US517531A - Induction electric railway - Google Patents

Description

(No Model.) 2 Sheets-Sheet 1;

G. E. ROEHL. INDUCTION ELEGTRIG RAILWAY.

No. 517,531. Patented Apr. 3, 1894.

' Fig.1.

WITNESSES:

. INVENTOR ATTORNEY \NI NAYIONAL umoeanmna COMPANY.

wAmmswN. n. c.

(No Model.) 2 Sheets-Sheet 2.

G. E. ROEHL. INDUGTION ELECTRIC RAILWAY. No. 517,531. Patented-Apr; 3,1894,

// L l l I l l I I l J WITNESSES: 7 Hug INVENTOR.

ATTORNEY UNITED STATES PATENT OFFICE.

CHARLES E. ROEHL, OF ST, JOSEPH, MISSOURI.

INDUCTION ELECTRIC RAILWAY.

SPECIFICATION forming part of Letters Patent No. 517,531, dated April 3, 1894. Application filed May 4, 1893. Serial No. 472,990. (No, model.)

Systems, of which the following is a full, clear,

and exact description.

This invention has forits object an improved method of delivering an induced electrical current to a street or tram car, for use in propelling, lighting, or heating the same.

Hitherto currents have usually been con- ,veyed to a car by one of the following methods: first, by the overhead trolley system in which a trolley arm is attached to the car makingelectrical contact with a bare trolley wire by means of a rolling wheel or sliding shoe, the trolley wire being stretched above the car and in electrical connection with the generator supplying the electrical energy; second, the conduit system, in which no overhead trolley wire is used, it being buried in a conduit and the current conveyed to the car by an arm passing down from the car through a slot in the conduit and making contact with the bare wire therein. Owing to the fact that exposed working conductors are employed in both of these systems, a low potential current must be employed which necessitates the use of large copper conductors, and where a large volume of current is to be transmitted, the cost of the copper conductors renders such construction very expensive.

It is the object of my invention to overcome the difficulties hitherto experienced in electric railway locomotion, due to the direct con nection of the railway motor on the car with the source of electric energy, by substituting for the system employing direct communication, one in which the motor has no direct connection with the generating dynamo, but is electrically insulated from it and is operated by an induced or secondary current. Many advantages result from such a system, such as the possibility of employing currents of very high tension but of small quantity and thus utilizing small'line conductors for transmitting large amounts of electrical energy.

ternating currents of hightension converted into currents of low tension by the use of a transformer or con verter, with this difierence,

however, that while in the lighting system the primary and secondary coils are fixed and immovable, in my system the primary coils are fixed and the secondary coils are mov= able. In fact, I employ two distinct circuits, the one or stationary circuit consisting of the generating dynamo, the primary coils, and the connecting wires, the otherthe movable circuitconsisting of the motor, the secondary coils, and the connecting wires; this second circuit being carried by the car which it is desired to propel. Each car will carry its ,own motor, secondary coil, and secondary core; The secondary coil and core will be carried in closed proximity to the primary coils which Will have alternating currents flowing through them. Secondary currents of an alternating character will be induced in the secondary coil, which currents will be utilized to actuate an alternating current motor, or may be first rectified and then supplied to a direct current motor of the ordinary type.

Several induction railway systems have been proposed but none have provided the means for preventing the loss of current through the primary coils when they are not in use. This is obviously a most important item, since on a road several miles in length, the loss through leakage of current through the primary coils would amount to hundreds of horse power per day, and thus render all such roads hithertoproposed commercially unsuccessful. It is upon this point that I claim a distinct advantage, as by'my novel from the coil and kept out as long as the car is to be supplied by the primary coil, thus allowing current to fiow through the latter and When the car comes along; the iron core is automatically withdrawn ICO induce a current in the secondary coil. All of this will be more fully described in the following detailed description, with reference to the accompanying drawings which form a part hereof and in which I have illustrated several of the very many forms in which my invention may be embodied; but it will be understood that I do not limit myself to the particular embodiments of the principles of my invention shown and described, nor to the details of construction pointed out, since these are onlya few plans of a great number which may be employed without departing from the spirit of my said invention.

Figure 1 represents diagrammatically and conventionally my improved induction railway system in its simplest form. Fig. 2 represents diagrammatically, a modification of my system wherein an overhead trolley wire is used. Fig. 3 is a side elevation of a car, and shows the construction and operation of one form of my induction system laid in the roadway; and Fig. 4: is an end elevation of the car and section of the roadbed.

The same letters of reference indicate the same parts in all the figures.

The induction railway system employs an alternating current, and is based upon the principle, that a coil of wire traversed by a rapidly changing current, such as an alternating or pulsating current, will induce another current in an adjacent coil, provided the latter is close enough to the former, and the induction eifect will be the greater provided the two coils are upon the same, or practically the same, iron core.

For the sake of distinction, I call the iron core upon which the primary coils are wound, the primary core, and the core upon which the secondary coils are wound, the secondary core.

In the roadway and preferably midway between the rails of the track, I locate the primary core 0 which is practically a continuous body of iron running parallel to the rails, although built up of sections. It is formed of plates or laminations of iron standing vertically and secured together in any desired manner. At suitable intervals along this core it is formed with depressed portions 0 around which primary coils P are wound. This depression is made so that the upper surface of the coil when in place will be substantially flush with the upper surface of the main core 0 which itself is flush with the surface of the roadbed. It is preferred to bring the sections of the core together end to end inside of the primary coils. The coils will be covered by plates 0' of any suitable non-magnetic material which will protect them from dirt, moisture, and injury. Adjacent to the primary coil is fixed in any suitable manner, a self-inductive resistance, consisting of a coil of wire II having a chamber inside into and out of which a soft iron core E is adapted to pass. This core is mounted upon a swinging arm or yoke e of any suitable form,which is pivoted at the point B and carries an extension which normally projects through an opening in the center of the primary core and up into the groove 0 formed therein.

These four cores E are normally held by gravity or a spring inside of their coils II. The primary coils are connected in multiple are with the main feeders W, XV which are supplied with current by an alternating current generator G. The primaries are connected on one side directly with one of the mains, but on the other side they are in series with their respective inductive resistance coils 11. It is well understood that so long as the cores E are within their coils, they will choke off and. prevent current from flowing in the branches to which they are connected and thus will prevent current from flowing in their respective primary coils. Therefore, the primary coils are practically out of the circuit while the cores E are within their coils, and the resistance which the primary coils would otherwise offer and also the leakage which might take place, is eliminated from the circuit except at the periods when the car is passing, which will be hereinafter referred to.

The car itself is represented by A; it carries the usual motor M, represented conventionally in Fig. 1. It also carries a secondary core A, the secondary coils S and the necessary circuits connecting the latter with the motor. The secondary core is a vertically laminated body of iron suspended beneath the car in any suitable manner directly over the primary core 0. This secondary core is preferably provided with a plurality of secondary coils S and with pole pieces or faces 0. located on each side of the coils and projecting nearer to the primary core than the main body of the secondary core. These pole pieces direct the magnetic lines of force and determine the shape and length of the magnetic circuit. They are, therefore, preferably provided with metallic brushes or other devices which make actual contact with the surface of the primary core and thus reduce the magnetic resistance between the two cores. The secondary core is provided midway along its under side with a downwardly projecting flange or keel as which extends throughoutthc entire length thereof and runs in the groove 0 in the primary core. This device is of non-magnetic material and its function is to strike the upwardly projecting ends of the levers or yokes e and swing them far enough to carry the cores E out of their coils and hold them in that position while the car is passing. The distance between the primary coils, the length of the secondary core and the number-of coils thereon,is to be such, that there will always be at least one secondary coil in the magnetic circuit of a primary coil.

The operation of the system is as follows: As before observed, the normal condition of the cores E is within the coils Hand no ourthe car is passing.

rent is flowing in the primary coils. When a car approaches, the forward end of the flange X strikes the projection on the yoke e and throws the core Eout of coil H; the self-induction of coil H is thereby reduced to zero or an inappreciable amount and primary coil P receives the alternating current from the mains W, W. At this time two of the pole pieces of the central core A between which are located one of the secondary coils S are approaching the active primary coil. The magnetic circuit established by the latter coil, therefore, includes all that portion of the primary and secondary cores between the two pole pieces of the secondary core and an alternating current is therefore induced in the secondary coil S, the voltage of which is in proportion to the ratio which the windings of the primary and secondary coils bear to each other, and it may be observed here that the voltage may, therefore, be as high as desired. The current thus induced in the secondary coil may be rectified by any suitable commutating devices on the car and used by an ordinary direct current motor to propel the car, or it may be used direct by an alternating current motor. As the car continues along the road, the primary coils are successively made active and inactive, in the manner described, and the coils are in circuit only when In Fig. 3 two primary coils are shown active. At the same time these produce two entirely independent magnetic circuits which induce independent secondary currents and they in turn may be joined to supply the motor. I

It will be observed that my invention differs materially from anything heretofore proposed in induction railway systems, and that its main features of advantage are the simplicity of construction and the greatest economy in operation. I have shown and described the iron cores as movable, but it will be understood that the same results may be reached by making the coil movable instead of the core, or both the core and coil may be made to move away from each other when it is desired the primary coil shall become active. The way illustrated, is, therefore, simplyone of the manyedift'erent examples which may be utilized and which the spirit of my invention embraces. The central idea is the utilization of the choking coil and the control of the same to render the primary coil active and inactive automatically. It is to be here noted also that I claim as a particular improvement and benefit of my system, that the primary or stationary iron core is parallel to the rails, forming a continuous length of iron between them, so that a secondary or movable core is always in contact with the primary core and never out of range of its inductive action, thus maintaining a practically uniform pressure in the secondary coils, and as a result, greatly increased efliciency.

All the wires used'in this system are insulated, no bare wires being employed. The

mains carrying the current from the generator may be buried in the roadway along the track, suitable provision being made for access at points where the primary coils are tapped into the mains. The self-inductive resistance will be underground and out of sight, and owing to its simplicity can'easily be maintained in order. As no electrical contacts are to be made or broken, derangement of the system is not likely to take place. It will be observed that as the primary core is made in sections, the coils may be first wound and afterward slipped over the ends when the sections of the core are laid in the road way.

At places where excessive power is required, such as grades and curves, larger primary coils may be located; this shows the flexibility of the system.

Fig. 2 shows a modification of myinvention wherein a trolley wire is used. The Wire is divided into insulated sections each of which is supplied with current from the secondary coil S which, in turn, derives its. current from the induction primary coil P, the primary coil being made active andinactive in a similar manner to that hereinbefore described. One

terminal of the secondarycoil is grounded and the current after passing through the motor therefore goes to ground.

I do not limit myself to the, exact form of the converter cores herein shown, nor to the exact manner or position of the coils thereon, as the same may be modified in various ways without departing from the spirit of my invention.

Having thus described my invention, I claim- 1. In an induction railway system, a roadbed provided with a magnetically continuous iron core separate from but extending parallel to the tracks, and aseries of primary coils located upon said core, in combination with a moving vehicle carrying a secondary core and coil in inductive relation to said primary core for the purpose set forth.

2. In an induction railway system, a road bed provided with a magnetically continuous iron core separate from but extending parallel to the tracks, and a seriesof primary coils located upon said core, in combination with a moving vehicle carrying a secondary core and coil in inductive relation to said primary core, said secondary core moving in contact with the primary core, substantially as described.

3. In an induction railway system, the combination of primary coils located along the roadway, secondary coils carried by moving vehicles and self-inductive resistances in series with the primary coils, for the purpose ling the effect of said resistances on the circuit, substantially as described.

5. In an induction railway system, the combination of a generator, mains for conveying electrical currents, a number of primary coils connected in multiple are with said mains, and each primary coil having connected in series with it a self-induction resistance, consisting of a coil of wire and an iron core movable with respect to each other, and means for antomatically moving said core and coil with respect to each other, for the purpose set forth.

6. In an induction railway system, the combination-of primary coils in the roadway, secondary coils on the vehicles, choking coils in circuit with the primary coils, said choking coils having iron cores, the cores being mounted upon pivoted levers, and a device carried by the cars which strikes said levers and moves the cores and coils with respect to each other, substantially as described.

7. In an induction railway system, a roadbed provided with a magnetically continuous, laminated, iron core separate from but running parallel to the track, and a series of primary coils evenly distributed upon said core, in combinationwith a moving vehicle carrying a secondary core and coil in inductive relation to said primary core, substantially as described.

8. In an induction railway system, a roadbed provided with a continuous iron core extending parallel to the track, in combination with coils surrounding the same at intervals, the surrounded portions being depressed or offset so that one side of the coil will be flush with the top of the core, substantially as described.

9. In an induction railway system, a roadbed provided with an iron core magnetically continuous but built in sections, the joints between which are surrounded by coils of wire, substantially as described.

10. In an induction railway system, a main circuit over which alternating currents flow, including at intervals along the roadway primary coils in combination with secondary coils and moving vehicles supplied with current from said secondary coils, and self-inductive resistance in series with each primary coil, and mechanisms carried by the vehicles for automatically varying the inductive action of said self-inductive coils, substantially as and for the purpose set forth.

In testimony whereof I subscribe my signature in presence of two witnesses.

CHAS. E. ROEI-IL.

Witnesses:

Jot-IN II. VAN BRUNT, IIUSTON WYETI-I.

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