entirely cut out. The resistance r' is used to prevent a short circuit of the machine G' when the field f2 is cut out by the controlling-switch Rh. The current for operating the motor M is taken from the auxiliary rail 2 and led to the circuits of the motor M in the same manner as shown in Fig. 2.

In the system shown in Fig. 9 the ratio of transformation of the transformer T is varied by varying the number of turns included in IOO IIO

its secondary. A transformer of the opendelta type is here shown and taps are led off from various points of the secondarywinding, said points being symmetrically arranged with respect to its middle point. The leads from the taps are connected to the segments of the controlling-switch Rh, and the central point of the secondary is connected directly with the rotary converter B. The arm b is divided. into two parts b and h2, insulated from one another, and each of which is connected with the rotary converter B, as shown. This arm is operated by the motor M, which is controlled by the switch S3, carried by the car, in the manner previously described with reference to Fig. 2. By the means just described the electromotive force impressed upon the alternating-ernment side of the rotary converter B may be varied and the electromotive force given out by the direct-current side varied accordingly. In order to maintain the fieldfs of the rotary converter B and the Iieldsf and f2 of the motors INI/sand M2 practically constant, the auxiliary rotary converter B, taking current directly from the line through the transformer T, is used. When the car arrives at braking dist-ance from the station, the connections on the car are made, as shown in Fig. 9, with one side of each of the armatures d and a2 grounded, while the other side remains connected With the third rail R. One side of each of the fields f and f2 is grounded, while the other side is connected with the rail 2 through the conductor 26. In operation the current generated by the motors lV and M2, acting as generators, flows from the armatures which are grounded on one side, through conductor 4', third rail R', conductor F', direct-current side of rotary converter B to ground, driving the rotary reversed, with a gradually-diminishing counter electromotive force on the directcurrent side, since the motor M operates to gradually cut out the secondary of transformer T, thus. causing the alternating-current side of the rotary to generate an alternating current with a diminishing electromotive force slightly greater than the continually-diminishing electromotive force of the secondary of the transformer T, thereby returning energy to the line L. Part of the current from the direct-current side of the rotary converter B flows through the conductor 28, rail 2, conductor 26, fields f' and f2 to ground and part flows through

conductor

28 and 29,' field f8 to ground. The current for operating the motor M is furnished by the rotary converter B' and is taken off from the rail 2, as before stated.

It will be understood in reference to the systems shown in Figs. 8 and 9 that the trolley or third rail should be divided up into sections and each section fed from the mainline through a separate and independent powertranslating device. This is necessarily so, because the armatures of the motors carried by the car are not disconnected from the third rail While the car is being brought to a standstill at or started from a station, and the potential varies throughout the Whole length of the section of third rail R', which is fed from the motor-generator or rotary converter.

On long and steep grades any one-'of the above-described translating devices might be located and adjusted and set by a controlling-switch, such as Rh, which when once set could not be changed except by some one located at that point and would not be aected by passing trains. By such means energy could be restored to the line When the train has attained a schedule speed beyond which it is not desired to go in descending the grade, and the braking effect of the motors acting as generators could be utilized on said grades. In such a case the motor M and the rails 3 and 4 would be unnecessary, and only the auxiliary rails I and 2 and in the systems shown in Figs. 8 and 9 only the rail 2 would be laid on said grade.

It will be further seen that in case one car should be standing at a station and another car should be approaching said station at full speed a collision would be prevented. In the systems shown in Figs. l and 2 this is due to the fact that the armatures of the motors on the car approaching the stations acting as generators would be short-circuited through the rails l and 2 and the motor-armatures of the car standing at the station, thus producing a tremendous braking effect and bring the moving carto a standstill almost instantly. In the systems shown in Figs. 8 and 9 the approaching car would be deprived of current or would receive current at an elect-romotive force below the normal electromotive force of the line if a car Was at the station or Within braking distance of the station.

In the use of my invention as applied vto electric railways it will be found that the current requirements of a long line on which frequent stops are made will be materially reduced. The trains or cars which are coming to a station will supply a considerable percentage of the power needed to operate other trains Which are still running at speed or are just starting.

Although I have shown and described an electric-railway system equipped with the proper apparatus for carrying out my invention, it must be understood thatI do not limit myself to such a system, as the invention is equally applicable to variously electricallyoperated devices which require frequent starting and stopping.

IVhat I claim as new, and desire to secure by Letters Patent of the United States, is-

l. In a regenerative system, a moving body, a motor or motors operatively connected to said moving body, means for connecting said motor or motors to act as generators, and a translating device located at a fixed point capable of transforming the gradually-dimin- IOO ishing electromotive force produced by said motors acting as generators into a practically constant electromotive force.

2. In a regenerative system. a moving body, a motor or motors operatively connected to said kmoving body and normally used for propelling said body, means for connecting said motors to act as generators, and a translating device located at a fixed point, normally connected to the source of power from which the said motors are supplied and capable of transforming the graduallydiminishing electromotive force produced by said motors acting as generators into a practically constant electromotive force counter to that of the source of power, whereby a current is caused to flow from the said motors acting as generators to the normal source of power.

3. In a regenerative system, adynamo-electric machine carried by a movable vehicle, receiving power from a normal source of supply and normally operating to drive said vehicle, means for connecting said machine to act as a generator driven by the momentum of the moving vehicle, means located at afixed point along the line of travel of said vehicle for receiving the electromotive force produced by said dynamo-electric machine and for transforming it into electromotive force counter to and greater than the impressed electromotivel force of the said normal source of power, and means comprising rails located at said fixed point and contact-shoes carried by the movable vehicle for connecting said dynamo-elec tric machine to said transforming means.

4. In a regenerative system, acombinationmachine located at a xed point and connected to a normal source of power, means for connecting said combination-machine to the motor or motors carried by a car or train, said motor or motors being driven by the momentum of the car or train and generatingacontinuously-diminishing electromotive force as the car or train is being brought to a standstill, electrically-operated means for varying inversely and simultaneously the fields of the com bination-machine so that the continuallydiminishing electromotive force impressed upon it will be converted into a practically constant electromotive force counter to and greater than the electromotive force of the normal source of power.

5. In a regenerative system, a dynamo-electric machine carried by a moving body and operated by the momentum of said moving body,a combinationemachine located at a fixed point and capable of receiving the electromotive force generated by said dynamo-electric machine and of transforming it into an electromotive force of higherpotential,and means consisting of contact-shoes carried by said moving body, and Yfixed rails for completing the circuit through said dynamo-electric machine and said combination-machine.

6. In a regenerative system, a dynamo-electric machine carried by a moving body and operated by the momentum of said moving body,a combination-xnachine located at a fixed point and capable of receiving the electromotive force generated by said dynamo-electric machine and of transforming said electromotive force into an electromotive force of higher potential, said combination-machine being so connected as to maintain the field of said dynamo-electric machine practically constant.

'7. In a regenerative system, a dynamo-electric machine carried by a moving body and operated by the momentum of said moving body, a combination-*machine located at a fixed point, and consisting of three machines the armatures of which are connected in series and mechanically coupled together, two of said machines being adapted to transform the electromotive force generated by said dynamo-electric machine into an electromotive force of a higher potential, and the third machine of said combination being adapted to maintain the lield ot' said dynamo-electric machine practically constant. and independent of the electromotive force generated by its armature.

8. In a regenerative system, a combinationmachine located at a fixed point and connected to a normal source of power, means for connecting one element of said combination-machine to a source of continuously-diminishing electromotive force located on a movable vehicle, electrically-operated means for inversely varying the fields of the combination-machine so that the counter electromotive force of one element of said machine will be maintained at a slightly lower potential than that of the continually-diminishing electromotive force impressed upon it and so that the electromotive force produced by the other element of said combination-machine will be slightly greater than and counter to that of the normal source of power.

9. In a regenerative system, a combinationmachine located at a fixed point and connected to a normal source of power, means for connecting one element of said combination-machine to a source of continuously-diminishing electromotive force located on a movable vehicle, means for inversely varying the elds of the combination-machine, so that the counter electromotive force of one element of said machine will be maintained at a slightly lower potential than that of the continuously-diminishing electromotive force impressed upon it and so that the electromotive force produced by the other element of said combination-machine will be slightly greater than and counter to that of the normal source of power, means carried by said movable vehicle for controlling the operation of said field-varying means, and means comprising fixed rails, and contact-shoes carried by the car for connecting said held-varying means with said controlling means.

lO. The combination of a controlling-switch located at a fixed point, means for operating said controlling-switch, means located on a movable vehicle for controlling said operat- IOO IIO

ing means, and means consisting of a shoe or shoes carried by said movable vehicle and a fixed rail or rails with which said shoe or shoes contact for completing the circuit through said controlling-switch-operating means and said controlling means.

11. The combination ot'a controlling-switch located at a fixed point, means for turning the arm of said controlling-stvitchin one direction, said means comprising a motor connected in series with a magnetic clutch mounted in the arm of said controlling-switch, means mounted on a movable vehicle for controlling the operation of said motor and magnetic clutch, and means for mechanically and automatically returning said controlling-switch arm to its normal position when said clutch becomes inoperative.

12. The combination of a composite machine located at a fixed point, a controllingswitch for varying inversely the fields ot said composite machine, means for operating said controlling-switch, and means located on a movable vehicle for controlling said operating means.

13. The combination of a composite machine located at a fixed point, a controllingswitch for varying inversely the fields of said composite machine, means for turning the arm of said controlling-switch in one direction, said means being controlled from a point on a movable vehicle, and separate and independent means for automaticallyT returning said controlling-switch arm to its normal position.

14. In a regenerative system,a combinationmachine located at a fixed point, means for varying inversely the fields of said combination-machine, means controlled from a point on a movable vehicle for operating said tieldvarying means in one direction, and separate means for automatical-ly restoring said fieldvaryingmeans toits normalposition when said last-mentioned operating means becomes inoperative.

15. In Va combination-machine, three armatures mechanically connected together,means for varying inversely the fields in which two of said armatures operate, and means for maintaining the field in which the third armature operates practically constant.

16. The combination of a motor operated from a constant-potential circuit, and means for controlling said motor consisting of a plurality of dynamo-electric machines having their armatures connected in series across the circuit-mains and mechanically coupled together, means for varying inversely the fields of two of said dynamo-electric machines so as to vary the electromotive force impressed across the armatureterminals of the motor, the field-Winding of said motor being independently connected to another of said dynamo-electric machines so as to maintain the field of said motor practically constant.

17. In a regenerative system, a plurality of fixed conductors located parallel to the line of travel of a moving vehicle and connected to a dynamo-electric power-translating device,

electric machine comprising a pluralityof elements having their armatures connected in series across a source of supply and having their fields arranged to be inversely varied, one or more motors operatively connected to a load, means for electrically connecting said motors to one of the elements of said composite machine, and electrically -operated means for gradually increasing or decreasing the tield strength of the element to which the motors are electrically connected and simultaneously and inversely varying the field of another element of. the said composite machine.

19. In an electric-railway system, a source ot supply, a composite-machine comprising a pluralityof elements having their armatures connected in series across said source, a switch operatively connected to the field-windings of said elements in such a manner that by the operation of the switch the fields of two elements will be simultaneously and inversely varied, a motive device for operating said switch, a car or train equipped with one or more propellingmotors, means including switch-contacts on the car or train and a contact shoe or shoes engaging a conductor or conductors along the roadway for connecting the propelling-motors across the terminals of one of the elements of said composite machine having a variable field, and additional means comprising switch-contacts on the car and a contact-shoe engaging a conductor along the roadway for controlling the operation of said motive device.

20. In an electric regenerative system, a source of supply, a dynamo-electric machine connected on one side to said source and adapted to transfer energy either from or to the source of supply, a car or train equipped with one or more propelling-motors, means including a conductor or conductors along the roadway and a contact shoe or shoes carried by the car or train for electrically connecting the said motors to said dynamo-electric machine, a regulating device for the said dynamo-electric machine constructed and arrangedto vary the electromotive force on the side of the machine to which said motors are connected, a motive device for operating said regulating device, and means comprising a conductor along the roadway and a contactshoe carried by the car or train for controlling the operation of said motive device.

21. In a regenerative' system, a moving body, a motor or motors carried by said moving body, means for connecting said motor or IOO IIO

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motors to act as generators, a power-translating,r device located at a fixed point on the line of travel of said moving body capable of transforming the gradually-diminishing electromotive force produced by said motors acting as genera-tors into a practically constant electromotive force, a field-regulating device for said power-translating device, a motive device for operating said regulating device, and means comprising a rail located at said fixed point and a contact-shoe carried by said moving body for controlling the operation of said motive device.

22. In combination, a source of currentsupply, a dynamo-electric power-translating device located at a fixed point and adapted to transfer energy to or from said source of supply, a car or train equipped with one or more propelling-motors, an auxiliary dynamoelectric machine for maintaining the lields of said motor or motors practically constant, a regulating device for the said dynamo-electric power-translating device, a motive device for operating said regulating device, and means comprising a conductor along the roadway and a contact-shoe carried by the car or train for controlling the operation of said motive device.

23. In combination, a source of currentsupply, a dynamo-electric power-translating device and an auxiliary dynamo-electric machine located at a xed point, a car or train equipped with one or more propelling-motors, a regulating device for said dynamo-electric translating device, a motive device for operating said regulating device, means for controlling said motive device located on said car or train. and means comprising conductors along the roadway and contact-shoes carried by the car or train for connecting said propelling-motors to said power-translating device, the fields of said motors to said auxiliary dynamo-electric machine, and the means for controlling the motive device to said motive device respectively.

24. In combination, a moving body, a motor or motors carried by said moving body, means for connecting said motor or motors to act as generators, a dynamo-electric powertranslating device located ata fixed point and capable of receiving the gradually-diminishing electromotive force generated by said motors acting as generators and transforming it into a practically constant electroniotive force, a regulating device for said dynamoelectric translating device, an electric motive device for operating said regulating device, and means comprising a conductor or conductors located at said fixed point and a contact shoe or shoes carried by said moving body for controlling the operation of said motive device.

25. In combination, a source of currentsupply, a dynamo-electric power-translating device located at a fixed point and adapted to transfer energy either to or from the source ot' supply, a car or train equipped with-one or more propelling-motors, means including a conductor or conductors along the roadway and a contact shoe or shoes carried by the car or train for electrically connecting the said motors to said dynamo-electric translating device, an auxiliary dynamo-electric machine located at said xed point for maintaining the fields of said motor or motors practically constant, and a conductor or conductors along the roadway and a contact shoe or shoes carried by said car or train for connecting said auxiliary dynamo-electric machine with said motor-fields.

In Witness whereof I have hereunto set my hand this 28th day of March, 1902.

ALBERT G. DAVIS.

Witnesses:

BENJAMIN B. HULL, HELEN OREORD.