US1515354A - Electrical system - Google Patents

Description

BEST AVAILABLE COP.

Nov. 11 1924.

L. H. MILLER ELECTRICAL SYSTEM an ina Filed Aug. 19, 1916 Patented Nov. 11, 1924.

UNITEDTSTATE'S BEST AVAILABLE COP.

PATENT .OFJFICE j Lrnns Y H. MULL or cnroAGoiriltritois.

I ELECTRICAL sewn Application filed August 19, 1916, Serial No; 532,859f'Renewe d January 30, 1922.

To all whom it may c0'n0em:

Be it known that I, LINDSAY H. MILLER, a citizen of the United States, and residing at Chicago, in the county of Cook and State of Illinois, have invented a new and Improved Electrical System, of which the following specification is a full disclosure.

This invention relates to an electrical system, and with regardto certain more spe;

eific features, to a powerplant embodying an internal combustion Iengine, .afdynamo connected; therewith, jv'o'rlz circuit and fa storagebattery. This invention an 'im' provement on the inv'ention'set forth inthe application'of Harvey S. Pardee for patent on electrical system, Serial Number 92, 3}; filedApril20,19 16."

One of the objects of the present invention is to provide electrical system constructed of parts easily obtained on the market, readily assembled, and capable of operation for an extendedperiod 'without'expert ate g. 1 ,i ,.;i I Another ob'e'ct isjtlie provision of simple, d ra and e en fappilat gmf.fie e hi ing current to agworl i fcircuit by, means ofa generator driven by an iiiternalcombustion engine or other engine:v inherently incapable of'startingitseljf. Another object is the provision of a sys tem of the above type infwhich a small storage battery may be effectively employed, in place of the large battery now commonly in use, the present system aflfordingauto matic operation, accuracy of regulation, and protection to the battery. Another object is'the rovision of an ef ficiient and inexpenis'vec arginq system for a st orage battery, so designed t at the generator may supply the lamps and charge the battery simultaneously without subjecting the lamps or other translating devices, to a voltage higher than the normal dischargevoltage of the battery.

Another object is the provision of improved apparatus of the above. type in which notice is automatically given to the operator in case his'atte'ntion is needed at any time, and this prior to any disconnection of the lamps from their source of current.

Another object is the provision of reliable and efficient means for controlling the analysis of'thi'slinventionl fi This invention "accordingly consists-in the features *of 'construct1on, -combin'altion of parts, and in-the 'uni'que' relations of the members and in the relative proportioning and dispositions thereof; all asmore completely outlined herei-n. Toenable others skilledin the art-so fully to comprehend the underlyin features thereof'thatthey may embody t esame' 'by the numerous modifications in structure and relation contemplated by ".this invention, drawings depictingdiagrammatically a preferred te m have been annexed gas Ya 1 part of this disclosure and"'in 'saiididrawings;

"Ifi'g'ure l'gisa diagnamm'atic representation of an electrical" system incorporating certain features of-th'e present invention; and "Figure 2 illustrates 'a'modification, relating primarily toasimplifi'cationof the re- In considering the relation of this invention"to the priorlart; it' may be noted that for many years there has been 'a demand foran electrical system in' which a work circuit,'for lamps, motors; or 'o ther translating devices, couldbesupplied with current fromfla dynamo driven by an internal-com-v bustion engine; with provision for furnishing a small amount or current as for nightlights, without requiringthe operation of the engine and generator at such times; a furtherfrequirement has beenthat the en tire system should be sufficiently automatic that no frequent or expertattention is needed, durable so that no expert inspection or repair would be required for long periods of time, and inexpensive both as regards first costs and operating costs, so

1 equal to the discharge voltage of the battery that the system is commercially applicable to small, isolated installations. In many, if not all of the present-day apparatus designed ,for. isolated power plants, the first cost and depreciation of the stor ag'epbatteiy is a large factor in the total GXPBIISQiiiCldent to the purchase and maintenance of the plant. As the descriptionof the present invention proceeds, it will be seen that these rigid requirements have been met,'1n an apparatus which is at. once inexpensive, autoinatic, efiicient and reliable.

Briefly, the present invention utilizes a combined generator and battery-charging booster which supplies a: voltage to the line and an excess charging voltage to the battery greater-than the voltage supplied to the line, whenever the generator. is running normallyg When the-generatoris not running, the booster armature winding of the combined; generator remains :jntthe battery circuit but generates n9 gvoltagebecause it is; at. restl There is; preferably provided an ampere-hour meterwith certain gCODtEIOtS and.

electrical connectionseto a .main SWlt0h=WhlCl1 operate thatswitch and-automatically start up-jzthe plant; and shut it down at the-proper tiinesn depending upon the state of-charge of the battery. Themaingswitch is arranged 3 also to close automaticallyfand start up the plant whenever thelamp load draws a current" excesslof-the capacitypf the-bat tery, which: in this casemay relatively 's'malln aThe main switchautomatically opens when: the lamp load 1 drops, down 5 1 610? the capacity; of the Z- andthe battery has; reaehecla. -.state near -fnllf charge ions auxiliary; devices maybe added to protect) the apparatus, give; an; alarm and to I cut- .off the engine-starting circuit .when the,

: stant of starting the engine,

This fluctuation of the lamp voltage and candle-power has the advantage of giving a distinct Warning to the operator whenever the engine is started.

- Referringnow to the accompanying drawings, there is illustrated at I a portion of the intake of an internal-combustion engine E: :1 butterfly or other valve V is located in the intake I and is adapted to be operated by means hereinafter described, so as to increase the fuel supply to the engine at certain times and to move in the opposite direction to decrease the fuel supply at other times." Mechanically connected to the engine E is a dyiiamo electric machine D,

which is utilized as a motor to start the engine and when the engine 15 running IS utilized as a generator to furnish current to the storage-battery B and to the work circuit IV.

An integrating meter 1, preferably an ainpere-hour meter as here illustrated, has a contact-making pointer or other indicator 2 which indicates the state of charge of the battery B and, in addition, effects certain circuit-changing operations hereinafter described. A valve-operating regulator 4, a main switch 6, a relay 7, a dynamo tripswitch.9 and a battery trip-switch 10, may also be provided. The structural ments and their assembly perhaps caii'be best described in connection with an explanation of the various operationsand circuit changes that occur in the several'phasesor events details of the various eleof the cycle of'operations, of the; system.

Assume, therefore,- that the engine and :dy name are at rest, that no-cu'rrent ,isfio iv'in'g in the work circuit and that-thefbatteryfis inza stateof partial chargesuch that the indicator 2 of the meter 1 stands at point 12.

Atthis time the switches 9' and IO'are closed; the contacts &6 are closed, the'inain switch 6 is open (down), the regulator 4 is in its open-throttle position (solenoid 13 down) in- Figure 1, with l the left-hand movable contactor l4tfth81'0f contactingwith its lefthand contactor 15, and the right-hand mov able 'contactor 17 of the relay is separated and the relay 7 is in the position indicated from its contactor 18. If now a lamp load w of less than, fOreXampIe, one ampere, be turned on in the work circuitiv, then current will flow fromthe positive side of the battery B, through the lead 19, battery tripswitch 10, lead 20, coil. 21 of the meter l.

lead 22, lamp-current coil 24 of the main switch 6 and lead 39 thence through any lamps L, L, that are turned on, thence tothe ground, from ground to'the grounded terminal 25 common to the two armature windings H of the dynamo D, through the low-voltage armature winding 26, negative brush 27 thereof, and lead 28, to the negative pole of the battery. The flow through the armature winding 26 encounters none but ohmic resistance, since the dynamo is at rest and the field excitation dead. This lamp load causes aslow discharge of the battery and consequently a slow clockwise movement of the indicator 2, which moves toward the start-charge contact 30.

\Vhon the indicator 2 reaches the contact 30, a circuit is closed from the positive side BEST AVAILABLE cos.

ing-block 36a quarter-turn, .through the ratchet 37. This rotation of the spacingblock 36 breaks the relay circuit at the contactors 14. 15, de-energizing the relay winding 33 and allowing the plunger 34 to be withdrawn upward by its spring into position for another throw. At the same time the contacts 14.- and 17-18 are closed. The coutactors 1718 close a circuit from the positive side of the batterytthrough elements 19, 10, 20, 21,- lead 40, right-hand movable contact- 17, contact-18, lead 41, voltage coili43 of the main-switch 6,- ground, elements 25, 26, 27 and 28 to the negative side of the battery.";This energizes the voltage coil-{13 of the main switch, which thereupon pulls upwardly 'its solenoid-core 44, with sufficient forceto close the contactsfi.

At about the same time,-the're1ay-R is 'sufiiciently energizedto separate the contacts 46 to remove-a'short-circuit around the en gine magneto 4:7, or,depending' upon the style of ignition used for the engine-the circuits might be altered so that the opera.- tion of the relay'R would close the ignition circuit; in -either case, the contacts 46 are intended to render the engine ignition operative when the-relay R is sufiiciently energized and inoperative at other'times.

The effect of closing the main contacts 45' is to close-amircuit from the positive side of the batter through'elements'lt), 10, 20, 21, 22, 45, dynamo current coil 48 of the main switch 6, coil of:-relay-' R, lead 49, dynamo trip-switch 9, lead 50, current coil '52 of the regulator 4, series field 54 of the dynamo D, positive brush 55, high-voltage armature winding -56,- intermediate or grounded terminal 25, low-voltage-winding 26, brush 27 and lead 28 to the negative side ofthe'battery. r

Simultaneously the shunt-field winding 58 and the voltage coil 59- of the regulator t','connectedin series, are energized; these coils are, for the moment, energized but slightly, however, owing to the heavy ohmic drop in the battery. A strong current flows through the circuit including the armatures and series field of the dynamo, causing the dynamo to rotate substantially as a series motor, with a large starting-torque, the series field 54- at this time predominating over the shunt field 58; this rotation of the dynamo rotatesthe engine E through the mechanical connections between them, and

this serves to start the engine. ;The. current through the current coil 48 ofthe main switch at this time tends to assist in closing the contacts 45 thereof more tightly, thus securing a firm and positive contact.

After the engine has started to rotate under its own power, the counter electromotive-force generated in the armature windings 26, 56, raises the voltage acrosstlie terminals of the dynamo, thereby increasing the power of the coil 59 and shunt field 58 and reducing the power in the series field 54L, until the dynamo voltage equals and then exceeds the battery voltage. Then the series field reverses, and thereafter, during the operation of the dynamo as a generator, the series field. opposes the effect of the shunt field. The series field is preferably strong enough relatively to the shunt field to afford a marked drooping of the dynamo-voltage characteristic.

Now that the engine is running under its own power, current is delivered from, the positive lead of the dynamo through theele; ments;52, 50, 9, 49, R, 4:8, 4:5, and thence in two. branches. The first branch includesthe lamp current coil 2%, main 39, lamps L, L, ground, and groundedlterminal 26 ofthe dynamo, giving at the lamps a voltage equal to the voltage across the high-voltageovinding 56 of the dynamoyin practiceithis is preferably 110 volts, although obviously any other suitable standard. ofvoltage may be used. The second branch includes the elements 22, 21, 20, 10, 19, thence through the battery to charge the same, thence through low-voltage or booster winding26 offthe dynamo, to the grounded terminal 25 of the dynamo; so that the voltage across the batteryis at this time equal to the sum of the voltages across the two windings 56, 26, of

the dynamo. The high-voltage winding carries preferably apressure ofllO volts, and

by proportioning the low-voltage,winding for, say, approximately let volts, the battery on charge receives 124 volts at its terminals,

which is a suitable charging voltage for a lead battery whose discharge voltage is 110;

however, these proportions may naturally be varied to meet the requirements of the particular battery to be used.

The dynamo voltage is maintained constant by suitable means such as the regulator 4., whose. solenoid 61 is pulled u wardly in case of a tendency to excessive v0 tag-e across the coil 59, to move the valve V toward its closed position, thereby reducing. the fuel supply and speed of the engine and consequently restoring the dynamo voltageto its normal value. or tendency to reduction of the voltage causes a lessened power of the coil 59.5Which allows the solenoid core 13 to drop slightly, thereby opening the valve. admitting niore fuel, speeding up the engine QJICLI'LYDMDO, 7

Similarly a slight reduction BEST AVAILABLE COP.

and restoring the voltage to normal. By means of this regulator, then, the dynamo voltage characteristic is determined so that despite changes in load, or the condition of the battery or other variables such as temperature and quality of fuel, the voltage on the load is not affected. It is possible by means of the compound winding on the regulator to give a rising characteristic to the dynamo voltage in order to compensate for voltage drop in the line leading to the lamp load. The compounding is effected by the current coil 52, which carries the output current of the dynamo and during normal operation opposes magnetically the potential winding 59. By properly proportioning the ratio of ampere-turns on the current and the potential windings 52, 59, it is possible to give a flat, a rising, or a falling characteristic to the voltage across the work circuit. This regulator compensates for the inherent drooping characteristic of the dynamo as well as for all other-conditions. It is preferably equipped with a dashpot or other suitable damping means 61 to' prevent'hunting' or over-regulation during ordin'ary load fluctuations and sudden closing of the valve due to the strong action of the current coil at the instant of starting the engine.

As the'charg'ing of the battery progresses, the meter indicator 2 moves-counterclockwise. When the indicator reaches the stopcharge contact 63, a circuit is closed from the positive main 490i the dynamo circuit, through elements 22, 2, 63, 64, contactors and 14 (closed as previously explained), coil 33 of relay 7,- to ground. This energizes the relay coil 33, which thereupon pulls downwardly its solenoid core 34, imparting a quartenturn through the ratchet 37, to the diamond-shaped spacing-block 36. This rotation of the spacing-block 36 breaks the circuit at the contactors 65, 14, andopens the circuit at the right- hand contacts 17, 18. The break at 65, 14', opens the circuit through which the relay had been previously energized, thus allowing the plunger 34 to be withdrawn by the spring 35 into position for another throw. The separating of the contactors 17, 18, opens the circuit through the voltage coil 43 of the main switch 6, and causes the switch to open its contacts 45, assuming still that the lamp load is one ampere or less. The opening ofthe mainswitch contacts 45 disconnects the dynamo from the battery and work circuit and deenergizes the coil of the underload relay R, which thereupon closes its contacts 46, deenergizing the engine ignition and causing the engine to stop. The conditions previous'ly assumed are now restored. namely, the engine and dynamo are at rest, and bat tery is on slowdischarge and supplies the one ampereor less that is required for the work circuit. As the battery slowly, discharges, t-he meter pointer 2 reaches again the start-charge contact 30, and the cycle above described is repeated.

An object of the relay 7 is to relieve the contacts on the meter 1 of the duty of carrying the current and breaking the inductive current through the voltage coil 43 of the main switch.

If at any time the current inthe work circuit rises above, say, one ampere when the dynamo is not running, the starting of the dynamo is cii'ected at once, without waiting for the battery to discharge to the state indicated by the start-charge contact 30 on the meter. This immediate starting of the engine is eii'ected through the lamp-current coil 24 on the main switch; this coil, when energized with more than, say, one ampere of current, raises the core 44 of the main switch 6, after which the starting of the dynamo is effected as in the preceding instance, where the coil 44 was raised by means of the voltage coil 43.v If now the battery be comes sufficiently charged to cause the indicator 2 to reach the stop-charge contact 63, the relay 7 will not be affected, as it is inits Figure 1 position. The voltage coil 43 of the main switch is de-energized at this time, but

the core 44 thereof does not drop, because i i there is more than one ampere of current in the lamp-current coil 24, and this coil is thus energized sufficiently to keep the main switch closed even though the voltage coil 43- is de-energized'. Nor does the underload relay R- operate to close the ignition contacts 46, because the current flowing throughthe coil of this relay is sufficient to keep the relay energized and the contacts 46 separated. The charging of the battery therefore continues, but at a decreasing rate, becausethe counter electromotive-force of the battery is increasing, and the impressed voltage (from the dynamo) is constant. As the charging progresses, the meter indicator rotates further' counter-clockwise, until it reaches the stop 67, indicating full charge, or it preferred, an overcharge. Further movement of the meter indicator is prevented by this stop; this does no harm to the meter, and

serves to indicate that the battery is fully charged, and also tends to insure that the indicator of the meter is in harmony with the condition of the battery. Then, when the lamp current falls below one ampere, the lamp-current coil 24- permits the-core 44 to drop, thereby opening the main switch, disconnecting the dynamo from the battery and lamps, and open-circuit'ing the underload relay R, which thereupon closes its contacts 46, de-ene'rgiz'ing the engine ignition and stopping the engine. The reason for preferably separating the stop-charge contact 63 and full charge stop 67 by an interval determined by the constants of the-system, is

that the charging current tapers ofl. markedly toward the end of the charge and considerable time is required for the indicator to move over this part of its travel' If the stopcharge contact 63 were t a point representing full charge, and the lamp load below one ampere, the engine would be kept running a long time with an insignificant current and consequently low efficiency. It is preferable to place this stop-charge contact 63 at a point representing about eighty to ninety per cent of full charge and to depend upon the exigencies of load conditions to run the engine long enough to efi'ect a complete charge and. occasionally a desirable overcharge of the battery; this will bring the indicator 2 ,up against ,the stop 67 and when the battery next goes on discharge the meter will be still instep with it. It will thus. be seen tha-t the engine is started at any time when thelamp current exceeds one ampere, and remains in operation as long as the lamp current remainsabovethat value, and supplies current to the lamps and to the battery, and that with the lamp current less than one ampere, the engine is started automatically, when the battery becomes sulficiently discharged, and is automatically stopped ,whentthe charging has progressed to a predetermined extent. It will be clear, moreover, that when the dynamo is at rest the lamps are supplied from the, battery through a circuit including the low-voltage winding of the dynamo, which, however, offers at this time only an ohmic resistance to the passage of the current therethrough, since thearmature is not rotating and the field is not energized; on the other hand, when thedynamo is in operation, the battery is charged at a constant voltage equal to the sum of the voltages across both of the dynamo armature windings, while the lamps are supplied fromthe high-voltage winding only, and at a constant voltage equal to the discharge voltage of the battery. In this way, the lamps receive practically the same voltage whether the battery is on charge or discharge, the battery receives on charge a constant impressed voltage in excess of its discharge voltage, and the ratio of charge to discharge voltages may be predetermined to meet the characteristics of the battery by properly proportioning the relative voltages of the two armature windings 'cf the dynamo. Again, the regulator provided for the purpose of maintaining a definite voltage characteristic operates directly upon the fuel supply to the engine, thus avoiding the losses and complication incident to other types of regulation; and by suitable design of this regulatorin combination with the drooping characteristic of the dynamo, the engine is caused to run at a higher speed at full load than at light load, thereby efiecting an engine operation conducive to fuel economy, since at light load, when less fuel needs to be taken into the engine, a lower speed is advisable in order to reduce the amount of throttling needed, and to maintain a more nearly constant and economical mixture of fuel and air throughout 9,- ground, and elements 25, 26,27 and28,

to the negative side of the battery. Thisjen; ergizes the coil 73 which ,opens the tripswitch 9, thereby disconnecting the dynamo from the battery and lamps, and protectin the battery from further;dischargev throug the dynamo. Atvthe same time, an alarm circuit may beclosed eitherby theclosing of the circuit at 2, 71,,or by the movement of the trip-switch 9.to its open-circuit positi0n;-the latter device is illustrated, conventionally as comprising the bell 75, thefcontacts 76 adapted to be closed when theswitch 9. is open and connections to battery and to ground; this bell would naturally be located within hearing distance of the operator, and

would continue to ring, using a negligible amount of currentfrom the battery, until the operator responds to the warning. An

additional warning, inherent in the apparatus consists in the decreasing voltage and candle-power of the lamps as the rapid discharge of the battery causes its voltage to drop to a marked extent. It will be noted that this opening of the dynamo trip-switch 9 does not disconnect the lamps from the battery, so that the operatorhas the use of i the lighting circuit for locating the trouble, and the work circuit is available for illumination and other purposes. If the battery discharges still furtherbefore the trouble is removed, the battery may be prevented from being permanently damaged, by another safety device, comprising the battery-trip contact 7 8, which is engaged by the meter indicator 2 when the latterhasmoved clockwise far enough to indicate a nearly-discharged condition of the battery. When the indicator reaches this contactj78, --a circuit is closed from the positive side of the battery, through elements 19, 10, 20, 2, contact 78, lead 79, coil 80 of battery trip-'switchlO, ground, and elements 25, 26, 27 and 28, to the negative side of the battery. This energizes the coil 80, which opens the battery trip-switch 10, thereby disconnecting 'the the r s eg te; b

BEST AVAlLABLE COP".

battery from the lamps and preventing any further discharge of the battery, except possibly the small current needed for the alarm circuit 75, 76 and for a trouble lamp 7'. if these circuits are connected to the battery side of the switch 10. Contact 78 also Serves as a mechanical stop to the meter movement 7 As an emergency device the hand-controlled switch 91 is rovided, which in connection with the lcac s and 92 is arranged to short-circuit the main switch 6 and eliminate itsuse in connection with the system whenever it becomes inoperative for any reason or is removed for repairs. By the use of this emergency switch 91, it is possible to continue the operation of the system nonautomatically whenever trouble develops in the control mechanism. aprotective device to prevent the wide opening oftlie throttle V whenever the coil 59 of its connections should open-circuit for any reason, tending to cause the engine to run away, there is provided a system of contactsand connections 98. which render the en ine ignition inoperative when the switch is e-energized, thus operating in a manner similar to theoperation of the underload relay R and its contact-s46.

, It is to benoted that-thecompounding of ulator 4, depends to a certain extent upon the'resistance of the battery. Thus, if

battery-were large with practically zero resistance, the voltage characteristic of the preferably be somewhat drooping, since the dynamo unit D operates in parallel with the battery unit B and electricalflmits in parallel will ordinarily. not diyide the load to the best advantage if their veltage characteristics are flat or rising. Howeyer, since in this case the resistance of the battery is of considerable magnitude, its

characteristic is markedly drooping and the character st c of the regulator may be made -.flat or somewhat rising and still not act to cause the unit-D to assume an excessive load in charging the battery in addition to the load of they work circuit. It is understood that the current winding 52 of the regulator 4 may either aid or oppose the winding 59. the proportibning and relations of, these windings depending upon the constants of the system. In respect to parallel operation,

thev division of L ad between the units l) and 4 B is somewhat analogous to the parallel operationof units DD and D. p

Furthermore, means are provided for preventing excessive speed of the engine due to accidental dropping of the load while the enginethrottle is openwithout requiring the use of a speed limiting overnor on the engine. This means is found the underload relay R, which becomes de-cnergized if an open circuit occurs in the gene'rator or generator mains, and renders the Cally protecte dffr'om over=speedi req mu the use of a speed, limiting engine ignitioninefiec'tive, "thereby stopping the engine. lVitho'utsuch means, an'o'pe'n circuit, as for example, between the: brush and commutator 56, wouldcause the'dy name to drop its loadpand the"- ar1i1ature windingZG-wuld then niotorize fr'oiirtlie battery through a circuit 10, 20, 21, 22,241, 39 1, Ii, gimme-25, 26, 27 and 28;'-th're suiting heavy ohmic drop in the battery would weaken the regulator' coil 59, which wcaild tend to open the eng ne'throttle, and there would he danger of the engine running away unless a speed limiting device were provided. The underload relay R; however, automatically stops the engine in an en'icrgcncy suchas this, andithe neccssity for a speed limit device to protect the engine from this danger isobviated. Means if the shunt field"is opeii circuited, the :regulator coil 59 willbe' cpmpletely de' ene'rgized, so that the plungeul' will'elos'c'fthe ignition contacts'98 and istop the .eng i'n'efon the other hand, if the. shunt field is shortcircuited, the increased current'iii'th re alator coil 59 will move the regulator core 13 to yalve-closin position,- in which case the fuel supply to t e engiiiewould be'tiu t'dow ii:

and as; a matter of fact the, regulator "coil would robabl hurn'out f so' 'thtitf it would completely de-en'ergized, and'then thelregulatorcore 13 would close the ignition c'ont ac-ts 98 and stops theen ins; so. that in anyevent, the engine would initomdfi- '5 without The'undrloadr'elziiy R serves to simplify the construction -'of the ma n switcli 6 as compared"witl1 the main switlr 6' ofQthe fPardee application 92,421, above mentioned, since it is ordlnarily desirable 't'o,h:ii-'e a main switch' closefts main contacts when the flux through its'core attains a definite.

value, and the closingof the switch should take place at or practicallynt this prede termincd value ofthe fiux. To d'ri-tlii's, the pull dueto the flux should be balanced fairly accurately against the springgor other'co'unteracting force, so that aslfght increasein the flu; will i switch; however, if the switch in its' opencircuiting position, is required to close tightly a set of auxiliary contacts, it isdifficult to secure this nicely-balanced action for accurate closing of the main contacts and at the same time preserve a tight. auxiliary contact until the moment 'ofiac tually closing the maincontac-ts. The present invention,.by elim nating any auxiliary contacts (in the main switch 6, thus simplifies materially the construction of the'sivitch;

device. A

BEST AVAILABLE coex In order to prevent the opening of the dynamo trip-switch 9 whenthe pointer is approaching the contact 71 in a counterclockwise direction, the contact 71 is insu lated on its side nearest the contact 78 so that the indicator slides by the contact 71 Without making electrical contact with it when approaching it in a charging direction (counter-clockwise), but does make electrical contact when approaching in a discharging direction (clockwise), that is, when the battery is, discharging. a

The description thus far has been directed to a system utilizing a. single engine.

In certain instances, it is more economical to divide the power supply of the plant among two or more units, and tohave one of these units of larger capacity than the other; for example,.in.a typicalinstallation a lamp load of one ampere or less would be suppliedby the batteryyalone; :the ordinary [ot the respective units. Whenever the 'lainp cu'rrent ,drops to aflpredetermined exentxi low therasi inis ta da fi ffe f f e ainperes",.th e''coils 5r. the mai'i'i' svYitchQlOG aiiown switch .106 toop'en, thereby dis- ;conn' ectingftl e dynamoDD from the load, fand leaving the circuits 'in'the condition in whichfthey were before the lamp load first.v

load of, say, fifteen amperes, would be supplied by a small engine such as the engine E, driving the double-current dynamo D, l

at approximately its full-load rating; a maximumload, 1 of, say, fifty amperes, would be-carried by a larger engine EE and dynamo DD, running either alone or in parallel with thesmaller: unit E, D. Thi s.,is

conducive to efiiciency of fuel consumption, I

because the units then operateat approximately full load,-whereas aninternal combustion engine running at low loads is relatively inetficient.

If a second engine EE and single-voltage dynamo DD .are to be added to the plant above described, the switch 100 in the work circuit. is opened,-and to its terminals are connected the leads 103, 105 to thermain switch 106 and thence to the dynamo DD. A preferred arrangement of parts is indicated in the drawings as comprising shunt and series windings 158, 154, the latter connected to the current coil 152 of the enginei'egulator 104E, thence to the dynamo-current coil 148 of the main switch 106, to the lead 103 above described. A manual switch 191 is provided in shunt to the main switch .106; and an underload relay RE is provided with contacts 146 so designed as to render the engine ignition inoperative when the dynamo current falls below a predetermined value. A voltage coil 159 on the regulator solenoid 113 is connected in series with the shunt field 158. The lamp current coil 124 of the main switch 106 is connected across the leads 103, 105, and carries lamp-current except when the manual short-circuiting switch 191 is closed; this switch'191 is used,

however, only when the main switch 106 is out of order. In operation, when the lamp current exceeds fifteen amperes, the lampcurrent coil 124: of the main switch is energized sufficiently to close the switch, whereupon current from the dynamo D flows through the dynaino DD to start the ,latter and after the engine EE has begun to roand 104C.;L .Th;is adjustment maybe arranged 4 to causethefiinit "EE, DD toassume all of 77 the load when first cut in and thus cause the ina in switch Gto open and shutdown the smaller ,unit D, E until such time as the lamp load exceedsjthe-capacityof EE, DD and causes a current greater than one ampere to flo w from' the battery, when the main switch 6 elo ses and startsthe unit D, 'Eiin the usualfgna'nifier. Or. the regulato'rs 4 and 104 may" be ,so adjusted that",when hotly-units arejrunning the division of load is at all tim'es fproport onedto the capacities exceeded, the {standard of fitteen amperes; that is, the'sinall cngineE remains'inoperation, driving the small dy a l I10 D to supply the lamps and charge the battery B. It is obvious that the difi'e'rent units'previoi slyf described need beof unequal .I II'J'Y- Theengiiic E may be connected to drive, a pump TP, pieterablyfprovided with a diapliragi ii or other typeof valve 99"arranged so that when the pressure on' the valve falls below a predetermined minimum, the valve will close the contacts 70, causing the voltage coil 43 of the main switch 6 to be enere .gized, thereby closing the contactse45', and

energizing the under-load relay- R, which thereupon 'opeiisfthe ignition contacts'tti, to start the engine.i idependently of the magnitude of the lamp load or the condition of the battery, thus providing a pressure controlled pump-starting apparatus. The pump is preferably provided with suitable means (not shown such as a by-pass valve, acting as an automatic unloading device to prevent excessive pressure.

As a modification, in the nature of arefinement and a simplification of. the above system, the main switch 6 may be combined with the trip switch 9. v

The undei'load relay R is preterably provided with a retarding device such as a dashpot (Z, to prevent the relay fromclosing the contacts 46 during the moment of reversal of dynamo current when: the engine has been started and the dynamo begins to generate.

- ion BEST AVAILABLE COP.

Theutrip switches 9 and 10 may be provided with auxiliary contacts (not shown), arranged to open the circuit of their respective windings, when the switches are tripped. These contacts relieve the meter contacts 71 and 78 of the duty of breaking an inductive circuit.

In Figure 2 there is illustrated a modified construction differing from Figure 1 primarily in the relay 7 which in Figure 2 is numbered 207. In the modification the relay 207 comprises an operating coil 233 whose core 234 is mechanically connected to the movable cont-actors 269 and 274 adapted to .co-operate respectively with the relatively fixed .contactors 268 and 277. The meter contact 263, which corresponds to a substantially full-charge condition of the battery is connected by the lead 264 to the righthand movable contactor 274. The startcharge meter contact 230 is connected by the lead 231 to the left-hand fixed contactor 268: and to the negative side of the relay coil 233,;whose, positive terminal is connected, first, through the lead 241 to the voltage coil. 243,,of the main-switch 206; second, through the lead 261 to the right-hand fixed contactor 277 of the relay 207; and third, to-one of the pump-controlled contacts 270, the other of these contacts being grounded.

Ihe,.. operation of the modification illustrated in- Figure 2 follows the description above given for Figure 1, save for certain differences which may be briefly enumerated. Assume that the voltage coil 243 is deenergi'zed and that the contacts 245 of the main switch 206 are open. It now a lamploadof say less than one ampere is turned on, in'lthe work-circuit, the battery discharges slowly until the meter pointer 202 travelsclockwise to the start-charge contact 230. Current will then flow from the positive pole of the battery, through the lead 222, voltage coil 243, lead 241, relay coil 233, lead 231, start-charge contact 230, meterpointer 202, to ground, and thence (referring now to Figure 1) through the intermediate terminal of the dynamo D,

armature winding 26, negative terminal 27, and lead 28, to the negative pole of the battry. "This energizes both the relay coil 233 and the main-switch voltage-coil 243.

Theenergizing of the relay coil 233 closes first the right- hand contactors 274, 27 7, and later closes the left-hand cont-actors 258, 269, No circuit changes are effected at this by the closing of the right-hand contactors 274, 277, because the circuit in which said contactors are located is open at the stop-charge meter contact 263. The closing of the left-hand relay contactors 268, 269, short-circuits the start-charge meter contact 230 and electrically locks the relay 207 in its closed position, by connecting the negative terminal of the relay coil 233 directly to ground. w

The energizing of the main-switch voltage-coil 243 closes the main-switch contacts 245. and serves to start the engine as above described in connection with Figure 1. T consequent charging of the battery causes the meter pointer 202 to travel counterclockwise toward the stop-charge contact 263. As the pointer 202 leaves the startcharge contact 230, there is no arcing. be-' cause this contact has been short-circuitcd at 268, 269, as above described.

lVhen the meter pointer 202 reaches the stop-charge contact 263. the relay coil 233 is short-circuited through the lead 261. right-hand relay contactors 277, 274, lead 264, contact 263, meter pointer 202, to ground. The relay 7 on being thus de-energized by the short-circuiting of its operating coil 23?; releases its core 234, which then returns to its initial position through the influence of a spring 2350i gravity, first breaking the left-hand contacts 268, 269, and later breaking the right-hand contacts 274, 277. The latter break opens the circuit including the main-switch ;voltage-eoil 243, and thus causes the main switch 206'toopen, and shut down the engine, unless thelam current through the -"main-switch currentcoil 224 is suflicient' tohold the main s'witch contacts 245 closed, as previously described in connection with Figure 1.

It will be noted that during the opening of the relay contacts, the initial=break of the circuit including the main-switch volt age-coil 243 occurs at the right-hand relay contacts 274, 277 these contacts may be bridged by a condenser-251, if desired, in order to prevent any objectionable -arcing. There is no arcing when the meter pointer 202 leaves the cont-acts 230 or 263,- because in neither instance is there any current flowing through the meter pointer at the time the pointer leaves the contact The relay 207 may be a smalland compactdevice of simple construction, and the parts'therefor may be readily obtained on the market at nominal cost; at no time is there a heavy current passing through any portion of the relay mechanism. In case the meter 201 is removed, as for inspection or repair, the relay 207 may be operated manually to start and stop the charging of the battery at the proper times. In' general, the various parts of the apparatus illustrated in Figure 2'are' assigned reference numerals two hundred higher than the reference numerals for the corresponding parts in Figure 1. Bearing this in mind, itis believed that the operation ofthe apparatus of Figure 2"will be clear from the foregoing, without further elaboration.

From the above, it will be seen that the BEST AVAILABLE cos.

several objects of the invention are achieved, and other advantageous results attained.

As various changes might be made in the above construction, and as the above invention might be embodied in dillerentforms, it is intended that all matter set forth in the above description and in the accompanying drawings, shall be interpreted as illustrative and not in a limiting sense.

Having thus revealed my invention, I desire to claim as new and secure by Letters Patent of the United States:

1. An electrical system combining a dynamo adapted to run as a motor to start an engine and to be run as a generator by the engine, a battery, a switch connecting the dynamo to the battery, and a current relay in the dynamo circuit adapted to stop the engine when the dynamo current falls below a predetermined value, said relay being provided with a retarding device to prevent the operation of the relay at the moment of reversal of dynamo current when the engine has been started and the dynamo begins to generate.

2. An electrical system combining a bat tery; a dynamo provided with shunt and series field windings; an engine coupled to the dynamo; a valve in the fuel supply to the engine; a work circuit; a main switch adapted when closed to connect the dynamo to the battery and work circuit; a relay adapted'to render inoperative the ignition of the engine to stop the engine when the dynamo current falls below a predetermined value; a meter provided with an indicator for indicating the state of charge of the battery; means controlled by the indicator for closing the main switch to energize the dynamo to start the engine when the battery is suflici'ently discharged, means controlled by the indicator for disconnecting the dynamo from the battery and work circuit and for operating an alarm when the battery is further discharged as by failure of the dynamo to start the engine, means operated by the indicator for disconnecting the battery from the work circuit when the battery is still further discharged; a regulator provided with a work-circuit-voltage coil in series with the dynamo shunt field and adapted to move the valve to regulate the fuel supply to the engine to maintain constant the voltage at the work circuit, and provided with a dynamo-current coil opposing the voltage coil to set a different standard of voltage at high loads than at low loads; a pump driven by the engine; and pumppressure-controlled means for closing the main switch to start the engine when the pressure of fluid delivered by the pump attains a predetermined value.

3. An electrical system combining a dy-- namo adapted to run as a motor to start an engine and to be run as a generator by the engine, a battery, a relay responsive to dynamo current adapted to stop the engine when the dynamo current falls below a predetermined value, said relay being provided with a retarding device.

4. An electrical system combining a dynamo adapted to run as a motor to start an engine and to be runas a generator by the engine, a battery, a relay responsive to dynamo current adapted to stop the engine when the dynamo current falls below a predetermined value, said relay being provided with a retarding device, to prevent operation of the relay immediatelyuponthedropping of said current to zero.

5. An electrical system combining a dynamo adapted to run as a motor to start an engine and to be run as a generator by the engine, a battery, a relay responsive to dynamo current adapted to stop the engine when the dynamo current falls below a pre determined value, sai'd relay being provided with a retarding device, a pump driven by the engine, and pump-pressure-controlled means for starting the engine when the pressure of fluid delivered by the pump attains a predetermined value.

In witness whereof, I hereunto subscribe my name, as attested by the two subscribing JosEPH BURKE.

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