Abstract: A tap changer has a bypass switch with a rotary pair of movable contacts engaging arc segmental fixed contacts of a length greater than the spacing between the movable contact which spacing is greater than the spacing between the fixed contacts of the bypass switch.

Abstract: The invention relate to a position signaling layout for a motor drive which also serves to activate an on-load tap changer, an off-circuit tap changer or a plunger core coil. Position signaling devices of this kind detect the position at a given time of the on-load tap changer or similar and transmit this information in the form of an electric signal. According to the invention, the device consists essentially of a board on which there are fixed signaling contacts and a pivoted cam disc which connects said fixed contacts electrically and links them to a terminal lead via a spring operated switch, activating the spring operated switch by means of its front cam contour.

Abstract: A multiphase reactor-switching tap selector has a single geneva mechanism operating three shafts which traverse phase plates carrying all of the contacts and the vacuum switching cell and rapid release mechanism for each of the phases. The geneva mechanism operates the tap selection contacts directly through its shaft and is coupled to other shafts for operating the preseslector contacts, the bypass contacts and the vacuum switching cells. All three shafts traverse all of the phase plates.

Abstract: A load switch has a housing, a pair of main contacts fixed in the housing, and a movable main contact pivotal on the housing between end positions in each of which it engages a respective one of the fixed contacts and through a middle position in which it engages neither of the fixed contacts. A central shaft extending along an axis and pivotal in both directions thereabout carries a cam having offset from the axis a cam formation. A mechanical link engaged between the cam formation and the movable contact can pivot it between its end positions and through its middle position on rotation of the cam about the axis.

Abstract: A center bolt LBOR switch 12 comprising a support ring 12-4 and a center bolt or threaded boss 12-2, and a nut 12-3 for securing the switch 12 to a transformer tank wall is disclosed. The disclosed invention allows a switch or other device to be mounted to the wall of a transformer tank without welding and without distorting the tank wall.

Abstract: An on-load tap changer of a step switch has a force-storage unit which has a charging slide continuously movable by a bidirectionally rotatable drive shaft and an output part that when tripped suddenly follows the movement of the charging slide and rotates a switching shaft. Respective switches for each phase are each actuatable by respective actuating elements that coact with edges of respective concentric cams rotatable by the switching shaft. An axially movable switching unit is mounted on the switching shaft and the switching unit carries cam disks for actuating the switches, each cam disk being subdivided into an upper and a lower subdisk with different shapes. The switching unit is movable in a direction dependent on the rotation direction of the drive shaft into an upper or a lower position.

Abstract: The invention concerns a switching arrangement for load change-over switches of step switches and for selector switches, wherein two switching contacts movable in two directions are present. The first switching contact is in the form of a main switching contact and is connected to the load derivation by means of a first vacuum switchgear cell. The second switching contact is in the form of a resistance switching contact which is likewise connected to the load derivation by means of a series connection comprising a second vacuum switchgear cell and a transition resistor. Both the main and the resistance switching contacts can be moved independently of one another and without mutual coupling or influence. The main switching contact always reaches the new fixed contact abruptly and independently of the switching direction before the resistance switching contact leaves the previous fixed contact.

Abstract: A tap changing circuit has each tap of a power transformer connected with a selector vacuum switching cell. The odd numbered cells and the even numbered cells are connected to respective sides of a load switch each including a further vacuum switching cell. The sides are bridged by a transition inductor or resistor.

Abstract: A load tap changer (LTC) comprising in part a diverter switch is disclosed. The diverter switch includes a movable main contact (38); first and second fixed main contacts (40a, 40b); a pantograph system (30) for translating a rotational motion of a shaft (22) to a substantially linear motion of the movable main contact; and a link system (10) comprising a gear (12) adapted to be rotated by a motor, a spring battery (26) for storing energy of the motor, link means (14, 16, 18) for coupling the gear to the spring battery, and the shaft (22) coupled to the link means, wherein the spring battery is operable to rotate the shaft and to thereby effect the movement of the movable main contact. A predetermined amount of rotation of the shaft effects a movement of the movable main contact from a contacting relation with the first fixed main contact to a contacting relation with the second fixed main contact.

Abstract: A vacuum switch bulb type change over switch of the invention is used for an on-load tap changer for changing over from a tap to a tap in an on-load state. The change over switch is formed of a plurality of single phase switch cassettes, and a common controller for the switch cassettes. Each cassette includes a plurality of vacuum switch bulbs and a plurality of coupling devices for the vacuum switch bulbs. The common controller includes a plurality of holding devices for holding the vacuum switch bulbs in an opened or a closed state to thereby hold the taps in predetermined states. The single phase switch cassettes are independently mounted on and coupled with the common controller through the holding device.

Abstract: The invention relates to a load selector for step switches in step transformers with two movable selector contacts. A suitable vacuum switch is located downstream of the first movable selector contact to switch the load current and a suitable switch for switching the compensation current is located downstream of the second movable selector contact. Both of the selector contacts are independently movable in such a way that one of the selector contacts moves slowly and the other selector contact rapidly moves or jumps between positions. The sequence of operation of the selector contacts is independent of the switching direction.

Abstract: A tap selector for an on-load tap changer includes two tap selector shafts (3, 4) made of metallic material and placed inside current collector rings (22). Movable contacts (6, 7) of the selector are supported by the shafts (3, 4) via contact holders (8) of insulating material. Between each current collector ring (22) and the shafts (3, 4) an insulating ring (21) is arranged. The fixed contacts (11) of the selector are supported by an electrically insulating, circular hollow cylinder (9) with a closed circumference, the contacts (11) being fixed to the cylinder wall by axial deformation. The cylinder (9) is provided with holes (10) for inspection and mounting. Each current collector ring (22) is connected by a screw joint to a current collector arm (24), which projects through a hole in the cylinder wall (9). Axial adjustment of the current collector arm (24) can be achieved by making the contact surfaces (25, 26) between the arm (24) and the ring (22) in the screw joint circularly curved in shape.

Abstract: A cast-resin transformer has a transformer housing, a plurality of windings each having a plurality of taps, respective contacts connected to the taps and mounted on the housing in respective arrays which are all identical, and respective identical mounting elements on the housing at each of the contact arrays. Respective identical step switches each serve a respective winding of the transformer and each have a switch housing secured to the respective mounting element of the transformer housing at the respective contact array and a step contact movable along the respective connector elements and electrically engageable therewith. A drive motor and a main shaft are connected to all of the step contacts for synchronously stepping the step contacts along the respective connector elements.

Abstract: A step-transformer selector has a generally cylindrical drum centered on an axis and provided with an annular array of selector contacts and, axially offset therefrom, with at least one polarity contact offset axially from the selector contacts. A selector shaft extends along the axis in the drum and rotatable about the axis to connect to selected ones of the selector contacts. A polarity switch having a pivot in the drum offset from the axis and a ring can rock in the drum on the pivot between a connecting position touching and connecting to the polarity contact and an out-of-service position offset from and out of contact with the polarity contact. A cam on the shaft engages a follower on the ring for rocking the ring from its out-of-service position into its connecting position at least once during each rotation of the shaft about the axis.

Abstract: A tap selector anti-arcing system is used with rotary tap selectors to prevent arcing as the selectors move from one tap to the other. A lockout mechanism includes a pair of lever arms located adjacent two Geneva gears. The Geneva gears include pins disposed on opposed sides thereof to actuate one lever arm to thereby move the other lever arm to interferingly engage the pin on the other gear if the gears move simultaneously to engage the neutral and eighth taps. An interrupter is opened by linkage connected to a cam disposed on the drive mechanism for the Geneva gears to open the circuit during the movement of the Geneva gears from one tap to another.

Abstract: A stepper drive for a step-type transformer has an upper geneva wheel rotatable about a wheel axis, a lower geneva wheel spaced below the upper wheel and also rotatable about the axis, and a driver rotatable about a driver axis adjacent the wheels and having an upper abutment engageable with the upper wheel and a lower abutment engageable with the lower wheel and offset by about 180.degree. relative to the driver axis from the upper abutment. A selector abutment is provided on the upper wheel offset from the axis thereof. A selector lever pivotal about a selector axis offset from the wheel axis is engageble with the selector abutment in end positions of the upper wheel. A blocking plate shiftable radially on the lever between an actuated position and an unactuated position is urged by a spring into the unactuated position.

Abstract: A puffer switch has a cylindrical shell filled with an electrically insulating gas, such as sulphur hexafluoride. A plurality of spaced parallel plates cooperating with the shell for defining a separate compression chamber or volume for each phase of an electrical power circuit that is to be switched. Located in each volume is at least one set of contacts which are subject to arcing as the contacts open or close. A movable contact in each of the sets of contacts has an associated impeller blade which is mounted to rotate with the movable contact and to sweep through the volume for compressing insulating gas in front of the impeller blade. A nozzle associated with the impeller blade directs the compressed insulating gas onto the set of contacts at a point where the arc is possible. The switch is assembled in a low cost manner by supporting spaced parallel plates defining the volumes between them as a slip-in unit which fits into a shell. A thermosetting plastic is used for parts which become hot.

Abstract: A switching system for a step transformer having at least two adjacent taps and a pair of terminals shiftable between the taps has a pair of fixed contacts normally connected to the terminals, a vacuum interrupter connected between the terminals and displaceable between an open-circuit position and a closed-circuit position, a pair of movable contacts each engageable with a respective one of the fixed contacts and forming therewith a respective bypass switch, and a cam rotatable about a cam axis and having a contact face and an axially oppositely facing interrupter face each formed with a respective operating formation. A drive rotates the cam about its axis through steps of a half revolution. A respective cam follower engaged between each of the movable contacts and the contact-face formation opens and closes one of the bypass switches on rotation of the cam through a half revolution and thereafter opens and closes the other of the bypass switches on rotation of the cam through a succeeding half revolution.

Abstract: A tap selector anti-arcing system is used with rotary tap selectors to prevent arcing as the selectors move from one tap to the other. A lockout mechanism includes a pair of lever arms located adjacent two Geneva gears. The Geneva gears include pins disposed on opposed sides thereof to actuate one lever arm to thereby move the other lever arm to interferingly engage the pin on the other gear if the gears move simultaneously to engage the neutral and eighth taps. An interrupter is opened by linkage connected to a cam disposed on the drive mechanism for the Geneva gears to open the circuit during the movement of the Geneva gears from one tap to another.

Abstract: A bridge-contact assembly used in combination with an inner contact ring and a contact terminal of an array concentrically surrounding the ring comprises a contact hoousing rotatable concentrically with and between the ring and array, a pair of bridge-contact jaws extending between the ring and the array and having inner ends gripping the ring and outer ends gripping a one of the terminals of the array, and a contact holder spacedly surrounding the pair of jaws and spacedly surrounded by the contact housing. At least one jaw spring supports the jaws in the holder and urges the jaws together and at least one holder spring supports the holder in the contact housing.

Abstract: A switch apparatus including a main housing, a fixed contact supported by the main housing, a shaft supported by the main housing for pivotal movement relative thereto, a movable contact supported by the shaft for common movement therewith, and a motor assembly for moving the shaft relative to the main housing between a closed position wherein the movable contact engages the fixed contact and an open position wherein the movable contact is spaced from the fixed contact. The shaft consists of two opposite halves mating along a longitudinally extending plane. The fixed contact may consist of two opposed spring-biased contact portions mounted in the housing.

Abstract: A load selector for switching over from one tap of a step transformer to the next includes fixed step contacts disposed on a circle and connected to taps of a step transformer. At least two switch contacts per phase are disposed in common on a pivotable contact carrier and are simultaneously pivotable on the circle. Two vacuum switches per phase are electrically built into the contact carrier and connected in series with the switch contacts. A cam race is disposed along the circle. Rollers run along the cam race for actuating the vacuum switches. The cam race and the rollers are current free. A slip ring is coaxial with the cam race and the circle. The cam race is disposed axially between and spaced apart from the fixed step contacts and the slip ring. Slip contacts slide on the slip ring. Each of the vacuum switches are eletrically connected between a respective one of the switch contacts and a respective one of the slip contacts.

Abstract: A cylindrical step selector for stepped transformer has its contact rings supported by horizontal conductors which extend out of the insulated cylinder surrounding the shaft which can displace the contact bridge along such ring and into engagement with a fixed contact. Externally of the cylinder, the conductors are aligned one above the other so as to be engageable by a pair of clamping bars which provide additional bracing. The conductors may be turned upwardly along these bars and held to the latter by straps.

Abstract: A cylinder of electrically insulating material provided with a plurality of stationary contacts has a shaft rotatably disposed therein about an axis of the cylinder and is formed with movable contact members engageable with the contacts, and a bearing assembly in which the shaft is journaled on the cylinder at least at one end thereof, the bearing assembly including at least two tubes of electrically insulating material traversing the wall of the cylinder at opposite sides thereof so that opposite ends of the tubes project beyond the cylinder, the projecting ends of the tubes having slits formed therein, and a bearing member of electrically insulating material supported centrally and nonrotatably by the tubes and supporting the shaft for relative rotation of the shaft and the bearing member, and respective wedges received in the slits for spreading the split ends of the tubes to anchor the tubes at the wall of the cylinder.

Abstract: A step selector for a stepped transformer has an electrically insulating cylindrical wall provided with fixed contacts, e.g. at different levels and, for each contact level, a radial arm composed wholly of electrically insulating material is affixed to a cylindrical shaft rotatable about the axis of the cylinder and within the latter. The radial arm has a flange lying against the shaft and extending over substantially 120.degree. of an arc thereof. An inward projection on the flange engages a recess in the shaft and the flange is held against the shaft by at least one band of fibrous material impregnated with a self-hardening synthetic resin. The outer end of the arm carries a contact bridge slidable on a contact ring which nonrotatably surrounds the shaft and lies in the plane of the respective fixed contact which is engageable by the bridge.

Abstract: A power selector assembly for a loudspeaker includes in one embodiment an audio transformer upon which a printed circuit board (PCB) is mounted via connector strips having pins for both securing the PCB to the transformer, and for individually electrically connecting foil contacts of the PCB to the multi-tapped primary and the secondary windings of the transformer. The transformer is mounted within a housing. An electrical wiper contact is resiliently mounted between the PCB and a knob retained in an access hole through the housing, for permitting the knob to be rotated for positioning the wiper contact to selectively electrically connect a foil terminal receiving an input signal to one of a plurality of contact foils of the PCB, for connecting the input signal to one of the taps of the primary winding associated with a desired power level. Other electrical connections on the printed circuit board provide for connecting a loudspeaker to the secondary winding.

Abstract: The present invention relates to a switching device for use in a series loop circuit, and more particularly to a switching device for uncoupling defective circuit components from the series loop circuit, for conducting quick trouble-shooting procedures to locate breaks or shorts in the circuit, and for enabling efficient preventive maintenance programs of the circuit components in order to keep them in good repair, with minimal shutdown time of the circuit or interruption in the supply of power to remaining circuit components. The device according to the invention includes a multi-position selector switch which permits in-situ testing of the circuit components so that down-time of the circuit is significantly reduced, and ease of maintenance is enhanced.

Abstract: An electrical switching system, and a method for switching this system, which is composed of two bus bars, a coupling switch which is connected between the bus bars and performs the circuit breaking and switching actions, and respective multiposition disconnect switches connected to the input and output lines or terminals. The multiposition disconnect switches are used to switch the terminals between bus bars without interruption of the current flowing through the respective terminals.

Abstract: A load selector has an insulating cylinder, provided with fixed selector tacts inverting contacts and common point rings, in the interior of which is displaced a drive crankshaft on which are supported commutator modules. The drive crankshaft includes a male coupling element, a female coupling element associated with an upper crank, an off-center tube and a lower crank. A rolling mechanism serves as a lower bearing, and a rolling mechanism serves as the upper bearing. A drain tube is coupled to a central siphon tube which leads to an outlet formed in the lower crank.

Abstract: A multiposition rotary transformer switch including a molded switch housing including a bore, an interrupted mounting flange located intermediate the ends of the bore and an interrupted key flange at one end of the bore, the flanges each including slots located at equally spaced intervals, the slots in one flange being offset from the slots in the other flange and a number of fixed contacts mounted on said housing, a dual voltage shaft assembly including a shaft having a drive nut at one end and a pair of floating contacts at the other end, and a tap changer shaft assembly including a shaft having a drive nut at one end and a floating contact at the other end, the shaft assemblies being adapted to be mounted in the bore in the housing and a reversible cap adapted to be mounted on the switch housing to enclose the end of the shaft assemblies in one position and mounted on the drive nut on the shaft in the other position to selectively rotate the shaft assembly with respect to the fixed contacts, the cap being

Abstract: A linear transformer switch adaptable for connecting the transformer windings in series-parallel or Delta-Y, the switch including a pair of dielectric plates having a number of sets of fixed contacts mounted in a parallel spaced relation, each contact having flat contact surfaces on each side, a bar mounted between the plates for linear movement, at least one sliding current carrying contact assembly mounted on the bar for each set of fixed contacts, each sliding current carrying contact assembly including a pair of conductive plates of a length sufficient to engage two fixed contacts and a pair of louvered contact sections mounted on each conductive plate, with the sections on one plate opposing the sections on the other plate, and a Geneva drive assembly operatively positioned to move the bar one step in each revolution of the bar and being operable externally of the transformer.

Abstract: A change-over switch for an on-load tap changer comprising a main arcing roller contact for achieving the arc interrupting function upon tap changing, a current-carrying roller contact, disposed in axial alignment with the main arcing roller contact, for achieving the current-carrying function upon current carrying, a current-carrying bushing, rotatably extending through the axes of the current-carrying roller contact and the main arcing roller contact, for providing a current-carrying path upon tap changing and current carrying, and a roller contact holder supporting opposite ends of the current-carrying bushing and accommodating both of the main arcing roller contact and the current-carrying roller contact.

Abstract: An on-load tap changer which comprises a rotary selector switch including a plurality of contacts which are divided according to phases into groups which are arranged in the axial direction of the tap changer, a rotary change-over switch including a plurality of contacts, and an intermittent drive mechanism connected between the selector switch and the change-over switch for intermittently transmitting the rotary motion of the selector switch to the change-over switch, the intermittent drive mechanism having an asymmetrical shape which provides a closest portion that is closest to the contacts of the change-over switch.

Abstract: A high voltage electrical switching apparatus including a base formed from a pair of flat dielectric plates supported in a spaced relation, a number of elongate elliptically shaped contacts positioned between the plates at equally spaced intervals, a dielectric bar mounted for linear motion between the plates, a pair of electrically conductive plates mounted on opposite sides of the bar, each conductive plate including a pair of louvered contacts spaced a distance apart sufficient to electrically interconnect two of the elongate contacts, and a Geneva drive assembly for moving the bar in steps of equal distance.

Abstract: A rotary, snap-action electrical switch suitable for immersion in the liquid dielectric of an electrical transformer. The switch includes a multi-position operating mechanism which latches each switch position while preventing contact rebound, absorbing all closing forces in the mechanism itself. A switch position indicator follows the movable contact, and not the actuating handle. A three-position embodiment of the switch rotates one end of a pivotable contact on a stationary contact, removing contact bias means from the current path. The remaining end is selectively engageable with either of two additional stationary contacts, as well as having a non-contact open circuit position. The pivotable contact is driven at a point intermediate its ends, to increase the torque arm and thus obtain the desired operating force with substantially reduced forces between the driving member and the contact carrier.

Abstract: A low voltage tap changer including a dielectric base fabricated from flat insulating sheet, a number of control decks mounted on the base, each deck including a corresponding number of cylindrical contacts, a continuous insulating shaft extending through each of the decks and being mounted for rotary motion with respect thereto, a number of pairs of curved contacts formed from flat copper sheet, mounted on the shaft and being positioned to engage the contacts, each of the pairs being self-aligning and biased to operatively engage the contacts and a Geneva drive assembly for rotating the shaft in a step-by-step manner and for locking the shaft in each position.

Abstract: A high-current shunt is disclosed for carrying current between relatively fixed and movable terminals in a mechanism for controlling the transfer of electrical energy. In one embodiment a plurality of generally oval, flexible, ribbon-like electrical conductors are used to bridge the gap between two spaced apart coaxial base members. Each ribbon-like conductor is suspended between the two base elements so as to have a generally U-shaped configuration. By connecting the conductors to each base element at a single point, the two base elements may be rotated relative to each other to a limited degree. Stacking and nesting of the ribbon conductors increases the current carrying capability. Good electrical contact is established within a relatively small volume and relatively little force is required to rotate the two elements relative to each other.

Abstract: A dual voltage under oil transformer switch formed from one or more phase switch units, fuse switch units and/or auxiliary switch units, each switch unit including a standardized molded switch block, shaft and rotor, the switch blocks including a contact deck for supporting a number of contact blades in a common plane, the rotor including a number of bridge contacts each having a number of double-bladed contact fingers for electrically engaging the contact blades, the rotor being mounted for axial movement on the shaft to accommodate variations in the planar position of the bridge contacts, the shafts being adopted for interlocking engagements and an operating handle assembly for positively locating and indicating the position of the switch position of the rotor in its switch block, the operating handle assembly, switch block, rotor and shafting having physical index members to assure proper interconnection of the switch units.

Abstract: A tap changer is adapted for being mounted both internally and externally to a transformer. The tap changer includes a frame having a planar portion and a flange portion generally transverse thereto. A plurality of contacts extend from the planar portion and are adapted for engaging the associated contacts of the transformer. A pivot control assembly is connected to the flange portion and defines a pivot axis. A shaft having a female coupling system adapted for engaging the pivot control assembly is mounted thereto for rotating the shaft. A brace is provided for positioning the shaft coupling system on the pivot control system. A displaceable disk having a spring mechanism is adapted for engaging the contacts while also simultaneously maintaining engagement of the coupling systems.

Abstract: The invention deals with an on-load tap changer having vacuum type switches, comprising:first vacuum switches for a main contact of which the ends on one side are connected to a plurality of tap selectors, and of which the ends on the other side are commonly connected; andsecond vacuum switches for breaking an overload, which are inserted in at least one series circuit consisting of said tap selector and respective of said first vacuum switches for said main contact, which exhibit superior breaking performance to said first vacuum switches for said main contact in said series circuit, which close earlier than said first vacuum switches for said main contact, and which open later than said first vacuum switches for said main contact.

Abstract: Six high-current conducting receptacles are seated in a panel suitably insulated therefrom about an opening embracing an axis of a shaft protruding therethrough of a six-position detented rotary switch. Three equiangularly spaced studs support a tap select dial formed with an opening that selectively exposes one of the receptacles at a time and a central opening accommodating the shaft of a switch adapter below connected to the rotary switch shaft and maintained in fixed relationship with the rotary switch shaft and the tap select dial. The shaft of the switch adapter extending through the central opening in the tap select dial carries a knob. A connector plug may pass through the opening in the tap select dial for engagement with the exposed receptacle.

Abstract: A circuit breaker with an arc shield characterized by a movable contact assembly which is rotatable between open and closed positions with respect to stationary contacts, and a cylindrical arc shield mounted on the assembly and rotatable therewith.

Abstract: A three-phase transformer including tap changing apparatus for switching the turns ratio between the primary and secondary windings of a transformer. The tap changer comprises a cable operated mechanism for moving a movable contact carrier relative to three sets of fixed contacts disposed in a linear pattern, the movable contact carrier supporting three movable contacts for engagement with any pair of fixed contacts in each set of contacts, whereby a cable operated mechanism provides a high degree of flexibility in switch mounting position on a transformer.

Abstract: A transformer tap changing switch including a rotary contactor shaft supporting spaced apart radially extending arms having roller contactor sets mounted thereon and yieldably biased into engagement with adjacent ones of an array of elongated cylindrical rod contacts supported between spaced apart switch frame plates. Each of the rod contacts includes a centrally disposed lug or blade type terminal located between the roller contactor assemblies and spaced sufficiently from each such that current flow along the rod contact elements between the terminal portions and the rotary switch contactors establish counteracting magnetic force fields which substantially cancel each other and eliminate any forces acting on the rotary contactor assembly. The switch includes a manually actuated lever for rotating the contactor shaft and which is provided with a switch position locking mechanism including a spring biased pin which projects into a selected hole in a position locking plate member.

Abstract: A circuit breaker mechanism for use with a transformer characterized by a pair of open-close load break switches operated by a single handle through two four-bar linkages for operating the switches simultaneously between three- or four-position combinations.

Abstract: Electrical contact apparatus comprises a center holder supporting a principal roller actuated by a telescopic movement and two oscillating auxiliary holders each equipped with an auxiliary roller.

Abstract: A diverter switch comprises at least two contact pairs, each pair having a fixed contact and a movable contact. The movable contacts are movably arranged on a pivoted current-carrying contact carrier. Each movable contact consists of two contact elements pressed by means of springs against the contact carrier on either side thereof. The current-carrying capacity of the movable contacts can be improved by means of silver plates arranged between the contact elements and the contact carrier.

Abstract: A device for transformation of alternating current-voltage which includes a core, a primary winding subassembly and a secondary winding subassembly. One or both of the primary and secondary winding subassemblies consists of at least one pair of equal turn and approximately equal resistance windings wrapped co-directionally around the core, and each having an equal number of tapped sections. A special tandem switch selectively interconnects tapped sections within winding pairs to provide a desired output terminal winding array such that all sections connected through the switch are energized, and are in the current carrying path at all selected switch positions, with selectively seriesed and selectively paralleled portions of the switch-coupled winding pairs being selectively encircuited at each switch position.

Abstract: A device for transformation of alternating current-voltage which includes a core, a primary winding subassembly and a second winding subassembly. One or both of the primary and second winding subassemblies consists of at least one pair of equal turn and approximately equal resistance windings wrapped co-directionally around the core, and each having an equal number of tapped sections. A special tandem switch selectively interconnects tapped sections within winding pairs to provide a desired output terminal winding array such that all sections connected through the switch are energized, and are in the current carrying path at all selected switch positions, with selectively seriesed and selectively paralleled portions of the switch-coupled winding pairs being selectively circuited at each switch position.

Abstract: In an on-load tap changer comprising a step selector operated by two shafts which are rotatable with respect to each other, a damping switch for temporarily switching in a damping resistor during a plus/minus or a coarse/fine switching operation is operated by a cam member fixedly mounted on one of the two shafts.