US2264986A - Regulator - Google Patents

Description

Dec. 3, 1941.

J. F. KOVALSKY REGULATOR Filed Feb. 23', 1939 5 Sheets-Sheet 1 WiTNESSES:

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ATTORNEY Dec. 2, 1941. J. F. KOVALSKY 2,264,986

REGULATOR Filed Feb. 23, 1939 3 Sheets-Sheet 2 Fig". 5,

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I REGULATOR Filed Feb. 25, 1939 s Sheets-Sheet a Fllq. 2

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ATTORNEY Patented Dec. 2, 1941 REGULATOR Joseph F. Kovalsky, Turtle Creek, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application February 23, 1939, Serial No. 257,949

Claims.

My invention relates to regulators of the type wherein the regulated quantity is controlled by a primary control device that is actuated by the joint action of an electromagnet and mechanical biasing means, and particularly to means for adjusting the sensitivity of such primary control device.

My invention is applicable to regulators of the type disclosed and claimed in a copending application of C. R. Hanna and S. Sentipal, Serial No. 203,876, filed March 23, 1938, for Regulators, and assigned to the same assignee as this application, which application became Patent No. 2,246,301 on June 17, 1941. The magnetic structure for operating the control element may correspond to that disclosed and claimed in an application of R. A. Geiselman, Serial No. 219,527, filed July 16, 1938, for Regulators, and assigned to the same assignee as this application, which application became Patent No. 2,235,400 on March 18, 1941.

In regulators of the character referred to a rheostatic control device is employed which includes a plurality of leaf springs arranged in a stack and connected to a plurality of spaced points along an associated resistor for varying the effective value of the resistor for controlling an electric circuit. The leaf springs are normally insulated from each other and carry contact members at one end which are free to move and which are normally biased against a stop which spaces them in such manner as to effect a separation of the several contact members carried by their free ends. A driving member is provided that is actuated by the resultant mechanical and electromagnetic forces exerted by the leaf springs, an electromagnet, and a biasing spring which opposes the force of the electromagnet. The driving member is adapted to move the several leaf springs together with their associated contact members relative to the stop to effect a sequential engagement thereof, and to shunt varying portions of the resistor connected between the several leaf springs to thereby vary the effective value of the resistor.

In order that the regulating device remains stationary at a particular position corresponding to a particular efiective value of the resistor, it is necessary that there be a slight variation between the pull curve of the electromagnet and the load curve for opposing its motion. Otherwise, the moving element of the regulator would remain stationary in any position instead of in one position only for a given excitation of the regulator winding and a corresponding given pull on the armature.

In the past, the degree of sensitivity of regulators of the character described have been adjusted by varying the pull on the spring opposing the force of the actuating electromagnet. In varying this force, the current through the electromagnet required to balance the spring force is changed, and the effective range of the voltage adjusting rheostat connected in series therewith for adjustingthe particular voltage to be regulated is correspondingly changed, thus limiting the voltage adjustment that may be made thereby.

It is an object of my invention to provide means for adjusting the sensitivity of a regulator of the class described without the necessity of increasing or decreasing the balance point or the winding current corresponding to a predetermined pull of the actuating magnet on its armature.

Other objects and advantages of my invention will appear from the following description of preferred embodiments thereof, reference being made to the accompanying drawings, in which:

Figure 1 is a diagrammatic view of circuits and apparatus comprising a regulator system employing the invention;

Fig. 2 is a side elevational view of the primary control element;

Fig. 3 is a side elevational view of a portion of the primary control regulator element illustrating one embodiment of the invention for adjusting the sensitivity thereof;

Fig. 4 is a diagram for explaining the operation of the structure shown in Fig. 3;

Fig. 5 is a side elevational view of another embodiment of the invention;

Fig. 6 is a diagram for aiding in the explanation of the operation of the structure shown in Fig. 5; and,

Figs. '7 and 8 are curves for illustrating characteristics of the primary control regulator element.

Referring to Figure 1, an electric generator I is illustrated having an armature winding 2 that is connected to circuit conductors 3 and 4, and a field winding 5 that is energized from the armature winding through a circuit including conductor 6, regulating resistor I, conductor 8, and a field adjusting rheostat 9. Spaced points along the resistor I are connected by conductors 12 to a plurality of leaf springs 13, corresponding ends of which are stationary and insulated from one another by thin layers of insulating material H, such as fish paper, and held together within a bracket l5 by a pressure plate I6 and retaining the ends thereof are adapted to engage aniri-L M clined surface [9 of a stop 22 in sequence as the group of springs is moved toward the left to 7 permit separation of the adjacent contact buttonsl8. For varying the effective value of the resistor I, a driving member 23 is .provided and carried by a lever 24 that is so mounted as to be moved about a pivot 25 in accordance with the resultant} forcesexertedthereon by an armature 32 and a tension spring 26, one end 21 of which is attached to the lever 24 and-the other end 28 of which is attached to an abutment '29; The armature 32 of magnetic material is mounted on the lever 24 and positioned in an air gap 33 between the'ends of a C-shaped core structure 34 having a winding leg about which a winding 35 is placed and connected to be energized from conductors 3 and 4'in accordance with the voltage to be regulated. a

The circuit of the winding 35 extends from line conductor 3 through conductor 36, voltage adjusting rheostat 31, conductor 38, the winding 35, conductor 39, the winding 42 of a stabilizing transformer 43, to the line conductor 4. The primary winding 44 of the stabilizing transformer 43 is connected by conductors 45 and 46 to be energized in accordance with the voltage across the field winding 5 of the generator I. to introduce stabilizing voltage impulses into the regulator control circuit. during changes in generator voltage. Astop 41 is provided on the lever 24 to limit the movement of the driving member 23 toward the right as shown in Fig. 1.

Referring to Fig. 2, the pivot line 25 is the plane of intersection of flatleaf springs 48, and leaf springs 53. The springs 48 extend horizontally from a bracket 49 carried onthe core structure 32, and a bracket 52 carried on the leaf arm Z l. The vertically positioned leaf springs 53 likewise extend between the brackets 49 and 52. The armature 32 is positioned in a space between opposite endsof the C-shaped core 34 providing two gaps 33 on opposite faces of the armature 32. The sum of the two air gaps is thus maintained constant as the overlap between the opposite armature faces and the ends of the corev structure 34 vary'with varying position of the lever 24. The inner surface 54 of the armature 32 is shaped to effect a varying pull with change in position suffici ent to compensate for the varying load on the lever 24 occasioned by the varying force of the increasing number of springs 13 exerted against the driving member 23 as this member moves toward the right, and to also compensate for the change in tension of the spring26. V

, In Fig. 1, the lever 24 is shown in its extreme right position limited by the stop 41 and the driving member 23 is suiiiciently toward the right. to raise each of th leaf springs [3 from the surface 19 of the stop 22, causing the several contact buttons [8 tobe in engagement with tween conductors l2 of the resistor i. As the generator voltage builds up and the energization of the winding 35 increases, the pull of the armature 32 against the force of the spring 26 increases, until it is sufiicient to move the lever 24 in acounter-clockwise direction about the pivot 25, and permit certain of the leaf springs 13 to engage the stop 22 in sequence, those shown at the right of the stack of leaf springs engaging first. When .a sufficient number of the leaf springs l3 have engaged the stop 22 to remove "the shunt circuit therethrough from a sufficient number of the portions of the resistor 1 to increase the effective value of this resistor, the

lever 24 remains stationary in a position to maintain the'd'esired voltage between circuit conductors 3 and 4. As the generator voltage varies in one direction or th other from its desired value,

- the energization of the winding 35 correspondthe correspondingbuttons onthe adjacent leaf springs to short circuit the .seyeralportions beingly varies to cause the lever 24 to move so as to .vary the number of leaf springs I3 resting against the stop 22 to increase or decrease the effective value of the resistor 1 sufli-ciently to correct for variations in the generator voltage from the desired value. 7

Referring to Fig. '7, curves 51, 58 and 59 represent pull curves, that is, the effective moment or torque exerted on the lever 24 about the pivot point 25 by the armature 32 upon varying positions from the innermost position of the armature 32 as it moves toward the left, as viewed in Figs. 1 and 2. The range in values of torque shown on the curve represents-relatively high values such as from full torque to, say, full torque to best show the nature of the curves. As previously explained, the shape of the armature 32 is such that as it moves outwardly or toward the left for a substantially constant current value, the pull decreases so as to compensate for the increasing load on the spring 26 resulting from the increasing number of leaf springs I3 that are raised from engagement with the stop member 22, and also to compensate for the decreasing force of the spring 26 as its length is slightly shortened. The three dotted line curves 62,. 63 and 64 represent load curves, that is, the mechanical torque which acts as a load on the electromagnet. The three load curves 62, 63 and 54 exert the same torque as that exerted by the electromagnet as shown by curves 51, 58 and, respectively, when the armature 32 is in itsinnermost position and vary progressively from the pull curve as the distance from that position increases. The three curves 51,58 and 59 may, for example, represent the pull curve of the regulating unit shown in Fig. 2 for current values of .11, .10 and .09 ampere through the winding 35 over the range of movement of the armature 32. It will be noted that as the current through the coil is decreased, the range or percentage variation of the load curve with respect to the this current effects a variation in the voltage drop across the voltage adjusting rheostat 31, effecting an inaccuracy in the regulator until this rheostat is readjusted, and likewise limiting the range of voltageadjustment permissible by .the rheostat 31.

In accordance with my inventionmeans are provided for varying the sensitivity of jthe llljr' mary regulating element without changing the pull curve. This may be done by mounting the abutment 29 on which one end of the spring 26 is attached, upon a support 65, as shown in Figs. 2 and 3 by any suitable adjusting means, such as a screw 66 extending through a slot 61 in the abutment 29 to permit vertical adjustment of the eyelet 28 carrying one end of the spring 26. In Fig. 3, the eyelet is shown in three elevations A, B and G, respectively, the effect of which is most easily understood by referring to Fig. 4, in which the arrows a, b and c represent, respectively the direction of the force of the spring 26 in the three positions. The lower arrow in Fig. 4 represents the pull of the magnet on the armature 32 about the pivot point 25. It will be noted that when the eyelet 28 is in position A, the force exerted in the direction of the arrow a acts about a lever arm 69. If the position of the eyelet 28 is moved to position B, the force of the spring 26 acts in a direction represented by the arrow b in Fig. 4 through a lever arm l which is less than the lever arm 69. Again, if the eyelet 28 is moved to the position C, the force of the spring 26 acts in the direction of the arrow 0 in Fig. 4 through a lever arm about the pivot line 25 represented by the dotted arrow line "H, which is less than the lever arm 10. If, therefore, the tension on the spring 26 in any one of the three positions A, B or C is a so adjusted that the torque or load is the same when the armature 32 is in its extreme right position, as shown in Figs. 1, 2 and 3, the three load curves A, B and C as shown in Fig. 8, will just balance the pull curve 68 in that position and the adjustment of the spring will not affect the pull curve. As the armature moves from its zero position on the diagram of Fig. 8, or in a clockwise direction about its pivot line 25 as shown in Figs. 1, ,2 and 3, the curves A, B and C represent the varying loadings in the three positions of the spring 26. These three curves all start at the same point on the curve 68 and droop progressively further below the curve 68 because of the decreasing lever arms 69, and H as shown in Fig. 4.

Referring to Figs. 5 and 6, another embodiment of the invention is illustrated, the general construction of the regulating control element being the same as that shown in Figs. 1, 2 and 3, except that instead of providing for varying the fixed end of the spring 26 connected to the eyelet 28 vertically in order to change the direction of the force of the spring 26 in the manner just described, the opposite end of the spring 28 is connected to an eyelet 12 that is carried by a bracket 13 on the lever 24 and held by a nut 14. The eyelet 12 is adjustable horizontally, or in a direction corresponding to the axis of the spring 26 so that the point of contact 15 of the spring to the eyelet may be varied, the effect of which is easiest understood by referring to Fig. 6.

If the point 15 is in its leftmost position as shown in Fig. 6, so that its direction of travel toward the right will be along the are 16, the horizontal movement effected by a predetermined arc may be represented by the distance 11 and the direction of the force of the spring 26 will move from that represented by the line 18 to the direction of the line 19 as the point 15 moves through the are '16, thus increasing the lever arm of the axis of pull about the pivot point from that represented by the dotted arrow 8| to that represented by the dotted arrow 82, so that the efiect of the loading is relatively high corresponding, for example, to that represented by curve A in Fig. 8. If, on the other hand, the point of connection 15 between the left end of the spring 26 and the eyelet 12 is represented by the point 15 in Fig. 6, its horizontal movement through an are 83 corresponding in angular degrees to the are 16 will result in a greater horizontal movement of the point 15 shown by distance 84, thus resulting in a greater decrease in the force of the spring 23 over the same angular movement. Also in the position chosen, the point '15 moves substantially directly along the original axis of the spring 2t, that is, along the line 18, so that the distance of this force from the pivot point 25 does not change appreciably as in the first chosen instant, resulting in a load curve such, for example, as the curve C in Fig. 8. For intermediate points of adjustment of the connection of the spring 26 to the eyelet 12 between that represented by points 15 and 15 in Fig. 6, correspondingly different load curves between those illustrated by curve A and C" in Fig. 8 may be established. All of these load curves represent adjustments of the regulating element in which the load on the magnet is the same for the zero or starting point of movement of the armature 32.

Referring to Fig. 8, curves 9! and 92 represent load curves corresponding to progressively lesser values of current flowing in the winding 35, with correspondingly lesser values of pull or the armature 32 throughout the range in movement of the armature than the current and pull represented by curve 68. If for example, the regulator is adjusted to have a 4% droop in load curve below the pull curve 68 throughout its range of movement, corresponding to load curve A, the regulator lever 24 will be at rest at the position represented by the point 93 when the current corresponds to the value represented by curve 9|. If the regulator is adjusted for a 6% or 8% droop in load, curves B and C, respectively, the regulator will balance in the positions represented by points 94 and 95 respectively in Fig. 8. Similarly, with a current value corresponding to the pull curve 92, the regulator will balance in positions represented by points 96, 9'1 and 93 respectively, for the three load curve adjustments represented by curves A, B and C.

Many modifications may be made in the arrangement of parts within the spirit of my invention, and I do not wish to be limited otherwise than by the scope of the appended claims.

I claim as my invention:

1. In a regulating system for controlling an electric quantity, 3. primary control device having a plurality of contact members, means for actuating said contact members in sequence comprising a driving member mounted for movement about an axis, biasing means for urging said driving member in one direction about said axis, electro-responsive means for urging said driving member in the opposite direction about said axis, and means for varying the effective lever arm through which the force of said biasing means acts for adjusting the variation in sensitivity of the device throughout its range of operation.

2. In a regulating system for controlling an electric quantity, a primary control device having a plurality of contact members, means for actuating said contact members in sequence comprising a driving member mounted for movement about an axis, biasing means for urging said driving member in one direction about said axis, electro-responsive means for urging said driving member in the opposite direction about said axis, and means for varying the effective lever arm through which the force of said biasing means acts for adjusting the variation in sensitivity of the regulator throughout its range of operation comprising means for adjusting the direction of application of the force of the biasing means to the movable member with respect to the radius of movement of the point of application thereof about the axis of movement.

3 In a regulating system for controlling an electric quantity, a primary control device having a plurality of contact members, means for actuating said contact members in sequence comprising a driving member mounted for movement about an axis, biasing means for urging said driving member in one direction about said axis, electro-responsive means for urging said driving member in the opposite direction about said axis, and means for varying the effective lever arm through which the force of said biasing means acts for adjusting the variation in sensitivity of the regulator throughout its range of operation comprising means for adjusting the point along the axis of application of the force of the biasing means at which the force is applied to the moving member.

4. In a regulating system for controlling an electric quantity, a primary control device having a plurality of contact members, means for actuating said contact members in sequence comprising a lever mounted for movement about an axis and a driving member carried thereby, biasing means extending substantially at right angles to the lever for urging the lever in one direction about said axis, electroresponsive means for urging said driving member in the opposite direction about said axis, and means for varying the effective lever arm through which the force of said biasing means acts for adjusting the variation in sensitivity of the regulator throughout its range of operation comprising a longitudinally adjustable supporting arm for one end of the biasing means positioned substantially parallel to the lever for adjusting the direction of application of the force of the biasing means to the movable member with respect to. the radius of movement of the point of application thereof about the axis of movement.

5. In a regulating system for controlling an electric quantity, a primary .control device having a plurality of contact members, means for actuating said contact members in sequence comprising a lever mounted for movement about an axis and a driving member carried thereby, biasing means extending substantially at right angles to the lever for urging the lever in one direction about said axis, electroresponsive means for urging said driving member in the opposite direction about said axis, and means for varying the efiective lever arm through which the force of said biasing means acts for adjusting the variation in sensitivity of the regulator throughout its range of operation comprising means for adjusting the point along the aXis of application of the force of the biasing means at which the force is applied to the moving lever.

JOSEPH F. KOVALSKY.

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