US1279283A - Method of and apparatus for electrical distribution. - Google Patents

Description

A. H. DARKER.

METHOD OF AND APPARATUS FOR ELECTRICAL DISTRIBUTION. I

APPLICATION FILED MAY Is. I916.

1,279,283. Patented Sept. 17,1918.

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ALFRED HENRY BARKER, OF BLACKHEATH, ENGLAND, ASSIGNOR TO J. STONE Q COMPANY, LIMITED, 01 DEPTIORD, ENGLAND.

METHOD AND APPARATUS FOR ELECTRICAL DISTRIBUTION.

.To all whom it may concern:

Be it known that I, ALFRED HENRI DARKER, a subject of the King of Great Britain, and-residing at Heathview, Mont- Relier Row, Blackheath, in the county of ent, England, have invented certain new and useful Improvements in Methods of and Apparatu for Electrical Distribution, of which the followin is a specification.

This invention re ates to a method of'and apparatus for electrical distribution and has particular reference to electrical car lighting and heating systems wherein the generator is driven from the axle of a railroad car or the shaft of an automobile or other vehicle t which the system is applied; and although useful in other systems, it is of particular value in connection 'with car ighting systems in which the generating dynamo is of the constant torque type. This invention is a division of my application Ser. No. 550,136, filed March 18,, 1910.

One of the primary objects of my invention is the provision of an improved method cut-1n speed at which the of electrical distribution in lighting and heating systems havin a battery to be charged, by means of w ich I elimlnate, the complicated automatic re lating means which must be employed, 5dr example, in electrical lighting systems of the constant current type in which the voltage of the dynamo must be automatically regulated by such means, or of the constant voltage ty e in which the current must be regulated l y similar means.

My invention further contemplates the provision of an improved method of electricaldistribution in a system of'the character described which is simple in character and is adaptable to varying service conditions, such, for example, as where a car'is used on a short run on.one day and on a long run the next. 7

Another object of my invention is the provision of an improved method of and apparatu for automaticall changin the ynamo wil deliver a useful current upon certain changes in the state of the battery charge.

A still further object of my invention-is I the provision of an improved method of Specification of Letters Patent. Patented Sept. 17, 1918.

Original application filed March 18, 1910, Serial No. 550,186. Divided 1916. Serial No. 97,654.

and this application filed Kay 15,

ppag e in a changing the moment of belt sli lightlng system employing a sllnning belt I type of dynamo.

I also provide improved apparatus for accomplishing the foregoing and for securing certain advantageous results which will o more fully hereinafter set forth.- I

The foregoing, together with such other ob ectS as may hereinafter a ear or are incldent to my invention I attain by means of a method and apparatusdiagrammaticallv indicated in the WlllCll only such parts ofthe system as are necessary to effect an understanding of vmy invention are illustrated, itbeing understood that the invention is not limited to the precise arrangement and means shown.

Referring to the diagram, the numeral 7 indicatesthe dynamo, and8 and 9 indicate the main leads with which theaccumulator orbattery 10 and lamps 11 are in circuit.

, The lamp circuit is controlled by means of a switch 12 and the main circuit is closed by an automatic cut-in-and-out switch 13 which maybe ofany preferred automatic type which is operated to close the main circuit when the voltage of the dynamo rises to a predetermined point,

The dynamo 7 is preferably of the constant torque type and is driven from the axle of the vehlcle to which the system is applied by means of a slip ing belt 14, which elt is adapted to slip on t e armature shaft pulley 15 when the train reaches a predetermined rate of speed. The moment of belt slippage is determined by the tension of the elt-which may be ad] usted in any suitable mannerand the load of the dynamo,

so as to cause the belt to sllp at a predetermined rate, say, for

' example, miles per hour. From zero rate up to 20 miles per hour, the armature shaft willrotate at a speed in direct ratio with that of the train, andwhen the rate of 20 miles per hour is attained, the belt will slip and the armature will revolve at a fixed constant number of revolutions for a 'ven load, regardless of the speed of the train.

It will be seen, therefore, that the generatoris a constant wattage machine and we accompanying drawings in will assume, for example, that the tension of the belt is such that the dynamo will generate 30 amperes at 30 volts or 900 watts at a predetermined rate of train speed, which we have assumed for the purposes of this specification to be 20 miles per hour. Owing to certain operative phenomena which those skilled in the art will understand, the wattage of a dynamo of this type will not vary quantitively from the predetermined standard adopted, although the voltage and amperage may and do vary inversely with respect to each other, as will further appear.

The dynamo is also so arranged that at a predetermined rate of train speed, say for example, 15 miles per hour, it will generate a voltage sufficient to operate the automatic cut-.in switch 13 so as to close the working circuit. The rate of s eed of the armature at this train speed will ereinafter be termed the cut-in speed of the dynamo.

In contradistinction to the constant current and constant voltage systems which have been heretofore referred to, the system employing a constant torque dynamo, when used in uniform service, does not require any means for automatically regulating either the current or the voltage so as to maintain the proper rates of battery charge, because as the voltage in the battery circuit rises, during the process of charging, the amperage will be correspondingly cut down, which will result in an automatically tapering battery charge, which secures a roper charging of the battery while at t e same time the injurious results of over-charging are avoided. Where, however, the service is not uniform, as for example, where a car is used one day on short runs during which the average rate of sustained train speeds is comparatively low, while on the next day it is used on a long run, during which the average speed attained may be higher and the points of stoppage less frequent, it is advisable to adjust the system to meet the changed service conditions in order to secure the most eificient results. This will be seen from the fact that in the first class of service mentioned, the battery would'have to be charged at a higher rate, owing to the periods of time available for this purpose, and to meet this condition, the tension of the belt, for example, would be increased, so that the dynamo would generate a greater output before the belt would slip. If a car adjusted for this class of service were used, however, on a long run, in which higher rates of speed are attained, this increased out ut would not be necessary. It is one of t e objects of my invention, as previously set forth, to make my improved system of electrical distribution adaptable to such varying classes of service as have just been described without necessitating manual adjustment of the apparatus. I may accomplish this in several ways but I prefer the following method: I

The shunt field of the dynamo which I have diagrammatically indicated at, d is normally in circuit across the mains through the switch 76 which is normally gravity held in. closed position, short circuiting an ad justable resistance 116, the pur ose of which will be set forth. Theswitch .6 is operated by an electro-magnetic device, preferably of the solenoid type, the core 75 of which is sucked. up by the action of the coil 74. The switch 12, when moved to one position, puts the lamps 11 in circuit and breaks the circuit in which the coil 74 of the electromagnetic device is located, and when moved to another position, breaks the lamp circuit and closes the circuit of the coil 74. The purpose of the apparatus 'ust described is to revent overcharging o the battery, as wil be clear from the following description of the operation.

As the battery 10 approaches a state of full charge, the voltage in the circuit rises because of the counter E. M. F. of the battery, and the coil 74 is so calibrated that it will be sufliciently energized to open the switch 76 when the battery voltage rises, for example, to 40 volts. 'When this voltage is reached, the core 75 will be sucked up, opening the switch 7 6 and breaking the normal circuit of the shunt field and completing such circuit through the resistance 116.

The effect. of inserting into the field this resistance 116 which may be of any redetermined character-is to weaken the eld and thereby change the load of the dynamo,

with the result that the belt will not slip on the pulley- 15 until the speed of the armature is greatly increased. 'In other words, the moment of the belt slippage is greatly retarded and the train must attain a relatively much higher rate of speed before the dynamo will generate a voltage sufficient to close or to hold closed the automatic cutin switch 13. Stated differently, the effect of the introduction of .the resistance 116 into the main field is to raise or step up the cut-in speed of thegenerator; that is, the speed at which the generator will produce useful voltage is greatly increased.

Bythis action of what may be termed the limiting device, the battery is fully protected against overcharge because as the .battery reaches afull state of charge and its voltage cons uently rises, the limiting device is actuate by the rise in voltage in such way as to practically cut off the flow of charging current to the battery during normal train speeds. In fact, I prefer to so arran e the resistance 116 that the generator Wlll be unable to deliver current to the battery until the train has reached a speed of approximately 40 miles per hour,

and will only be able to deliver an appreciable charglng current at higher rates .of speed, the amount of resistance being determined so as to make it impossible for the dynamo to generate an injurious charging current until a rate of trainspeed is attamed which is at present impossible in railway service. It will be understood, of course, that when the voltage drops 'to a predetermined point, the core 75 will be released and the switch 76 will be gravity closed, thus short-circuiting the resistance 116 and reestablishing normal field conditions.

From the foregoing it will be seen that by my improved method and apparatus, I change the moment of belt slippage b altering one of the factors by means of whic said moment of belt slippage is determined by an automatic means actuated upon a change in the state of the battery charge. In the preferred method which I have described hereinbefore, the factor which is thus altered is the field stren h of the dynamo; but'it will be unders that other factors which determine the moment of'belt slippage may be thus altered.

It will also be seen that by my improved method I alter the cut-in speed at which the dynamo will deliver a useful current to the consuming circuit, with the result that the various advantages and beneficial results hereinbefore pointed out are obtained.

It will also be noted that the system is very simple and very efficient in operation and that many of the disadvantages which are incident to the systems requirin automatic regulating devices are obviated I claim:

1. In a car lighting system the combina-, tion of a dynamo having a predetermined cut-in speed standard at which it will generate a useful current, an accumulator to be charged thereby, and automatic means actuated by change in the voltage for altering one of the components producing said standard and thereby setting a new standard of cut-in speed at which the dynamo will deliver a useful current.

'2. In a car lighting system, the combination of a sli plng belt dynamo having a predetermine cut-in speed standard at which it will generate a useful current, an accumulator to be charged thereby, and automatic means actuated by change in the voltage for altering one of the com onents producing said standard and there y setting a new standard of cut-in speed at which the dynamo will deliver a useful current.

3. In a car lighting system, the combination of a dynamo having a predetermined constant torque, an accumulator to be charged thereby, and means automatically actuated by change in the difference of potential for altering one of the components producing said constant torque thereby automatically changin the cut-in s eed at which the dynamo will eliver a use 1 current.

4. In a car lighting system, the combination of a dynamo, an accumulator, an automatic cut-in switch automatically closed on a predetermined dynamo voltage, the said dynamo having a predetermined cut-in speed standard at which such voltage is gen erated, and automatic means actuated by change in accumulator voltage for altering one of the components producing said cutin speed standard, thereby setting up a new standard of cut-in speed at which the dynamo will deliver a useful current.

5. In a car lighting system the combination of a slipping belt dynamo, an accumulator to be charged thereby, and means automatically actuated upon a change in accumulator voltage for altering one of the factors determining the moment of belt sli page.

11 testimony whereof I have hereunto signed my name and afiixed my seal.

ALFRED HENRY BARKER. [L- 5.]

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