US700847A - Regulator for alternating-current circuits. - Google Patents

Description

No. 700,847. Patented May 27, I902.

C, P. STEINMETZ.

REGULATOR FOR ALTERNATING CURRENT CIRCUITS.

(Application filed Aug. 16, 1897.)

(No Model.) 2 Sheets-Sheet l.

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m: nnmus PETERS co PHOTO umu. us-mum u c No. 700,347. Patented may 27, 1902. c. P. STEINMETZ.

REGULATOR FORALTERNATING CURRENT CIRCUITS.

(Application filed Aug. 16, 1897.)

(No Model.) 2 Sheets-Sheet 2,

UNITED STATES PATENT OEEIcE.

CHARLES P. STEINMETZ, OF SOHENEOTADY, NEWV YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

REGULATOR FOR ALTERNATlNG-CURRENT CIRCUITS.

forming part of Letters Patent N0. 700,847, dated May 27, 1902. Application filed August 16. 1897. Serial No. 648,362. (No model.)

To It whom it may concern:

Be it known that I, CHARLES P. STEINMETZ, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Regulators for Alternating-Current Circuit-s, (Case No. 594,) of which the following is a specification.

Myinvention relates to alternating-current systems of distribution, and more particularly to systems in which it is desired to vary the voltage at the work within considerable limits without waste of energy or voltage. In many cases, as in starting synchronous or induction motors, it is desirable to vary the voltage through a wide range for a short time. Thus when starting a synchronous motor a reduction of voltage is desirable toreduce the excessive starting-current. Resistance or reactance in series with the motor is inefficient, since it wastes the voltage, and thereby reduces the starting-torque per ampere of current supplied from the mains. By a compensating device-that is, a transformer using the same winding as primary and secondarythe starting-torque of a synchronous or induction motor is reduced only in proportion to the reduction of current taken from the mains. The torque per ampere of main current remains unchanged. After the motor is started the regulator can be adjusted so as to raise the voltage at the motor-terminals until full voltage is reached. These devices are particularly useful where a limited supply of power is available.

The main features of my improved regulator comprise a two-part adjustable magnetic core structure and compensator-coils, one foreach phase when used on a polyphase circuit. The compensator-coils are connected across the mains, and the motor or other regulated circuit is connected to corresponding intermediate points in the compensator-coils, so that these coils have a series branch that is, a portion in series with the load and a shunt branch-that is, a portion in parallel with the load. The coils are located on an iron core structure; the core and coils are so arranged that the series and shunt branches of the windings may be put in inductive relation to one another in a closed or practically closed magnetic circuit, or when desired either branch of the compensator-coils may be put in a closed magnetic circuit and the other branch left in an open or practically open magnetic circuit. When the two branches of the compensatorwinding are in inductive relation, voltage will be consumed on the series side and transformed into current on the shunt side, so that the voltage at the motor-terminals will be one-half or other desired fraction of the main voltage. WVith the magnetic circuit of the series branch open and that of the shunt branch closed the series branch consumes practically no voltage, leaving full voltageat the motor-terminals. lVith the magnetic circuit of the series branch. closed and that of the shunt branch open the series coil acts as an inductance, and there is a maximum drop of voltage around it, leaving a minimum voltage at the motor-terminals.

To illustrate further, assuminga main circuit of six thousand volts and a motor requiring, say, three thousand volts and ten amperes for starting purposes, the regulator will be adjusted so that the series and shunt branches of the compensator-coils are in inductive relation. The regulator acting as a true compensator, five amperes will be taken from the mains at six thousand volts and transformed without waste of voltage, giving ten amperes at three thousand volts at the motor-terminals. If then still lower voltage at the motor-terminals is desired, the regulator will be adjusted so as to preserve the series branch of the compensator coils in closed magnetic circuit, but to withdraw the shunt branch. The regulator then acts as an inductance-coil, occasioning a greater drop across its terminals and reducing the voltage at the motorterminals. If, on the other hand, a rise in voltage at the motor-terminals is desired from the condition first assumed, the regulator will be so adjusted as to withdraw from the magnetic circuit the series branch of the compensator-coils, leaving the shunt branch in a closed magnetic circuit, so

that the shunt turns become practically idle, and the series turns consume less and less voltage until, if desired, the voltage at the motor-terminals equals or practically equals the main-line voltage. In reality, therefore, my regulator will act as a true compensator, making the voltage at the motor-terminals a half or other desired fraction of the main voltage and may, furthermore, regulate the voltage from this value either up or down, as may be desired.

The accompanying drawings show different applications of my invention.

Figure 1 is a diagrammatic view of a regulator for three-phase circuits in which only the iron parts are moved. Fig. 2 is a similar view of another form of the device in which the series and shunt branches of the coils are relatively movable. Fig. shows an arrangement whereby the magnetic circuit of either branch of the compensator-coils may be practically closed while the circuit of the second branch is practically open. Fig. iis a view of the invention applied to quarterphase circuits. Figs. 5 and 6 are diagrams illustrating the circuits of the devices in Figs. 1 to 3 and Fig. I, respectively.

In Fig. l, a I) c are the lines from the generator or other main circuit. E is a ringshaped laminated magnetic structure similar in general shape to those commonly employed with ind uction-motors, feeder-regulators, and such apparatus. As shown, it has six projecting polar portions e e e ff f The compensator-coil A has its series branch A located on pole e and its shunt branch A located both on pole c and pole f, the two branches occupying, therefore, dilferent angular positions on the core E. Similarly the two remaining com pensator-coils B C have their series branches B C located on two of the other poles e e and their shunt branches B C each embracing two of the poles, as 6 e f The motor or other regulated circuit has its leads a Z) 0 connected with the compensator-coils at correspondingintermediatepoints between what I have termed the series and shunt branches. In each compensator-coil, therefore, the series branch is in series with the corresponding branch of the motor-circuit and the shunt branch in parallel with the same branch of the motor-circuit. Mounted for rotation around an axis .9, within the iron structure E, is aninternal iron shuttle G, also laminated, having three poles d d d. By changing the relative positions of the polar portions of the shuttle G and of the ring structure E the magnetic circuit can be varied, so as to include both the series and shunt branches of the compensator-coils in a closed magnetic circuit, and therefore in a position to transform energy from one branch to the other most efficiently or to gradually withdraw the series and shunt branches from inductive relation by opening the circuit of the series branches and leaving the magnetic circuit through the shunt branches closed.

no action of the device illustrated in Fig. 1, more fully explained, is as follows: In the illustrated position of the parts the magnetic circuit is closed through the series and shunt branches of the compensator-coils A 13 C. These branches are therefore in inductive relation, and the regulator acts like a true compensator or single-coil. transformer, lowering the voltage in the regulated circuit, though without waste of the main-line voltage. Upon rotating the shuttle G, however, the magnetic circuit through the differentpoles gradually changes until when the poles of the shuttle are opposite the poles f f f the series branches A 13 C of the compensator-coils will be in open magnetic circuit, and thus idle orconsuniiing practically no voltage. The shunt branches A B C of the coils are still in a closed magnetic circuit through the polar projections/"f and the poles of the shuttle. These branches are now practically out of inductive relation with the series branches and take practically no current. Substantially full voltage will now be found in the regulated circuit. An induction-motor IM is shown in diagram connected to the regulated circuit a l) e.

In Fig. 2 I illustrate another arrangement. In this case instead of the series and shunt branches of the con'ipensator coils being mounted in different angular positions on the same core the shunt branches A B C are respectively mounted upon the poles of the shuttle G and are movable relatively to the series branches A 3 C, mounted upon the alternate poles of the ring structure E. Taking current through the device and regulated by it is a synchronous motor SM, having the exciter X, connected in the usual way. W'ith this embodiment of my invention in the position shown the coil branches A A &c., are in inductive relation, the series branches consuming part of the generator-voltage and transforming it into current in the shunt branches. By turning the movable structure, however, the shunt branches A d:c., move away from the series branches A, &c., and out of inductive relation with them. The voltage across the series branches thus decreases and that across the motor-terminals increases until ultimately with the branches A the, standing in front of the projections f there is practically no inductive action between the series and shunt branches, the series turns consume practically no voltage, and hence full voltage is available at the terminals of the motor SM. The magnetic circuit through the shunt branches A dye, is closed through the projections from the shuttle G, and these branches are without current except the small. magnetizing current.

Another three-phase device is illustrated in Fig. 3. In this all of the coils are shown occupying different angular positions on the internal toothed structure G, and the external laminated magnetic structure E has only In the illustrated posi- ICC tion a mutual induction takes place between the respective series and shunt branches A A &c., which are in a closed magnetic circuitthrough the projections E, &c.; but upon relative movement of the two parts of the core structure in one direction the series branches A, &c., are brought into open magnetic circuit and out of inductive relation to the shunt branches, while the shunt branches A 850., remain in closed magnetic circuit through the projections E, thus giving full voltage on the leads ct I) c. \Vhen the motion of the core structure is reversed, however, so that the shunt branches A &c., are brought into open magnetic circuit while the series branches A, &e., remain in closed circuit, the regulator acts as a reactive coil and the voltage across the work-circuit is cut down. Thus by the relative motion of the two parts of the structure the voltage at the motor-terminals may be varied from practically nothing to full generator-voltage without change of connection. It will be understood that this arrangement will give agreater range of regulation than the constructions of Figs. 1 and 2, since regulation is possible both up and down from the intermediate compensator position with the series and shunt branches in inductive relation. This structure is therefore a typical embodiment of the invention in its most complete form.

The diagram of connections for all of these devices thus far described is that shown in Fig. 5, in which the reference-letters indicate the same parts as in the other figures illustrating the mechanism employed. The leads to the motor-terminals or other regulated branch circuit are tapped out at a I) c between the series and shunt branches of the compensator-coils A A &c., and the main circuit is connected at the points a b c. It is evident, however, that the terminals might be reversed and the main circuit connected at the points a b c and the leads to the motor terminals taken from the points ct b c.

In Fig. 4 a similar arrangement to that shown in Fig. 2 is applied to a quarter-phase circuit, and the actions are substantially the same as those already described with reference to Fig. 2. The diagram of windings for this last modification is shown in Fig. 6. The terminals of the two branches of the main quarter-phase circuit are at a b c d. The terminals of the motor-circuit are a. b c d, which connect with the center of the compensator-coils. The compensator-coils are connected across the branches of the main circuit and have a common joint 0.

In all the modifications shown in the several figures of the drawings the core structure is provided with three sets of polar projections, each set comprising as many poles as there are phases in the current supplied and one set being rotatable with respect to the other two. Thus in Figs. 1, 2, and 3, which show a regulator wound for three phase currents, each set comprises three polar projections, while in Fig. 4, which shows a regulator wound for quarter-phase currents, each set comprises four polar projections. The series portions of the compensator-coils embrace the polar projections of one set, the shunt portions embrace the polar projections of another set, and the third set is unwound.

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

1. In a regulator for alternating-current circuits, the combination of a core structure comprising relatively movable members, with compensator-coils so arranged thereon that by adjustment of the said core structure a magnetic circuit can be closed through both portions of the respective compensator-coils, or through a single portion only.

2. In a regulator for polyphase circuits, the combination of a core structure composed of external and internal parts, angularly adjustable with reference to each other around an axis, compensator-coils connected atintermediate points to the regulated circuit, and arranged upon the core structure in such a manner that a magnetic circuit can be closed through both parts of the respective compensator-coils, or through a single part only, by adjustment of the core structure, as set forth.

3. The combination of a stationary core part, an adjustable core part, and a compensator-winding, the two parts of which occupy difierent angular positions on one of said core parts, as set forth.

4. In a regulator for alternating-current circuits, the combination of a core structure comprising two relatively adjustable members, one of said members provided with two sets of polar projections, and the other with a single set, and compensator-coils having portions embracing the polar projections of one member; the polar projections of the other member being unwound.

5. In a regulator for alternating-current circuits, two relatively adjustable members, one of said members having two sets of polar projections and the other having only a single set, in combination with compensatorcoils, each comprising a series portion. and a shunt portion, the series portions of said coils embracing the polar projections of one set, the shunt portions embracing the polar projections of a second set, and the third set being unwound.

6. The combination of an alternating-current circuit, a branch circuit, a compensatorwinding through which the second circuit is connected with the first circuit, and means for adjusting the parts making up the core of the regulator so that the series and shunt portions of the compensator -winding may be placed in inductive relation to one another, and gradually withdrawn from inductive relation by opening the magnetic circuit of the series portion of the compensator-winding and simultaneously closing the magnetic circuit of the shunt portion, as set forth.

7. The combination in a regulator for polyphase circuits, of a core structure composed of external. and internal polar parts adjustable With reference to each other around an axis, a compensator-coil for each phase, part of which is in series and part in shunt with the load on the corresponding branch of the regulated circuit, and means for adjusting the core structure so as to put the series and shunt branches of the compensator-coils in inductive relation with one another for lower voltages in the regulated circuit, and at another time gradually withdraw them from inductive relation until at maximum voltage the shunt branches of the compensator-coils stand in a closed magnetic circuit, and are practically idle, While the series branches of the compensator-coils stand in a practically open magnetic circuit, as set forth.

8. In a regulator for alternatingcurrent polyphase circuits, the combination of a core structure, compensator coils having series and shunt branches with relation to a regulated circuit, and means for varying the magnetic circuit through the series and shunt branches of the compensator-coils such that (ct) said series and shunt branches may be in inductive relation in a closed magnetic circuit; (b) the series branch may have its magnetic circuit closed and that of the shunt open; (0) the shunt branch may have its magnetic circuit closed and that of the series open; as set forth.

9. In a regulator for polyphase circuits, the combination oi a core or cores, a compensatorcoil for each phase of the circuit having a portion in series and another portion in shunt with the regulated circuit, and means for varying the mutual induction between the shunt and series portions of the coils, and also their self-induction in order to change the distribution of Voltage between different portions of said coils, as set forth.

10. The combination with an alternatingeurrent motor, of a regulator therefor consisting of a com pensator-coil connected across the main circuit and havingaseries and shunt portion between which the motor connection is made, a magnetic core structure for the compensator-coil, and means for regulating the voltage at the motor-terminals by varying the mutual induction and self-induction of the series and shunt branches of the com pensator-winding.

In Witness whereof I have hereunto set my hand this l-tth (lay of August, 1897.

CHARLES I. STITEINh [ETL Witnesses:

B. B. IIULL, A. H. ABELL.

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