US1164671A - Alternating-current electric-despatch system. - Google Patents

Description

K. E. STUART. ALTERNATING CURRENT ELECTRIC DESPATCH SYSTEM.

APPLICATION man APR. 6. 1914.

1.,1fi4cfiY1L Patented Dec. 21, 1915.

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wlTNEslsEsM Q PPLICATION FILED APR-6.1914.

Patented Dec. 21, 1915.

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Ma y I UI I HHIHH HHUMH W TNEssss W ATTO NEY K. E. STUART.

ALTERNATING CURRENT ELECTRTC DESPATCH SYSTEM.

APPLICATION FILED APR 6, 1914.

Llwfil. Patented Dec.21,1915.

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K. E. STUART.

A'LTERNATING CURRENT ELECTRIC DESPATCH SYSTEM.

APPLICATION FILED APR. 6, I914. 1 1%?1, Patented Dec. 21, 1915.

5 SHEETSSHEET 4.

Wad m FL w n WITNESSES COLUMBIA PLANOGRAPH cm, WASHINGTON, D. cv

K. E. STUART.

ALTERNATTNG CURRENT ELECTRIC DESPATCH SYSTEM.

APPLICATION FILED APR-6,1914- LT@%,6?T Patented. Dec. 21, 1915.

5 SHEETS-SHEET 5.

A TTORNEY- WITNESSES coLuMulA )LANOGRAIH CO-.WASIHNGTON. u. M

KENNETH E. STUART, OF LONDON, ENGLAND.

ALTERNATING-CURRENT ELECTRIC-DESPATGI-I SYSTEM.

$pecification of Letters Patent.

Patented Dec. 2t, 1915.

Application filed April 6, 1914. Serial No. 830,090.

To all whom it may concern Be it known that I, KENNETH E. STUART, a citizen of the United States, residing in the city of London, England, have invented new and useful Improvements in Alternating-Current Electric-Despatch Systems, of which the following is a specification.

My invention relates to an electric railway system, suitable for the despatch of-mail, parcels, freight, and other purposes, in which the cars or trains are without operators or motor-men thereon and are controlled from points external to the cars or trains.

My invention resides in an electric railway system of the character above referred to in which the cars or trains are driven by motors to which is delivered alternating current energy.

My invention resides also in a method of an apparatus for electro-dynamically brak ing a car or train by ineansof its alternating current motor, particularly when it is an induction motor; and my invention resides in a method of anapparatus for electrodynamically braking an alternating current motor for whatever purpose used.

My invention resides also in a block system for the automatic or manual control of the alternating current car motor, and more particularly in a block system making possible cooperation between adjacent block sections to close and reopen the block sections under certain circumstances, particularly for the automatic control of cars.

It will be understood that my invention is not limited to the employmentof alternating current motors except where so expressly stated in the claims.

My invention resides infurther features of method and apparatus hereinafter described and claimed. I

For an illustration of one of many forms my invention may take, reference may be had to the accompanying drawings, in which:

Figure 1 is a diagrammatic view illustrating the connections between a three phase induction motor upon a car and the contact conductors for supplying current thereto. Fig. 2 is a diagrammatic view illustrating the production of a stationary field in a three phase induction. motor for braking purposes. Fig. 3 is a diagrammatic view illustrating the application of the same braking principleto a system in which the primary and secondary elements of an intor carried by and driving the car.

duction motor are developed into a plane, oneelement placed upon a car and the other element disposed permanently along the trackway so as to propel the car by cooperation with the element thereon by induction. Fig. 4 is a diagrammatic view of a terminal station together with generators and the con nections between the same and the control apparatus and the contact conductors. Fig. 5 is a diagrammatic View showing a block section complete, including control appara tus, main and auxiliary conductors, and the connections between them. Fig. 6 is a similar diagrammatic View of a station at another point of the system. Figs. 7 and 8 are diagrammatic views of alternate positions of a controller for the braking section in ad vance of a station. Figs. 9, 10 and 11 are diagrams of the three difiierent positions of the controller of a station section. Fig. 12 is a side elevation, partly in section, of a contactor. Fig. 12 is a top plan view of the arm and contacts of Fig. 12. Fig. 13 is a sectional view, some parts in side elevation, of a relay.

Referring to Fig. 1, T and T are two contact conductors extending along the path of travel or traclrway for the traveling car whose wheels travel upon the track rails T T''. S and R represent the stator and rotor respectively of a three phase induction me- The stator is for simplicity shown as wound like a gram ring, in sections or parts .9, s and 8 one per phase, but it is to be understood that any type of stator and stator winding may be employed. In the example illus trated the stator windings 8 s and s are related in delta or mesh connection with the three conductors of a three phase alternating current system of energy supply.- The rotor R is shown as of the'simple short circuit squirrel cage type, but it must be understood that my invention comprises as well the employment of alternating current motors having wound rotors with or without collector rings. And it will be further understood that the principles of my invention are present whether the primary is the stator and the secondary the rotor, or whether the primary is the rotor and the ,7 Referring to secondary the stator. And it will be further understood that my invention is not limited to the employment of three phase current, but is equally applicable to a two phase system or any system operating upon the induction or other principle in which a stationary field can be created by connecting one or more phase windings to a source of direct current. S S are the traveling contacts or collector shoes for one phase, placed preferably at or near the ends of the traveling car, and S S are the traveling contacts or collector shoes for another phase, while the traveling contact N may be a wheel or' the car through which connection is maintained with the third phase through the running rails T 1 l and I I are insulators interposed and sub-dividing contact conductors T and '1, respectively, into electrically independent sections. The distance between the insulators I I is preferably made equal to or less than the distance separating the contacting parts of the associated collector shoes S S in order that there may be no appreciable interruption of the current supply to the motor while the car is passing over the sections. The short section of contact conductor between two insulators such as 1 I is insulated from the main power current supply afforded through contact conductors T T and connects by conductor m with control apparatus, 7

Fig. 2 the rotor R and stator Sare represented as in Fig. 1. D is a source of direct current, such as a direct current generator of suitable voltage, one

of whose terminals t is connected to both terminals of windings nor the stator Sand whosev other terminal t is connected with the'common terminal of windings s and s of'the stator. Under these circumstances a stationary magnetic field, that is, a magnetic field which does not progress or rotate with respect to the stator, is established, and such stationary field corresponds with the magnetic field which would be moinentarily.produced once in each revolution in the same stator by the rotary magnetic field produced by the three phase current operating in the usualway. It will be obvious that if the stator winding is traversed byv direct" current as described, any rotation or movement of therotor in either direction in this stationary magnetic field will cause heavy current to be induced in the rotor conductors, and that under these circumstancesi'the further movement or rotation of the rotor in the same directionwill be powerfully resisted. In other words, the rotor, which always tends to maintain a speed synchronous with the rotary magnetic field ofthe stator when energized by alternating current now tends, in the case of application of direct current to the stator windings, to come to rest, in which case the speed of the field is zero.

In Fig. 3 the pole pieces P of the primary of an induction motor are shown developed out straightinto a plane, and the primary windings are shown in their most simple form, in star connection, together with the connections with the direct current generator D. r he effect of this excitation by direct current is to create with the arrangement of pole pieces shown, one north and one south pole, each having three poles it. It is to be understood l10\\'06l' that this could be repeated to any desired extent and any other form of lap or wave winding substituted. The secondary oi the motor in this case consists of traverse conductors embedded in laminated iron and short circuited at their ends, precisely as if any form of squirrel cage rotor were developed out straight. It will be understood that the secondary may be carried by and drive the car while the primary is distributed along the path or travel or traclrway; and it will be understood that the principle of my invention is applicable whether it be the pri mary or the secondary that is placed upon the moving car.

Referring to Figs. -l-, 5 and 6, the direction of tratiic is indicated. by the arrows, and the return tracks and rails and contact conductors are indicated in dotted lines in Figs. land (5, and are not fully illustrated since they are similar to arrangement, controls,

etc, to those hereinafter described.

In Fig. 4, a three phase alternating current generator A of suitable 'oltage and frequency for the operation of the cars at the higher speeds has one of its phase terininals connected with the bus or conductor B which is connected with the track trails T, T; and the other two phase terminals of the generator A are connected respectively with the conductors 9 and 10, which are main feeder conductors extending throughout the length of the railway line. A. second three phase alternating current generator A of voltage and frequency suitable :for starting the cars has one of its phase terminals connected with the bus or conductor B while its other two phase terminals are connected respectively with the conductors 11 and 12 which are also main feeder conductors extending throughout the length of the railway line. A direct cur rent generator D which supplies current for the electric braking of the trains by means above described, and also for the signaling and for the operation of the mechanism of the automatic block system, hereinafter described, has one of its terminals connected to the bus or conductor B and its other terminal to the main feeder conductor 8 which extends throughout the length of the railway line. As-indicated the generators A,

A and D have their shafts coupled togetherand are driven by any suitable means such as the engine or motor E. It is to be understood however that, except when the advantage from such mechanical connection of the generators hereinafter described is desired, each generator may be separately driven, or any two of them mechanically coupled with each other. A three phase transformer T serves to step down or reduce the voltage of the alternating current generator A" to a voltage suitable for mow ing a car at slow speed. within the stations. Two of the secondary phases of this transformer are connected with conductors 19 and 20 respectively while the third phase terminal connects with the bus or conductor B connected to the track rails T, T. The conductors l9 and 20 communicate with the manually operated controllers (l and C of which (l controls the cars upon their arrival. at the station and C controls thi-u'n within the station.

As shown in Figs. l and (3, both controllers C and C are in their normal or braking positions in which. direct current is supplied through them to the two contact conductors T and T of their respective sections. This operation will be understood by reference in this connection to Fig. 1, from which it will be understood that through these controllers Figs. l and 6, direct current from generator D passes through conductor 8. to contacts 3 of the controllers, through the controllers through their contacts 4: and 5 connected in parallel to the contact conductors T and T respectively. From these contact conductors T and T as will be understood from Fig. 1, current passes through traveling contacts S and S through phase windings s and sof the motor stator S back through traveling contact or car wheel to the running rails T", and then to the other terminal of the generator D, Fig. at. This direct current excitation of the stator, as explained in connection with. Fig. 2, causes the electrodvnamic braking of the car by the motor. This same braking position of the controller G shown in Fig. 8, while in Fig. 7 another position of the controller C for starting the car or train is shown. In this latter position contacts a and are again in communication with the contact conductors T and T respectively and through the controller with contacts 2 and 1 respectively in communication with conductors 20 and 19 respectively of the step down transformer T As a result, low voltage low frequency energy from generator A will be supplied to the motor stator S through contact conductors T and T the third connection being through the wheel or traveling contact Vi with the track rails T '1 connected through conductor B with the third terminal of the secondary of trans- I quenc'v from the generator A over the insulators ll 1" the car passes on former T". This energy causes the motor to rotate and to drive the car at low speed. Thus it will be understood that a car or train arriving from the right toward the left, Fig. -l-, or from the left toward the right, Fig. 6, will be braked and brought to rest because the controllers C are normally in the braking position. Then the operators at the stations may shift the controllers to the positions corresponding with F 7 in which case the car is re-started at slow speed and delivered on to the station section controlled by controller U As previously stated the normal condition of each controller C is the braking position for bringing the car to rest on the station section. As shown in Fig. 9, each controller C has a position for starting the car or train forward as described in connection with Fig.7 with relation to controller C The braking position of controller C above referred to, is shown in Fig. 10; but the controller C has a third position, indicated in Fig. 11, for reversing the motor and driving the car baclnvardly.

Comparing Fig. 11 with. Fig. 9 it will be seen that therelations of contacts -l and 5 \1'6 reversed with respect to the supply contacts 1 and 2. This means that by throwing the controller C" into position shown in Fig. 11, the contact conductors T and T are interchanged in their relations with respect to the secondary of the t 'ansformer T whereby the direction of 'nogression of the rotary magnetic field produced by the stator of the motor is reversed with consequent reverse in direction of the torque developed by the motor. 1

By throwing the controller 0 into the starting position, Fig. 9, a car or train will move forward in the direction of the arrows from the station section of Fig. l, over the insulators 1 I and enters upon the section between l? and 1*, whose contact conductors T and T are adapted to be brought by contactor K into communication through conductors 11, 12 receiving current from the generator al This section may be an acceleration section whereon the cars are accelerated to a predetermined intermediate speed, at which speed they may safely leave the section and pass on to the next section 1*, l" which supplies current at higher fre- Un passing to the section between I and l where the motor takes current from conductors 9, 10 at the aforementioned higher frequency from alternator A and on this section the motor and car are accelerated to full speed. It then passes over the block sections. Fig. 5, and arrives at another station, Fig. 6,. where it passes over insulators l, I on to the section I, 1 whose cont-act conductors T and T are in communication through Elli) rect current thereto.

conductors l1 and 1:2 with the low frequency generator A The motor arriving on this section While it is running at a speed above synchronism for the frequency of generator AF, the kinetic energy of the car is more or lessabsorbed by driving the induction motor .at this supersynchronous speed in which case it is an asynchronous or induction generator delivering current back into the conductors 11, 19.. The speed of the car is thus reduced by this regenerative action and when it is reduced to the point where the speed of the motor is below synchronism for the frequency of generator A the generator A? drives the motor and car forward until the car passes over the insulators I I on the section l 1 under the control of controller C which in its normal position causes the braking of the motor by application of di- On this section the ca r will come to rest or may be admitted to the station section I I by shifting the controller C to the starting position, Fig. '7.

The braking upon the section I, ll being regenerative, as above explained, the energy given up by a car as its speed decreases is usefully employed in assisting the generator A to driveany other car at the time in communication with such generator, or is employedin' directly driving another car that may be at the'same time accelerating While in communication with the feeders 11,

12; or the energy delivered by a car being so negatively accelerated may drive the ternator A as a motor, or assist it to such extent that the ener Y iven 113 bv the car isdelivered through the coupling between the generator A and the generators A and D to drive or assist in driving them, or either of them, so that in fact the energy being given up by a car-so negatively acc-elerating is usefully applied in other parts of the system for driving or braking them, or supplying current for the control or signal circuits, or for any other purpose.

If desired, a greater number of steps in both the positive and negative acceleration of the cars can of course be obtained in the same Way by employing additional alternators delivering current at other frequencies and similarly associating them with the sections and controllers. And as to the brain ing by employment of direct current there 'may be introduced into the direct current circuit, at the inception of the braking action, a'resistance, thus preventing too strong a stationary field while the car is still traveling at high speed; this resistance may be entirely cut out or cut out by steps to further increase the strength of the stationary field. I

For the purposes'of the automatic block system the railway line is divided into blocks, and each block is sub-divided into sections to permit stepby-step braking when it is necessary to bring a car to rest in the block and stepby-step acceleration in re-starting it, the braking and acceleration being accon'iplished as hereinbefore described.

Fig. 5 illustrates one complete block extending between insulators l" and I, there being thus two sections 1', I and I, I. The section 1*, 1 corresponds with section 1, I of Fig. 6 above described and serves to decrease the speed of a car down to the intermediate siced, and upon entry to section I, I the car may be braked from intermediate speed to rest, and re-startcd and accelerated to the intermediate speed.

The block sections are under the control of contactors K K K, K, etc, which are shown diagrammatically in Figs. 4-, 5 and 6. Any suitable type of contactor may be employed for this purpose. An illustration of one type which may be used is found in Figs. 12 and 12 in which S and S represent solenoids having cores C and (1, connected respectively through links U and L with the arm A pivoted at P and carrying at its one end the contacts B, B adapted to enter between and make contact with the contacts I, l and P P respectively; and carrying at its other end the contacts B", B P adapted to enter between and bridge the contacts P P 1 P and P P" respectively. The contacts 13 and P l?" are omitted from contactors K K and K lVhen solenoid S is energized contacts P P and P 1 are bridged and remain so until solenoid S is energized when contacts P P, P 1"" and P" P" are bridged and remain so until the solenoid S is again energized. Contacts P P are permanently connected with each other by conductor P as are also P 1" by conductor P The section I 1*, Fig. i, is controlled by contactor K which in its normal position connects the contact conductors T and T of this section with the intermediate mains 11 and 12, and which in its other position connects contact conductors T T to the direct current main 8 for braking purposes. In Fig. elcontactor K is shown in this its other or braking position, its solenoid S having been last energized thus connecting conductor 8 through contacts P", P and contacts P P with the contact conductors T and T respectively. And when the contactor K is in its other position in response to energization of its solenoid S, intermediate main 11 connects through contacts P and P with contact conductors T and main 12 connects through contacts P and l loo mains 9 and 10 through P P and P P And in its other position, in response to energization of its solenoid S connects these same contact conductors to the intermediate trequency mains 11 and 12, through P P and P P this being the position indicated in Fig.

The section 1?, I is under the control of the two contactors K and K Contactor 1K in its one position connects both contact conductors T and T of this section with the direct current main 8 through the contacts P P and P P this being the braking position indicated in Fig. 5, pursuant to energization of its solenoid S In its other or normal position contactor K connects the contact conductors T and T ith the contactor K"; thus in response to energization of solenoid S of contactor K? these contact conductors T and '1 connect through contacts P P and P, P with conductors (Z and a connected to contacts 1 and P of contactor K which normally, that is, pursuant to energization of its solenoid 5%, connects its contacts P and P through its contacts 1 and P with the high frequency mains 9, 1O communicating with the generator A contactor K in its alternative position, that illustrated in Fig. 5, connecting its said contacts P and P with its contacts P P connecting with the intermediate or low frequency mains 11 and Accordingly this section 1 I has three possible connections, one for braking, an

other for starting and the third for full,

speed. These contactors are controlled by the relays R R R R, R and R which control. the solenoids of. these contactors. These relays are shown diagrammatically in Figs. 1, 5 and 6 and may be of any suitable type. One suitable form of construction is shown in Fig. 13.

In Fig. 13 there is shown a horizontal section, some parts in plan, of a suitable type of relay, the solenoid core C being disposed horizontally and related to the solenoid coils S and S l/Vhen the solenoid S is energized it draws the core C in the direction of the arrow. VV "W are contacts between which passes the metallic sleeve 7' which is mounted upon the brass rod 9 attached to the core C The sleeve 7 in the position shown bridges or connects the contacts W Vi. When the core C is moved in opposite direction by energization of solenoid S the insulating material it comes between the contacts N thus breaking circuit between them.

In the case of relay R Fig. 5, a second pair of stationary contacts N W are shown. In this case when its solenoid S is energized connection between contacts W between contacts W and established between contacts W, W. The solenoids S of the relays are connected between direct current main 8 and the short sections 13 18, 14c 14, to 18 18, respectively. As a car passes over one of these short sections current will flow from the direct current main '8 through the solenoid S. of the corresponding relay to one of these short sections disposed between neighboring sections or" the contact conductor T for example. From such short contact conductor section the current passes (see Fig. 1) through the traveling contacts or shoes S S through the stator winding of the motor, through traveling contact or wheel W to the track rails T T which are connected with the other terminal of the direct current generator 1). Thus connection is made first through the forward contact shoe S and then through the rear contact shoe S communication therefore lasting during the time required for the car to travel twice the distance between the shoes 3 ,3 The alternating current in the stator winding of the motor does not affect the passage ofthe direct current therethrough and as the resistance of the stator or primary winding of the motor is negligible as compared with that of the solenoid S the effect is substantially the same as if the circuit through the solenoid S were closed through a path carrying in all parts. only direct current; and the strength of the direct current passed through solenoid S and the stator winding is too small to atl'ect the motor and the sell? induction of the solenoid is too great to per mit it to be appreciably affected by alter nating current. If desired further self-induction can be introduced into the direct current system as by inserting the inductance S', Fig. 1, between one terminal of the generator D and the bus B.

When the relays are operatedby energization of the solenoids S connection is establishedthrough their contacts V1 W between the direct current main 8 and the auxiliary conductors 13, 14, 15, 16, 17 and 18 respectively, extending along the railway. These solenoids S of the relays are each connected between the track rails T, T and the auxiliary conductors of the succeeding relays, respectively, with the result that each relay, as it is operated, restores the preceding relay to its normal position. For eX- ample, when the solenoid S of relay B is energized. connection is made from the direct current conductor 8 through the con tacts W WV of relay R thus connecting conductor 8 withconductor 1 1 which it will be found, Fig. 4, connects through solenoid S of relay R with the track rails T T Accordingly when solenoid S of relay R is energized solenoid S of relay R is energized thus breaking connection between contacts W W of relay R With these auxiliary conductors are connected also lamps or other signaling devices as L L L L and L Figs. 4 and 6, whose other terminals are connected to the track rails T T Accordingly when a car has passed on to section 1 I solenoid S of relay R has been temporarily energized, thus bridging its contacts W 7 and placing conductor 13 into communication with conductor 8so that current flows therefrom through conductor 13, light or indicating device L to the track rails or other terminal of the generator D, thus causing L to glow, if a lamp, or to give any other indication if it be of another type of indicating device. This would indicate to the operator in the station that there is a car on the first section and the same indication would be given at the station in Fig. 6 through device L at that station connected in parallel through conductor 13 with the device L in Fig. 4. And so on throughout the line indicating devices will indicate in succession and show to the operators at the stations the location despatched from the. station section, Fig.4,

to the section 1 I in passing over the short section 1 I the relay R is operated lightingthe lamps L in both stations, as above described. WVhen the car reaches the short section I, 1*, it operates the relay R by its solenoid S bringing auxiliary conductor 14 into communication with direct current main 8, thus energizing solenoid S of relay R to interrupt connection between direct current main 8 and conductor 13 with the result that lamp L at both stations are extinguished. But there is also a con ncction between conductor 14s and the solenoid S of contactor K which is therefore operated to connect the contact conductors T and T with the direct current main 8, this being the braking or closed position of section 1 I as illustrated in Fig. 4. If now another car should be dcspatched by controller on to section 1 I it will be braked to rest on this first section because of the above-described position ofcontacsolenoid S which is in communication with conductor 15 which has been brought into communication with conductor 8 by solenoid S of relay B through its contacts Vi, Vi, and causes extinction of previously lighted lamps, and energizes others of the indicating lamps at both stations in the manner above described. Proceeding, the car passes over short section I, 1, operating relay R which brings conductor 16 into communication with direct current main 8. This conductor 16 will be found to have connections with solenoids S of contactors K K and K that is, all of the contactors of the sections of Fig. 5, thus closing the block by the contactors taking the position shown in Fig. 5; that is, the first section 1 P is in communication with the low frequency mains 11 and 12, and the next section I, I is in the braking condition. The conductor 16 has a further connection with the solenoid S of contactor K, Fig. 4:, and the other terminal of this solenoid S, instead of being connected directly to the return rails T, T, is connected with conductor 21 which extends along the railway to the contactsP", P, of contactor K through which contacts P P" conductor 21 communicates with the track rails T T when the contactor K is in the closed position shown in Fig. 5. Accordingly the car in passing over the block, Fig. 5, closes it and because of energization of solenoids S of contactor K Fi g. l, opens the preceding block on a section thereof, because, upon ener ization of its solenoid S, contactor 19 will dis-connect the contact conductors T T from direct current main 8 and bring those contact conductors into communication with low frequency conductors 11, 12. Such opening of a preceding block or section of a block is absolutely dependent upon the closure of the succeeding block, so that a block once closed cannot be opened until the succeeding block is closed. Proceeding, the car passes over the short section I, l. the preceding block remaining closed, since, notwithstanding the interruption of connection between conductor 16 and conductor 8 by energization of solenoid S of relay R by relay It, the contactors K K and K remain in the conditions illustrated. in Fig. 5 through their solenoids S have been de'e'nergized. ith the controller C in the position shown in Fig. 6, the car would now come to rest in the position indicated for the motor, M Fig. 6. If a second car be following, it will come to rest at M F 5, on the section I, I which has been put into braking condition by contactor K and the lamps L and L will remain lighted in both stations so long as these sections are occupied.

The first car may now be caused to enter the station, Fig. 6, by throwing the coin troller C at that station into the starting position. Passing over the short section 1 I the car causes the relay R to be actuated lOE') by its solenoid S thus bringing the auxiliary conductor 18 into communication with the direct current main 8. Conductor 18 is connected with the solenoid S of contactor K", and with solenoid S of contactor K and also, through contacts W, W of relay it with solenoid S of contactor K the remaining terminals of these three solenoids ti communicating with conductor 22 which connects through contacts 6 and 7 of controller C Fig. 6, when in the braking position there indicated, with the track rails T, T

If the block, in Fig. 5, is unoccupied, the relay R will be in its normal position with its contacts W bridged or connected with each other, and connection of conductor 18 at such time with conductor 8 will cause current to flow through the solenoids S of all thecontactors controlling the block of Fig. 5, thus opening the block, that is, connecting its contact conductors with the high frequency mains 9 and 10. If, however, the block is occupied, as indicated in Fig. 5, by a motor M the relay R will be in its alternative position as illustrated in Fig. 5, and connection between contacts W", W is interrupted while contacts W W of relay R are bridged or connected. In this case connection of conductor 18 with conductor 8 will cause current to flow through solenoids S of contactor-s K and K but not through solenoid S of contactor K. This would cause connection of contact conductors T and T of section I I with the high frequency mains 9 and 10 and the connection of contact conductors T T of section 1*", l, to the low frequency intermediate or starting mains 11, 12, through the left hand contacts of contactor K conductors (Z, e and the right hand contacts of contactor K The connection of the conductor 22 with the controller C as described, insures against energization of any of solenoids S of contactors K K and K when the controller C is in any other than the braking position. Accordingly after a car has been admitted to the station, the preceding block section cannot be opened until the controller has beenreturned to the braking position.

. Since one terminal of the solenoid S of relay R is connected with conductor 16, the relay It is reset by energization of its sol.e noid S by the neXt approaching car pass ing over short section I, I operating relay R bringing conductor 16 into communication with conductor 8 through its contacts VV'" It will of course be understood that there canbe any number of blocks on the railway according to its length or the distance between stations; and that each block may have more sections than herein described.

And, it will be also understood that step-bystep braking may be accomplished, if desired, by impressing direct current of dif ferent voltages upon the primary winding of the motor.

It is obviousthat modifications may be made in the method and apparatus for car'- rying the various features of this invention into effect without departing from the spirit and scope of my invention.

What I claim is:

1. In an electric railway system, a car, an alternating current inductionmotor thereon for driving the same, contact conductors extending along the path of travel of said car for delivering alternating current to said motor, and switching means external to said air communicating with the primary of said motor through said contact conductors and with a source of uni-directional current for braking said car.

2. In an electric railway system, the combination with a car of an alternating current induction motor thereon for driving the same, contact conductors extending along the path of travel of said car and communicating with the primary of said motor, a source of alternating current, a source of direct ctr-rent, and a controller external to said car for disconnecting said source of alternating current from said contact conductors and connecting said source of direct current to said. contact conductors for braking said car.

3. In an electric railway system, a can a polyphase induction motor tiiereon for driv ing the same, a plurality of contact conductors extending along the path of travel of said car and connnunica ting with the different phase windings of the primary of said motor, a source of direct current, and a controller external. to said car for connecting said source of direct current to said contact conductors for delivering direct current through the primary windings of said. motor for braking said car.

l:- in an electric railway system, a car, an alternating current motor thereon for driving the same, contact conductors extending along the path of travel of said car for delivering alternating current to said motor, sources of alternating current of different frequencies, a controller external to said car controlling connection between said contact conductors and one of said sources delivering current of one frequency, and means for connecting independent sections of said contact conductors with another of said sources delivering current of another fre quency.

5. ln an electric railway system, a car, an alternating current motor thereon for driving the same. contact conductors extending along the path of travel of said car for delivering alternating current to said motor,

' conductors and one of said sources delivermg current or one frequency, and automatic means for connecting independent sections said contact conductors with another of said sources delivering current of another frequency.

'6. In an electric railway system, a car, an

alternating current motor thereon for driving the same, a block comprising aplurality of sections of contact conductors, a source of direct current, a source of alternating current, automatic means for connecting said source of direct current with said contact conductors for braking said car and for connecting said source of alternating current with said contact COlltiUCtOiS for driving said car, and a controller external to said car controlling said automatic means.

7. In an electric railway system, a car, an alternatingcurrent motor thereon for driving the same, a block comprising a plurality of sections oi contact conductors, a source of direct current, sources of alternating currents of different frequencies, automatic means for connecting said direct current source with said contact conductors for braking said car and for connecting a source of alternating current oflow frequency with conductors for starting said car and for connecting another of said sources of alternating current of higher frequency with said conductors for driving said car at higher speed, and a controller external. to said car controlling said automatic means.

8. In an electric railway system, an alter nating current motor thereon for driving the same, contact conductors extending along the path of travel of said car in communication with said motor, a source'of alternating current, automatic switching means external to said car controlling connection between said source and said contact conductors, an d a controller external to said car controlling said switching means.

9. In an electric railway system. a car, an alternating current motor thereon for driving the same, contact conductors extending along the path of travel of said car in communication with said motor, a source of alternating current, switching means external to said car controlling connection between said source and said contact conductors, a. direct current circuit controlling said switching means, and a controllerexternal to said car controlling said circuit.

10. In an electric railway system, a car, an alternating current motor thereon for driving the same, contact conductors extending along the path of travel of said'car in communication with said motor, a source of alternating current, Switching means external to said car controlling connection between said source and said contact conductors, a direct current circuit controlling said switching means, means cooperating with said car controlling said direct current circuit, and a controller external to said car controlling said switching means.

11. In an electric raihvay system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, sources of alternating and direct current, and switching mechanism controlling connection of said sources with said contact conductors.

12. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said our and communicating with said motor, sources of alternating and direct current, and switching mechanism for connecting said sources with said contact conductors at different times.

13. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said our and communicating with said motor, sources of alternating and direct current, and switching mechanism external to said car controlling connection of said sources with said contact conductors.

14:. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said our and communicating with said motor, sources of alternating and direct current, and switching mechanism external to said car for connecting said sources with said contact conductors at dili'ercnt times.

15. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, sources of alternating and direct current, switching mechanism external to said car controlling connection of said sources with said contact conductors, a circuit controlling said switching mechanism, means coiiperating with said our controlling said circuit, and a controller external to said car controlling said switching mechanism.

16. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, sources of alternating and direct current, switching mechanism external to said car for connecting said sources with said contact conductors at dillerent times, acircuit controlling said switching mechanism, means cooperating with said car controlling said circuit, and a controller external to said car controlling said switching mechanism.

17. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and conni'innicating with said motor, a source of direct current, and means for closing the circuit of a winding of said motor through said contact conductors and said source of direct current.

18. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and comnninicating with said motor, a source of direct current, automatic means responsive to movement of said car for closing a circuit through a winding of said motor and said direct current source and said contact conductors, and a controller external to said car controlling said means.

19. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, a source of direct current, and means external to said car for closing the circuit of a winding of said motor through said contact conductors and said source or" direct current.

20. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, a source of direct current, automatic means external to said car responsive to movement of said car for closing a circuit through a winding of said motor and said direct current source and said contact con ductors, and a controller external to said car controlling said means.

21. In an electric railway system, a car, an alternating current induction motor thereon, contact conductors extending along the path of travel of said car and communicating with St id motor, sources of direct and alternating current, and means for dis-connecting one of said sources from and connecting another of said sources to said contact conductors.

In an electric railway system, a car, an alternating current induction motor thereon, contact conductorsextending along the path of travel of said car and communicating with said motor, sources of direct and alternating current, automatic means responsive to movement of said car for dis connecting one of said sources from and connecting another of said sources to said contact conductors, and a controller external to said car controlling said means.

23. In an electric railway system, a car, an alternating current induction motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, sources of direct and alternating current, means for dis-connecting one of said sources from and connecting another of said sources to said contact conductors a circuit controlling said means, and

means external to said car cooperating with said car to control said circuit.

2a. In an electric railway system, a car, an alternating current induction motor thereon, contact conductors extending along the path of travel of said car and communicat ing with saidmotor, a controller external to said car, a source of direct current, and connections whereby said controller brings said source of direct current into circuit with said motor throughsaid contact conductors.

In an electric railway system, a car, an alternating current induction motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, a controller external to said car, and sources of direct and alternating current, said controller in one position connecting said motor through said contact conductors with a source of alternating current and in another position with a source of direct current.

26. In an electric railway system, a car, and alternating current induction motor thereon, contact conductors extending along the path of travel of said car communicating with said motor, means dividing said contact conductors into sections, a source of direct current, electro-magnetic means associated with a section of said contact conduc tors for connecting said source of current therethrough with said motor, and switching means associated with another section of said contact conductors, said switching means in one position causing delivery of sa d direct current to said motor through sa d contact conductors, and in another pos1t1on connecting said motor through said contact conductors with a source of alternating current.

27. In an electric railway system, a car, and alternating current induction motor thereon, contact conductors extending along the path of travel of said car communicating with said motor, means dividing said contact conductors into sections, a source of direct current, electro-Inagnetic means associated with a section of said contact conductors for connecting said source of cur- .rent therethrough with said motor, and

switching means associated with another section of said contact conductors, said switching meansin one position causing delivery of said direct current to said motor through said contact conductors and in another position connecting said conductors with a source of alternating current, and a circuit controlled by said switching means preventing interruption of connection between said source of direct current and said first named section until said switching means is returned to position for connecting said second section with a source of direct current.

28. In an electric railway system, a car,

and alternating current induction motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, means dividing said contact conductors into sections, a source of direct current, electro-magnetic means associated with a section of said contact conductors forconnectlng said source of current 'there'through with said motor, and switching means associated with another section of said contact conductors, said switching means in one position causing delivery of said direct current to said motor through said contact conductors, and in another position connecting said motor through said contact conductors with a source of alternating current, a circuit controlled by said switching means preventing interruption of connection between said source of direct current and .said first named section until said switching means is returned to position for connecting said second section with a source of direct current, and a third section in advance of said first named section, electromagnetic means associated with said third section for connecting the same with a source of either direct or alternating current, and a circuit controlling said last named electromagnetic means and controlled by said electro-magnetic means of said first named section for disconnecting said third section from a source of direct current when said first named section is connected with a source of direct current.

29. In an electric railway system, a car,

an alternating current induction motor thereon, contact conductors extending along the path of travel of said car and communieating with said motor, sources of direct and alternating current, electro-magnetic means for connecting said contact conductors with either a source of direct or a source of alternating current, and a controller external to said car controlling said means.

30. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, sources of alternating current of different frequencies, electro magnetic means in one position connecting said contact conductors with a source of alternating currentand in another position connecting said contact conductors with a source of alternating current of different frequency, and a controller external to said car controlling said means.

31. In an electric railway system, a car, an alternating current induction motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor,-sources of direct and alternating current, electro-magnetic means for connecting said contact conductors with either a source of direct or a source of alternating current, a circuit for controlling said electro-magnetic means, means cooperating with said car controlling said circuit, and a controller external to said car controlling said electro-magnetic means.

, In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, sources of alternating current of different frequencies, electro-magnetic means in one position connecting said contact conductors with a source of alternating current and in another position connecting said contact conductors with a source of alternating current of different frequency, a circuit for controlling said electro-magnetic means, means cooperating with said car controlling said circuit, and a controller external to said car controlling said electro-magnetic means.

33. In an electric railway system, a car, an alternating current induction motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, sources of direct current and of alternating current of different frequencies, electro-magnetic switching mechanism in one position connecting said contact conductors with a source of direct current and in another position connecting said contact conductors with a second electro-magnetic switching mechanism, said second electro-magnetic mechanism in one position connecting said contact conductors with a source of alter nating current and in another position connecting said contact conductors with a source of alternating current of different frequency, and a controller controlling said first named switching mechanism.

3%. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, said contact conductors divided into independent sections, sources of direct current and of alternating current of different frequencies, electro-magnetic switching mechanism associated with a section of said contact conductors and adapted to disconnect said contact conductors from a source of alternating current of one frequency and connect said contact conductors with a source of alternating current of dif ferent frequency, and electro-magnetic switching mechanism for connecting said contact conductors of another section with a source of direct current or with a source of alternating current, and a controller controlling said switching mechanisms.

In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, said contact conductors divided into independent sections, sources of direct current and alternating current of (litterent frequencies, electromagnetic switching mechanism associated with a section of said contact conductors and adapted to disconnect said contact conductors from a source of alternating current of one frequency and connect said contact conductors with a source of alternating current of different frequency, electromagnetic switching mechanism for connecting the contact conductors of another section with any of said sources of current, and a controller controlling said switching mechanisms.

86. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, sources of direct current and alternating current, means for connecting said contact conductors with a source of alternating current, a contact conductor in terrupted by a section of contact conductor, a control circuit adapted to be closed through a source of direct current said section of contact conductor and said motor, a relay in said control circuit, a circuit controlling said means controlled by said relay, and a controller controlling said means.

37. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, sources of direct current and alternating current, means for connecting said contact conductors with a source of alternating current, a contact conductor interrupted by a section of contact conductor, a control circuit adapted to be closed through a source of direct current said section of contact conductor and said mot r, a relay in said control circuit, and an indicator controlled by said relay.

38. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, sources of direct current and alternating current, means for connecting said contact conductors with a source oi alternating current, a contact conductor interrupted by a section of contact conductor, a control circuit adapted to be closed through a source of direct current said section of contact conductor and said motor, a relay in said control circuit, and a circuit for resetting a relay controlled by another section of said contact conductor controlled by said first named relay.

39. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, means for dividing said contact conductors into a plurality of longitudinal sections, sources of alternating current of different frequencies, a source of direct current, a controller for connecting a section of said contact conductors with said source of direct current for braking said motor, a second section in advance of said section, connections from. the contact conductors of said second section with a source of alter nating current of low frequency, a third section in advance of said second sec ion, and means for connecting the contact conductors of said third section with one of said sources of alternating current of higher frequency.

4-0. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, means for dividing said contact conductors into a plurality oi longitudinal sections, sources of alternating current of different frequencies, a source of direct current, a controller for connecting a section of said contact conductors with said source of direct current for braking said motor, a

second section in advance oi said section,

connections from the contact conductors of said. second section with a source of alternating current of low frequency, a third section in advance of said second section, electr anagnetic means for connecting the contact conductors of said third section with any of said sources of current, and a circuit controlling said electro-magnetic means controlled by said controller.

4-1. in an electric railway system, the combination with a car, of an alternating motor thereon, contact conductors extending along the path of travel of said car, a block section, automatic means associated with the contact conductors of said block section for opening and closing said block section, a section of contact conductors following said block section, a controller associated with the contact conductors of said following section for bringing said motor into a braking circuit, said controller having contacts preventing opening of said block section. except when said controller is in braking position.

42. lin an electric railway system, the combination with a car, of an alternating current motor thereon, contact conductors extending along the path of travel. of said car, a block section, automatic means associated with the contact conductors of said block section for opening and closing said block section, a. section of contact conductors following said block section, a controller associated with the contact conductors of said following section for bringing said motor into a braking circuit, said controller having contacts preventing opening of said block section except when said controller is in braking position, and a third section between said block section and said following section for reducing the speed of said motor.

43. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, sources of direct current and alternating current, means for connecting said contact conductors with a source of alternating current, a contact conductor, a control circuit adapted to be closed through a source of direct current said section of contact conductor and said motor, a relay in said control circuit, a circuit for resetting a relay controlled by another section of said contact conductor controlled by said first named relay, and indicators controlled by said relays.

44:. In an electric railway system, a car, an alternating current motor thereon, contact conductors extending along the path of travel of said car and communicating with said motor, a source of alternating current, and a controller in one position connecting said contact conductors with said source of alternating current and in another position reversing the connections between said contact conductors and said source of alternating current for reversing said motor.

45. In an electric railway system, a car, an alternating current motor thereon, con tact conductors extending along the path of travel of said car and communicating with said motor, sources of direct and alternating current, and a controller in one position connecting said contact conductors with a source of direct curent and in two other positions connecting said contact conductors with a source of alternating current, said controller in one of said last named positions reversing the crmncctions between said contact conductors and said source of alternating current for reversing said motor.

In testimony whereof I have hereunto affixed my sigiiiature in the presence of the two subscribing witnesses.

KENNETH E. STUART.

\Vitnesses N. E. ROGERS, O. J. VVonTrr.

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

Washington, I). C.

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