Abstract: An electrical apparatus and method for matching the input power source and output impedance of the electrical apparatus utilizes electromagnetic devices having two or more inductive windings, which may be connected in various series and/or parallel circuit configurations, by inserting them into a circuit board specially configured to accept my improved electromagnetic devices, and attaching jumpers to the circuit board for selecting the particular inductive windings to be incorporated into the electrical apparatus. The windings not selected for a given electromagnetic apparatus remain unconnected within the electromagnetic device.

Abstract: A planar inductor has a spiral coil, insulating layers stacked on both surfaces of the spiral coil, and ferromagnetic layers stacked on the insulating layers, wherein each ferromagnetic layer has a saturation magnetization 4&pgr;MS of 10 kG or more, and a thickness of 100 &mgr;m or less.

Abstract: A flux-controlled variable transformer can control voltage at a high speed without using any voltage adjusting tap. The transformer has a first and second magnetic circuits. The first magnetic circuit is composed of a first and second U-cut cores (13 and 11) which contact at their cut ends with each other in the state either of the two cores has been turned by 90.degree. in a twisting direction relative to the other. The primary winding (14) is wound in common around the second magnetic circuit and the first U-cut core (13) of the first magnetic circuit, the secondary winding (17) is wound around the second magnetic circuit and a control winding (12) is wound on the second U-cut core (11) of the first magnetic circuit. The magnetic flux linking the primary and secondary windings (14 and 17) can be controlled by change of the magnetic resistance in the first magnetic circuit with the primary winding (14) by changing a value of exciting current flowing in the control winding (12).

Abstract: A flyback transformer has a high-voltage bobbin. The bobbin is provided with a focus-pack connection terminal in addition to electronic-component mounting terminals. The focus-pack connection terminal is connected to one of the electronic-component mounting terminals which provides the desired high voltage. When the desired voltage changes, the focus-pack connection terminal is simply connected to another one of the electronic-component mounting terminals corresponding to the changed voltage, easily changing the focus-pack supply voltage.

Abstract: A coil assembly for use in an inductive apparatus, is comprised of a conductive material, either copper or aluminum, continuously wound around a circular or rectangular shape. At a predetermined number of turns, a terminal or tap is formed in the conductor. The tap is essentially a bump in the conductor that will protrude from the coil and be accessible to make connections to it after the coil assembly is complete. The insulation of the conductor is removed from the outside edge of the bump to form a point of contact. A C-clamp, formed from spring steel or other conductive material, functions to secure an external conductor having a lug attached to an end of conductor to the formed terminal. A bolt through the lug is secured by a tapered depression in the C-clamp that functions as a nut. The C-clamp includes an extension that provides additional pressure between the point of contact and the lug to make an electrical contact with a portion of the formed tap and the lug.

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 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: An apparatus for applying a variable voltage to an electric load utilizes a transformer with several taps to provide different voltage levels for the load. The load is connected to alternate taps by a switching device, which is operated by a control device responsive to short interruptions in the power supply to the load. Short interruptions in power can be generated by rapidly turning one or more existing power switches in circuit with the load off and on again, so remote control is possible from several locations. Apparatus with the above structure is particularly suitable while employing a toroidal transformer for dimmer control of halogen lamps.

Abstract: A pancake-type transformer particularly suited for connection to an inductor for inductively heating crankshafts is comprised of a single turn secondary defined by a plurality of generally U-shaped tubular conductors interleaved between the turns of a tubular, multiturn primary conductor having opposite ends connectable across a source of power. The conductors of the secondary have opposite ends each interconnected with a corresponding one of a pair of terminal blocks connected to a tubular inductor. The terminal blocks are outwardly adjacent the primary and secondary conductor portions at one end of the transformer and include corresponding current collectors which extend inwardly across the opposite sides of the conductor portions at the one end of the transformer. Coolant for flow through the secondary conductors is communicated with the opposite ends thereof through coolant passageways in the current collectors.

Abstract: A winding configuration for a transformer equipped with a load tap changer which maintains an impedance balance when the transformer is connected in parallel with another transformer in the field. The winding configuration, from the core outward, consists of a first compensating winding, a low voltage (LV) winding, a load tap changer (LTC) winding, a high voltage (HV) winding, and a second compensating winding. If the impedance of the transformer has to be lowered to match the impedance of the existing unit in the field, the second compensating winding is coupled in series with the LV winding. If the impedance of the transformer has to be increased to match the impedance of the existing unit in the field, the first compensating winding is coupled in series with the LV winding.

Abstract: A cooling tube (T) is incorporated into each conductor (C1) of the coil. The current carried by this conductor is divided between the strands which are maintained in thermal contact with the tube even in transposition or twist areas in which the conductor undergoes particularly marked deformations. The conductor features at least one half-turn twist between the electrical terminals of the coil.

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 variable inductance RF coil assembly including an air-core, high-voltage coil, a printed circuit board installed inside of the coil, the circuit board carrying a plurality of switch contacts corresponding in location and in number to the turns of the air coil, a contact plate attached to the circuit board and having contact fingers corresponding in location and in number to the switch contacts, and a rotary, stepped cam cylinder mounted to the circuit board, the cams corresponding in location and number to cam-follower sections of the contact arms on the contact plate. Unidirectional rotation of the stepped cam cylinder causes progressive communication between the cam steps and the cam-follower sections. Such communication causes the contact arms to connect with the switch contacts on the circuit board thereby progressively and continuously shorting out each successive turn of the coil thereby to adjust the inductance thereof.

Abstract: A high-voltage winding for core-form power transformers is disclosed that uses two different conductor configurations within a single coil to minimize eddy current losses. The winding includes a first elongated conductor bundle formed from a plurality of thin enamel coated conductor ribbons arranged in side by side relation. A plurality of second elongated conductor bundles are each formed from at least one bundle section having a multiplicity of elongated insulated conductor strands arranged in side by side relation. Each of the conductor strands is less than 40 mils thick. The coil includes a top end section, a body section and a bottom end section. The body section is spirally wound with the first conductor bundle. The top and bottom end sections are wound with the second conductor bundles. In windings that include tap connectors, the tap section is also wound with one of the second conductor bundles.

Abstract: One of a plurality of taps of at least one transformer is selected by choosing a predetermined plug to mate with a predetermined jack. The connection arrangement between each transformer and a corresponding jack is such that each pin of a respective jack is operatively connected to a predetermined transformer tap of the corresponding transformer whereby the corresponding taps of each of the transformers are connected to different corresponding pins for each of the corresponding jacks. Further, the starting tap of each transformer is operatively connected to the same corresponding pin of the jack corresponding to the transformer. A plurality of plugs, the number of plugs corresponding to one less than the number of pins of the jacks, is included whereby each plug has a plurality of mating pins corresponding to the pins of the jack. Each mating pin of each plug which corresponds to the pin of the starting tap is operatively connected to a first supply terminal.

Abstract: The invention is directed to an AC power supply for portable welding machines or the like which employ a transformer of either single or multi-phase power wound around a cylindrical core. The core is constructed from a continuous length of steel alloy ribbon. The individual windings of both the primary and secondary are spaced apart. In operation the transformer is submerged in a heat transfer medium to provide cooling thereof by heat transfer therefrom. The transformer may have either a tapped primary or secondary or both to provide secondary amperage for the intended use of the transformer. An external cooling radiator may be employed to provide additional cooling to the heat transfer medium.

Abstract: A winding system for gas-cooled transformers, comprising windings disposed around a core; and at least one insulation torus, consisting of an insulating mass, said torus having embedded therein electrodes electrically connected to an adjoining winding for suppression of the electric field intensity between sinding and electrodes. The winding connected to the electrodes is divided into separate winding sections across the height of the winding, and each of these sections is connected to one electrode.

Abstract: To compensate for voltage ratio errors in a cascaded core instrument potential transformer, the coils of an outer coupling winding otherwise utilized to magnetically couple an adjacent pair of cores together are electrically connected into the primary winding circuit to either add its turns to or subtract its turns from the primary winding turns in order to bring the secondary winding output voltage within acceptable accuracy tolerance limits.

Abstract: The transformer comprises a magnetic circuit (8) as well as, in the case of each phase, a high-voltage electric circuit (17) and a low-voltage electric circuit (18) both wound around at least one section of the magnetic circuit (8).The electric circuits (17, 18) are arranged in at least one electrically insulating annular coil form (11) which, under service conditions, is interposed between the electric circuits (17, 18) and the aforementioned section of the magnetic circuit (8).Utilization in particular for improving the occupation of electric windows by the magnetic circuit and of magnetic windows by the electric circuit.

Abstract: A split structure type transformer has a core upper and lower split-up secondary windings and a primary winding which are wound about the core, a single tap winding having a plurality of tap winding parts and a plurality of tap terminals, and a single tap selector. The secondary windings are respectively connectable to independent loads, with only one end of the tap winding being connected to the primary winding, and the tap terminals are respectively connected to terminals of the tap selector. A pair of tap winding parts, connected to the same terminal of the tap selector, are arranged adjacently along the axial direction of winding. Each of the tap winding part pairs may be replaced by a single tap winding part which is formed by winding a single strand having a cross-sectional area which is twice a cross-sectional area of a strand used for winding each tap winding part pair.

Abstract: A transformer circuit including a primary coil with first and second voltage divider segments arranged in phase with equal inductances and a plurality of taps on the second segment. A switch is used to selectably ground one of the taps for varying the voltage impressed on the second segment. The transformer also has a secondary coil including first and second voltage divider segments arranged 180.degree. out of phase and having equal inductance. The secondary coil is heavily insulated, and the primary and secondary coils are coupled together to provide an output equal to the sum of the voltages applied to the segments of the secondary coil so that the transformer output can be varied by switching from one tap to another of the second segment of the primary coil and that the secondary coil can be heavily insulated and isolated from ground.

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: An on-load tap-changing transformer in which its high-voltage winding is axially divided into parallel-connected halves, and an end conductor constituting part of the high-voltage winding is connected to the other terminal of each of the halves. A coarse tap coil connected by the end conductor to the other terminal of each of the halves of the high-voltage winding is disposed adjacent to the associated half, and a fine tap coil connected to the coarse tap coil through a coarse tap selector used for the change-over of the tap position to the taps of the coarse tap coil is disposed at a radial position spaced apart from the coarse tap coil. The end conductor is wound together with the conductors of the fine tap coil.

Abstract: The invention relates to a regulating winding for a transformer in which a plurality of helical current-carrying conductor loops are connected in series with each other, whereas a plurality of non-current-carrying helical potential control loops are provided adjacent to the current-carrying loops and are connected to appropriate ones of the current-carrying loops in such a way that a substantial increase in the series capacity of the regulating winding is obtained with a relatively small increase in the space required for the regulating winding.

Abstract: Different line-cord sets connect an electrical device to different supply voltages, assuring that the supply voltage matches the device. Each line-cord set has a uniquely keyed socket and a wall plug. A device receptacle receives the line-cord's keyed socket. An adjustable key on the device mates with the socket's key and rejects nonmating sockets to admit the socket into the receptacle and adjusts the device's input voltage to match the supply voltage.

Abstract: A converter transformer for an AC-DC converter is assembled by connecting three transformer units at an installment site. In the respective transformer units, first, second and third iron core legs are received in oil tanks. On the first and second core legs are mounted series-connected first and second primary windings, respectively. On the second and third legs are mounted first and second secondary windings respectively. Coupling windings connected in parallel are mounted on the respective legs. The primary windings and the secondary windings are electromagnetically coupled.

Abstract: A regulating transformer including a base winding and a plurality of auxiliary windings adapted to be connected in whole, or in part, to said base winding. The ends of each auxiliary winding and a point between its ends are passed through a bushing to a change-over switch arranged outside the transformer tank. The base winding of the transformer is connected to the movable contact of a first change-over switch. The movable contacts of continuous change-over switches are interconnected. The movable contact of the last change-over switch is connected to an outgoing line. Each change-over switch has a movable contact that can be selectively engaged with either of a pair of fixed contacts. One of the fixed contacts is connected to one of the ends of an auxiliary transformer winding. The other of the fixed contacts is connected to a point, or tap, between the ends of the auxiliary winding.

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: Low, middle and high voltage windings are wound on a magnetic core in this order, the high voltage winding having a high voltage line terminal at its center and neutral terminals at both ends. Two middle voltage partial windings are coaxially wound on the outside of the high voltage winding at upper and lower positions separated by a necessary distance for insulation. One end of each of the middle voltage partial windings are connected to the neutral point of the middle voltage winding, and the other ends thereof are each connected to the respective tap windings of two tap changers. Thus, the middle voltage partial windings and the tap changers constitute a parallel circuit in which a circulating current flows thereby to induce magnetic flux in each of the middle voltage partial windings and tap windings. The middle voltage partial windings and tap windings are so wound that the magnetic coupling therebetween through the induced magnetic flux can be reduced.

Abstract: A universal battery charger/adapter unit is disclosed comprising a wall power unit and a separate cable which may be plugged into an appliance. The wall unit makes available different AC and DC voltages. A selected pluggable cable section is wired to selectively connect appropriate AC or DC voltages to the appliance being powered. The cable section has the further characteristic that current limiting or current regulating elements may be incorporated therein to improve the particular AC or DC voltage or current characteristics of the power unit with respect to that particular load. A battery nest can be permanently connected to a special bifurcated plug allowing the recharging of rechargeable AA, C or D size batteries in addition to 9 volt batteries. Interchangeable shims are used to compensate for various battery sizes.

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: Tap changing apparatus for switching the turns ratio between the primary and secondary windings of a three-phase transformer. The tap changer includes three mounting boards, one for each phase of the transformer. Each board contains a plurality of stationary contacts arranged in a circular pattern around an axis of rotation and connected to taps from various sections of the transformer windings. A movable contact assembly is associated with each set of stationary contacts and is rotatable around the center axis of each respective contact set. Each movable contact assembly is affixed to a worm gear which operates to rotate the movable contacts between successive stationary contacts in each respective contact set.

Abstract: An arc welder has a transformer comprising a pair of flat aligned primary coils of aluminum strip wound on opposite parallel legs of a rectangular open frame core and a pair of aligned secondary coils of the same strip material wound on the same opposite parallel core legs in lateral spaced relationship with the primary coils, a flexible strip encircles each pair of aligned coils tightly banding them against lateral distortion, a flux shunting core encapsulated in molded plastic material is slidably movable through the core between the pairs of aligned coils, and mechanism for slidably moving and locking the shunting core in adjusted positions is operated by a single handle. One secondary coil of the pair comprises two windings, one wound over the other to provide two output ranges. In a modification, the addition of an outboard choke coil of round wire provides a third output range.

Abstract: Disclosed is a transformer of a large capacity for an ultra-high voltage which comprises a core leg coaxially wound sequentially with at least a low voltage winding, a high voltage winding composed of an upper and a lower winding section operated in a parallel connection and having a lead conductor led out from a center portion of the high voltage winding and extending to a terminal to be connected to a high voltage transmission line as well as connection leading-out wires taken out from the top and bottom end portions of the high voltage winding, and an upper and a lower tap winding disposed vertically spaced from each other with a predetermined distance and respectively connected to the upper and lower winding sections of the high voltage winding so as to be operated in a paralled connection therewith.

Abstract: A high speed a.c. voltage regulator comprises a transformer having a plurality of switchable primary windings across which an unregulated voltage is impressed and which control the regulated voltage, and a secondary winding across which the regulated voltage is generated. During a regulation period, which comprises one cycle of the unregulated voltage frequency, peak unregulated input voltage is compared against an upward ramping reference voltage to control a source of clock pulses, where the instantaneous level of the reference voltage is related to the number of clock pulses generated during a regulation period. The number of clock pulses generated during a regulation period controls the switchable windings.

Abstract: A digital tuning device for accurate selectable tuning of a resonant circuit. The inductive and capacitive elements of the resonant circuit are connected by a transformer device whose turns ratio is variable in accurate digital increments. Since the reflected reactance is related to the square of the turns ratio and since the resonant frequency varies as the inverse square root of the reactance, the resonant frequency of the circuit is directly related to the turns ratio.