US2036305A - Regulating equipment - Google Patents

Description

;April 7,

- lava/flan WITNESSES F. L. SNYDER REGULATING EQUI PMENT Filed April 25, 1954 4 Sheets-Sheet l April 7 1936. F. L SNYDER' REGULATING EQUIPMENT Filed April 25, 1934 4 Sheets-Sheet 2 INVENTOR April 7, 1936. F, L. SNYDER 2,036,305

REGULAT ING EQUI PMENT WITNESSES April 1936. F. 11.. SNYDER REGULATING EQUIPMENT Filed April 25, 1954 4 Sheets-Sheet 4 INVENTOR //'n L. 5 yaefi fig m atented Apr7,193$ 2,0365% PATENT QFFHQE? Rueonernve Franklin 1L. Snyder, Sharon, Pr, to Westinghouse Electric & Manufacturing Come pany, East Pittsburgh, Pa, a. corporation of Pennsylvania Application April 25, i934, Serial No. 322283. tliaims. (Cl. Wil -H9) My invention relates to apparatus for adjustas conditions may require, reversing switches, ing the voltage of alternating-current electrical adapted to be actuated when the tap-changer circuits, and it has particular relation .to equipoccupies the zero component value position, are ment capable of effecting such adjustment in a utilized. With this particular arrangement of plurality of. steps without interrupting the load the windings and associated switches, I have current of the circuit. found it possible to effect adjustment through In maintaining constant the voltage supplied a given range with a transformer having conto load centers through distribution or feeder siderably less kilovolt ampere rating than that circuits, regulating apparatus is required to comformerly required. Preferably, the tap-changer l0 pensate for variations in the voltage of the power and reversing switch assemblages, marked hrs.- to urce and for changes in the circuit-impedprovements in the mechanical design of which ance' drop which result from load-demand fiucmy invention contemplates, are built into tuations. My invention is directed to a stepsingle compact unit which may be integrally type of voltage adjustor or regulator which he fixed to the housing structure of the associated cause of its low-cost and other desirable charactransformer apparatus.

teristics is particularly well suited for applica My i ven itself, tfigethel with additifingfi tion to feeder circuits of the relatively high advantages thereof, will best be understood voltage low-current ratings which are so prevathrough the following description of a specific lent in present-day rural, suburban and certain embodiment when taken in conjunction with the other distribution systems. accompanying drawings, in which? my One object of my invention is to reduce the Figure l is a persmctive view showing the cost of equipments for regulating the voltage external appearance of one preferred form. of of alternating-current circuits. the voltage-regulating equipment of my inven- Another object of my invention is to simplify tion when designed for application to a three= step-type regulators involving multi-tap trans-. phase circuit; 25 former windings and underload tap-changing Fig. 2 is a diagrammatic view of the apparatus mechanisms. and circuits comprised by each circuit phase oi A further object of my invention is to reduce the regulating equipment of Fig. 1; the capacity of the regulating transformer Fig. 3 is a chart showing the sequence of equipmentrequired by a given installation by operation of the several switches utilized by the 30 employing Switching means adapted to reverse tap-changing and winding-connection reversing the connections of the regulating-component mechanisms of the syste pp g- Fig. 4 is a diagrammatic view of apparatus An additional object of my invention is to and circuits modified to regulate a circuit, the

provide a load tap changer mechanism which current in which exceeds the rated capacity of requires only a small amount of space and the corrective-component supply winding and which changes taps with the simplest possible associated tap-changer; mechanical means. Fig. 5 is a diagram showing one manner A still further object of my invention is to which three or the assemblages shown in Fig. 2

provide improved mechanical means for actu may be combinedyas in the unitoi Fig. l, to no ating the tap=changer and the switches which efiect regulation of a three-phase circuit.

serve to shift the component-supply winding Fig. 6 is a view taken on a horizontal section from one to the other of two voltage controlling through the ntegral unit oi Fig. 1 showing how ranges. the parts therein are constructed and arranged;

#15 The voltage-adjusting equipment of my inven- Fig. l is a sectional view taken on the line tion essentially comprises, for each phase of the Vl'i i or 6 illustrating the mechanical circuit to be regulated, a special regulating transdetails of the improved tap-changing and. re iormer having an exciting winding, which need versing switch assemblages comprised by the be of but small capacity, energized toy the circuit equipment of Figs. 1 and 6;

so voltage and a multi tap series winding adapted 8 is a sectional view taken on the line 59 to introduce corrective components into the cir- W'iIVIIiiof Fig. 7 showing the operating mech-. cuit. To adjust the magnitude of these co l-- anism for the reversing switches of Figs. 1, 6 and ponents without interrupting the circuit current, Z;

an underload tap changer is provided and to Fig. 9 is a sectional view taken on line Ill-IE1.

as change their direction from buck to boost, cl Fig. 7 showing the construction oi. the tap g5;

changer switches of Figs. 1, 6 and '7 and their operating mechanism;

Fig. 10 is a sectional view taken on line XX of Fig. 7 showing similar details of the reversing switches; and

Fig. 11 is a diagrammatic view illustrating the manner in which the tap-changer and reversingswitch mechanisms are interconnected with the windings of the main regulating and the tapbridging transformers comprised by each circuit phase of the previously illustrated equipment.

Referring first to Fig. 2 of the drawings, the voltage-adjusting means of my invention are there diagrammatically represented as comprising, for each phase of the circuit to be regulated, a transformer having an exciting'winding l2, connected to receive energization from the voltage acting in the supply side of the circuit, designated by conductors l3 and I5, and a series winding l4 inductively related to the firstnamed winding and adapted, through the utilization of tap-changing means l6 and reversing switch means 18, to interconnect the supply conductor l3 with one of the conductors I! of the regulated circuit ll-IS.

The tap-changing means I6 are associated with the winding H which is provided with a plurality of taps designated as a to e, inclusive, which are respectively connected with switch segments A to E, with which segments a pair of movable members X and Y, joined with the ends of a tap-bridging auto-transformer windinglli, are adapted to selectively cooperate. The series connection of winding H with the regulated circuit includes one end 22 of the winding, the mid-point 23 of the tap-bridging winding 20, and switches J, K, L and M, comprised by the connection reversing means 18. By properly actuating, as in the sequences set forth by the table of Fig. 3, the tap-changing and reversing switches, the voltage of the regulated circuit may, in the case of the five-tap winding shown, be varied with respect to that of the supply circuit in nine separate steps.

In the improved system of my invention about to be described, the tap transfer switches, involving the bridging winding segments X and Y and the series winding tap segments A to E, inclusive, perform all of the load switching operations so that all arcing is confined to these switches. The reversing switches J, K, L and M merely reverse the series section ll of the regulating auto-transformer winding as the tap changer passes through the neutral position. Since the voltage across these switches is practically zero when they are operated, no arcing takes place at their contacts. Furthermore, with this method of changing taps the number of transformer tap leads required for a given number of operating positions is only one more than half the number of those positions and an equally reduced number of load switches only are required per phase. The tapbridging winding 20 is, in addition, short-circuited on each operating position, thereby eliminating its exciting current and resistance loss exceptduring the transition period while chang- Y-A are closed, as are also the reversing switches J and L, and all of the remaining switches in the system are in their circuit-opened positions.

For this closure combination, the full length of winding I4 is connected between the conductor i3 of the supply circuit and the conductor I! of the regulated circuit, this connection being such that the voltage induced in winding [4, as a result of the flux produced by the exciting winding I6, aids or directly adds to that of the supply circuit and thereby increases the potential appearing between the regulated-circuit conductors l5 and [1. When the equipment occupies position No. 1, therefore, there is produced in the regulated circuit a maximum value of voltage for a given supply circuit potential. In this position, as well as in each of the eight others, the tap-bridging winding 20 is shunted through the tap segment with which switch segments X and Y are simultaneouslyconnected.

To reduce by one step, corresponding to the distance between the taps a and b of winding ll, the voltage introduced by this winding into the regulated circuit, the adjusting equipment is actuated to position No. 2. During such actuation, segment Y is first shifted from tap segment A to tap segment B, and segment X then follows with a similar transfer the completion of which places the equipment in the new position.

Still further reductions in the regulated voltage may be effected by advancing the equipment to position No. 3, in which the active connection is shifted to winding tap c, and thence to position No. 4 in which the connection is I made with tap d. In position No. 4, only the voltage appearing between taps d and e is introduced into the regulated circuit. To make the voltage exactly equal to that of the supply side of the circuit the equipment is further advanced to position No. 5 in which the segments X and Y are caused to contact tap segment E, which being connected with the end 22 of winding [4 reduces the component of corrective voltage to zero. In this position'it will be noted that reversing switches K and M have also been closed, this closure taking place in a circuit already completed through switches J and L and hence between different parts of which substantially no voltage appears.

To reduce the regulated voltage below that of the supply side of the circuit, the equipment is advanced to position No. 6. This advancement includes an opening of reversing switches J and L, which opening allows the active winding circuit to be routed in the opposite direction through reversing switches K and M. As a result of this connection reversal, the voltage of the winding II is introduced into the system in a manner that it opposes or bucks the supply circuit voltage, so that when the equipment has advanced to position No. 6, in which the bridging transformer segments X and Y contact series windings tap segment D, the regulated voltage is reduced by one step.

Further advancement of the equipment to position No. 7 increases the reduction by another step to which ay be added additional steps by further advancements to position Nos. 8 and 9. In position No. 9, in which the active connection is established through winding tap a, the full length of the winding I4 is effective in reducing the regulated voltage with respect to that of the supply side of the circuit.

To progressively raise the regulated circuit voltage, the equipment may be actuated from position No. 9 to position No. 1,-\through a series of operations which are exactly the reverse of those just described.

The system of Fig. 2 requires that the series winding I4 of the main regulating transformer and also the tap changing and reversing switches associated therewith be capable of carrying the full load current of the regulated circuit. For the relatively high voltage, low current distribution circuits previously referred to, this presents no difficulties in design and permits of a very economical and satisfactory equipment. The method just described is, however, also appli-, cable to the regulation of circuits in which the current rating exceeds that of the adjusting apparatus. Dne preferred manner of applying the apparatus to such a high current circuit is illustrated in Fig. 4 in which a series transformer 28 is interposed between the circuit and the adjusting apparatus. For such a combination no separate series winding section is required and the taps may be made directly to the single shunt-connected winding 30 of the regulating transformer. The sequence chart of Fig. 3 ap plies to the system illustrated in Fig. 4 as well as to that in Fig. 2. Since the system of Fig. 2 is the one most commonly utilized, the preferred mechanical arrangement of parts and improved equipment designs of my invention will be described in connection therewith.

In the explanation of suchpreferred forms 0 mechanical construction, I have illustrated an equipment adapted for the regulation of a threephase circuit, which equipment comprises three of the regulating-transformer, tap-changing and reversing-switch combinations shown in Fig. 2 interconnected in suitable manner as illustrated in Fig. 5. Thus, each of the three phases of the circuit is provided with the regulating transformer comprising shunt and series windings l2 and I4, the tap changing equipment if and the reversing switches Ill. The exciting windings 52 are connected for energization from the conductors 32 of the supply side of the circuit, while the series windings I4 are adapted for connection between these conductors and the conductors 34 of the regulated side of the circuit. Switch actuating equipments arranged to effect parallel operation of the switches in each of the three groups are suitably provided.

All of this equipment is housed inside of a sheet metal tank structure, the external appearance of a preferred design of which is illustrated in Fig. 1. Protruding from the top of the structure are a plurality of insulator-supported ter-. minals 38 through the medium of which the supply and regulated circuit conductors, represented at 32 and 34 in Fig. 5, are connected with the windings. of the transformers housed inside of the rear portion 36 of the structure and the transfer and reversing switches mounted in a separate compartment 46 which is formed integral with one side of the transformer compartment which is adapted to be filled with insulating oil and which is provided with the usual cooling or radiator tubes 40.

The view of Fig. 6, taken along a horizontal section through the structure of Fig. 1, illustrates one preferred manner of arrangement of the apparatus comprised by the complete voltage adjusting equipment. The three regulating autotransformers, each of which comprises the before-described windings l2 and 14, are positioned side by side in the rear'tark compartment 35,

as indicated by the outlines 42. Also mounted in this compartment are the tap bridging autotransformers, each of which comprises the before described winding 20, indicated in Fig. 6 by the outlines 44.

integrally fixed to one side of this transformer housing structure is the auxiliary compartment 46 which serves to house the tap changing and reversing switch assemblies. This switch compartment is also adapted to be filled with insulat ng oil. An inspection plate 48 is provided on the front as is also an opening 50 through which a position indicating dial, shown at 52 in Fig. 7, may be viewed.

In addition, the equipmentillustrated in Figs. 1 and 6 comprises a third compartment or housing 54 in which automatic control apparatus is positioned. Since this apparatus of itself forms no part of the present invention, no detailed showing or description of it is herein made.

As is shown by Figs. 6 to 10, inclusive, in which the adjusting apparatus .is illustrated as occupying its position No. 5, the segments A to E of each of the tap-changing equipments i6, which segments are connected with the taps of the series winding l4 of each of the regulating transformers, are in the form of protruding metal plates mounted upon a vertically positioned panel or strip 56 of insulating material, while the associated movable fingers X and Y, connected to the ends of each tap-bridging transformer winding 20, are carried by a panel 58 of insulating material which is supported by bracket members 69. These members cooperate with a vertically mounted worm shaft 62 which. when rotated, causes them, together with the equipment attached thereto, to move vertically.

The main drive shaft 52 is provided with two independent screw-like grooves best shown in Fig. 9 at 85 and 86, the one of which, as the shaft is rotated in a given direction, serves to move the cooperating brackets 60 downwardly to their illustrated lower limit of travel at which time control thereof is transferred to the second of the grooves which serves upon continued rotation of the shaft in the same direction to move the members 60 upwardlyalong the length of the shaft.

In operation of the tap changer, the-shaft 52 may be driven in any suitable manner as manually or through the medium of a motor 88 shown in Fig. 7 as interconnected with the shaft through the medium of suitable reduction gearing. Thismotor may be controlled by means of the apparatus housed inside of the control compartment 54 (Figs. 1 and 6). The before-mentioned position indicating disk 52 is connected through suitable gearing to be moved in accordance with the rotation of shaft 62.

Likewise, the reversing switch equipment l8 for each of the circuit phases comprises two conducting material disk members '64 and 6B which are carried by a second vertically mounted shaft 68. which, when rotated, causes these members to jointly or selectively interconnect sets of cooperating contact members fill and ll, respectively, which are mounted upon a strip of insulating material I2, with the associated sets of contact members J and M and L and K which are similarly mounted upon spacedly positioned insulating material strips 13 and 14.

The reversing switch shaft 68 is mechanically interconnected with the first-named shaft l2 through a train of gears comprising, as is best shown in Figs. 7 and 8, a pinion member 16, a cooperating gear, 11, a second pinion 18, and a gear 19 meshing therewith. This last named gear is mounted upon a shaft 86 which carries a disk member 8| near the periphery of which a pin member 82 is mounted. This pin is adapted to fit into a slot 83 in a Geneva-gear element 84, which is mounted upon. the reversing switch shaft 68, and serves to impart motion thereto in a manner to be further explained.

The connections indicated by the simplified diagram of Fig. 11 are established between the transformers, housed in the rear compartment 36 of the regulating unit, and the switching devices, housed in the front compartment 46, through the medium of insulated conductors. Thus the taps a to c of the series winding l4 of each of the transformers are connected by means of leads 90 (Fig. 9) to the stationary segments A to E, inclusive. Similarly, connection from the ends of each tap-bridging transformer winding 20 are made with the movable contact segments X and Y through the medium of leads 9| which are attached to a pair of vertically positioned metal strips 92 and 93 against which strips contact fingers 94 and 95, respectively connected with segments X and Y, are respectively adapted to slidably bear. These fingers are supported from the movable panel of insulating material 58 before mentioned.

Each set of reversing switches, comprising the disk members 64 and 66, is interconnected with the transformer windings and the circuit conductors through the medium of leads 91 in the manner indicated in Figs. 10 and 11. These connections are so made that when the switch disks occupy the intermediate position illustrated, contact finger 10 is electrically connected with both of 'the associated fingers J and M and finger II is similarly connected with the associated fingers L and K. Rotation of the shaft 68 in a counterclockwise direction interrupts the connection of {fingers K and L while rotation of the disk carrying shaft in the clockwise direction similarly interrupts the connection of fingers M and K. i-

Since in Figs. 6 to 11, inclusive, the switching apparatus is illustrated as occupying position No. 5, the carriage panel 58 is there represented at the lower limit of its travel and the reversing switch segments are in their intermediate positions. This combination produces the circuit closures indicated under column 5 of the sequence chart of Fig. 3, for which combination, the voltage of the regulated side of the circuit is equal to that of the supply side, no corrective component being introduced by the series windings l4.

Rotation of the drive shaft 62 causes the carriage assemblage, including contact fingers X and Y, to move upwardly, thereby shifting the connections of tap winding 20 from tap segment E to D, C, B or I}. When the shaft rotation is in one direction, the pin 82, in being rotated by the shaft 80 through the gear mechanism before described, shifts the Geneva gear member 84 to one side of its neutral position, thereby causing the reversing switch disks 64 and 66 to connect the winding l4 in boosting relation to the supply circuit. Similarly, a rotation of the shaft 62 in the opposite direction causes the reversing switch disks 64 and 66 to reverse this connection so that the voltage of winding l4 bucks or opposes that of the supply circuit.

In both instances, the operation of the reversing switches takes place in a circuit of substantially zero voltage so that there is no arcing at the switch contacts. In other words, the connection at the reversing switches is changed before the contact members X and Y have been biased upwardly into active contact with tap segment D.

This operation having been effected, the pin 82 moves out of the slot 83 in the Geneva gear member 64 and does not again contact it until the tap changing equipment has been returned to closely approach position No. 5, at which time re-entry of the pin into the slot takes place, and upon a continuance of rotation of the worm shaft 62, the reversing switch segments are returned to their intermediate position and rotated in the opposite direction and to their other limiting position in which the winding i4 is reversed in its connection between the supply and regulated circuits.

In connection with the tap-changing mechanism, it is to be noted that each of the stationarily mounted tap segments A to E, inclusive, is of a length slightly greater than the spacing between the cooperating movable contact members X and Y, and that the spacing between the adjacently positioned tap segments is slightly less than the spacing between members X and Y. As a result, when the illustrated equipment is in any one of its nine operative positions, both ends of the tap bridging winding 20 are connected to the same stationary tap segment and the resulting desired short-circuiting of the bridging winding is thereby effected without the use of the special or separate switch which heretofore has been required.

As contact-members X and Y are advanced from one stationary tap segment to the next, the leading member contacts the adjacent segment before the lagging member leaves the original segment and in this manner accomplishes the desired tap bridging operation. For the intermediate or transition positions of the equipment, the active circuit through the apparatus is thus established through but one-half of the bridging winding 20, which active circuit is supplemented by a path through the second or other half of the bridging winding as soon as the operating or full-on tap position of the equipment has been reached. I

Although the means for rotating the shaft 62 of the switching assemblage forms no part of the present invention, it may here be pointed out that when a motor such as is shown at 88 in Fig. 7 is utilized to rotate the shaft, the control means for the motor will include, in addition to operation initiating equipment, apparatus adapted to discontinue its operation as soon as it has advanced the switching equipment to the succeeding full-on tap position. In case the correction thereby effected by this single step is insuflicient, initiation of motor operation will again be effected for continuance during a succeeding step. In this manner, it is assured that the equipment will stop only when in the full on-tap positions.

Since all arcing is confined to the tap segments A to E, inclusive, and their cooperating movable members X and Y, the reversing switches may be made of asimpler and less expensive design than were they too to be subjected to arcing duty.

Preferably, as has already been indicated, the casing 46 in which the switching devices are housed is adapted to receive insulating oil, the presence of which oil not only functions to ei-= fectively quench any arcs which tend to be set up at the tap changing switch contacts, but also serves to properly lubricate the moving parts comprised by the several switches and their actuating mechanisms.

Although I have shown and described a certain specific embodiment of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as necessitated by the prior art and by the scope of the appended claims.

I claim as my invention: a

1. Regulating apparatus for adjusting the portion of a multi-tap transformer winding which is in active connection with an electrical circuit and for reversing the connection when said active winding portion is adjusted to zero comin a manner that when rotated it shifts the 4 contact fingers through their extreme position at one end of the segment line in which the winding portion in active circuit is zero, means, comprising switches, for reversing the winding in its connection with the circuit, a. reversingswitch actuating shaft, and means, comprising a Geneva-gear connection between, said two shafts, whereby a movement of the shaft firstnamed through its said zero-winding portion range effects a switch-actuating movement of the second-named shaft.

2. Apparatus for changing from one to another of the taps of a multi-tap transformer winding the connection with a current-carrying electrical circuit comprising, in combination with a tap-bridging impedor, a plurality of contact segments respectively connected with the winding taps and stationarily mounted in, spaced straight-line relation, a pair of impedor-connected contact fingers, a movable member for spacedly supporting said fingers in engageable relation with said segments, and a shaft positioned to parallel said line of contact segments and adapted to threadedly engage said movable member in a manner that when rotated in a given direction it efiects a shifting of the contact fingers from an extreme position at one end of the line of contact segments to a corresponding position at the opposite end of the line and then back to the first-named position.

FRANKLIN L. SNYDER.

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