US1869555A

US1869555A - Control system for farm lighting plants

Info

Publication number: US1869555A
Application number: US427000A
Authority: US
Inventors: Leo C Frank
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1930-02-08
Filing date: 1930-02-08
Publication date: 1932-08-02
Anticipated expiration: 1949-08-02

Description

Aug. 2, 1932. I c. FRANK w 5 CONTROL SYSTEM FOR FARM LIGHTING PLANTS Filed Feb.,8. 1930 14 I I -I I L 80 \80 A? 6 33 3 INVENTOR Leo CZFranh ATTORNEY gine sticksl, thus Patented Aug. 2, 1932 UNITED STATES L120 0. FRANK, OI ICmSPOB-T. TBIG & IA N'Ul'ACTUmG PATENT. OFFICE CONTROL "8m 36B rm LIGHTING PLANTS Application lied Iebrury 8, 1930. Serial Ho. 427,000.

This invention relates generally to control systems for electric power plants such as are used for farm lighting, the operation of air plane beacons'or similar service.

More particularly, this invention relates to automatic electric-generating systems including, among other elements, a battery, an engine, a dynamo-electric machine and loadline circuits and adapted for use on automobiles, or in isolated places, such as country residences, farm homes, places wherethe attendant is partially or totally unskilled in the art of managing such plants, or generat ing plants for airplane beacons, which are often very isolated and where the attendant, whether skilled or unskilled, merely makes periodic inspection of the plants to provide the necessary gasoline and oil.

An object of this invention is the provision of an electric-power unit which shall be simple in construction, automatic and efiicient in operation and which may be readily installed.

A more s cific object of the invention is to provide ih r protection a inst over-voltage, over-load and continu cranking when the engine fails to start.

A further object of the invention is to provide for automatic starting of the engine when the load on the line exceeds a predetermined value and for automatic stopping of the engine when the load on the line decreases to a predetermined value, and for controlling the uel supply to the engine during starting operations to provide for feeding an amount of fuel proportional to the current in the load-line and control circuits.

Another object of the invention is to provide for varying the choking of the engine during the starting operation and for controlling such varyin choking over a predeter mined range during a predetermined interval of time,

It is also an object of this invention to pro-' vide for automatic and manual starting of the generatingnplant and providingfor expeditious cran ng protection in case the enocking. the armature of the d namo-electric machine.

O t er objects and advantages will be apparent from a perusal of the followingspecification, especially when done in conjunction with the accompanying drawin wherein Fig. 1 shows, diagrammatically, t e various elements of this invention disposed in operative relation; and Fig. 2 shows, diagrammatically, a modified arrangement of the starting switch.

In the diagrammatic showing of the automatic electric-generating system, 1 designates a series line relay for automatically con trollingEthe starting and stopping of the engine in response to load conditions in the

load lines

12 and 32. Associated with the control system, and particularly with the series-line relay 1, are a air of

control relays

2 and 3 which control t e starting operation of the engine through the dynamo-electric machine M, acting as a motor.

To protect against continuous cranking, in case the motor fails to start the engine, a tbermo-electric time Iimit relay 4 is provided. Associated with the engine, but more particularly with the carburetor of the engine, is an automatic-choking device 5 and an auxiliary time-limit choking device 7 and, intermediate the carburetor and the engine, is disposed a series governor 9. .Reference character 8 designates another relay disposed for operation to isolate the battery B from the generating system in case the voltage de- 80 creases to a predetermined value either through excessive dischar e of the battery or because of a short-circmt on the line.

e series governor 9, during operation of the engine E and machine M, controls the fuel supply, and the amount fed to the engine is proportional to the load. on the line. However, during manual starting efl'ected through the operation of-the push-button switch as? sembly 6, disposed adjacent .to the armature of the series governor 9, the overnor is held open to ensure an ample fue supply during such manual starting.

Referring more particularly to the elements in the drawing, 1 represents a series line relay and comprises an actuatin coil 23, an armature 2'4, and a contact-bri ging member 29 disposed for operation by the armature. The armature 24 maybe biased towards a position in which-the contact members of the relay are open, by means of a' spring 26 positioned between an upper fixed support 25 and a washer 27 secured to the lower end of the spring and held in any given position on the armature 24 by a nut 30 mounted on a screw-threaded extension 28 of the armature. The spring 26 and the ar-' I mature 24 are secured against rotation.

" than six amperes will maintain it c spring on the armature.

' ener izing current traversin through conductor a certain posltion,

The nut, below the washer and in threaded engagement with the extension 28 on the armature, is provided with graduations for cooperation with an index on the washer 27. By a manipulation of the nut, the biasing effect may be adjusted to any desired value and, in consequence, the current flowing through the coil necessary to hold contact members 31 closed may be predetermined. The position of the nut 30 and hence, the degree of compression initially applied to the spring when the rela is in the open position, will determine bot the pull in and the drop out values of current flowing in the coil 23 at which the relay will either close or open its contact members.-

Forexample, if the nut 30 is adjusted to for instance, the position shown in the drawing a current of six amperes ma be required to ener lze the coil to close t e contact members 0 the relay 1. When the relay is closed, a. current of less losed. Therefore, if the current be reduced to a value below six amperes, a balancing point will be reached at which the ma etic all of the coil on the armature will be ance t e pull of the If the current be reduced still further, the force exerted by the spring will become greater than the magnetic pull of the coil, and the relay will be actuated to open its contacts. The value of the coilthe coil at whic the relay will drop out or open may be as low as three amperes.

In the drawing, B designates the battery, which is of the 32-volt type. However, it is obvious that the number of individual units of the battery may be changed so that any other volta e, such, for example, as 110,.may

rovide j onnected directly across the battery terminals, is a low-voltage control relay 8 having an actuating coil 14 and contact members 13 disposed to open the loaddine circuit to isolate the battery from the generating system in case of excessive discharge of the hator because of the heavy current that may be drawn by the dynamo-electric machine M' in case the rotor becomes locked during the starting operation. The circuit for the low-voltage relay may be traced from the positive terminal of the battery B,

actuating coil and conductor of the battery.

14 of: relay 8, conductor 15 12, to the negative terminal Connected in series with the valve in housing 86 in direct 11, contact members 13,

load line is an a nmeter- A which may be mounted on a panel-board in some convenient place for observation.

The actuating coil 20 of the series governor 9 is connected in the conductor 19.

The function of the series governor, during normal automatic operation,-.is.to open the proportion to the load current. As shown, the actuating coil 20-acts directly on -armature 85. Dis posed adjacent to-th'e 'series governor, is a push-button assemblage 6.comprising a supporting member 89, -a push-button 87, a spring 88 disposed intermediate the pushbutton 87 and the supporting member 89 to bias the contact 93 of the ush-buttcn upper or open position. slow the supporting member 89, are pivotally mounted a pair of contact members 92 and .94 biased by springs 91 toward a given position against stops 90. Secured to. the lower portion of contact member 93 is a stem provided with. a notch with which a latch 97, secured toa su port 96, is disposed to engage.

en the plant is to be manually started,- push-button 87 is depressed against Y the action of spring 88 untll contact 93 bridges the pivotally mounted

contact members

92 and 94, thereby closing acircuit in. parallel to the contact membersof the seriesline re-; lay above referred to. When'it is desired to charge the battery, push-button 87 is deto the pressed to permit the latch 97 to engage the I notch in the pro ecting portionfofthe contact 93. When this takes place, the project: ingportion'also-engages the armature of the series governor and disposes the valve of, the governor. to a desired open position, thereby causing the engineto operate at a. predetermined comparatively-high speedr whereby the dynamo-electric machine generates a voltage sufficiently high to charge the battery.-

Controlledby theoperation of the series line relay 1, it isa time-limit thermo-electric protective cranking device 4- comprising a pair of

bi-metallic strips

69 and 70 rigidly fixed, at one end, to a support; To the free end of the

strips

69 and 70 is loosely secured a push rod 98 to engage a latch member held in a given position against a support 104 by means of'a spring'106. The tension of the spring may be adjusted by means of nuts 107 disposed on a' threaded extension 108 secured to support 104 and projecting through a relatively large opening in the latch member 105. Adjacent to the upper bi-metallic strip 69 is' disposed anelectric heater 7! which is subject to the voltage of the generating system. Wound about the bi-metallic strip 70 is a current coil 82 connected in the system to. carry, either the starting current drawn by the dynamo M operating as a motor or the current generated by heater 77 wil be somewhat lower.

- such conditions.

means the dynamo when functionin as a generator during loaded operation of t esystem.

Attention is called to the fact that heater 82, while wound about the bi-metallic strip 7 0, is nevertheless in the vicinity and in heattransfer relation to the bi-metallic strip 69. The purpose of this arrangement is to compensate for any change in voltage thatmay take place in the system. For instance, if the heating efiect of the heater 77 be insuflicient, because of low battery voltage, to cause a deflection of the bi-metallic strip 69 through a given ran in a required predetermined interval of time, the heater 82 causes sufiicient heating of bi-metal strip 69 to provide for the required deflection.

When the engine is warm for instance at 7 0 F. and the oil in consequence not viscous, the cranking current will be small and the voltage of the battery will not be affected during cranking. The heater 77 is, therefore,

subject to normal battery voltage and, since the heating effect of heater 82 under these conditions is negligible, will cause operation of the protective cranking device after a predetermined interval of time.

When the engine is cold, for instance at 32 F. and the oil correspondingly more viscous, the cranking current will be much greater and the volta e of the battery impressed on Under these conditions the effect of heater 82 is a preciable and b its collateral heating of strip 69 aids heater 77 sufliciently to cause deflection of this strip over a predetermined range during the same interval of time required for the higher temperature. Heater 82 thus compensates for any drop of voltage of the battery during cranking.

For a very lowtemperature, for instance zero, the voltage drop of the battery during cranking may be so much that heater 77 alone could not trip the protective cranking device. However, for the very low temperature the heater 82, with the slight aid of the heater 77 insures operation of the protective cranlz-- ing device after a given interval of time. Tests have indicated that the protective cranking device, of this invention, will always operate in about a minute and a half for temperature changes ranging from 0 F. to 70 F.

If, during starting operation, the engine shaft should be locked and thus the voltage applied to the motor be across a stationarv armature, the current would be excessive and, in consequence. the voltage of the battery would be quite low. Under such conditions, the effect on the heater 77 might not be uflicient to cause the protective cranking device 4 to function in time to protect the armature circuit and other circuits of the system. The heater 82, therefore, ensures a-rapid actua tion of the protective cranking device under is dis forming an important part Adjacent to the

bi-metal strips

69 and 70 osed a support 109 having a screwthrea ed projecting stem- 113 carrying nuts 112 and a sprin 111, the tension of which may be adjusted y the nuts 112. Interniediate the spring and the support 109, is disposed a contact-carryin member 110 having a relatively lar e o emng through which the stem 113 extentfs. lhe number 110 may thus be moved towards the right, as ona pivot, and is biased to a given position against the support- 109 by spring 111.

Intermediate the ends of member 110, is positioned a contact 99 for engagement with the contact 35 when the member 110 is in the position shown in the drawin Upon deflection of either one or both 0 the

bi-metal strips

69 and 70, latch member105 is moved to a lower position so that the projecting portion 115 on the latch member 105 extends into the opening 114, thereby opening the

contacts

35 and 99. As soon as projection 115 enters the opening 114, latch member 105 cannot operate to close the

contacts

35 and 99 and, if the protective cranking device has functioned, it is necessary for an attendant to reset the

members

105 and 110 in theposition shown. 1

Also controlled by the series-line relay are a pair of

control relays

2 and 3. The control relay 2, including the actuating coil 44, con tact members 45 and contact-bridging member 46, operates after the actuation of the series line relay to close a circuit for the dynamo M. 1

The relay 3 is provided with a air of actuating coils 49 and 50, the actuating coil 49 being subject to the voltage of the battery and the actuating coil 50 being subject to the cranking current taken by the dynamo M. when operating as a motor. During cranking operation, the magnetic efiect of the

coils

49 and 50 is cumulative and operates to close the contact members 73 by the contact-bridging member 74. After the engine has started and drives the dynamo M as a generator, the current in the actuating coil 50 reverses and thus its magnetizing effect is in opposition to the magnetizin effect of the voltage coil 49. The compoun -wound relay 3 controls the current passing through the heater 77, the actuating coil 61 of the engine-choking device 5 and the heater 65 of the time-limit engine-choking device. If the engine starts before the protective cranking device 4 operates, contact members 73 are opened, and the circuits to actuating coil 61' and the

heaters

65 and 77 are broken, as desired.

The compound-wound relay, since it controls the operation of the protective cranking device, provides for starting protection, thus preventing depletion of the battery because of continuous cranking. If, during operation, the speed of the engine E, for some reason, becomes excessive, thus raising the V0".-

' and conductor 12, to

- excessive,

age of the system abnormally high, energization of coil 49 alone will be sufiicient to cause the closing of contacts 73, whereas, if the speed remains normal but the load becomes coil 50 alone will be suificient to cause closing of the contacts 73. The ratio of the turns of

coil

49 and 50 is so chosen that the stated functions take place. From this three-fold function of the compound-v wound relay, it is apparent that this relay provides, in a very simple manner, ing protection, over-load protection and overvo tage protection of the generating system. The operation of the device is as follows: Assumin that a number of switches 80 are closed, t en, if the current flowing in the work circuit or load line is below a predetermined value, as, for example, below .six amperes, the storage battery will suppl the current. If the current demand excee s six amperes the contact members 31 are closed, thereby establishing an engine-starting circuit through the motor. As the engine comes up to normal speed, the dynamo is driven as a generator to take up the load in the work circuit.

The circuits mentioned may be traced from the positive terminal of the battery B, through conductor 11, contacts 13 of the lowvoltage relay8, conductor 17, ammeter A, conductors 18 and 19, actuating coil 20 of the series governor 9,

conductors

21 and 22, actuating coil 23 of the series line rela 1, conductor 32, load 33, switch 80 and con uctor 12, to the negative terminal of the bat- T f the current in the load exceeds a predetermined value, the series-line relay closes contact 31, thereby establishing a circuit from the energized conductor 32, through contacts 31, bridged by the eontact bridging member 29 and conductor 34, to contact 99. Since, during starting operation, the elements of the protective cranking device are in the position shown in the drawing contacts and 99 are in engagement, thereby establishing three parallel circuits. V

The circuit for the engine ignition is established, through conductor 36, primary 3 of the transformer of the ignition system 10, condenser 38, and interrupter 39 in parallel the negative terminal of the battery. Disposed adjacent to the primary 37 of conductors 42 leading to the engine block and spark terminal 41, respectively.

The second parallel circuit established through the

contacts

35 and 99 may be traced, through conductor 43, actuating coil 44 of control relay 2, conductor 47, actuating coil. 50 of the compound-wound relay 3, conduc-' tor 51 and conductor 12, to the negative batterIy terminal.

11 parallel-circuit relation to the actuating. coil 44 is an actuating coil 49 by means for crank- -nal and, through conductor 60,actuatin'g coil is a secondary having a pair of a conductor 48 and the conductor 47. -During this stage of operation, the effect of

thecoils

49 and 50 is additive. However, before the actuation of the control relay 2, the combined magnetic effect of

coils

49 and 50 is not suflicient toclose the contacts 73 by the bridging member 74.

The control relay 2, upon energization, however, operates to close contacts 45 by the contact-bridging member 46, thereby establishing a motorer'cuit for thedynamo-electrio machine M. This circuit may be traced from the positive battery'terminal, through conductor 11, contacts :13, conductor 17, ammeter A, conductors 18 and 81,-heater 82, conductor 52, series field winding 53, co ductor 54, armature of the dynamo M, conductor 56, contact 45.,'bridged by the contact bridging member 46 'conduct,or 47, actuating coil 50, conductor 51- 'and conductor 12, to thenegativ'e terminal of the bat-- fiery Disposed in parallel. circuit relation to the armature 55, is a.sl unt'field winding-57, a shunt field resistor 58 and aconductor 59. Closure of the contacts,45' by the contactbridging member 46 and establishing the circuits just described causes the heavy cranking current: to pass through actuating co'l 50, the combined magnetic eflect of

coils

49 and 50 thus operating to close'con'tacts-73' by the contact bridgin-g member 74. =Glosure ofcontacts 73 establishes a circuitfromcon-z tact 35 to contact 9 conductor 72, contact 73-bri'dged by the :contact bridging 'mem-* ber 74 of the compound .wound relay 3,-'and conductor-7 5, through-a plurality of parallel circuits and through the protective t'me-limit engine cranking device 4,. the engine-choking device 5- and the time-limit engine choking device 7. These circuits may be traced from the energized conductor 75, through conductor 76, heater 77,; conductor 78 I and conductor 12, to the negative battery termi- 61 of the engine-choking device 5, conductor 62, conductor 63, conductor 7 8 and conductor 12, to the negative terminal of the battery and 7 also from conductor 75,- --through conductor 64, heater 65 of the time-limit engine-choliing device '7, conductor 63 and'conductors 78 and 12, to the negative, terminal of the battery.

If the engine fails to start within a predetermined interval -o'f' time, the combine action of the current heater 82 and the'voltage heater 7 7 operates to break the contacts 35 and'99, thus directly interrupting the ig-,

nition circuit of the engine and: the circuit for the control relays-2 and 3. =Deenergization of the control-relays 2 and '3 causes an interruption of the electrical-energy supply to

heaters

77 and 65 and the actuating coil 61.

Since the actuation of the protective cranking device causes a movement o'f'the latch eeann verses, opposing'the effect of the coil 49 and thus causing the separation of the contacts 73. This operation of contacts 73 prevents the protective cranking device from function' ng. When the load again decreases to some predetermined low value, for instance, to 3 amperes, the series line relay drops into the position shown in the drawing, the engine stops and the battery assumes the load.

During cranking, heater is energized, as above pointed out, and actuating coil 61 operates to completely close the valve in the tube 66, Energization of heater 65 causes a downward deflection of the bi-metal strip 68 and thus varies the biasing effect of the s ring 71 interposed between the free end of t e bimetal strip and a valve disc 67 seated in an auxiliary opening of the housin 69 of the time-limit choking device. It wi be apparent that the seating pressure of valve disc 67 varies from a maximum, during the initial stages of starting, to a minimum after a predetermined interval of time. To ensure that the bi-metal strip 68 shall be deflected over a given range in a given time, it is designed to be relatively insensitive to ambient temperature and is mounted within the housing of the time-limit choking device u on a heatinsulating block, thus reventing t e dissipation of the heat transmltted from the heater 65 to the bi-metal strip 68. The subject matter of this time-limit choking device is covered in a separate ap lication of L. C. Frank J. D. Conant, filed anuary 30, 1930, Serial No. 424,616 and assigned to Westinghouse Electrio 8; Manufacturing Company.

The manual starting means above discussed need not necessarily be connected in the circuits as shown but may be disposed as shown in Fig. 2. In Fig. 2, the conductor 100, the contacts 101, the push-button 102 and the conductor 103 correspond to the conductor 79, the contacts'92 and 94, the pushbutton 87 and the conductor 95.

. I do not limit myself to thespecific structural details, connections herein set forth, as various other modifications thereof may be made without departing from the spirit and scope of this invention, as defined in the appended claims.

I claim as my invention:

1. In an electric-generating system, in combination, an internal-combustion en 'ne, a dynamo-electric machine, a battery, a oad line and a system of control comprisin a series line relay for closing a motor circuit or the engine starts with n a given time arrangement of parts or circuit said dynamo-electric machine tocrank said engine when the load in the line exceeds a predetermined amount, an electrically con-' trolled time-limit protective cranking device for interrupting the motor circuit should the engine fail to start within the time limit of the protective cranking device, and an electrically controlled time-limit engine choking device for varying the choking of the engine during the cranking operation over a predetermined range during a predetermined interval of time.

2. In an electric-generating system, in combination, an internal-combustion engine, a dynamo-electric machine, a battery, a load line and a system of control includig a series line relay for closing a motor circuit for said dynamo-electric machine to crank the engine when the load in the line exceeds a predetermined amount, and an electrically controlled time-limit engine-choking device for varying the choking of the engine during the cran ing operation over a predetermined range during a predetermined interval of time.

3. In an electric-generating system, in combination, an internal-combustion engine having a carburetor, a dynamo-electric machine, a battery, 8. load line, and'a system of control for the dynamo-electric machine to crank the engine including a thermo-electric protective engine-cranking device, an. engine-choking I device, a preheater for the air passing to the carburetor, a control relay for closing the motor circuit, a compound-wound relay having a current coil and a voltage coil controlled by the control relay for closing the circuit to the preheater, the engine-choking device and the protective cranking device and a series linerelay responsive to the load on the line for controlling the operation of the control relayand the compound-wound relay.

4. In an automatic electric-generating system of the demand-starter type having a batterly, a dynamo, load-line circuits, an interna -combustion engine and control circuits for the system, said control circuits including a time-limit protective cranking device having a pair of bi-metal strips, an electric heater energized by the voltage of the system adjacent to one o tric heater energized by the cranking current adjacent to the second strip and being also the strips, a second elecn tion of the latch to cause a cessation of the m cranking operation.

5. In an automatic electric-generating system, in combination, a battery, load line'circuits an internal-combustion engine, a dynamo-electric machine for o eration as a motor to crank the engine an for operation as a generator by said engine to su limit device for limitin the cranking period ply the load on the line, a series'line relay or automati cally starting the engine when the load on the line exceeds a predetermined value and for causing the stopping of the engine when the load decreases elow a predetermined value, a series-line governor for the engine, means for starting the engine manually, regardless of the load on the line, and means associated with the manual starting for locking the governor to open position a predetermined extent, whereby the engine maintains a relatively high speed, thus causing the dynamo to generate a voltage sufficiently high to cha'ge the battery and also to supply the loa 6. In an automatic electric-generating system, in combination, a batter load-line circuits, an engine, a dynamo-e for o ration as a motor to crank the engine and or operation as a generator by -the engine to char e the battery or supply the load or both, as esired, a relay for iso ating the battery from the system upon a decrease of the voltage of the battery to a predetermined minimum, and automatic-starting means for the engine, and control relays controlled by either of said starting means for establishing a motor circuit for the dynamo to crank the engine and for causing a varying choking of the en 'ne over a predetermined range during a pre -etermined interval of the cranking period.

In an automatic electric-generating SySr tem, a battery, load-line circuits, an engine having an "ignition circuit, a dynamo-electric machine for o ration as a motor to crank the engine an for operation as a generator by the engine to supply energy to the system, an electroma netic engine choker, an auxiliary thermo- Iectric engine choker, a thermoelectric protective engine-cranking device responsive to the cranking current and to the voltage of the system and designed to operate a predetermined time interval after being energized to interrupt the circuits of the choking devices, the ignition circuit, the motor circuit of the and the voltage-res onsive tective cranking evice, t ereby causing 'a cessation of thecranking operation.

8. Inan automatic electric-generating systern of the demand-starter type having a batte a dynamo, load-line circuits, an engine an control circuits for the system, said control circuits including a thermoelectric timeof the engine to a re etermined va us, and a compound-woun relay having a current coil disposed to be connected in series with the dynamo and a connected across ectric machine voltage coil disposed to be the battery terminals, the

Leeann;

LEO C. FRANK.

dynamo-electric machine rtion of the proampere turns of the series coil relative the voltage coil so chosen that the series 0011 acts additive y to the voltage coil during