US1722194A - System of distribution - Google Patents

Description

July 23,v 1929. H. D. BROWN ET AL 1,722,194

- SYSTEM OF DISTRIBUTION Y Filed June 13 1927 n nun I! HI!!! I Patented July 23, 1929.

UNITED STATES PATENT OFFICE.

HERBERT D. BROWN AND CAMIL A. SABBAH, OF SCHENECTADY, NEW YORK, AS- SIGNORS TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

SYSTEM OF DISTRIBUTION.

Application filed June 13, 1927. Serial No. 198,526.

Our invention relates to alternating current systems of distribution and more particularly to improvements in constant-potential constant-current transforming devices in which the desired transformation is effected by the employment of suitable combinations of inductive and capacitive devices connected in an arrangement known as the monocyclic square.

The monocyclic square fundamentally comprises a combination of'four equal reactances, two capacitive and two inductive, arranged alternately in a closed circuit in such a manner as to transform a constant voltage impressed across one diagonal of the diagrammatic square arrangement into a constant current across the otherdiagonal of the square or vice versa. Heretofore various arrangements based on the principles of the monocyclic square have been proposed and used, but these arrangements have presented various operating difficulties.

Some of the outstanding objectionable operating characteristics of the simple monocyclic square arrangements are the possibilities of short circuit conditions in the constant-potential circuit when the load circuit is interrupted, destructive rises ofvoltage across the inductive and capacitive. units upon the occurrence of resonant circuit conditions, and'excessive variations in current in the load circuit when the voltage in the constant potential circuit varies. 4

' One of the objects of our invention is to provide a new and improved arrangement to eliminate the possibilities of excessive current in the constant-potential supply circuit and destructive rise and possible breakdown of the inductive or capacitive units in a transforming device embodying the principles of the monocyclic square upon the occurrence of a: break or high resistance in the load circuit.

Another object of our invention is to provide a new and improved transforming device employing the principles of the monocyclic square whereby the variations of load current with changes in voltage of the constant-potential circuit is reduced.

A further object of our invention is to provide a new and improved arrangement of inductances'and capacitances employing the principles of the monocyclic square which shall, first, be more reliable in operation; second, reduce the cost of construction; third, reduce the weight; fourth, reduce the electrical losses; and, finally, secure minor advantages to be hereinafter more fully pointed out and specified.

Our invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims,

In the single figure of the drawing, which is a diagrammatic representation of one em bodiment of our invention, 1 and 2 indicate the conductors of a constant-potential circuit and 3 and 4 indicate the conductors of a constant-current circuit having therein translating devices 5 which require constant current for their operation, and which for purposes of representing a typical constant-current circuit are shown as series are lamps. The conductor 1 is connected to one terminal of an inductive device comprising coils 7 and 8 and the conductor 2 is connected to another inductive device comprising coils 9 and 10; all of the aforementioned coils being positioned on the same magnetic core 11. For purposes ofexplanation.v these coils are referred to as separate coils, but it is to be understood that each inductive unit may comprise a single coil tapped at an appropriate point. The conductor 1 is also connected to one terminal of a capacitive device or condenser 12, which has its other terminal connected to a junction point 13 between coils 9 and 10. Similarly, conductor 2 is connected to one terminal of a capacitive device or condenser 14;, which has its other terminal connected to a. junction point 15 between the coils 7 and 8. A capacitive device 16 is connected in series with the translating device 5 in order to neutralize the inductive re actance of coils 8 and 10. The arrangement, therefore, comprises two paths in parallel from conductors 1 and 2, wherein the first other diagonal of the same square with the coils 8 and 10 in series with the translating devices 5.

The above described arrangement of inductive and capacitive devices embodies the well known principles of the monocyclic square. In accordance with our invention, however, the inductive devices are placed on the same core and during operation under load the inductive reactance which is in series with the capacitive reactance of con- :7 denser 14L isthe reactance due to the self inductance of coil 7 plus the mutual inductance of coils 7 and 8. In a slmilar manner the 111- ductlve reactance 1n series with the condenser 12 is the reactance due to the self inductance of coil 9 plus the mutual inductance of coils 9 andlO. These inductive devices are so arranged that the reactive voltages of the self inductance of the coils in the load circuit and the mutual inductance of the load coils and other coils of the monocyclic square will be such as to maintain the power factor of the transforming device at substantially unity. At the same time the reactance due to the self inductance of coils 7 and 9 respectively is arranged to differ from the reactance 'of condensers 14 and 12 respectively in order to hunt the current traversing the Inductance and condenser to a predetermined value when the load circuit is open. This condition is preadily obtained since coils 8 and 10 become inactive when the load circuit opens and hence it is not possible with this arrangement to approach resonant conditions because the inductive reactance under these conditions in a given branch does not equal the capacitive reactance. For aset designed so that the open load reactor current is twice the normal load current and operating with a substantially unity power factor load the reactor and condenser kilovolt-ampere rating is reduced approximately 25 per cent from the corresponding ratings required for the simple arrangement of the monocyclic square. With the elimination of resonant current conditions excessive rise of voltage across the inductive and capacitive units is prevented thereby minimizing the possibilities of puncturing the insulation of the inductive device "or the dielectric of the condenser.

M In the presentarrangement contrary to the 1 prior practice where the inductive devices are placed.onseparate'cores it has been found de sirable to designthe corerfor the inductive turn riseswith the line voltage. Consequently, theload current which isequal to the line voltage divided by a positive function of the inductive reactance will have a smaller change when the voltage of the constant potential supply circuit changes. Vith a low flux density, the eddy current and hysterisis losses in the core will be smaller and, therefore, the

efliciency of the transforming device will be higher.

While we have shown and described a particular embodiment of our invention, it will be obvious to those skilled in the art that changes and modifications may be made without departing from our invention, and we, therefore, aim in the appended claims to cover all such'changes and modifications as fall within the true spirit and scope of our invention. v

What we claim as new and desire to secure by Letters Patent of the United States, 1s 1. In combination, a plurality of capacitive devices, and a plurality of inductive devices each comprising a plurality of winding sections in inductive relation, said capacitive'devices and said inductive devices being arranged to form a monocyclic square in which one of said winding sections of each of said QO inductive devices is connected to traversed only by the current to be supplied by said plurality of inductive and capacitive devices.

2. In combination, a plurality of capacitive,

devices, and a plurality of inductive devices arranged on a common magnetic core having an operating flux density under predetermined operating conditions below the point of inflection of the; lower part of the magnetization curve, said capacitive and inductive devices'being connected to form a monocyclic' square for transforming from constant potential to constant current.

3. The combination ofa plurality of reactances of opposite signcomprising inductive 5 and capacitive devices connected alternately in a closed circuit, said inductive devices being arrangedto have a common magnetic circuit, a supply circuit connected across two alternate Junction points between adjacent inductive and capacitive. devices, and a receiv ing circuit connected across two alternate junction points between adjacent inductive and capacitive devices other. than the points of connection of said supply circuit, said inductive and capacitive devices being arranged to provide .une ual and opposite reactance voltages only w en said receiving circuit is interrupted .4. The combination with a constant-current receiving circuit, of a plurality of reactances of opposite sign comprising inductive and capacitive devices connected alternately in a closed circuit, said inductive devices being arrangedon a common magnetic core and each lncluding a coil inserles wlth sa1'd,re-'

ceiving circuit connected at alternate junction points between ad acent lnductive. and capacitive devices in sand closed circuit, and

a constant potential supply circuit connected across two alternate junction points between adjacent inductive and capacitive devices other than the points of connection of said re ceiving circuit, each of said capacitive devices being arranged to have a higher reactance voltage than each of said inductive devices when said receiving circuit is interrupted.

5. The combination with a supply circuit and a receiving circuit, of means for converting electrical energy from a constant potential in said supply circuit to a constant current in said receiving circuit, said means comprising four reactances of opposite sign comprising lndllCtlW? and capacitive devices connected alternately in a non-resonant closed circuit and having said supply circuit connected to alternate junction points between adjacent inductive and capacitive devices and said receiving circuit connected across alternate junction points between adjacent inductive and capacitive devices other than the points of connection of said supply 011- cuit, and means including a winding inductively associated with said inductive device and energized in accordance with the current in said receiving circuit for equalizing the reactive voltages in the respective arms of said converting means when current traverses said receiving circuit.

6. In combination, a constant potential circuit, a constant current circuit, a branch circuit having reactive devices in series comprising an inductive 'device having two coil sections with one coil section connected in series with a condenser across said constant potential circuit and the other coil section connected in series with said constant current circuit, and a second branch circuit having reactive devices connected in the reverse order in parallel to said first branch across said constant potential circuit comprising an inductive device having two coil sections with one coil section connected in series with a condenser and the other coil section connected in series with said constant current circuit, each of said inductive devices being provided with a common magnetic circuit and arranged so that the self inductance and mutual inductance of the coil sections of the inductive devices shall be such that the system power factor is substantially unity and the current traversing said constant-current circuit is substantially independent of the resistance of said constant-current circuit.

7. In combination, a constant potential supply circuit, a constant-current receiving circuit, two inductances each comprising two coil section arranged on the same magnetic core, two condensers, said inductances and condensers being connected in a monocyclic square for interconnecting said supply circuit and said receiving circuit with a coil section of each inductance connected in series with said receiving circuit, and a condenser connected in series with said receiving circuit for neutralizing the inductive reactance of said coil sections connected in series with said receiving circuit.

In witness whereof, we have hereunto set our hands this 10th day of January, 1927.

HERBERT D. BROWN. CAMIL A. SABBAH.

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