US1796810A

US1796810A - Electrical generating system

Info

Publication number: US1796810A
Application number: US404488A
Authority: US
Inventors: Edwin X Schmidt; Walter O Baer
Original assignee: Cutler Hammer Inc
Current assignee: Cutler Hammer Inc
Priority date: 1929-11-02
Filing date: 1929-11-02
Publication date: 1931-03-17
Anticipated expiration: 1948-03-17

Description

March 17, 1931. E. x. SCHMIDT ET AL 1,796,810

ELECTRICAL GENERATING SYSTEM Filed No v. 2. 1929 UNIT NO. 1 L mm" m. .2

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Patented Mar. 17, 1931 nairso STATES PATENT OFFIQLE CGEEORATION OF DELAWARE- "\T X. SCI-IIMIDT, OF WHITEFISH BAY, WALTER O. BAER, OF IEILW'AUKEE, .LECSNSIN, ASSIGNORS TO CUTLER-HAMMER, INC, OF IJIL'WAUKEE, 'WISCOHSIN, A

ELECTRICAL GENERATING SYSTEM Application filed November 2, 1929. Serial No. 404,488.

Another object is to provide a controller of the aforesaid character which provides for automatic stopping of either generator unit upon starting of the other generator Various other objects and advantages of the invention will hereinafter appear.

T e acconi anying drawing illustrates a 7 seem embodying the invention "l now be described, it being underiia he system illustrated is suscepti- .iiication without departing from nirit and scope of the appended claims.

lrawing 1 schematically illustrates an autoontrol system embodying the inven- 2 din grammatically illustrates a preform of starter which 1s employed in corn ection w th each of the as en ine drivon units shown in Fig. 1, and

2:1 an across-the-line diagram illus- 01 elements shown in Fig. l. ill-g to Fig. 1 the same illustrates a L J small generator unit 1 and a lar e generator unit 9., each of which includes a generator G in ernal combustion engine E for O e same. Each of said units is pro- "tii a starter S, and as hereinafter a controller G cooperates with the to render the small unit 1 operaly current to service mains in or light load conditions and to large unit 2 operative to supply ti" the circuit connections of certain of' current to said service mains when the load exceeds the capacity of said former unit. Also as hereinafter set forth controller C cooperates with the starters S of

units

1 and 2 to effect stopping of either generator unit upon starting of the other generator unit.

Generators G of the

units

1 and 2 are of the same type, and as shown in Fig. 2 each is provided with an armature A, series field windings F and F and a shunt field wind ing F lso as shown in Fig. 2 each of said generators is provided with a starter including a starting switch 5 and a main switch 6. Starting switch 5 provides for connection of the generator to a storage battery B for operation thereof as a motor for cranking of the engine, and as hereinafter set forth said starting switch is controlled through the medium of a normally open relay 7, a normally closed governor operated switch 8, and normally closed auxiliary contacts 6 associated with main switch 6. Relay 7 is provided with normally closed auxiliary contacts 7 for closing a magneto ground circuit 9 for the engine and said relay is provided with a shunt winding 7 and a series winding 7 Main switch 6 provides for connection of generator G to mains Z and Z and the same is provided with a shunt winding 6 and a series winding 6. Main switch 6 is also provided with normally open auxiliary contacts (i for establishing a charging circuit for the battery B through a resistance r.

The above described starter functions and operates in the following manner. An automatic start is made by connecting a load across the mains Z -Z Upon connection of a load across said mains circuit is established from thenegative side of battery B through the series winding 7 of relay 7 to main Z thence through the load to main K through the shunt winding 7 of relay 7 and through resistance r to the positive side of battery B. WVinding 7 effects response of relay 7 and said relay in responding removes the ground connection GR from the magneto of the engine and establishes an energizing circuit for starting switch 5 exgizing circuit for starting switch 5.

switch 5 and through the series field F to the right hand terminal of said armature. The generator G then operates as a motor to crank the englne E.

It will be observed from Fig. .2 thatthe winding 6 of main switch 6 is connected across the armature A and series field winding F? and when the engine functions to drive the generator, current is supplied to said winding to effect response of main switch 6. Main switch 6 in responding interrupts the aforedescribed energizing circuit for starting switch 5 extending through auxiliary contacts 6 and establishes circuit from the right hand terminal of the armsture A through series field winding F through winding 6 to main Z whereby the load connected across mains Z -Z is supplied with current by generator G. Also upon response of main switch 6 the auxiliary contacts 6 thereof establish a charging circuit for battery B through the medium of resistance r. Winding 6 holds switch 6 in closed position as long as .a load is connected across mains Z Z and upon removal of such load said winding is deenergized to permit opening of main switch. 6.

As aforestated starting switch 5 is energized through the medium of the governor operated switch 8. When the generator operates at a speed in excess of its cranking speed switch 8 opens to interrupt the ener- Thus should the load be removed from mains Z Z and reconnected thereto before the engine speed is reduced below cranking speed the open governor switch 8 prevents closing of the motor starting circuit unnecessarily and so avoids a direct connection between the battery and the generator terminals while the generator is developing its higher voltage.

From the foregoing it will be observed that the starter illustrated in Fig. 2 pro vides for automatic starting of the generator unit upon connection of a load across the supply mains and for automatic stop ping thereof upon removal of the load.

The controller C as shown in Fig. 1 includes an electroresponsive switch 10 which is provided with normally closed contacts 10 for connecting the mains ofthe small generator unit 1 to the service mains L L? and normally open contacts 10 for connecting the mainsof the large generator unit. to said load circuit. The

change-over unit set forth.

provioed Relay 11 as shown in Fig. 1 is normally with a movable contact member engaging a contact 11 and movable into engagement with a contact 11 Said relay is provided with a pair of

series operating windings

11 and 11 and a shunt holding winding 11 Relay 12 is normally closed and is provided with a shunt operating winding 12 while relay 13 is normally open and is provided with a shunt operating winding 13 Also as shown in Fig. 1 the change-over switch 10 is provided with normally open auxiliary con acts 1O? and normally closed auxiliary contacts 10, the latter contacts being adapted to open following closure of the contacts 10*. a

The function and operation of controller C and the cirr i't connections therefor will now be more fullydescribed in connection with 3. ins snown in this figure the and 2 are permanently main L an with knife hand position main Z ted to service main L of contacts 10 of transof unit 1 through tl fer switcn 10 and windings 11and 11 of relay 11. It is thus apparent that if one of the switches LS 1s closed-to connect a load across service mains L L the small generator unit remains in operat on as long as the loel on service mains Eff-L does not exceed the capacity of said unit.

When the load connected across service mains Il L exceeds the capacity of the small generator unit 1, relay 11 responds under the action of its

windings

11 and 11. Upon response of relay llthe winding 11 of said relay is connected across mains We? of the large generator unit through the medium of auxiliary contacts 10 of transfer switch 10 and the contacts 11 of said relay. Also upon responsev of relay 11 the operatin winding 10 of transfer switch 10 is con nected across mains Z -Z of the large generator unit through the medium of relay 12 and contacts 113 of relay-11. (loil 11 is of relatively lowresistance and upon connection thereof across mains Z Z said coil acts as a load on the large generator unit 2 to effect starting of said u t as described in connection with 2. When the voltage across the mains Z Z of the large generator 2 reaches a predetermined value wind- 10 effects response of transfer switch 10 and the service main L is disconnected from main Z of ti e small generator unit 1 by marl by winding 11 as long as ti transfer 01 ening of contacts 10 and is connected to main Z of the large generator unit 2 by clo sure of contacts 10 Upon disconnection of tee load ii the small generator unit 1 the same steps as set forth in connection with 2 J c load connected across the service nia' Li -L is then supplied with current by the large generator unit 2. Upon opening oi contacts 10 of the transfer switch the windings l1 and 11 of relay 11 are lie-energized but said relay is then held in its operated position by its winding li which i energiL-ied as hercinbefore described. Upon cl of contacts 10 of the transfer switch the auxiliary contacts 10 or said switch open to interrupt the energizing cir cult for winding 11 and relay 11 is then held in its operated position by its winding 11 which now carries the entire lead cur rent. Transfer switch 10 in responding establishes a maintaining circuit for itself extending through its auxiliary contacts 10 and the relay 12.

Relay 11 is held in its operated position. e current demand exceeds the capacity of the small generator unit 1. However, w rent demand decreases to a less than the capacity of the small '3ir3l'Et e) tor unit 1 relay 11 drops out and connects the operating winding 13 of the mains oi the large generator unit 52 through the medium of the auxiliary contacts 10 of transfer switch 10. Relay 13 then responds to connect the operating winin 12 frelay 12 across the mains /'tor the small generator unit 1 in parallel with a resistance Resistance 7 and coil. 12 of relay 12 act as a load across the mains Z-Z of the small generator unit and said unit is then started as hereinbetore set forth. ll hen the voltage across mains Z Z of the small generator unit 1 builds up to a given value winding 12 oi? relay effects response of said relay to interrupt the aforedescribed energizing circuit for switch 10. Transfer switch 10 then returns to normal position to re-conncct the load on the ser ice mains LL to the small generator unit 1. As set forth in connection w h 2 the generator units are aut matically stopped under no load conditions. Thus upon return or" transfer switch 10 to normal position the large generator unit 2 stopped and the small generator unit 1 remains in operation as long there is current demand or until the current demand exceeds the capacity thereof. I

IV hen lzniiie switch 14: is moved into right hand position the small generator unit 1 is rendered inoperative since the service main I is then connected to main Z of the large generator unit However, as is apparent from the description in connection with Fig. 2 the large generator unit 2 is then operative to supply current to the service mains L L upon connection of a load across the same.

lVhat we claim as new and desire to secure by Letters Patent is:

1. In a system of electrical distribution, in combination, two generator units of different capacities, separate means for starting each of said units upon current demand across the mains thereof, a load circuit normally connected to the mains of the smaller of said units, means for starting the larger of said units when the currentv supplied by said smaller unit to said load circuit exceeds a given Value and means acting upon starting of said larger unit to connect the mains thereof to said load circuit and to disconnect themains of said smaller unit from said load circuit.

2. In a system of elec rical distribution, in combination, two generator units of different capacities, separate means for starting each of said units'upon current demand across the mains thereof, a load circuit nor mally connected across the mains of the smaller or" said units, means for starting the larger of said units when the current supplied by said smaller unit to said load circuit exceeds a given value, means acting upon starting of said larger unit to connect the mains thereof to said load circuit and disconnect the mains of said smaller unit from said load circuit, means for restarting said smaller unit when the current supplied by said larger generator unit is loss than the capacity of said smaller unit and means acting upon restarting of said smaller unit to reconnect the mains thereof to said load circuit and to disconnect the/mains of said larger unit from said load circuit.

3. In a system of electrical distribution, in combination, two gas-engine-operated generating units of dilierent capacities, a com: mon load circuitnormally connected to the smaller of said units, means for starting the smaller of said generator units upon current demand in said load circuit, means for starting the larger of said generator units when the current supplied by said smaller unit to said load circuit exceeds a given value, and means responsive to a given volt age across the mains of said larger unit for disconnecting said load circuit from said smaller unit and for connecting said load circuit to the mains of said larger unit.

4. In a system of electrical distribution, in combination, two gas-engine-driven generating units of different capacities, a common' load circuit to be supplied thereby, separate means for starting each of said units upon current demand across the mains thereof, an electromagnetic switch normally connecting said load circuit across the mains of the smaller of said units and responsive to a given voltage across the mains oi the larger of said units to disconnect said load circuit froin rsaid smaller unit and to connect the same totlie mains of said larger unit, and means for starting the larger of said generator units when the current supplied by the smaller of said generator units to said load circuit exceeds a given value.

5. In a system of electrical distribution, in combination, two gasengine-operated generating units of diilerent capacities, a common work circuit to be supplied thereby, an automatic controller associated with each of said units for starting the same upon current demand across the mains thereof, a switch normally connecting said work circuit to the smaller of said generatorunits and responsive upon given current conditions across the mains oi the larger of said units to disconnect said work circuit from said smaller unit and to connect the same to said larger unit, means for starting said larger unit when the current supplied by said smaller unitexceeds a given value, said means including a relay responsive to given current conditions in said load circuit to eiiiect loading of said larger unit tor-"starting thereof. r

6. In a system of electrical distribution, in combination, two gas-engine-operated generating units of different capacities, a common work circuit to be supplied thereby, an automatic controller associated with each of said units for starting the same upon current demand across the mains thereof, a switch normally in a position to connect said Work circuit to the smaller of said generator units and responsive upon given current conditions across the mains of the larger 01" said units to disconnect said work circuit from said smaller unit and to connect the same to said larger unit, means including a relay responsive to given current conditions across the mains of said smaller unit to effect starting of said larger unit, and means including a relay for starting saio smaller unit when the current supplied by said larger unit to said load circuit is below a given value.

7. In a system of electrical distribution, in combination, two gas-engine-operated generating units of ditlerent capacities, a common work circuit to be supplied thereby, an automatic controller associated witheach of said units for starting the same upon cur rent demand across the mains thereof, a switch normally connecting said work circuit to the smaller of said generator units and responsive upon given current conditions across the mains of the larger of said generator units to disconnect said work circuit from said smaller unit and to connect the same to said larger unit, means responsive to given current conditions in said load circuit to effect loading of said larger unit starting thereof.

In witness whereof, we have hereunto subscribed our names.

EDWIN X. SCHMIDT. WALTER O. BAER.