US3233049A - Integral selector switch and transfer switch unit for tapped regulating transformers - Google Patents

Description

Feb. 1, 1966 A. BLEIBTREU 3,233,049

INTEGRAL SELECTOR SWITCH AND TRANSFER SWITCH UNIT FOR TAPPED REGULATING TRANSFORMERS Filed July 2, 1963 s Sheets-Sheet 1 Wmwrop Alexunder Bleibtreu by Atty- Feb. 1, 1966 A. BLEIBTREU 3,233,049

INTEGRAL SELECTOR SWITCH AND TRANSFER SWITCH UNIT FOR TAPPED REGULATING TRANSFORMERS Filed July 2, 1963 Sheets-Sheet 2 53 l 2,7 I 48 F/GE 28 58 so i I: 62 52 T 30 63 l 47! se ll F 47 i 43 I '2 73 64 /l r I 4| l I t 65C 72L I 72 i 65b? j I j H g 65c 77 Iii l e7 67 1F 1F 66 I so 27 66 39 38 74 Q I F 9| 6 i I .i s H & 1 1 O I V o 34 l 22 I 1 g I s l 7 220 j 37 I I J flvmwroq:

Alexund er Bleibtreu 23 I8 230 33 M X by Atty.

Feb. 1, 1966 .BLEIBTREU 3,233,049

INTEGRAL SELEC SWITCH AND TRANSFER SWITCH T FOR UNI TAPPED REGULATING TRANSFORMERS Filed July 2, 1965 3 Sheets-Sheet 5 & i

Alexander Bleibtreu by An;

United States Patent Ofi ice 3,233,049 INTEGRAL SELECTOR SWITCH AND TRANSFER SWITCH UNIT FOR TAPPED REGULATING TRANSFORMERS Alexander Bleibtreu, Regensburg, Germany, assignor to Maschinenfabrik Reinhausen Gebriider Scheubeck K.G., Regensburg, Germany Filed July 2, 1963, Ser. No. 292,353 Claims priority, application Germany, July 12, 1962, M 53,532 11 Claims. (Cl. 200-11) This invention relates to tap-changing regulating transformers, i.e. transformers including one or more tapped windings which make it possible to regulate the voltage of the transformer. I

Tap-changing regulating transformers include selector switches and transfer switches. The former serve the purpose of selecting any desired tap along a tapped transformer winding intended to be connected into an electric circuit. Selector switches are not required to interrupt current-carrying circuits, or to close on current carrying circuits. These two tasks are assigned to and performed by the transfer switches, i.e. the latter perform all switching operations under load.

The taps of tapped transformer windings are conductively connected to the selector switches. The selector switches are, in turn, conductively connected to the trans fer switches. As a result, tap-changing regulating transformers comprise complex systems of leads between the selector switches and the transfer switches. Since selector switches and transfer switches are generally arranged in different tanks or housings, and since the tanks or housings of transfer switches are generally filled with oil, it is necessary to provide a large number ,of oil tight bushings to conductively interconnect selector switches and the transfer switches.

It is, therefore, one object of the invention to provide switching systems for tap-changing regulating transformers including coordinated and integrated selector switches and transfer switches which systems have simple conductive means for the interconnection of selector switches and their transfer switches.

It is another object of the invention to provide switching systems for tap-changing regulating transformers comprising selector switches and transfer switches which systems form compact structural units that can readily be assembled and disassembled with a minimum of labor and with a minimum of tooling.

Another object of this invention is to provide integral selector switch and transfer switch structures which are constructed substantially symmetrically around a central axis of symmetry and which structures have conductive means arranged substantially along said axis of symmetry for conductively interconnecting its two constituent switch 7 units.

Still another object of the invention is to provide switching systems for tap-changing regulating transformers dispensing with the complex systems of leads or wiring normally found in such switching systems.

Still another object of the invention is to provide switching systems for tap-changing regulating transformers wherein the conductive connections between the selector switches and the transfer switches are shielded and encapsulated and out of the way when access to the same is not needed such as, for instance, when the arcing contacts of the transfer switches are being checked by maintenance personnel and when there is no need to inspect the electrical connections between the selector switches and the transfer switches, these connections being subjected to a minimum of wear and tear.

The above objects and additional objects and advantages of the invention will become more apparentfrom 3,233,049 Patented Feb. 1, 1966 the ensuing description of the invention, and of a specific embodiment thereof, when read in connection with the accompanying drawings.

Referring now to the drawings:

FIG. 1 is a diagrammatic representation of a switching system for a tap-changing regulating transformer embodying the present invention;

FIG. 2 is a vertical section taken along 11 of FIG. 3 and shows a system of the kind shown diagrammatically in FIG. 1 and includes the essential structural details of such a system;

FIG. 3 is a section along.3-3 of FIG. 2; and

FIG. 4 is a section along 4-4 of FIG. 2.

Generally tap-changing regulating transformers comprise three phases and windings for each of the three phases. The tapped winding of each phase is operatively related to a selector switch and to a transfer switch. A tap-changing regulating transformer having three tapped windings comprises therefore three selector switches, one for each tapped winding, and three transfer switches, each transfer switch being connected to one of the three selector switches and each transfer switch switching one phase of the three phase circuit. FIG. 1 shows a tapped transformer winding T pertaining to one phase of a three phase transformer which is Y-connected. The letter Y has been applied to indicate the neutral point of the system and the letter U has been applied in FIG. 1 to indicate that the winding T is a phase winding of a polyphase system U, V, W. Winding T, is provided with a number of taps consecutively numbered 1 to 16. Reference character S has been applied to generally indicate a selector switch connected to the taps of transformer winding T, and reference character T has been applied to generally indicate a transfer switch conductively connected to selector switch S. One terminal of transfer switch T is conductively connected to the neutral point Y of the system. Selector switch S comprises a hollow vertical column 17 of insulating material and a plurality of fixed tap contacts to which reference characters 1 to 16 have been applied. Fixed tap contact 1 is conductively connected bylead 1" to tap 1, fixed tap contact 2' is conductively connected by lead 2" to tap 2, etc., and fixed tap contact 15 is conductively connected by lead 15 to tap 15, and fixed tap contact 16 is conductively connected by lead 16" to tap. 16. No reference characters have been applied in FIG. 1 to taps 3 to 14, inclusive, the numbering of these taps being obvious. Taps 3 to 14, inclusive, are connected by leads to the fixed tap contacts to which the same reference character has been applied with the addition of a prime. The leads conductively connecting taps 3 to 14 to tap contacts 3' to 14' have only been shown in part in FIG. 1 in order not to encumber this figure with an excess of lines. All odd numbered tap contacts 1' to 15' of selector switch S are arranged in a circular pattern on a relatively high level and all even numbered tap contacts 2 to 16 of selector switch S are arranged in a circular pattern on a relatively low level. Contacts 1' to 16' may be arranged in a cylindrical surface indicated in FIG. 1 by two ellipses to which reference character F has been applied. Selector switch S further comprises an upper fixed circular or annular slide contact 18 and a lower fixed circular or annular slide contact 19. The two contact arms or contact bridges 20 and 21 are pivotable about the vertical geometrical axis of column 17. To be more specific, the upper bridge 20 adapted to selectively interconnect any of the odd numbered tap contacts 1' to 15' and annular slide contact 18 has as its fulcrum the point of intersection of the axis of column 17 with the plane of the upper horizontal ellipse F, and the lower bridge 21 adapted to selectively interconnect any of the even numbered taps 3 the point of intersection of the axis of column 17 with the plane of the lower horizontal ellipse F. Each arm or bridge 20 and 21 may be pivoted about its respective fulcrum by appropriate operating means not shown in FIG. 1 and described below in connection with FIG. 2. Annular contact 18 is conductively connected to a current-carrying rod 22 extending ina direction longitudinally of column 17 and ending above in a plug contact 24 adapted to cooperatively engage a female or socket contact 26 forming part of transfer switch T. In like fashion annular contact 19 is conductively connected to a currentcarrying rod 23 extending in a direction longitudinally of column 17 and ending above in a plug contact 25 adapted to cooperatively engage a socket contact 27 forming part of transfer switch T.

Transfer switch T comprises a pair of movable main contact bridges 28 each adapted to conductively interconnect a pair of fixed main contacts 30 and to part from such a pair of main contacts 30. Transfer switch T further comprises a pair of movable auxiliary contact bridges 29 each adapted to conductively interconnect a pair of fixed auxiliary contacts 31 and to part from such a pair of auxiliary contacts 31. All fixed contacts 30 and'31 of I transfer switch T are arranged in a cylindrical surface and all contact bridges 28 and 29 of transfer switch T are adapted to be moved selectively radially inwardly out of engagement with a cooperating pair of fixed contacts and 31, respectively, or radially outwardly into engagement with a pair of cooperating fixed contacts 30 and 31, respectively.

All the upper fixed contacts 30, 31 of transfer switch T are conductively connected to the neutral point Y of the electric system. Transfer switch T further comprises a pair of switch-over resistors 32 hav- 7 ing upper ends each connected to one of the lower pair of fixed auxiliary contacts 31. The lower ends of switching or switch-over resistors 32 and the lower pair of fixed main contacts 30 are conductively connected to female contacts or sockets 26 and 27, respectively, cooperatively engaged by plugs 24 and 25, respectively.

In the position of the parts shown in FIG. 1 the following circuit is established: Tap 6, tap contact 6', bridge 21, annular or ring contact 19, rod 23, plug 25, socket 27, left lower contact 30, left contact bridge 28, left upper contact 30, neutral point Y. Hence tap 6 is effective and all the other taps of the tapped winding T are ineffective.

the contact bridges 28 and 29 of transfer switch T. The

first step consists in engagement of left auxiliary contacts 31 by left auxiliary contact bridge 29. The second step consists in engagement of the right auxiliary contacts 31 by right auxiliary contact bridge 29. Thereupon the left main contact bridge 28 parts from its cooperating fixed main contacts 30. Since the right resistor 32 is connected to tap 15 by the intermediary of contacts 26, 24, rod 22 and contacts 18, 2t) and 5, the closing operation of right auxiliary bridge contact gives rise to a circulating current. This circulating current is superimposed upon the load current and must be interrupted by the operation of transfer switch T. Parting of left main bridge contact 28 from its fixed main contacts 30 is followed by engagement of right fixed main contacts 30 by their cooperating right main bridge contact 28. Thereupon left I auxiliary contact bridge 29 parts from the left auxiliary contacts 31, thus interrupting the above referred to circulating current. Finally right auxiliary bridge 29 may part from its cooperating fixed contacts 31.

FIG. 1 illustrates a so-called pennant transfer switch or briefly P-transfer switch. The gist of pennant transv fer switches of P-transfer switches resides in the fact that prior to interrupting a circuit including a given tap of a tapped transformer winding, another pre-selected tap-in the instant case tap 5is being connected into the circuit by the intermediary of an ohmic resistor. A pennant invention. Other types of transfer switches may be substituted for the pennant transfer switch shown in FIG. 1. Other kinds of transfer switches which may readily take the place of the pennant transfer switch shown in FIG. 1 have been described in the copending patent application of Alexander Bleibtreu, filed January 31, 1963, Ser. No. 255,291, now Patent No. 3,174,097, for Transfer Switch for Tap Changers for Regulating Transformers, and reference may be had to that application for further details regarding other transfer switches which may take the place of the particular transfer switch T shown in FIG. 1.

Assuming now that it is intended to move from tap 6the tap shown to be effective in FIG. 1-to tap 7 rather than to the lower tap 5. This is achieved by pivoting arm 20 in clockwise direction as seen in FIG. 1 from tap contact 5 to tap contact 7' while leaving arm or bridge 21 of selector switch S at rest on tap contact 6. As a result, tap contact 7 is conductively connected to the lower right fixed main contact 31 of transfer switch T by the intermediary of rod 22 and cooperating plug and socket contacts 24 and 26. Subsequent operation of transfer switch T in the fashion which has been described above results in disconnecting neutral point Y from tap 6 and connecting that point to tap 7.

' In FIGS. 24 the same reference characters as in FIG. 1 have been applied to indicate like parts. FIG. 2 shows, in part, three transfer switches and three selector switches, one switch for each phase of a three phase circuit, but the parts pertaining to two of the three phases have been largely omitted in FIG.' 2 in the same general fashion as in FIG. 1'. In FIG. 2 reference character S has been applied to generally indicate a selector switch, reference character T has been applied to generally indicate a transfer switch arranged above selector switch S, and reference character 32 has been applied to generally indicate a plurality of switch-over resistors arranged above the selector switch S but below the transfer switch T. As shown in connection with FIG. 1 the contact arms or contact bridges of the selector switch S must be operated alternately, i.e. while one of the arms is moved from one of the fixed tap contacts the other arm remains at rest, and vice versa. Such a movement could be effected manually, but is preferably effected by means of an appropriate Geneva gear drive. Reference character G has been applied to generally indicate the housing of a Geneva gear drive for operating the selector switch S arranged below the Geneva gear drive.

'The selector switch S comprises a vertical column 17 of insulating material housing a plurality of vertical currentcarrying rods. FIG. 2 shows two of these rods to which reference numerals 22 and 23 have been applied and FIG. 3 shows three pairs of such rods, one for each phase of a three phase circuit. The two rods 22, 23 shown in FIG. 2 pertain to one phase of a three phase circuit, as explained in connection with FIG. 1. A three phase selector switch and transfer switch system therefor comprises a total of six current carrying rods as clearly shown in FIG. 3. The lower end of current-carrying rod 22 is inserted into a terminal 33. The latter is conductively connected to fixed annular slide contact 18 which is adapted to be engaged by a contact bridge pivotable about the axis of column 17 and having a radially outer end adapted to selectively engage any'of a group of fixed tap contacts in the fashion shown in FIG. 1 and described in connection with that figure. The contact bridge 20 (see FIG. 1) engaging annular contact 18 may be operated by 34, and reference numeral 15' has been applied to that fixed tap contact for indicating the latter. The vertical current-carrying rod 23 is conductively connected to a lower annular contact not shown in FIG. 2 but shown in FIG. 1 and designated therein by the reference numeral 19 and in operative engagement with a contact bridge 21. The contact bridge 21 of FIG. 1 is operated by the vertical insulating rod 37 of FIG. 2 which, in turn, is operated by gear 38 arranged in gear housing G. Other details of selector switch S are preferably designed in accordance with the disclosure made in the copending patent application of Alexander Bleibtreu, filed December 13, l962, Ser. No. 246,289 for Selector Switch for Tapped Regulating Transformers and reference may be had to this application for such details. The upper end of insulating column 17 is closed by a closing member 39 of metal and rods 22 and 23 project from the inside of column 17 transversely through closing member 39 to the outside of column 17. To this end rods 22 and 23 are wrapped in insulating material, i.e. they are surrounded by tubular insulators 22a, 234 which form bushings jointly with rods 22 and 23.

The transfer switch T of FIG. 2 comprises four movable bridge contacts corresponding to contacts 28 and 23 of FIG. 1. FIG. 2 shows but one of these bridge contacts to which reference character 28 has been applied. Contact bridge 28 is adapted to be moved radially outward into engagement with a pair of fixed contacts 30 or radially inward out of engagement with fixed contacts 30.

The three phase transfer switch T shown in FIGS. 2-4 further comprises a cylindrical tank accommodating a coaxial supporting structure. That structure includes a bottom frame member 41, a top frame member 42 and a plurality of vertical rods or bars 43 of insulating material. The latter are angularly displaced and spaced and supported by frame members 41. 42. Thus parts 41, 42, 43 form a squirrel cage structure. Tank 40 may contain, and will normally contain, a body of oil (not shown). Terminal 44 is integral with tank 1 which may be made of a appropriate insulating material. This terminal is intended to connect the transfer switch to the neutral point of the regulating transformer indicated by reference character Y. i If tank 1 is made of a casting resin terminal 44 of the transfer switch T may be in the form of an insert in the casting as shown in the upper left corner of FIG. 2.

Top frame member 42 is made of metal and provided with contacts cooperatively engaging with terminal 44.

A structure substantially in the shape of a second radially inner squirrel-cage is suspended on frame member 42 by means of screws 45. The above mentioned second structure substantially in the shape of a squirrel-cage comprises the upper plate member 46, the lower plate member 47 and three conductive vertical bars 48 extending parallel to the common axis of tank 1 and first squirrel- cage structures 41, 42, 43. Bars 48of which but one is shown in FIG. 2-enclose angles of 360/ 3:120 degrees. The upper end plate 53 and the lower end plate are fixedly mounted upon, and pivotable jointly with, operating shaft 49 for contact bridges 28, 29, which shaft rests in bearings 50, 51. Shaft 49 is arranged in coaxial relation to tank 4%) and to insulating column 17 and to squirrel- cage structures 41, 42, 43 and 46, 47, 48, respectively. Rods 52-of which but one is shown in FIG. 2 and of which one is provided for each phaseare spaced from shaft 49 and extend parallel to shaft 49. The upper ends and the lower ends of rods 52 are loosely guided by the upper end plate 53 and the lower end plate 55, respectively. The upper ends of rods 52 are mechanically tied to the upper end plate 53 by means of helical tension springs 54 of which but one is shown in FIG. 2. In like fashion the lower ends of rods 52 are mechanically tied to the lower end plate 55 by means of helical tension springs 56 of which but one has been shown in FIG. 2. Reference numeral 57 has been applied to indicate a plurality of upper contact operating arms and reference numeral 58 has been applied to indicate a plurality of .lower contact operating arms. Each contact operating L arm 57, 58 has. a radially inner bearing 59 and a radially outer bearing 60. Rods 59 extend through the radially inner bearings 59 of contact operating arms 57, 58. The bearings 60 on the radially outer ends of each pair of contact operating arms 57, 58 support a vertical rod 61 which, in turn, pivotally supports a contact carrier 62. Contact carriers 62 insulatingly support the aforementioned contact bridges 28 and 29 extending parallel to operating shaft 49 of which but one is shown in FIG. 2. The aforementioned upper and lower plate members 46, 47 are provided with radially extending slots or grooves 46, 47, respectively, engaged by and guiding the upper and the lower ends of contact carriers 62. Because of this function of plate members 46, 47 the same may be referred-to as guide plates.

As mentioned above the upper end of each contact bridge 28, 29 and the lower end of each contact bridge 28, 29 are adapted to cooperate with a pair of fixed contacts 3t) and 31, respectively of which but one pair 30 is shown in FIG. 2. Each pair of fixed contacts 30, 31 is supported by one of the aforementioned vertical bars 43 forming part of squirrel- cage structure 41, 42, 43. As mentioned above, bars 43 are made of an appropriate insulating material and they are preferably H-shaped in cross-section. Thus each bar 43 defines a radially inner channel-shaped space and a radially outer channel-shaped space. Contacts 38, 31 are accommodated in the radially inner channel-shaped spaces defined by bars 43. Contacts 3t), 31 are supported in position on bars 43 by means of screws 63, or equivalent fasteners. As shown in FIG. 2 the heads of these screws 63 are located in the radially outer channel spaces defined by rods or bars 43. Therefore the heads of the screws 63 supporting fixed contacts 30, 31 are readily accessible from the outside of radially outer cage structure 41, 42, 43. The same applies as to screws 64, or equivalent fasteners, securing insulating bars 43 to parts 41 and 42.

The circuitry of FIG. 1 calls for the provision of four contact carriers 62 and of four contact bridges 28, 29

and of four pairs of fixed contacts 30, 31 per phase. In other applications the number of contact carriers, contact bridges and of pairs of fixed contacts per phase may be smaller than four, or larger than four. Thus the structure of FIG. 2 may include six pairs of fixed contacts and six movable contact bridges per phase.

The current path of the. transfer switch T of FIG. 2 is substantially the same as explained in connection with FIG. 1. The current path extends through lower fixed arcing contacts 30, contact bridges 28 and upper fixed contacts 30. Upper fixed contacts 30 are conductively connected by leads not shown in FIG. 2 to element 42 which, in turn, is conductively connected to the neutral point Y of the three phase system by the intermediary of terminal 44.

The kinematic theory underlying the structure of FIG. 2 is set forth in detail in United States Patent 2,680,790 to Bernhard Jansen, June 8, 1954 for Load Changeover Swith for Tapped Transformers Using acombination of Contact Movements and reference may be had to that patent for additional information regarding this subject. The operation of the structure of FIG. 2 is briefly as follows: Pivotal movement of operating shaft 49 results in pivotal or rotary motions of end plates 53, 55 transmitted to rod or shafts 52. The pivotal motion of rods or shafts 52 about the vertical axis of transfer switch T causes movement of contact carriers 62 relative to guide plates 46, 47, the upper and lower ends of contact carriers 62 sliding in grooves 46, 47 of guide plates 46, 47. As a result, contact bridges 28 and 29, respectively, are moved in the proper sequence radially either outwardly into engagement with fixed contacts 30, 31, or inwardly out of engagement with these fixed contacts. I

It will be apparent from the foregoing that transfer switch T and selector switch S dispense entirely with .fiexible connections, or braids, for connecting the movable contact bridges 28 and 29 to annular contacts 18, 19;.

Since contact bridges 28, 29 are insulated from their supports 62 all the movable parts within the transfer switch T may be made of metal rather than of insulating material which greatly contributes to the ruggedness of transfer switch T. The ruggedness of transfer switch T is due in particular to the presence of the squirrel-cage type structure comprising guide plates 46, 47 and the three conductive squirrel-cage bars 48.

Though the double break feature embodied in the structure of FIGS. 1 and 2 greatly increases the life of the cooperating pairs of contacts 28, 30 and 29, 31, respectively, it is of great importance to be able to readily obtain access to all parts of the switch which are subjected to wear and tear. Heretofore the inspection and/ or replacement of the radially outer fixed contacts was a relatively difiicult task, requiring a radially inward retraction of the contact bridges and their supporting structures. Performance of this task calls for special tools and highly skilled labor. The structure of FIGS. 1-4 greatly facilitates inspection and/or replacement of fixed contacts 30, 31. All that is required to this end is removal of the contact supporting insulating bars 43 from parts 41 and 43. This can readily be achieved since the heads of barsupporting screws 64 are arranged on the radially outer surfaces of bars 43.

Bearing 51 for operating shaft 49 is arranged on a hearing support 65b which, in turn, is supported by insulating member 41 forming part of the aforementioned cage 41, 42, 43. Insulating cylinder 65 is arranged in coaxial relation to insulating tank 40 and insulating column 17 of switch S and further arranged below part 41 and bearing support 65b. Cylinder 65 is suspended by means of screws 65a from parts 41, 65b and arranged in the lower portion of insulating tank 40 not occupied by transfer switch T. The vertical duct 65c defined by insulating cylinder 65 accommodates a plurality of pairs of female contacts 26, 27 each cooperatively engaged by the bare upper ends 24 and of contact rods 22 and 23, respectively.

FIG. 4 shows more in detail the plug-in contact means for conductively connecting selector switch S and transfer switch T. In FIGS. 2 and 4 reference character 66 has been applied to indicate means defining ducts for guiding the bare upper ends 24, 25 of conductor rods 22, 23. The female contact means 26, 27 include superimposed pairs of spring biased horizontal finger contacts 67 hugglng rod contacts or plug contacts 24, 25. Female contact means 26, 27 further comprise a base 68 supported by insulating cylinder 65 on the inside thereof. Current is conducted from finger contacts 67 to base 68 through the intermediary of flexible conductors or braids 70. The upper ends of bases 68 form terminals for leads 69 (FIG. 2) included in the current paths from selector switch S to transfer switch T. The upper side of insulating cylinder 65 defines a pair of slots '72 each for the passage of one of the pair of leads 69 from the inside of insulating cylinder 65 to the outside thereof. Transfer switch T may be provided, in addition to the arcing contacts shown in FIG. 1 and described in connection therewith, with cooperating pairs of relatively movable current-carrying contacts. Such contacts are designed to shunt the main arcing contacts 28, of FIG. 1. Leads 69 may be connected to the fixed current-carrying contacts of which one has been shown in FIG. 2 and indicated therein by reference numeral 73. For a more detailed disclosure of the arrangement of current-carrying contacts in a transfer switch of the kind shown in FIGS. 1 and 2 and described in connection therewith reference may be had to the aforementioned copending patent application of Alexander Bleibtreu, filed January 31, 1963, Ser. No. 255,291 for Transfer Switch for Tap Changers for Regulating Transformers.

der 65 supports a pair ofparallel spaced insulating plates- 74, forming supports for the switching resistors generally indicated by reference character 32. Numeral 76 has been applied to indicate rods having ends projecting into registering holes in plates 74 and '75. Thus rods 76 are firmly held in position by plates 74 and 75. Rods 76 surround insulating cylinder 65in form of two concentric shells as clearly shown in FIG. 3. Mounted on each rod 76 is a tubular core 77, preferably made of a ceramic insulating material, and wound around cores 77 are resistance wires 73 to be used as switch-over resistors. Radially extending partitions 79 sub-divide the aforementioned switch-over resistors into groups of five, each such group being substantially in the shape of a sector of a cylinder ring.

Gears 36 and 38 in housing G of FIG. 2 are Geneva gears operated from a vertical shaft 80 by the intermediary of crank shaft 51. Crank shaft 91 is provided with driving pins adapted to engage the slots formed by Geneva gears 36, 38 and the alternate operation of gears 36, 38, operating rods 34, 37- and the contact bridges 20, 21 operated by these rods is due to the angular displacement of the aforementioned driving pins on crankshaft 91. Such Geneva gear drives for alternate operation of the movable contacts of selector switches are generally known in the art and, therefore, need not be described in detail in this context. A Geneva gear drive of this general character has been disclosed in detail in the copending patent application of Alexander Bliebtreu, filed June 18, 1963, Ser. No. 288,- 636, for Improvements in Regulating Transformers, and reference may be had to this application for further details on Geneva gear drives for achieving alternate operation of the movable contacts of selector switches.

The entire switching system T, G, S, is intended to be placed in the transformer tank, i.e. the tank housing the transformer whose circuitry is controlled by the switching system T, G, S.

It will be apparent from the foregoing that the electrical connections between selector switch S and transfer switch T are centrally located and do not encumber the switching system T, G, S and are not in the way of service and repair personnel. The transfer switch T may be lifted as a unit out of insulating tubing or insulating case 40, resulting automatically in a separation of male contacts 24, 25 from female contacts 26, 27. This makes for a very simple disassembly of the switching system T, G, S, and vice versa, a very simple assembly thereof.

Although I have shown and described in considerable detail a specific structure embodying my invention, it is to be clearly understood that the same was merely for the purpose of illustration, and that changes may be made by those skilled in the art without departing from the spirit and scope of the invention as defined in the following claims.

I claim as my invention:

1. A switching system for tap-changing regulating transformers comprising in combination:

(a) a selector switch having a hollow centrally arranged insulating column supporting on the outside thereof a pair of annular fixed contacts, tap contacts circularly arranged around each of said pair of annular contacts and pivotable contact arms for conductively connecting each of said tap contacts to one of said pair of annular contacts;

(b) a transfer switch inside of a cylindrical housing arranged above said selector switch, said transfer switch having circularly arranged fixed contacts, cooperating radially movable contacts, contact operating means for causing relative movement of said fixed contacts and said movable contacts in a predetermined sequence, an operating shaft for operating said movable contacts extending along the axis of said housing, and said transfer switch further including a fixed frame structure inside said housingsupporting said fixed contacts, said movable contacts and said contact-operating means;

(c) means of insulating material defining a vertical duct, said duct defining means being arranged inside of said housing in coaxial relation thereto and below said fixed contacts, movable contacts and said contact-operating means of said transfer switch and integral with said fixed frame structure thereof;

(d) closing means for the upper end of said insulating column of said selector switch; and

(e) means conductively connecting said pair of annular contacts of said selector switch and said fixed contacts of said transfer switch, said connecting 'means including plug contact means having ends inside of said insulating column and projecting upwardly across said closing means into said duct, and said connecting means further including socket contact means arranged inside said duct, supported by said duct defining means and cooperatively engaged by said plug contact means.

2. A switching system for tap-changing regulating transformers comprising in combination:

(a) a selector switch having a centrally arranged hollow insulating column, annular radially inner fixed contact means arranged'immediately adjacent said column in axial relation thereto, radially outer fixed tap contact means circularly arranged around said column, rotatable contact arms for conductively connecting said tap contact means and said annular contact means, and said selector switch further including means for closing the upper end of said column;

(b) a transfer switch inside of a cylindrical housing arranged above said selector switch in coaxial relation to said insulating column thereof, said transfer switch having circularly arranged fixed contacts, radially movable contacts cooperating with said fixed contacts and contact-operating means for causing relative movement between said fixed contacts and said movable contact in a predetermined sequence, said transfer switch further having a fixed frame structure supporting said fixed contacts, said movable contacts and said contact-operating means and said transfer switch further including an operating shaft for said contact operating means extending along the axis of said housing;

(c) means of insulating material defining a vertical duct, said duct-defining means being arranged inside said housing of said transfer switch in coaxial relation thereto below said transfer switch and integral with said fixed frame structure thereof; and

(d) means conductively interconnecting said annular fixed contacts of said selector switch to said transfer switch, said interconnecting means including bushings supported by said closing means for the upper end of said column, said bushings including vertical rods projecting, from the inside of said column transversely through said closing means to the outside of said column, and said interconnecting means further including female contacts arranged in said vertical duct, supported by said duct-defining means and cooperatively engaged by the upper ends of said rods. 7

3. A switching system for tap-changing regulating transformers comprising in combination:

(a) a rotary selector switch including a plurality of circularly arranged tap contacts, a hollow insulating column arranged coaxially to said plurality of tap contacts and terminals situated inside of said column for connecting said selector switch to a transfer switch;

(b) a cylindrical housing arranged above said column in coaxial relation thereto;

(c) a transfer switch arranged inside said housing occupying but the upper portion thereof, said transfer switch including circularly arranged fixed contacts, radially movable contacts cooperating with said fixed contacts and contact-operating means for causing engagement and disengagement of said fixed contact and said movable contacts in a predetermined sequence, said transfer switch further including a driving shaft for said contact-operating means arranged in coaxial relation to said column and to said housing;

(d) means of insulating material defining a vertical duct coaxial to said column, said duct-defining means occupying but the lower portion of said housing and separating said duct from a radially outer space of said lower portion of said housing;

(e) a plurality of current-limiting switching resistors to be inserted into the current path leading from said selector switch to said transfer switch during a switching operation of said transfer switch arranged inside said radially outer space of said lower portion of said housing;

(f) closing means for the upper end of said insulating column of said selector switch; and

(g) means for conductively connecting said selector switch terminals to said transfer switch and said switching resistors, said connecting means including a plurality of electrically insulated vertical rods extending from the inside of said column across said means into said duct, and said connecting means further including a plurality of female contacts arranged inside said duct, supported by said duct-defining means and each cooperatively engaged by the upper end of one of said plurality of rods.

4. A switching system for tap-changing regulating transformers comprising in combination:

(a) a rotary type selector switch including a central vertical insulating column having a closing structure at the upper end thereof and having radially outer tap contacts and radially inner annular contacts arranged around said insulating column in coaxial relation thereto, said selector switch further including radially extending pivotable contact arms for conductively connecting said tap contacts and said radially inner annular contacts;

(b) a plurality of bushings projecting transversely through said closing structure each having an inner conductor conductively connected with the lower end thereof to one of said radially inner annular contacts;

(c) a rotary type transfer switch having a frame structure supporting all the contact making and the contact breaking parts thereof and including an operating shaft arranged above said selector switch in coaxial relation to said insulating column thereof;

((1) a tubular insulating structure depending from said frame structure of said transfer switch and arranged above said selector switch in coaxial relation to said insulating column thereof;

(e) means for conductively interconnecting said selector switch and said transfer switch, said interconnecting means including a plurality of female contact structures placed inside of and supported by 'said cylindrical insulating structure and circularly arranged around the common axis of said insulating column of said selector switch and of said transfer switch; and

(f) the upper end of said inner conductor of each of said plurality of bushings forming a plug contact cooperatively engaging one of said plurality of female contact structures.

5. A switching system for tap-changing regulating transformers comprising in combination:

(a) a rotary type selector switch including a central vertical insulating column having a closing structure at the upper end thereof and having radially outer tap contacts and radially inner annular contacts arranged around said insulating column in coaxial relation thereto, said selector switch further including radially extending pivotable contact arms for conductively connecting said tape contacts and said radially inner annular contacts;

(b) a plurality of bushings projecting transversely through said closing structure each having an inner conductor rod conductively connected with the lower end thereof to one of said radially inner annular contacts;

(c) a rotary type transfer switch having a frame structure supporting all the contact making and contact breaking parts thereof and including an operating shaft arranged above said selector switch in coaxial relation to said insulating column thereof;

((1) a tubular insulating structure depending from said frame structure of said tnansfer switch and arranged above said selector switch in coaxial relation to said insulating column thereof;

(e) a plurality of interconnecting structures placed inside of and supported by said tubular insulating structure and arranged circularly around the axis thereof, each of said plurality of interconnecting structures including a radially inner portion in the form of a female contact and a radially outer portion in the form of a terminal for a lead connecting said female contact to a point of said transfer switch; and

(f) the upper end of said conductor rod of each of said plurality of bushings forming a plug contact cooperatively engaging said female contact of one of said plurality of interconnecting structures.

6. A switching system for tap-changing regulating transformers comprising in combination:

(a) a rotary type selector switch including a central vetrical insulating column having a closing structure at the upper end thereof and having radially outer tap contacts and radially inner annular contacts arranged around said insulating column in coaxial relation thereto, said selector switch further including radially extending pivotable contact arms for conductively connecting said tap contacts and said radially inner annular contacts;

a (b) a plurality of bushings projecting transversely through said closing structure each having an inner conductor conductively connected with the lower end thereof to one of said radially inner annular contacts;

(c) a rotary type transfer switch having a frame structure supporting all the contact making and the contact breaking parts thereof and including an operating shaft arranged above said selector switch in coaxial relation to said insulating column thereof;

(d) an insulating structure depending from said frame structure of said transfer switch and defining a vertical duct having a longitudinal axis, said insulating structure being arranged above said selector switch in coaxial relation to said insulating column thereof;

(e) means for conductively interconnecting said selector switch and said transfer switch, said interconnecting means including a plurality of contact structures placed inside said duct and supported by said insulating structure and circularly arranged around said longitudinal axis of said duct; and

(f) the upper end of said inner conductor of each i of said plurality of bushings forming a plug contact cooperatively engaging one of said plurality of contact structures.

7. A switching system as specified in claim 6 wherein said insulating structure supports current-limiting switchover resistors conductively connected to said transfer switch to be inserted during switching operations of said transfer switch into current paths including said inner conductor of each of said plurality of bushings.

8. A switching system as specified in claim 6 wherein said insulating structure supports a pair of spaced horizontal insulating plates and wherein said insulating plates support current-limiting wire switch-over resistors conductively connected to said transfer switch to be inserted during switching operations of said transfer switch into current paths including said inner conductor of each of said plurality of bushings, said resistors being arranged in substantially concentric shells around said insulating structure.

9. A switching system for tap-changing regulating transformers comprising in combination:

(a) a transfer switch including a cylindrical container,

a plurality of pairs of superimposed registering fixed contacts arranged in a cylindrical surface coaxial with and spaced from said container, a plurality of sequentially operable vertical contact bridges each adapted to be moved radially outwardly inside of said container and to be moved radially inwardly inside of said container to engage one of said plurality of pairs of fixed contacts and to part from one of said plurality of pairs of fixed contacts, operating means for said contact bridges comprising a vertical shaft, and a frame structure for supporting said fixed contacts, said contact bridges and said operating means thereof;

(b) an insulating structure defining a vertical duct depending from said frame structure of said transfer switch and arranged in coaxial relation to said cylindrical container thereof;

(c) a rotary type selector switch operatively related to said transfer switch and arranged below said insulating structure, said selector switch including a central vertical insulating column having a closing structure at the upper end thereof and having radially outer tap contacts and radially inner annular contacts arranged around said insulating column in coaxial relation thereto, said selector switch further including radially extending pivotable contact arms for conductively connecting said tap contacts and said radially inner annular contacts;

((1) a plurality of bushings projecting transversely through said closing structure each having an inner conductor conductively connected with the lower end thereof to one of said radially inner annular contacts and projecting with the upper end thereof into said vertical duct defined by said insulating structure; and

(e) means for conductively interconnecting said selector switch and said transfer switch, said interconnecting means including a plurality of female contact structures placed inside said duct and supported by said insulating structure, each of said plurality of female contact structures being cooperatively engaged by the upper end of said inner conductor of one of said plurality of bushings.

10. A switching system for tap-changing regulating transformers comprising in combination:

(a) a selector switch including circularly arranged fixed tap contacts, a pair of fixed annular contacts arranged in coaxial relation to said tap contacts and a pair of pivota'ble contact arms for selectively connecting each of said tap contacts to one of said pair of annular contacts;

(b) a transfer switch arranged above said selector switch and including pairs of circularly arranged fixed contacts, radially movable contact bridges cooperating with said pairs of fixed contacts and contact-operating means for sequentially operating said contact bridges in a predetermined sequence;

(0) a frame structure supporting said pairs of fixed contacts, said movable contact bridges and said contact-operating means of said transfer switch;

(d) a cylindrical housing for said frame structure, said pair of fixed contacts, said contact bridges and said contact-operating means arranged in coaxial relation to said pair of annular contacts;

(e) a first tubular insulating member arranged inside said housing in coaxial relation thereto and integral with said frame structure;

(f) a second tubular insulating member arranged outside of said housing below said first insulating member in coaxial relation thereto supporting said pair of annular contacts of said selector switch;

(g) a closing structure for the upper end of said second insulating member; and

(h) means for conductively connecting said pair of annular contacts of said selector switch to said pairs of fixed contacts of said transfer switch, said connecting means including bushings projecting across said closing structure for said upper end of said second insulating member, said bushings having internal conductor rods extending into said first insulating member, and said connecting means further including cooperating male and female disconnect contacts arranged inside of said first insulating member.

11. A switching system for tap-changing regulating transformers comprising in combination:

(a) a selector switch including a plurality of circularly arranged tap contacts, a pair of fixed annular contacts arranged in coaxial relation to said plurality of tap contacts and a pair of pivotable contact arms for selectively connecting each of said plurality of tap contacts to one of said pair of annular contacts;

(b) a transfer switch arranged above said selector switch and including pairs of circularly arranged fixed contacts, radially movable contact bridges cooperating with said pairs of fixed contacts and contact-operating means for sequentially operating said contact bridges in a predetermined sequence;

(c) a frame structure supporting said pairs of fixed contacts, said movable contact bridges and said contact-operating means of said transfer switch;

(d) a cylindrical housing for said frame structure, said pairs of fixed contacts, said contact bridges and said contact-operating means arranged in coaxial relation to said pair of annular contacts of said selector switch;

(e) a first vertical tubular insulating member arranged inside said housing suspended (from said frame structure and open at the lower end thereof;

(f) a second vertical tubular insulating member arranged outside said housing below said first insulating member in coaxial relation thereto supporting said pair of annular contacts of said selector switch;

(g) means for closing said second insulating member at the upper end thereof;

(b) a pair of bushings projecting transversely across said closing means and including a pair of contact rods each having a lower end conductively connected to one of said pair of annular contacts of said selector switch and having an upper end projecting into said first tubular insulating member; and

(i) a pair of female disconnect contacts conductively connected to said pairs of fixed contacts of said transfer switch, arranged inside of said first tubular insulating member and each engaged by said upper end of one of said pair of contact rods.

References Cited by the Examiner UNITED STATES PATENTS 1,666,729 4/1928 Biek et a1. 339196 1,935,163 11/1933 Parsons 338302 X 1,985,927 1/1935 Jansen.

2,680,790 6/ 1954 Jansen 200--6 2,697,212 12/1954 Castelli 339l76 X 3,020,518 2/1962 Camping et a1. 339191 3,034,542 5/1962 Blanco.

3,054,080 9/1962 Jepson 339196 X KATHLEEN H. CLAFFY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

Claims (1)

1. A SWITCHING SYSTEM FOR TAP-CHANGING REGULATING TRANSFORMERS COMPRISING IN COMBINATION: (A) A SELECTOR SWITCH HAVING A HOLLOW CENTRALLY ARRANGES INSULATING COLUMN SUPPORTING ON THE OUTSIDE THEREOF A PAIR OF ANNULAR FIXED CONTACTS, TAP CONTACTS CIRCULARLY ARRANGED AROUND EACH OF SAID PAIR OF ANNULAR CONTACTS AND PIVOTABLE CONTACT ARMS FOR CONDUCTIVELY CONNECTING EACH OF SAID TAP CONTACTS TO ONE OF SAID PAIR OF ANNULAR CONTACTS; (B) A TRANSFER SWITCH INSIDE OF A CYLINDRICAL HOUSING ARRANGED ABOVE SAID SELECTOR SWITCH, SAID TRANSFER SWITCH HAVING CIRCULARLY ARRANGED FIXED CONTACTS, COOPERATING RADIALLY MOVABLE CONTACTS, CONTACT OPERATING MEANS FOR CAUSING RELATIVE MOVEMENT OF SAID FIXED CONTACTS AND SAID MOVABLE CONTACTS IN A PREDETERMINED SEQUENCE, AN OPERATING SHAFT FOR OPERATING SAID MOVABLE CONTACTS EXTENDING ALONG THE AXIS OF SAID HOUSING, AND SAID TRANSFER SWITCH FURTHER INCLUDING A FIXED FRAME STRUCTURE INSIDE SAID HOUSING SUPPORTING SAID FIXED CONTACTS, SAID MOVABLE CONTACTS AND SAID CONTACT-OPERATING MEANS; (C) MEANS OF INSULATING MATERIAL DEFINING A VERTICAL DUCT, SAID DUCT DEFINING MEANS BEING ARRANGED IN SIDE OF SAID HOUSING IN COAXIAL RELATION THERETO AND BELOW SAID FIXED CONTACTS, MOVABLE CONTACTS AND SAID CONTACT-OPERATING MEANS OF SAID TRANSFER SWITCH AND INTEGRAL WITH SAID FIXED FRAME STRUCTURE THEREOF; (D) CLOSING MEANS FOR THE UPPER END OF SAID INSULATING COLUMN OF SAID SELECTOR SWITCH; AND (E) MEANS CONDUCTIVELY CONNECTING SAID PAIR OF ANNULAR CONTACTS OF SAID SELECTOR SWITCH AND SAID FIXED CONTACTS OF SAID TRANSFER SWITCH, SAID CONNECTING MEANS INCLUDING PLUG CONTACT MEANS HAVING ENDS INSIDE OF SAID INSULATING COLUMN AND PROJECTING UPWARDLY ACROSS SAID CLOSING MEANS INTO SAID DUCT, AND SAID CONNECTING MEANS FURTHER INCLUDING SOCKET CONTACT MEANS ARRANGED INSIDE SAID DUCT, SUPPORTED BY SAID DUCT DEFINING MEANS AND COOPERATIVELY ENGAGED BY SAID PLUG CONTACT MEANS.

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