US1429381A

US1429381A - Electrical apparatus

Info

Publication number: US1429381A
Application number: US246432A
Authority: US
Inventors: Thomas W Varley
Original assignee: Safety Car Heating and Lighting Co
Current assignee: Safety Car Heating and Lighting Co
Priority date: 1918-07-24
Filing date: 1918-07-24
Publication date: 1922-09-19
Anticipated expiration: 1939-09-19

Description

T. W. VARLEY.

ELECTRICAL APPARATUS. APPLICATION FILED JULY24, 1912.

1 129,381 Patented Sept. 19, 1922.

(114 new oz 6. V4, r

Patented Sept. 19, 1922.

UNITED STATES PATENT OFFICE.

THOMAS W. YABLEY, OF NEW YORK, N. Y., ASSIGNOR TO SAFETY OAR HEATING 6a LIGHTING COMPANY, A CORPORATION OF NEW JERSEY.

nmac'rarcn. arram'rus.

Application filed July 24,

To all whom it may concern Be it known that I, THOMAS W. VAnLn r, a citizen of the UnitedStates, and a ramdent of the city, county, and State of New York, have invented an Improvement in Electrical Apparatus, of which the following is a specification.

This invention relates to electrical apparatus, and with regard to certain more specific features, to apparatus for generatin electrical energy for the lighting of railway cars. I

Among the objects of the invention may be noted the. provision of a method of and apparatus for generating current from a variable-speed source of power with a minimum of complication of parts; and for efiiciently lighting railway cars 'with power obtained from the car axle, with a minimum of expensive regulatin devices and other auxiliary apparatus. (Stber objects will be in part obvious and in part pointed out hereinafter.-

The invention accordingly consists in the features of construction, combinations of elements, arrangement of parts, and steps and sequence of steps which will be exemplified in the structure hereinafter described-and the scope of the application of which will be indicated in the following claims. a

-In the accompanying drawing in which is shown one of various possible embodiments of this invention, the figure is a diagrammatic illustration of a car-lighting system showing my invention.

In electrical systems such as those for fur-.

nishing light and power on railway trains, great difliculty has been encountered in furnishing a dependable current at all times and at a reasonable cost. \Vith the increasing extent to which cars are interchanged and routed beyond the tracks of a. single railway, it is importantthat each car be a self-contained unitso far as its lighting is concerned, and the so-called head-end or constant-speed dynamo located at or near the engine and driven by steam therefrom,

- is not suitable for such cars in view of the lack of standarization of train-lighting voltages and for other causes. It is thus preferable to obltdin the power for lighting from ti! 1' itself rather than from some other car. The so-called straight storage 1918. Serial 1%. 246,482.

have been iound expensive ,and tirbublesome in many instances, because of the comp llcation of the parts or the lack of accurate regulation of the generator, or both.

As the description progresses, it will be seen that w1th the apparatus and method of the present invention, there is provided an axle system in which these disadvantages of expause and complication are minimized. without sacrifice of close regulation and aul tomatic operation throughout the various condltions to which such a system may be subjected.

Referring now to the accompanying drawing, there is illustrated at 1 a shaft adapted to be driven from the axle of a railway car by means of suitable transmission, such as a pulley'2 on the shaft 1, connected as by a belt 3 'to the pulley 3 on the axle 3 of the railway car. The speed of the shaft thus varies with the speed of the car. On this shaft are mounted three sets of

armature windings

4, 5, 6, as well as commutators 8, 9. The first and

second windmgs

4, 5, are associated with magnetic circuits. 10 and 11, of which parts are indicated in the drawing, and are connected with each other in such a way that the voltage of the winding 4 is opposed by the voltage of the winding 5, so that'the net voltage, which ma be measured at the

brushes

13, 14, is equal to the difference between the voltages of these two windings. The magnetic circuit 10 is excited by the field coil 15, and is normally substantially saturated throughout the ordinary range of as from the

brushes

18, 19, bearing on the commutator 9 connected to' the third or exciter armature winding 6, this latter winding being associated with the field coil 21 connected in this instance across the

brushes

13, 14. Increase of speed of the shaft 1 increases thevoltage at the

exciter terminals

18, 19, and thereby increases the current in the field coils l5, l6, and increases the flux in the magnetic circuits 10, 11, and increases the voltage in the

armature windings

4 and 5. The net generator voltage, however, measured at the

brushes

13, 14, is not increased provided the voltages in the

windings

4 and 5 have increased equally. Throughout the normail range of speed, that is, from twenty miles per hour up to an average maximum train speed, these voltages in the

windings

4 and 5 increase equally with increase of speed, and conversely decrease equally with decrease of speed. This relation between the voltages of the

windings

4 and 5 is effected through the dissimilar saturation of the magnetic circuits 10 and 11. The former circuit reaches saturation at a lower speed than the latter, and, as above noted, the characteristic curve for this circuit becomes approximately horizontal at a lower value of field current, and therefore at a lower speed than does the characteristic curve for the circuit 11 This means that with increasing speed the two characteristic curves are separated by decreasing distances, but these decreasing distances, when multiplied by the increasing speed values, to indicate the voltages in the

windings

4, 5, produce practically constant products, so

that the voltages of the

windings

4 and 5.

increase in similar amounts with increase in speed, and therefore the net generator voltage, measured at the

terminals

13, 14, is maintained substantially constant throughout speed changes. From this it is clear that throughout normal ranges of speed the voltage of the generator is independent of speed changes.

lVhen the generator is connected-to a storage battery 24, and to lamps 25, through an automatic switch 26, the operation of the generator effects the charging of the battery when the generator voltage is high enough to close the automatic switch. The generator also at such times preferably supplies current to the lamps 25, through a suitable automatic lamp regulator LR, the details of which form per se no feature of the present invention. When the generator speed is below its normal range, the automatic switch 26 opens, and thus when the train is running slowly or is at rest, the lamps 25 are furnished with current from the battery 24.

Inasmuch as the generator delivers cur rent at substantially constant voltage, the battery is protected from overcharge. In order to protect the battery from an excess of current when the battery is depleted, a

cumlative series coil 28 may be mounted on the field of the exciter in such a way as to add its effect to that of the shunt coil 21, in exciting the armature 6 which furnishes current to the

field windings

15, 16. The series coil 28 may be connected to be responsive to a function of the generator current, and as indicated in the drawing, it is preferably connected to receive the total generator current. The efl'ect of current in this series coil 28 is to produce a higher excitation in the magnetic circuits 10, 11,

for a given train speed than would otherwise be produced for that speed. In other words, the excitation is what corresponds to a higher speed than the actual speed. The characteristic curves, as above noted, approach each other with increase of speed, so that the vertical distance between them at the higher equivalent speed due to the current in the series coil 28, is less than the vertical distance between the curves at the actual train speed. The generator voltage is thus less than it would otherwise be for such train speed. And this lower voltage reduces the current that would otherwise be delivered by the

armatures

4, 5, and protects the battery from excessive current. And this of course applies, no matter what the train speed may actually be, since the characteristic curves approach each other with increase of speed throughout substantially the entire normal range of speeds.

Stated another way, the total field excitation increases with increase of speed. The net field excitation decreases with increase of speed. The net field excitation multiplied by actual speed indicates net generator voltage. Current in the series coil 28 produces abnormally high total field excitations. This means abnormally low net field excitation for that speed. And thus the generator voltage, which is indicatedby the product of net field excitation by speed, is made ab normally low by current in the series coil 28. Said series coil thus acts as a current limiting or reducing device, to protect the battery from excessive current.

At excessive speeds such as 80 miles per hour, the saturation curves of the two mag netic circuits are preferably so close together that even when multiplied by the higher speed, the resulting generator voltage is less than enough to deliver full output to the battery. The generator output is thus reduced at these excessiv'e speeds, and if desired the generator voltage may be reduced suiiiciently to cause the main switch to open at such speeds.

The operation of this apparatus is such that at all speeds it is. in stable equilibrimn. That is, upon a tendency to error, such as might be occasioned by change of speed or other variable factor, the apparatus autowith the reversed polarity of t e magnetic circuits 10 and 11, causes the polarity of the

armature windings

4 and 5 and hence the polarit of the generator at its

terminals

13, 14, to be the same as before. There is thus no need of a pole-changer or other current-reversing device, either manual or automatic, in the use of thisapparatus for railway train-lighting or in other fields where the source of ower is subject to re.- versal in direction 0 drive.

From the above it will be seen that the several objects of the invention are achieved, and other advantageous results attained.

As many changes could be made in,the above construction and many ap arently widely different embodiments an variations of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or -shown in the accomanying drawings, shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

1. In apparatus of the class described, in combination, an armature, exciting means therefor comprising apairof magnetic cir-, cuits differentially effective upon said armature, and operating at unequal degrees of saturation, an exciter adapted 'to excite both of said circuits at said unequal degrees of saturation, a work circuit connected with the armature, and a series coil on the exciter connected in series with at least part of the work circuit, to limit the current therein by raising the strengths of said fields.

2. In apparatus of the class described, in combination, an armature, exciting means therefor comprising a, pair of magnetic circuits differentially efiective upon said armature, one circuit reaching saturation at a lower field strength than the other circuit, the armature voltage being substantially constant throughout the normal range of speed of the apparatus, an exciter adapted to excite both of said fields, a work circuit connected with the armature, and a series coil on the exciter connected in series with at least part of the work circuit, to limit the current therein by raising the strength of said fields.

8. In apparatus of the class described, in

combination, an armature, exciting means.

point, upon atendency to "excess current throu h said coil.

4. n apparatus of theclass, described, in combination, a variable speed shaft and a pair'of armature windings driven thereby,

a pair of magnetic circuits associated there-' w1th and operating at unequal degrees of saturation, an exciter driven from said shaft and adapted to furnish increased excitation to said circuits with increase of speed, a

on the exciter in series with the generator load connected to the armature, and a coil and at least apart of it's load, to increase I the excitation to said circuits for limiting the current through said coil.

5. In apparatus of the clas described, in combinat on, a variable speed shaft and a pair of amature windin driven thereby, a

pair of magnetic circults associated therei with and operating at unequal degrees of saturation, an exciter driven from said shaft and adapted to furnish increased excitation to said circuits with increase of speed, a

battery adapted to be charged from said armature windings, a work circuit connected with the battery, and means responsive to changes in battery current, associated with the exciter, to increase the excitation to said circuits for limiting the current 1 through said last means. V

6. In appar'atusof theclas described, in combination, a variable speed shaft and a pair of armature windings driven thereby, a Y pair of magnetic circuits associated theren with and operating at unequal degrees of saturationfthe more saturated circuit being associated with the winding of higher volt-v age,'an exciter driven from said'shaft said exciter receiving its excitation from. said pair of armature windings and adapted to z? furnish increased excitation to said circuits I with increase of speed, whereby the generator voltage is substantially constant throughout changes in speed, a battery adapted to be charged from said armature, at a speed above a predetermined limit, a relay adapted to automatically disconnect said battery from said armature circuit when the speed falls below said limit and.

a work circuit connected with thebattery.

7 In apparatus of the class describedyin combination, an armature having apair of opposed windings, exciting means therefor comprising a pair of magnetic circuits differentially efiective upon said armature,

and operating at unequal degrees of saturation, an exciter adapted to excite both of said circuits, a work circuit connected with the armatures, a series coil on the exciter connected in series with at least part of the work circuit to limit the current therein by raising the strength of said fields, and an exciting field on said exciter energized by said opposed armature windings.

8. In apparatus of the class described, in

combination, a'variable spee'd shaft andapair of opposed armature windings driven thereby, a pair of magnetic circuits associated therewith and operated at unequal degrees of saturation, an exciter driven from said'shaft and adapted to furnish increased excitation to said circuits with an increase of speed,"a load connected to the armature, a coil on the exciter in series with the generator and-at least a part of its load to increase the excitation to said circuits for limiting the current through said coil, and an exciting field on said exciter energized by said opposed armature, windings.

9. In apparatus of the class described, in,

combination, an armature having a pair of opposed windings, exciting means therefor comprising a pair of magnetic circuits differentially effective on said armature, one circuit reaching saturation at a lower field strength than the other circuit, the armagized by said opposed armature windings,

In testimony whereof, I have signed my name to this specification this 22nd day of July, 1918.

THOMAS W. VARLEY.

,and an exciting field on said exciter ener-