US340685A - sprag-ue - Google Patents

Description

(No Model.) 2 ShetsSheet 1.

F. J. SPRAGUE.

ELECTRIC RAILWAY.

No. 340,685. Patented Apr. 27, 1886.

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(No Model.) 2 SheetsSheet 2.

P. J. SPRAGUE.

ELECTRIC RAILWAY. N0 340,685. Patented Apr. 27, 1886.

UNITED STATES PATENT OFFICEO FRANK J. SPRAGUE, OF NE\V YORK, N. Y.

ELECTRIC RAILWAY.

To ctZZ whom it may concern Be it known that I, FRANK J. SPRAGUE, of New York city, in the county and State of New York, have invented a certain new and useful Improvement in Electric Railways, of which the following is a specification.

In an application for patent filed by me of even date herewith 1 have set forth means for braking an electric railway car or train, such means being an im n'ovement on those set forth in my Patent No. 318,668, dated May 26, 1885. In that patent the train was braked by increasing the counter electro-motive force of the motor until it should overcome the initial, whereby the dynamo-electric machine, which normally acts as a motor to propel the train, becomes a braking-generator, and the energy of the moving train is expended in current upon the line. In this case, after the machine becomes a generator, it is necessary to continue to increase the field magnet strength, because the decrease in speed of the train tends to diminish the counter electromotive force, and this tendency has to be counteracted. When the limit of increase of field strength is reached before the train stops, other means have to be employed, as stated in the patent referred to, to bring the train to a complete standstill. In the application mentioned this was accomplished by closing a local armaturecircuit through a resistance, leaving the fieldmagnet .in connection with the line, whereby the energy of the moving train was expended in said local circuit.

My present invention relates to an improvement upon this; and it consists, mainly, in placing in said local circuit the operating magnet or magnets of an eleetro-magnetic brake acting,when energized, upon the wheels of the car. The power of this brake may be regulated by varying the strength of the field magnet ol' the machine, or an adjustable resistance may be placed directly in the brakeeircuit for this purpose, or both may be used. I prefer to provide, also, means whereby, in case of any accident to the machine, or for any other purpose, the line current may be thrown upon the brake-magnets to stop the train.

My invention is illustrated in the annexed drawings, in which Figure 1 is a plan View of a railway-car truck. and motor with the con- "OIFICATION forming part of Letters Patent 1013401385, dated April. 2'7, 1886.

Serial No. 183,894. (X0 model.)

nections in diagram, the same running under ordinary conditions; Fig. 2, a similar view of the same truck with the machine running as a generator and the brake in action, and Fig. 3 a side view of an electro magnetic brake which I prefer to use. p

A is the truck of a car. B is the armature, and G the field-niagnet,ot the dynamoelectric machine, mounted upon the truck and normally propelling or assisting to propel the car. It is preferred to place a motor upon each truck of each car of a train. Motion is communicated from the armatureshaft of the mo tor to the driving-axle D by cog-wheels E It.

F F are the main rails of the track. These form one side of the circuit, while the other is formed by the insulated intermediate rail,G.

H H are supply-conductors connecting the track with the generating station. (Not shown.) One terminal of the motor is a spring or brush, 1, supported in any suitable manner and bearing on axle I). The other is the contact-rollers .IJ, which run on intermediate rail, G.

The switches and regulating apparatus are, for clearness,slrown in the drawings apart from the motor and car. It will of course be understood, however, that these devices are placed in any convenient situation upon or within the car.

K is the lield and arn'iature regulating apparatus, such as is set forth in my Patent No. 321,150, dated June 30, 1885. It consists of resistanceeoils a. a. for the field circuit, con- .neeted with short contact-blocks b Z) and long contact a, and coils (l d for the armature-circuit, connected with short contacts 6 c and long contact f. Arms 9 9" travel on these blocks.

IJ is the brakecircuit switch. It has three stationary contact -plates, 71 It 7:", and a moving plate, It is adapted to close the armature to line, to close the armature upon the brake-circuit, or to close the line upon the brake-circuit, 'as will be presently explained.

M is a simple circuitreversing switch for the armature-circuit, used to change the direction of rotation of the motor.

N is an adjustable resistance for the brakecircuit.

\Vhen the regulating devices are as shown in Fig. 1, the machine is running as a motor, its circuits being as follows: from contact-- spring I by wire 1 to arms 9 g ofswitch k, where the circuit divides, the field-circuit being by g, coils a a, block 0, wire 2 to fieldmagnet, and wires 3 3 to rollers J J, while the armature-circuit is from g to block f, wire 4 to circuit-reverser M, wire 5 to commutatorbrush, through armature-wire 6 to circuit-reverser again, wire 7 to plate h of switch L, plate 6 to h, wireS to wires 3 3, and to J J.

When itis desired to stop the train, the arm 9 is moved so as to cut out coils a a, strengthen the field-magnet, and increase the counter electro-motive force. This is continued until the counter electro-motive force overcomes the initial and the machine becomes a generator, and

afterward, as the train slows down, until all the coils a care cut out of circuit. The current generated will then begin to drop, and the machine would again become a motor, and the train would not be stopped; but when the two opposing electro-motive forces become equal, as will be shown by indicator S, of quantity and direction of current to still further brake the train, the switch L is shifted to the position shown in Fig. 2, which disconnects the armature from the line and throws it on the brake-circuit, the field-magnet still remaining in connection with the line. The circuits are now as follows: The

field-circuit is the same as already described.

The armature-circuit is from positive brush by wire 5, switch M, wires 13 and 9 to 10, where part goes to brake-magnets O O and part to magnets l? P, thence by wire 11. to resistance N, wire 12 to block it of switch L, contact ito h", wire 7 to switch M, wire 6 back to other commutator-brush.

The brake which I prefer to employ-though any efficient form of electromagnetic brake may be used instead-consists of two electromagnets, O O or P P,eaeh of which has an iron core, it, having pivoted to it an arm, I, carrying an iron brake-shoe, m. Normally the brake-shoes are held away from the wheels by a spring, a. The brake-shoes may have removable surfaces of non-magnetic material, if desired.

When the magnets are energized in the manner just explained, the brake-shoes become magnetized therefrom, and are attracted by the iron wheels Q Qand drawn toward the same, so as to brake said wheels. A brake apparatus of this kind is preferably placed between the two wheels on each side of each cartruck. This brake acts the same, no matter in which direction the current is. Its power may be regulated by adjusting resistance N or by regulating the strength of the field-magnet of the motor by the adjustment of arms 9', which is the preferred mode of regulation; or both may be used.

I am aware that in electromagnetic brakes it has been proposed to employ magnets with movable cores attracted toward the wheels, and also magnets which themselves are movable bodily toward the wheels. I employ, as just described, pivoted movable extensions,

which is a simple constructiomand permits of the ready removal of the wearing parts for repair or renewal.

In case of any accident occurring to the motor when it is desirable to quickly arrest the momentum of the train, the line-current may be thrown upon the brake-magnets by turning switch L to its third position, so that plate t bridges h h. This makes the circuit from brush I, wire 1, regulator K, wires 4, 9, and 10 to brake-magnets, wire 11, resistance N, plates h i h, wire 8, wires 3 3 to J J.

I do not claim herein, broadly, the local armature-circuit, or said local circuit including an adjustable resistance, when the field-magnet is normally connected with the line, since these features are claimed in the'application above referred to.

While I have described my invention only with reference to a simple shunt-wound machine, it is evidently equally applicable to a compound machine having main field-coils in shunt relation to the armature and other fieldcoils in series with the armature. In this case the main field-coils remain connected with the line when the connection of the armature and series coils is changed.

What I claim is- 1. The combination,with a car or train of cars on an electric railway, of a braking-generator operated 'by the motion of the train, having its main field-magnet coils supplied from the line and its armature supplying a local circuit, and an electro-magnetic brake operated by the current in said local circuit, substantially as set forth.

2. The combination, with a car or train of cars on an electric railway, of abraking-generator operated by the motion of the train, having its main field-magnet coils supplied from the line and its armature supplying a local circuit, an

electro-ma gnetic brake operated by the current in said local circuit, and means for regulating the strength of said field-magnet, substantially as set forth.

The combination,with a car or train of cars on an electric railway, of abraking-generator operated by the motion of the train, having its main field-magnet coils supplied from theline and its armature supplying a local circuit, an electromagnetic brake operated by the current in said local circuit, and an adjustable resistance for regulating the current supplied to said main field-coils, substantially as set forth.

4.. The combination, with a car ortrain of cars on an electric railway, of a braking-generator operated by the motion of the train, having its main field-coils supplied from the line and its armature supplying a local circuit, an electro magnetic brake operated by the current in said local circuit, and an adjustable resistance in'said local circuit, substantially as set forth.

5. The combinatiomwith a car or train of cars on an electric railway, of a dynamo-electric machine having its armature-shaft mechanically connected with a driving-axle, and its main field-coils supplied from the line, means for electrically connecting the armature either with the line or with a local circuit, and an electro-magnetic brake operated by current in said local circuit, substantially as set forth.

6. The combination, with a car or train of cars on an electric railway, of a dynamo-electric machine having its armature-shaft mechanically connected with a driving-axle and its main field-coils supplied from the line, means for electrically connecting the armature with either the line or a local circuit, an electromagnetic bralce operated by current in said local circuit, and means for regulating the strength of the field-magnet, substantially as set forth.

7. The combination of a car or train of cars on an electric railway, a dynamo-electric machine having its armature-shaft mechanically connected with a driving-axle and having its main field-magnet coils supplied from the line, an electromagnetic brake, a local armaturecircuit, means for connecting said local circuit with the magnet or magnets of said brake, and means for connecting the line with said magnet or magnets, substantially as set forth.

8. The combination, with a car-wheel, of a brake comprising an electro-Inagnet having a fixed core and a movable extension of said core in proximity to said wheel, and a circuit for energizing said magnet, substantially as set forth.

9. The combination, with two car-wheels, of an electro-magnet between the same having a movable core and two pivoted extensions, each of which is in proximity to one of said wheels, and a circuit for energizing said mag net, substantially as set forth.

This specification signed and witnessed this 7th day of November, 1885.

FRANK J. SPRAGUE.

\Vitnesscs:

A. W. RIDDLE, E. G. ROWLAND.

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