US2523784A - Oscillatory relay device - Google Patents

Description

P 1950 I H. 'r. SEELEY 2,523,784

OCILLATORY RELAY DEVICE Original Filed July 27, 1948 M Fhgl.

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Inventor:

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His Ab oorney.

Hrold T. Seele'y,

Patented Sept. 26, 1950 2,523,784 OSCILLATORY RELAY DEVICE Harold T. Seeley, Lansdowne', Pa,, assignor to General Electric Company, a corporation of New York Original application June 24', 1946, Serial No. 678,871, now Patent No.v 2,445,804, dated July 27, 1948. Divided and this application October 24, 1947, Serial No. 781,965

My invention relates to improvements in relay devices and more particularly to improvements in reversible torque relay devices andespecially substantially instantaneously operating reversible torque relays of the electromagnetic type.

This application is a. division of my copending application, Serial No. 678,871, filed June 24, 1946, issued on July 27, 1948 as Patent 2,445,804 and assigned to the assignee of this invention.

An object of my invention is to provide a reversible torque motion-rectifying relay device wherein a movable circuit controlling element is operated by a force always in substantially the same direction regardless of the direction of the relay torque and always of substantially the same magnitude for torque of like magnitude in either direction. Another object of my invention is to provide a substantially instantaneously operating electromagnetic reversible torque relay with a. contact controlling motions-rectifying structure which is particularly adapted for synchronizing systems of the type. disclosed in my application, supra h se and other ob ects f: my nv ntion will hereinafter appear in more detail.

In accordance with my invention, I provide a substantially instantaneously operating reversible torque relay comprising a rotatably mounted member, a movable supported circuit controlling element, and motion-rectifying means controlled by the rotatable member for exerting on the element an operating force of substantially the same magnitude and direction in' response to torque of like magnitude exerted on the rotatable member in either direction.

My invention will be better understood from the following description when considered in connection with the accompanying sheet of drawings, and its scope will be. pointed out in the ap! pended claims.

In the accompanying sheet of drawings, Fig. 1

6 Claims. (Cl. 20091,)

diagrammatically illustrates an automatic syn,

chronizing device embodying the invention disclosed and claimed in my copending application, supra. and llu tra d he ei f r the p p s o showing one embodiment and application thereof of my present invention; Fig. 2 is a plan view of a contact controlling arrangement for a reversble torque relay emb dy my in en a d Fig. 3 is an angle diagram explanatory of the operation of the synchronizing devic shown in and the'one I have chosen schematically to illus trate is of the so-called induction cup or cylinder type disclosed in United States Letters Patent Reissue 21,813, dated May 27, 1941, and assigned to the assignee of this invention. For simplicity in illustration, '1 have omitted the magnetic structure of the relay and shown only the op erating coils 25 and 26 which are mounted on the inwardly projecting poles of a magnetic stator, not shown. The induction cylinder, not shown, is mounted on a shaft 21 so as to rotate in air gaps between the inner ends of the polar projections and another stationary magnetic stator, not shown, within the cylinder. Arranged to be actuated in response to rotation of the shaft 21 is a contact controlling element 28 oscillatably supported at 29"preferably on a leaf-spring 29 and arranged to control double-throw contact sets Ia and Ib. It will of course be apparent to those skilled in the art that the contact 28 may be otherwise suitably pivotally supported for its relatively limited angular movement between the stationary contacts Ia and Ib. This contact controlling element 28 is biased for clockwise movement by suitable means such as a relatively light spring 30 which is preferably adjustable as shown, for example, in Fig. 2. This adjustment controls the angle at which the contacts Ib will close to initiate the closure of the circuit breaker.

The coils 25 are so wound and series connected in a single winding circuit including conductors 3|, 32, and 33 that when energized by an alternating electric quantity such as the voltage Eb across the secondary winding of the bus potential transformer l0, as shown, they present at any instant alternate poles of like polarity and adjacent poles of different polarity at the ends toward the shaft 21. Similarly, the coils 26 are so wound and series connected in a single wind ing circuit including conductors 34, 32, and 33 that when energized by an alternating electric quantity, such as'the voltage Eg across the secondary winding of the generator potential trans! former l I, as shown, they present at any instant alternate poles of like polarity and adjacent poles of diiferent polarity at the ends toward the shaft 21. The maximum torque angle of the relay I may be controlled by suitable means such as an adjustable resistance 35 in series with the windings 2,6 of the conductor. The torque on the shaft 2'1. then is proportional to EbEg sin (-0) Eb and E9 being respectively the voltages across the secondaries of the transformers I0 and ll, 5 the phase angle between these voltages, and 0 the angle of minimumtorque. In practice 0, is ad-, justed to substantially zero degrees by means of the resistance 35 This torque relation is particularly advantageous relatively to the critical phase relations of the voltages. At these critical phase relations, as will hereinafter appear,

torque reversal occurs, that is the electromagnetically produced torque passes through zero and as it increases to a predetermined value t overcomes the light spring 30 to open the contacts Ib and close the contacts Ia and the spring 30 overcomes the electromagnetically produced torque as it decreases below the predetermined value if and passes through zero in the opposite direction whereby to open the contacts Ia and close the contacts Ib. In the neighborhood of these torque reversal points, variations and inequalities of the voltages Eb and Eq produce the minimum effect on the electrical torque. In other words, departure of these voltages from their normal values and lack of equality between these Voltages does not materially shift the phase relation at which torque reversal occurs. Consequently, such variations and inequalities as may commonly occur do not adversely affect the safety of the indicated connecting operations. In order to have closure of the contacts Ia, occur at phase angles in a predetermined range each side of phase coincidence but not including phase coincidence, I provide in accordance with myinvention means for moving the contact controlling element 28 counterclockwise as viewed in Figs. 1 and 2 from the Ib throw to the Ia throw whenever the torque of the relay I exceeds the predetermined value t which is suiiicient to overcome the force of the spring 39 regardless of the direction of this torque. For this purpose I provide, in accordance with my invention, motion-rectifying means controlled by the rotation of the shaft 2'! for exerting on the contact controlling element 28 an operating force of substantially the same magnitude and direction in response to torque of like magnitude exerted on the shaft in either direction. As shown more clearly in Fig. 2, this motion-rectifying means comprises a double crank member 36 which has a hub portion 31, which is so secured to the relay shaft 2'! as to rotate therewith. Also, as shown, this crank member 36 has two crank arms or projections 38 and 39 on the same side of the contact controlling element 28 as the contacts Ib. In the arrangement shown in Fig. 2, the pivotal axes of the shaft 21 and the contact controlling element 28 and a line joining the two I'o contacts, only one of which appears in this view, are parallel and in substantially the same plane. Also; the projections 38 and 39 are so positioned as to come into substantially the same plane in the Ib throw of the contact controlling element 28 when the torque due to the biasing means or spring 38 predominates to move the contact controlling element to the Ib position. In order to have the desired operating action on the contact controlling element 28, I so position the diametrically opposite projections 38 and 39 relatively to the axes of rotation of the shaft 21 and the element 28 as to exert on the element an operating force tending to move it into engagement with the Ia contacts with the same effect and direction for torque of like magnitude exerted on the shaft 21 in either direction by the electromagnetic means comprising the windings and 28. For this relative diametrically opposite positioning of the pins 38 and 39, it will be assumed, as shown in Fig. 2 that 1- and R represent the distances between the axis of the shaft 21 and the pins 38 and 39 respectively and s represents the distance between the pivotal axes of the shaft 21 and the contact controlling element 28. Then for a given torque t 4 exerted on the shaft 2'! in a clockwise direction, a force is exerted on the projection 38. It will now be assumed that instead of this force F1, a parallel force 1 is exerted on the contact controlling element 28 in a line through the axis of rotation of the shaft 21. Then the following equation results:

the shaft 21. Then the following equation results:

from which results Since these imaginary applied forces f1 and f2 are to have the same magnitude for a given torque i applied to the shaft 2'! regardless of the direction of the torque t, the values of f1 and f2 as given above are equated as follows:

t(sr) t(s+R),

is Rs This equation simplifies into the form R(s1')=r(s+R) since the torque t is assumed to'have a predetermined value and always turns the element 28 in the same direction because of the arrangement of the parts. Solving this equation for R, there results In other words, from the foregoing equation, assuming values for r and s, the value of R can be so compulted as to insure that for a given torque t regardless of its direction but sufficient to overcome the bias of the spring 33 and move the contact controlling member 28 toward the contacts Ia, the contact controlling element 28 is effectively actuated by the same force acting in the same direction at a given point of the contact controlling element.

For controlling the synchronizing connection so as to confine it to a predetermined relatively small range each side of phase coincidence when the frequency difference is below a predetermined value, the energization of the auxiliary relay A is effected only when the Ia contacts of the relay I are closed while the contacts l2l3 of the relay T are closed. Thus for example the circuit of the energizing winding 4'8 of the relay A is from one side of the control source 6 through a conductor 4!, the contacts l2l3 of the frequency difference responsive relay T, a conductor 42, the b switch 5 of the circuit breaker 2, conductors 43 and 44, the Ia contacts of the instantaneous phase difference responsive relay I, a conductor 45, the winding of the relay A and a conductor 46 to the other side of the control bus. When this circuit is completed at a predetermined value of phase difference, the relay A seals itself through its contacts 41' and remains energized as long as the contacts I2-l3 of the relay T remain closed. Subsequently, as the torque t of the relay I decreases so that the spring 30 predominates to close the contacts Ib, the energizing circuit of the winding '8 of the closing control relay 1 is completed. This circuit is from one side of the bus 6 through the conductor 4|, the contacts I2--l3 of the relay '1, the conductor 42, the b switch 5, the contacts 4'! of the relay A, the conductor 45, the contacts lb of the relay I, a conductor 48, the winding of the relay 1, the b switch 4 and conductors 49 and to the other side of the control bus 6. Upon the energization of the closing control relay 8, its contacts 9 are closed to complete the circuit of the closing winding 3 from one side of the control source 6 through the conductor 50, the closing winding 3, the contacts 9 of the relay 1 and a conductor 5| to the other side of the control bus whereby to effect the closing of the circuit breaker 2.

For further explanation of the operation of the synchronizing device shown in Fig. 1 and particularly the relay I embodying my invention, reference will now be had to the angle diagram of Fig. 3 to illustrate a concrete application of reversible torque relays embodying my invention. It is to be understood, however, that relays embodying my invention are not limited in their application solely to Synchronizing devices. The angle diagram of Fig. 3 may be considered to be the face of a synchroscope having a pointer P which rotates clockwise about the center 0 when the generator frequency is greater than the bus frequency and counterclockwise when the generator frequency is less than the bus frequency. In the particular example illustrated, the contacts I2-|3 of the relay T are open through the phase difference range 80-180-280. However, if the frequency difference is slow enough, the relay T tends to start closing its contacts around 80 and also 280 depending upon whether the generator frequency is lower or higher than the bus frequency. If the frequency difference remains below a predetermined cut-off value through the phase angle range 800-280, the contacts l2-l3 of the relay T may close. The Ia contacts of the relay I are closed over the phase difference ranges 25-80155 and 205- 280-335. The 1?) contacts of the relay I are closed over the phase difference ranges 340-0-- 20 and 160-180-200. Over the phase difference ranges 20-25, 155-160, 200-205 and 335-340, the contacts In and 1b of the relay I are open.

It is of course to be understood that the fore-.

going figures merely represent a particular way in which the adjustments are made for a given application. Obviously other phase relations can be established as desired, as will be apparent to those skilled in the art.

Assuming now that the pointer P 'is at the 180 position and moving counterclockwise, then the contacts l2l3 of the rela T are open, the contacts Ib of the relay I are closed and the contacts Ia of the relay I are open. At 160, the II) contacts open and at 155 the Ia contacts close. At 80 the movable contact l2 of the relay T starts in the closing direction but does not close until some later angle depending on the frequency difference and time setting. If the frequency difference is excessive, the contacts l2--l3 of the relay T are not closed at 25 when the Ia contacts open. Consequently, the auxiliary relay A is not energized, and, therefore, the closing control circuit remains deenergized when the If) contacts close at 20. Proceeding counterclockwise through phase coincidence or 0, the Ib contacts open at 340 and the Ia contacts close at 335. If the frequency difference is not considerably above the cut-off setting or predetermined safe minimum value, the con tacts |2-I3 of the relay T have closed so that the auxiliary relay A is energized at 335. Continuing counterclockwise, the contacts |2--|3 of the relay T open the circuit of the auxiliary relay A at 280 so that the closing control circuit of the circuit breaker is not completed when Ib closes at 200. If the frequency difference becomes zero and changes sign before the contacts of the relay T open, then the movement of the pointer is clockwise and the Ia contacts open at 335, but the auxiliary relay remains sealed through its own contact and the closed contacts of the relay T. Consequently when the II) contacts close at 340, the closing control circuit of the circuit breaker is completed. Such reversals of frequency difference in the quadrants between 270 and 0 and 0 and constitute the best chances for synchronizing with an unsteady water wheel, a poorly adjusted governor or both, all of which produce reversals of frequency difference at random values of phase difference together with such wide fluctuations of frequency that the frequenc difference is usually within the synchronizing range for only a fraction of a slip cycle following one of these reversals. Synchronizing devices embodying my invention are particularly adapted to take advantage of these conditions.

If the frequency difference decreases gradually from above cut-off setting to below cut-off setting, then assuming a start at 180 and proceeding counterclockwise, the closing sequence is: the Ib contacts open at the Ia contacts close at 155. the contact [2 of the relay T starts in the closing direction at 80 and closes just before 25", the relay A is then energized through the contacts l2--l3 of the relay T and the contacts Ia to seal itself before the contacts Ia open at 25, and at 20 the contacts Ib close to effect the closing operation of the closing control circuit.

If the frequency difference decreases gradually from below cut-off setting to above cut-off setting, then assuming a start at and proceeding clockwise, the closing sequence is: the con tacts Ib open at 200, the contacts Ia close at 205 the contact l2 of the relay T starts to close at 280 and finally closes just before 335, and the relay A is energized through the contacts 12-13 of the relay T and the contacts Ia and seals itself before 335 where the contacts Ia open, and at 340 the contacts Ib close to complete the closing control circuit through the contacts l2l3 of the relay T, the contacts 41 of the relay A and the contacts 1b of the relay 1.

While I have shown and described my invention in considerable detail, I do not desire to be limited to the exact arrangement and concrete example shown, but seek to cover in the appended claims all those modifications that 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:

l. A relay comprising a rotatably mounted member, means for exerting on said member a reversible variable torque, a pivotally supported contact controlling element extending transverse the axis of the member, and motion-rectifying mechanism including a pair of projections carried by said member on opposite sides of the axis at distances proportioned for exerting on said element an operating force of substantially the same magnitude and direction in response to torque of like magnitude exerted on said member in either direction.

2. A relay comprising a rotatably mounted member, means for exerting on said member a reversible variable torque, a pivotally supported contact controlling element extending transverse the axis of the member, spaced contacts mounted on opposite sides of said element adjacent the free end thereof, means biasing said element into engagement with one of said contacts, and means including diametrically opposite projections carried by said member at distances from the axis thereof proportioned for efiectively exerting on said element an operating force tending to move the element into engagement with the other of said contacts and having the same magnitude and direction in response to torque of like magnitude exerted on said member in either direction,

3. A relay comprising a rotatably mounted member, electromagnetic means adapted when energized by two electric quantities differing in phase to exert on said member a reversible variable torque having a direction and magnitude dependent on a function of the phase angle between the quantities, a pivotally supported contact controlling element extending transverse the axis of the member, and two spaced projections carried on opposite sides of the axis of said member engageable with said element, said projections being so positioned relatively to the axes of rotation of said member and said element as effectively to exert on the element an operating force of substantially the same magnitude and direction in response to torque of like magnitude exerted on the member in either direction by said electromagnetic means.

4. A relay comprising a rotatably mounted member, electromagnetic means adapted when energized by two electric quantities difi'ering in phase to exert on said member a reversible variable torque having a direction and magnitude dependent on a function of the phase angle between the quantities, a pivotally supported contact controlling element extending transverse the axis of the member, spaced contacts mounted on opposite sides of said element adjacent the free end thereof, means biasing said element into engagement with one of said contacts, and means controlled by said member for moving said element into engagement with the other of said contacts including two spaced projections movable by said member and simultaneously engageable with said element when the element is in engagement with said one contact, said projections being diametrically positioned relatively to the axes of rotation of said member at distances therefrom proportional to exert on the element an operating force tending to move the element into engagement with the other of said contacts and having substantially the same magnitude and direction in response to torque of like magnitude exerted on the member in either direction by said electromagnetic means.

5. A relay comprising a rotatably mounted current conducting member, electromagnetic means comprising two windings adapted when re spectively energized by two electric quantities differing in phase to exert on said member a reversible variable torque dependent on the product of the quantities and the phase angle therebetween, a pivotally supported contact controlling element extending transverse the axis of the member, spaced contacts mounted on opposite sides of said element adjacent the free end thereof, means biasing said element into engagement with one of said contacts, and means movable by said member comprising two spaced projections simultaneously engageable with said element when the element engages said one of said contacts, said projections being positioned diametrically on opposite sides of the axis of rotation of said member and so spaced relatively to the axes of rotation of said member and said element as effectively to exert on the element an operating force tending to move the element into engagement with the other of said contacts and having substantially the same magnitude and direction in response to torque of like magnitude exerted on the member in either direction by said electromagnetic means.

6. In a synchronizing device for controlling the closing operation of a switch to effect the connection of two sources of alternating electromotive force when substantially in phase and of substantially the same frequency, a rotatably mounted inductive current conducting member, electromagnetic means comprising two windings adapted when respectively energized by the electromotive forces of said sources to exert on said member a reversible variable torque dependent on the product of the electromotive forces and the sine of the phase angle therebetween, a piv otally supported contact controlling element extending transverse the axis of the member, spaced contacts mounted on opposite sides of said element, means biasing said element into engagement with one of said contacts, and means carried by said member comprising two diametrically opposed spaced projections simultaneously engageable with said element when the element engages said one of said contacts, said projections being so positioned relatively to the axes of rotation of said member and said element as effectively to exert on the element an operating force tending to move the element into engagement with the other of said contacts and having substantially the same magnitude and direction in response to torque of like magnitude exerted on the member in either direction by said electromagnetic means.

HAROLD T. SEELEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,680,708 Traver Aug. 14, 1928 1,755,064 Kennedy Apr. 15, 1930 1,906,468 Jonas May 2, 1933 1,915,095 Jump June 20, 1933 2,115,597 Traver Apr. 26, 1938 2,134,956 Scheg Nov. 1, 1938 2,177,400 Almquist Oct, 24, 1939 2,217,759 Mahnken Oct. 15, 1940 2,315,469 Warrington Mar. 30, 1943 2,408,901 Arnot Oct. 8, 1946

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