US1681519A

US1681519A - Regulating system

Info

Publication number: US1681519A
Application number: US126382A
Authority: US
Inventors: James R Craighead
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1926-08-02
Filing date: 1926-08-02
Publication date: 1928-08-21
Anticipated expiration: 1945-08-21

Description

Aug. 21, 192s. 1,681,519

J. R. CRAIGHEAD REGULATING` SYSTEM Filed Aug. 2, 1926 PL2. l. F'Lg.

Inventor: James RCraLghead,

D 9 @M T/yf l-ILs Attorrweg.

Patented Aug. `21, 1928A,

UNITED STATES Lesina PATENT OFFICE- JAMES R. CRAIG-HEAD, OF SCHENECTA'DY, NEW YORK, ASSIGNOR `T0 GENERAL ELEC- TR'IO COMPANY, 'A CORPORATION OF NEW YORK.

REGULATING SYSTEM.

Application mea august 2,'1926. serial Nn. 126,382.

My inventionl relates to regulating systems and more particularly to voltage regulating.

other branch being a comparatively small` load whose effect on the regulation of the transformer is small. It is evident that if both loads are connected in multiple to the transformer secondary, changes in the heavy load,

as for instance, elevator motors will causechanges in the voltage applied to the small load comprising translating devices which, for instance, may be incandescent lamps. Since incandescent lamps are sensitive to voltage variations, objectionable'lamp flicker will occur. 'lhe foregoing illustration of elevator motors and incandescent lamps is paralleled in potential transformer practice by a heavy load consisting of a synchronism indicator and a light load comprising translating devices such as a voltmeter and wattmeter. 1n either case, it is equally desirable that the regulation of the transformer shall not cause the voltage on the load of constant-voltage char-l acteristics to vary.

An obj ect of my invention is to prevent objectionable variations in the voltage impressed on load circuits which require substantially constant voltage when said load circuits are energized in parallel from the same transformer with load circuits having electrical characteristics which cause variations in the ratio of voltage transformation and phase angle of said transformer.

My 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 drawing, Fig. 1 is a diagrammatic illustration of an embodiment of my invention, particularly adapted for metering applications; Fig. 2 is amodication thereof adapted for general applications; and Fig. 3

is a furthermodification of the arrangement shown in Fig. 2.

Referring to Fig. l of the drawing, 1 indicates the conductors of an alternating current supply circuit. A. potential transformer 2 having a primary winding 3 and a secondary winding 4 is connected to be energized from the supply circuit. A light load device, such as a voltmeter 5, and a comparatively heavy load device, such as a 'synchronism indicator 6, are connected in parallel across the secondary winding 4 of the main transformer. An auX- iliary transformer 7 having a primary winding 8 and a secondary winding 9 is connected to be responsive to the'voltage of the supply circuit 1. The voltmeter 5 is provided with a main actuating winding 10 and an'aux'- iliary actuating windingl 11. The main actuating Winding 10 is connected to be responsive to the voltage across the secondary winding 4' of the main transformer. The secondary winding 9 of the auxiliary transformer is lconnected to the secondary winding 4 ofthe main transformer and through the auxiliary winding 11 ofthe voltmeter to the other side of the secondary of the main transformer.

The

secondary windings

4 and 9 are connected and arranged so that when the secondary winding of the main transformer develops the same voltage, with due regard to the ratio of turns, as is supplied to the primary winding, the resultant voltage of

windings

4 and 9 ,will be zero. lVhen, due to the effectof the heavy load 6, the secondary winding 4 of the main transformer develops less voltage, with due regard to the ratio of turns, tha-n is supplied to the primary winding 3, the difference of voltage is applied to the auxiliary coil 11 in such a manner that the total effect of the two coils inthe voltmeter will give practically a constant reading in spite of changes in the heavy load on the main transi former. The electromotive force produced in the winding 11 is equal to the difference between the supply circuit voltage and the load circuit voltage when the supply circuit voltage is divided by the transformer turn ratio.

Referring to Fig. 2, a somewhat similar ar;

rangement is shown, but in this case the difference of the voltage generated by the main transformer 2 and the auxiliary transformer 7 is applied through a second auxiliary transformer 12, having a primary winding 13 and a secondary Winding 14. A load circuit 15 of constant voltage characteristics, shown diagrammatically as incandescent lamps, is connected in'parallelacross the secondary ofthel vload circuit'15. In this case the difference in voltage generated by

transformers

2 and 7 is applied to the primary winding 13 of transformer 12 which furnishes a voltage through its secondary winding 14 in seriesY with the voltage of the main transformer 2 to maintain a substantially constant voltage across the incandescent lamp circuit with changes of loady f on the motor circuit.

In' F ig. 3, the main transformer 2 is shown connected in the same manner as in Fig. 2, but the auxiliary transforming means comprises a transformer 17 having a three-legged core 18., A primary winding 19 is positioned on one leg a secondary Winding 20 is positioned on another leg, and a tertiary winding 21, usually arranged with the same number of turns as the secondary winding 20, is positioned on the middle leg. The primary winding 19 is connected to be energized from the supply circuit 1. The secondary winding 20 is connected in parallel with thesecondary winding 4 of the main transformer, and the tertiary winding 21 is connected in series with the load circuit 15. A variable load circuit, shown as a motor load 16, is connected in parallel with the load circuit 15 across the secondary of the main transformer 2.`

The operation of the arrangement shown in Fig. 3 is as follows: If it be assumed that the motor load 16 represents an elevator. motor load or similar motor load, starting and acceleration of the motor will require heavy fluctuating currents which would ordinarily cause poor regulation on the main transformer with consequent variations in voltage impressed across thelamp circuit. The secondary windings 4 and 2O of the

transformers

2 and 17 respectively are so positioned and arranged that for light load conditions, the two secondary windings develop voltages which are equal and inopposition. When, due to the-effect of the motor load,-thye secondary winding 4 of the main transformer develops less voltage, with due regard to the ratio of turns, than is supplied to its primary winding, the auxiliary transformer receives diiferentvvoltages on its primary and secondary windings. If these voltages were equal, the flux developed in the core l18 would pass only through the primary winding 19 and the secondary winding 20 and I no voltage would be generated in the tertiary winding. However, since these two voltages are unequal, the flux developed on the primary side of the core 18 will be greater than that developed on the secondary side. and the vunits than the main transformer.

dierence in ux will pass through the tertiary coil 21 and generate a voltage proportional to the difference of voltage between the primary winding 19 and the secondary winding 20. This voltage is introduced in series with the load circuit 15 and will maintain a substantially constant voltage across the lamp circuit with variations in voltage across the secondary of the main transformer. It will be apparent, however, that the tertiary winding 21 may be arranged to excite an auxiliary coil in an instrument, similarly to the arrangement shown in Fig. 1, instead of introducing a corrective voltage in series with the load of constant voltage characteristics. Whether an auxiliary coil in an instrument is energized by a corrective voltage and a main coil is enerized by the voltage from the main trans- 'ormer, or the resultant voltage applied directly to translating devices such as instruments or lamps is obtained by introducing a corrective voltagein series with the voltage from-the main transformer, there is in each case a composite energization or effect.

The auxiliary transformers as shown in each of the lfigures may be very much smaller It is also to be noted that, since the whole scheme of correction is based Aon the difference between the primary and secondary voltages of the main transformer, with due regard to the ratio of turns, the correction will obviously apply to phase angle between primary and secondary voltage as well as to. ratio. This feature is important for all applications in metering.

While I have shown and described several embodiments of my invention, it will be obvious tothose skilled in the art that changes and modifications may be made without dcparting from my invention,-and I, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. In combination, an alternating current supply circuit, a transformer connected to said supply circuit, a load circuit comprising a plurality of branch circuits connected in parallel to be energized from said trans- A former, and means for introducing into one of said branch circuits an electromotive force proportional to the difference between the supply circuit voltage, divided bythe transformer turn ratio, and the load circuit voltg2. In combination, .an alternating current supply circuit, a main transformer connected to said supply circuit, a load circuit comprising a plurality of branch circuits connected v Ibranch circuits', and an auxiliary transformer for interconnecting said supply circuit and said winding for applying to said winding a voltage dependent upon the difference between the voltage applied to said auxiliary transformer and the voltage of said load circuit.

3. AIn combination, an alternating current supply circult, a main transformer connected to said supply circuit, a pluralit .of load cirent upon the difference between the voltage of the secondarl winding of said auxiliary transformer an load circuits, and means for combining the Jenergization vfrom said winding and the voltage of said one of said load circuitsto pro# duce the effect of a voltage in another of said load circuits which is substantially unaffected bythe variations in ratio of voltage transformation and phase angle of said main transformer upon changes of load in said first-mentioned load circuit.

4. In combination, an alternating current supply circuit, a main transformer connected to said supply circuit, a plurality of load cir-` cuits arranged to be energized in parallel from said transformer, and means for introducing a- 'voltage in series with one of said circuits comprising a winding connected to be energized in accordance-with changes in the ratio of transformation of said main transformer due to changes in load in the other load circuit.

5. In combination, an alternating current supply circuit, a main transformer connected to said supply circuit, a plurality of load circuits connected to be energized in parallel from said main transformer, an auxiliary transformer having a primary winding connected to said supply circuit and a secondary I. winding connected to the secondary winding 0f said main transformer, and a third winding associated'with the windings of said -auxiliary transformer for supplying' a corrective voltage to one of said load circuits 1n accordance with the variations in the ratio of voltage transformation of said main transformer from its theoretical value. v

6. In combination, an alternating current supply circuit, a main transformer connected to said supply circuit, a load circuit of constant voltage characteristics, and a load circuit of variable current characteristics connected to be energized in parallel from said main transformer, an auxiliary transformer having a primary winding connected to said supply circuit and a secondary winding con- Y nected to the secondarv winding of said main transformer, and a tlird winding associated with the windings of said auxiliary trans former for maintaining a voltage in said first mentioned circuit substantially unaffected by the voltage ,of one of said4 '-7. In combination, an alternating currentv supply circuit, a main transformer connected to said supply circuit, a circuit from which a load requiring a substantially constant voltage is energized, a circuit from which a load requiring comparatively larger and variable amounts of/power is energized, said load circuits being arranged to be connected in parallel with said main transformer, and an auxiliary transformer comprising a primary winding connected to said supply circuit, a secondary winding connected to be responsive to the secondary voltage of said main transformer, and a tertiary winding connected and arranged for introducing a voltage in `series relation with said first mentioned circuit in accordance with the variations in the ratio of voltage transformation of said main transformer from a predetermined value.

8. In combination, an alternating current supply circuit, a main transformer connected a load requiring a substantially constant voltage is energized, a circuit from which a load requiring varying amounts 0f power is energized, said load circuits being arranged to be energized in parallel from said main transformer, an auxiliary transformer connected to said supply circuit and arranged for generating a secondary voltage equal to the open circuit secondary voltage of said main transformer, and a winding in circuit with said first mentioned load ,circuit connected to be responsive to the difference in voltage between the secondary windings of said main and auxiliary transformers.

9. In combination an alternating current supply circuit, a main transformer' connected to said supply circuit, a circuit from which translating devices are energized, a circuit fromwlich a load requiring varying amounts of power is energized, said circuits being connected to be energized in parallel from said main transformer, an auxiliary transformer having a core comprising three winding legs, a primary winding on one of said legsconnectcd to said supply circuit, a secondary winding on another of said legs connected to the secondary winding of said main transformer, and means comprisingn a tertiary winding on the remaining leg arranged to producea corrective voltage for supplying in conjunction with said age is energized, a circuit from which a load requiring varying amounts of power is enersaidoutside legs connected to the secondary gized, said load circuits being arranged to be Winding of said main transformer, and a 10 energized in parallel from said main transtertiary Winding on said intermediate leg for former, an auxiliary transformer having a supplying a correctivevoltage to said first core 'comprising two outside legs and an-inmentioned circuit.

termediate leg, a primary Winding on one of In Witness whereof, I'have hereunto set my said outside legs connected t0 said supply hand this 30th day of Julyf1926.

circuit, a secondary winding on the other of A JAMES R. CRAIGHEAD.