US1691095A - Electrical system of distribution - Google Patents

Description

L. H. VON OHLSEN ELECTRICAL SYSTEM OF 'DISTRIBUTIQN Nov. '13, 1928.

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Patented Nov. 13, 1928 UNITED STATES PATENT orr'lca,

more a. vow one, on NEW HAVEN; counncrrorm, assronon TO THE sun can HEATING a monrme COMPANY; A CORPORATION or NEW Jamar.

ELECTRICAL svsrnm or nrs'rnmurron.

Application .flled February 20, 1926. Serial No. 89,619.

This invention relates to electrical systems of distribution, and more particularly to such systems wherein it is desired supply cur rent to current-consuming devices at a voltage less than the voltage of the source of current.' 1

One of the objects of this 1nvent1on 1s to provide a thoroughly practical and yet simple apparatus and system for supplyingelectrlcal energy to current-consuming devlces at I a voltage difiering from that ofthe mam source of supply. Another object 1s to prov de a system and apparatus of the above-mentioned character which will be of efficient and thoroughly dependable action and 1n WhlCll the electrical energy at the point of consumption may be given certain desired characteristlcs even though the latter may diifer widely from the characteristics of the main source of enorgy. Another object of this invention is to provide a system and apparatus in wh ch a storage battery or other current-consuming device may be supplied with energy from a source Whose voltage is materlally greater than that of the battery or other currentconsuming device, and in which the characteristics of the energy supplied may be dependably controlled throughout the widely,

varying conditions of practical use. Another object is to provide a regulating apparatus for systems of the abovementioned character capable of highly efiicient and henceeconomical operation, as well as of high precision of operation in practical use. Another object is to provide regulating apparatus of the above-mentioned nature capable of dependably safeguarding a storage battery against over-charge and particularly adapt-- ed for use in systems of the above-mentionedcharacter. Another object is to providea system of regulation capable of such flexlbllity of application. and arrangement in systoms of the above-mentioned character that widely varying conditions of practical use may be successfully met. Other objects will be in' part obvious or in part pointed out hereinafter.

The invention accordingly consists in the.

form such as a trolley or a Similar reference characters refer to simi lar parts throughout the various. views of the drawing.

As conducive to a clearer understanding of certain features of this invention, it may at this point be noted that, particularly in electrically propelled railway vehicles even though the vehicle be supplied with electrical energy at a generally relatively high volta e, there are a number of current-consuming evices, generally associated with auxiliary or train circuits, which it is desired to operate at a voltage oftentimes much less than the transmission line voltage. Characteristic of such devices mention may be made of the sig nal lights, the lighting circuit which may constitute the primary source of illumination for the vehicle, the remote or multiple unit control devices, a storage battery, and others; such devices may be intended to be operated at a voltage commensurate with that of a sixteen, cell storage battery and hence in the neighborhood of forty volts, while the voltage of the transmission or of the main power circuit of the vehicle may be for example, six hundred volts. To provide a system of distribution and regulating apparatus capable not only of supplying the relatively high voltage translating devices with energy, but also such relatively low voltage devices as have been illustratively mentioned hereinabove withenergy, and at the same time adequately safeguarding the storage battery, where against over-charge, is among the dominant aims of this invention.

With this preliminary understanding, reference may now be made to the drawing and acteristic of railway practice, one terminal of the generator is grounded as at 12. The

vehicle carries a suitable current-collecting dev1ce 13 which may take any appropriate shoe, in order that electrical energy may becollected from the transmission line 11 while the'vehicle is in transit or at rest. A conductor 14 leading from the collecting device 13 may lead current to various devices on the vehicle and among these may be mentioned one or more of the driving motors of the vehicle, or a motor for driving the air compressor of the air brake system of the vehicle. These motors or devices are generally intended to operate at a voltage commensurate with that of the source 10, and one of these devices, preferably talring the form of a compressor motor, is indicated at 15. A switch 16 in the conductor 14 may control the current supplied to the translating device 15, and the switch 16 may be of any suitable form either manually controlled or automatic.

Among the relatively low voltage devices, which it may be desired to operate upon the vehicle, there is illustratively shown in Figure 1 a lam 17 connected across the lam circuit conductors 18 and 19 and to the latter is connected a storage battery 20, as illustrative also of another form of current-consuming device which it may be desired to supply with energy at a. relatively low voltage. In many instances it may be desirable to include a storage battery among these relatively low voltage devices in order that the battery may act to supply current to the remaining low voltage devices when the circuit of the translating device or motor 15 in unavailable (as when the switch 16 is open) or when the main force or power, such as the generator 10 is temporarily out off. Such relatively low voltage devices must, therefore, be adequately protected against over-voltage, whereas the storage battery itself must be further protected against overcharge.

In order to supply such low voltage devices with energy from the relatively high voltage source, the former are arranged to be in cluded in the circuit of one of the relatively high voltage translating devices. Thus, referring to Figure 1, the closure of switch 16 will be seen to complete a circuit which may be traced as follows :--from the generator 10 (grounded as at 12), transmission line 11, collector 13, conductor 14, switch 16, motor 15, conductor 21, coil 21 inserted therein, storage battery 20 (and the devices connected in parallel thereto conductor 22 to ground at 23. The flow of current, therefore, to the motor 15, will likewise supply energy to the storage battery 20 and to the devices connected in parallel to the latter.

In order, however, to safeguard the current-consuming devices against over-voltage, and to safeguard the storage battery against over-charge, where a storage battery is included among these relatively low voltage devices, there is provided a by-pass circuit in turn provided with regulating devices arranged to insure such a division of current between the low voltage devices and the bypass circuit that the former are adequately and dependably safeguarded against such detrimental effect as have been illustratively pointed out hereinabove.

Very desirably the division of current between such low voltage devices and the bypass circuit is controlled by a variable resistance' preferably taking the form of a carbon pile, but where conditions in practice may be widely different, circumstances may be met with which impose upon such a regulating device conditions which it alone is ineffective efficiently to meet, and particularly is this the case where relatively large amounts of energy and relatively high voltages must be taken care of by the regulating device. A dominant feature of this invention resides in the provision of regulating apparatus capable readily and efliciently of copin with such practical difiiculties as those illustratively set forth hereinabove.

The by-pass circuit above-mentioned will be seen to include conductor 24 (extending from the common connection between the motor 15 and the storage battery 20) a suitable resistance 25, a variable resistance 26 in the form of a carbon pile, switch member 27 of a switching device generally indicated at 28, contact 29 of switch 28, resistance 30, variable resistance 31 preferably in the form of a carbon pile, and thence by way of conductor 32 to ground as 23 (to which the other terminal of the battery 20 is connected by conductor 22). The switch 28 may be of any suitable form and is illustratively shown as of the solenoid type; in addition to the holding coil 21 therefor, there is active upon the core' 33 a lifting coil 3 1, one terminal of which is connected by conductor 35 to conductor 2 1 and hence to the common point of connection between the motor 15 and battery 20, and the other terminal of which is connected by conductor 36 to ground at 23. The coil 34 and the parts operated upon thereby are so proportioned that. the normal voltage of the battery 20 is ineffective to raise the switch member 27 into circuit-closing position. But the closure of switch 16, to make operative the translating device or motor 15, results in impressing across the battery 20 and hence across the terminals of coil 3% a voltage momentarily high enough to cause coil 34 to close switch 28; the closure of switch 28 completes the lay-pass circuit hereinbefore described and thus establishes two parallel circuits which the current passing through the motor 15 may take to ground at 23.

Operative upon the free or unanchored end of carbon pile 26 is one arm 37 of a bell crank lever generally indicated at 38 and pivoted at 39; a springAO tends to swing lever 38 in such a direction that the arm 37 tends to re lieve the pressure upon the carbon pile 26. At the left-hand end of lever 38, as viewed in Figure 1, thereis connected the core 41 of a solenoid provided with several windings.

' One of these windings 42 is connected by conchored end the arm 45 of a bellcrank lever generally indicated at 46 and pivoted at 47; a spring 48 acts upon the lever 46 .So as to cause the latter to relieve the pressure on the carbon pile 31 while the action of spring 48 is opposed by a solenoid, the core 49 of which is connected to the lever 46 and is operated upon by several windings, one of which, coil 50, is connected as by conductors 51 and 52 across the resistance unit 30-31.

By way of illustration, it may be assumed that the normal capacity or range of opera tion of the carbon piles 26 and 31 is the same, but it is to be specifically understood that the ca acity or range of action of these carbon pi es may be differently proportioned without departing from the spirit or scope of this invention. And Where the capacity and range of each of the carbon piles 26 and 31 is t e same, the resistances 25 and 30 respectively associated therewith are made of a correspondingly proportionate value and hence of the same resistance. The coil 42 operative upon the carbon pile 26 and the coil 50 operative upon the carbon pile 31 are so proportioned with respect to the parts they operate upon that each will bring about an increase in the precsure upon their respec- I tive carbon piles when a voltage is impressed upon them 1n excess of one-half of the voltage which it is intended to maintain substantially constant across the low voltage curdevice, such as the storage battery 20 or t e lamps 17, for example, and

the resultant decrease in pressure on the carbon piles causes such a decrease in the resistance in the by-pass circuit that the voltage drop across the by-pass circuit is decreased and brought back to its normal or intended value. And where a storage battery is included so as to be charged, the aggregate voltage to which the coils 42 and 50 respond is preferably so chosen that it is commensurate with the maximum back E. M. F. which the battery attainsat substantially full 4 charge. In this manner'the battery may be protected against over-charge.

In order, however, to insure the intended division of the regulating function'between the several regulators and in proportlon to their respective capacities (hereinabove assumed illustratively as equal), each solenoid is provided with an additional winding; thus there is made active upon coil 50 an auxiliary coil 53 and upon coil 42 there is made active an auxiliary coil 54. These two coils 53 and 54 are connected in series and their circuit will be seen to extend from the midpoint of the storage battery 20, thence by way of conductor 56 through coil 53, conductor 57, then through coil 54 and by way of conductor 58 to switch contact 59 on the switch 28. l J

Should the voltage. impressed across the bat-tery 20 rise above its intended or normal value, then the resultant increase in the energization of coils 42 and 50 will bring about such a reduction in the resistance of the by pass circuit that the potential drop therethrough is decreased and brought back to the intended value corresponding to the voltage intended to be maintained across the battery 20. But should, during this operation of the regulating devices, one coil, such as coil 42, bring about a less decrease in the resistance of its carbon pile 26 than is brought about by the coil 50 in its carbon pile 31, then there is brought about such a difference in potential between the point 55 and the switch contact 59 that. a flow of current takes place through the circuit in which coils 53 and- 54'are included. The coils 53 and 54, more,- over, are so related to coils 50 and 42, re-

spectively, that the resultant flow of currenttherethrough under the above assumed condition causes coil 54 to assist. coil 42 and coil 53 to oppose the action of coil 50. This strengthening of the action of one main winding ofthe solenoid and weakening of the other at once brings about such changes in the pressures .on the respective carbon piles that the flow of current through the coils 53 and 54 is reduced to zero and thus each carbon pile is made 'to maintain control over its proportionate share of the voltage drop in the b'y-pass circuit.

Should the coil 50 bring about a less in crease in pressure on its associated carbon pile 31 than the coil'j42.has brought about with respect to' its associated carbon pile 26, then the current flowing through the circuit in which coils 53 and 54 are included becomes reversed and coil 53 now assistscoil 50 and coil 54 now opposes coil 42. The strengthening of the effect of one solenoid and the weakening of the effect of the other is thus made promptly to bring about an equalization and readjustment to equality of not only the energy handled by each of the regulating devices, but. also; of the propor tionate share of the potential drop in the bypass circuit which each regulating device should maintain.

Where the current-consuming device is a storage battery such as the battery 20 of Figure 1, the by-pa-ss circuit. is hence so controlled that the impression acros'sthe battery of too high a voltage is prevented, and consequently there is also avoided a charging of the battery at too high a rate; and it. will also be seen that as the battery 20 approaches substantially full charge the increase in its back E. M. F. to a value approaching or substantially reaching that value which the regulating devices are arranged to control, or according to circumstances, to maintain substantially constant, the charging current to the battery will be materially cut down, the battery will hence be substantially floated, and the overcharging of the battery thus prevented.

In the arrangement shown in Figure 1 it has as hereinbefore set forth been assumed that the several regulating devices are substantially the same capacity and that hence each is to take care of a like or equal share in the regulating function; it will therefore be apparent that under these assumed conditions the point represents the mid-point of the potential gradient. through the storage battery 20, and that the point 59 represents the mid-point of the potential gradient through the by-pass circuit. The circuit in which the equalizing coils 53 and 54 are included is hence connected across these two points 55 and 59 so that any difference in the operation of the several regulating devices will cause, electrically speaking, a shifting of the point 59 to one side or the other of the mid-point of the potential gradient through the by-pass circuit; but such a shifting at once causes a difierence of potential between the points 55 and 59 and the resultant flow of current throu h the coils-53 and 54, in a direction depen ent upon the direction in which the point 59 is electrically shifted, will brin about, as hereinabove described, such a sci-correcting action that the point 59 is automatically maintained at the mid-point of the potential gradient through the by-pass circuit.

Should the two regulating devices be of capacities other than equal, so that each, together with its associated fixed resistance, is to maintain a potential drop different from that maintained by the other, then the conductor 56 is connected to such a point in the storage battery 20 that the division of the potential of the battery 20 by the positioning of the point 55 will represent such a proportion as the capacity of one regulating device bears to the capacity of the other.

It may further be pointed out that, should the translating device 15 be made inoperative as by opening the main circuit as at the switch 16, the supply of current to the current-consuming deviceysuch as the battery 20 ceases, as well as does also the current through the by-pass circuit and hence through the holding coil 21 on the switch 28; the coil 34 of the switch 28-will thus be alone operative upon the switch and being energized by the voltage from the battery 20 is, as hereinabove noted, insufficiently effective to hold the switch 28 closed. The latter therefore opens, the opening thereof being insured by a weaking of coil 34 by a reverse current flowing through the current Luil 21 due to the tendency of the battery 20 to discharge through the by-pass circuit.

The train line or other circuits intended to be operated at a lesser voltage than the voltageof the transmission line may thereupon be supplied with current. from the battery 20.

In Figure 2 I have illustrated fragmentarily a modification of certain features of my invention showing how the latter may be carried out in instances where a storage battery is not included among the current-consuming devices which it is intended or desired to supply. In Figure 2 the conductors 18 and 19 representing, for example, the conductors of a lighting circuit or train line across which are connected such current-consuming devices as the lamps 17 there is connected to the conductors 21 and 22 and hence also bridged across the conductors 18 and 19 of the lamp circuit a resistance and where the regulating devices are, as assumed in connection with Figure 1, of like capacity, the conductor 56 forming part of the circuit in which the adjusting coils 53 and 54 are included is connected to a point 55 in the resistance 60 which represents substantially the mid-point of the gradient of the potential drop through the resistance 60. The opera-.

ation of the system and apparatus with a current-consuming device such as the resistance 60 substituted for the storage battery 20 of Figure 1 will be, it is believed, readily understood from what has been set forth hereinabove in connection with Figure 1. 1nd where the regulating devices may be of different capacities, or where it may be desired that they, together with their associated fixed resistances, take care of and control other than equal potential drops in the by-pass circuit, the shifting of point 55 along the resistance 60, just as was, the case with the shifting of point 55 along the electrodes of the series of cells making up the storage battery 20, may be made to bring about any desired proportionate regulating effect between the two regulating devices. 1

It will thus be seen that there has been provided in this invention a system and apparatus in which the several objects of this invention, as well as many thoroughly practical advantages, are successfully achieved. It will be seen that the apparatus is automatic, of thoroughly dependable action throughout and is well adapted to meet the Widely varying conditions of practical use. In this lat ter connection, it might be pointed out that the current necessary to operate the translating device 15, the latter being hereinabove assumed as taking the form of a motor driving the compressor of the air brake system of the vehicle or train, may vary throughout relatively wide ranges, but it may be noted that the apparatus and system of this invention preted as illustrative and not in a limitingsense.

I claim as my invention:

1. 1n apparatus of the character described,- in combination, a source of current having serially connected thereto a translating device and a storage battery, a by-pass circuit in shunt relation to said storage battery and having included therein two variable resistance units, circuit-closing means in said bypass circuit and positioned intermediate of said two resistance units, means for controlling each ofsaid resistance units in accordance with a function of the current supplied to said storage battery, and means controlled by said circuit-controlling device and adapted to insure a division of the controlling function of said last-mentioned means in substantial accordance with the respective capacities of said resistance units.

2. In apparatus of the character described, in combination, a source of current having serially connected thereto a translating device and a storage battery, a by-pass circuit in shunt relation to said storage battery and havingincluded therein two variable resistance units, coils each responsive to a function of the current supplied to said storage battery and each adapted to control one of said variable resistance units, and means operative upon each of said coils and arranged to affect the operation of its associated coil so that each variable resistance unit is prevented from exceeding a predetermined ratio of its range of action with respect to the range of action of the other variable resistance unit.

3. In apparatus of the character described, in combination, a source of current having a translating device and a storage battery connected thereto in serial relation, a plurality of variable resistances included in a by-pass circuit shunted about said battery, means for controlling each of said variable resistances so that theirtotal action is to prevent the voltage impressed across the battery from.

exceeding a predetermined value, and means arranged to cause a division of the controlling function among said resistances in accordance with their respective regulating capacities.

4. In apparatus of the'character described,

in combination, a source of current having a translating device and a storage battery connected thereto in serial relation, a plurality of variable resistances included in a by-pass circuit shunted about said battery, means for controlling each of said variable resistances so that their total action is to prevent the voltage lmpressed across the battery from exceeding a predetermined value, and electrical1y responsive means having the respective terminals thereof connected-to points in said battery and said by-pass circuit which are of substantially the same potential and adapted to afiect said controlling means to maintain the regulating function of said resistances withln their respective regulating capacities. 5. In apparatus of the character described, in combination, a source of current and a current-consuming device connected thereto;

and means for controlling a function of the current supplied to said device from said source comprising a plurality of regulators, and means arranged to insure a division of the controlling function between said'regulators in accordance substantially with their respective regulating capacities.

6. In apparatus of the character described, in combination, a source of current, and a current-consuming device connected thereto; means for controlling a function of the current supplied to said device from said source comprising a plurality of regulating devices arranged in a series circuit shunted about said current-consuming device, and electrically responsive means having its respective terminals connected to points in said currentconsuming device and said series circuit which are substantially the same potential ,7. In apparatvs of the character described,

in combination, a source of current, and a current-consuming device connected thereto; a bypass circuit shunted about said currentconsuming device and having included therein two variable resistance units, means for controlling each of said units in response to a function of the current supplied to said device, and means for insuring a division of the controlling function between said variable resistance units in accordance substantially with their respective capacities comprising electrically responsive means having the respective terminals thereof connected to points in said current-consuming device and in said by-pass circuit which are of substantially the same potential but at such points in the potential gradient that the latter is divided into and having included therein two variable resistance units in serial relation, means for controlling each of said variable resistance units in substantial accordance with a function of the current supplied to said device, and means adapted to increase the efiect of one of said last-mentioned means and decrease the efi ect of the other when the ratio of the potential drop across one of said units to the potential drop across the other departs from a predetermined value.

9. In apparatus of the character described, in combination, a source of current, and a current-consuming device connected thereto; a by-pass circuit shunted about said device and having included therein two variable resistance units in serial relation, means for controlling each of said variable resistance units in substantial accordance with a function of the current supplied to said device, and electro-magnetic means operative upon each of said controlling means and adapted to increase the eiiect of one and decrease the effect of the other when the ratio between the potential drops across the said two resistance units departs from a predetermined value.

10. In apparatus of the character described, in combination, a source of current, and a current-consuming device supplied thereby; a by-pass circuit-shunted about said current-consuming device and having includ ed therein two variable resistance units connected in series, and means for controlling each variable resistance unit so as to 'maintain substantially constant the potential drop therethrough.

11. In apparatus of the characater described, in combination, a'source of current, and a current-consuming device supplied thereby; a by-pass circuit shunted about said current-consuming device and having included therein two variable resistance units connected in series, means responsive to the potential drop across one of said resistance units for controlling the value of the latter, means responsive to the potential drop across the other resistance unit for controlling the value of the latter, and means arranged to change the standard of operation of one of said controlling means when the ratio of potential drops across the said two resistance units departs from a predetermined value.

12. In apparatus of the character described, in combination, a source of current, and a current-consuming device supplied thereby; a by-pass circuit shunted about saidcurrent-consuming device and having included therein two variable resistance units connected in series, a voltage coil for controlling each of said variable resistance units and arranged to be responsive to the potential drop across its associated resistance unit, and a coil for modifying the action of each of said voltage coils and arranged to assist mined value.

13. In apparatus of the character described, in combination, a source of current, and a current-consuming device supplied thereby; a by-pass circuit shunted about said current-consuming device and having included therein two variable resistance units connected in series, a voltage coil for controlling each of said variable resistance units and arranged to be responsive to the potential drop across its associated resistance unit, and electromagnetic means for afiecting the action of each of said voltage coils and having its terminals connected one between said two variable resistance units and the other to such a point in said'current-consuming device that the potential drop through the latter will be divided into portions proportionate respectively to the capacities of said variable resistance units.

14. In apparatus of the character described, in combination, a circuit having included therein a source of current and a current-consuming device; a by-pass circuit shunted about said device and having included therein a plurality of regulators; means arranged uponsaid circuit becoming effective to close said by pass circuit; and means arranged to insure a division of the controlling function between said regulators in accordance substantially with their respective capacities.

15. In apparatus of the character described, in combination, a circuit having included therein a source of current and a current-consuming device; a by-pass circuit shunted about said device and having included therein a plurality of regulators; means arranged upon said circuit becoming effective to close said by-pass circuit; and electrically responsive means, controlled by said lastmentioned means, and arranged to insure a division of the controlling function between said regulators in accordance substantially with their respective capacities.

16. In apparatus of the character described, in combination, a circuit having included therein a source of current, a translating device and a storage battery in series, a by-pass circuit shunted about said storage battery and having included therein means for controlling the division of current therebetween and said battery in substantial accordance with the state of charge of said battery, and means responsive to effective condition of said first-mentioned circuit adapted to close said by-pass circuit.

17. In apparatus of the character described, in combination, a circuit having included therein a source of current, a translating device and a storage battery in series,

a by-pass circuit shunted about said storage battery and having included therein means for cont-rolling the division of current therebetween and said battery in substantial accordance with the state of charge of said battery, a switch for controlling said by-pass circuit, and a coil for cont-rolling said switch connected across said battery but inefi'ective at normal battery voltage.

18. In apparatus of the character described, in combination, a source of current and astorage battery adapted to be charged thereby; a by-pass circuit about said battery having included therein a plurality of current-controlling devices, and means adapted to close or open said by-pass circuit in accordance with effective or inefi'ective condition respectively of said source of current.

19. In apparatus of the character described, in combination, a source of current, and a storage battery adapted to be charged thereby; a by-pass circuit shunted about said battery and having included therein a plurality v of current-controlling devices, a

switch for controlling said by-pass circuit, and electrically responsive means controlled by said switch and arranged to insure a division of the controlling function of said devices in accordance substantially with their respective capacities.

20. In apparatus of the character described, invcombination, a source/of current, and a storage battery adapted to be charged thereby; a b -pass circuit shunted about said battery and aving included therein a plurality of current-controlling devices, a switch adapted upon said source becoming effective to close said by-pass circuit and upon said source becoming ineffective to open said bypass circuit, and means controlled by said switch for insuring a division of the controlling function among said devices in accordance substantially with their respective capacities.

In testimony whereof, I have signed my name to this specification this 16th day of February, 1926,

- LOUIS H. VON OHLSEN.

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