Abstract: An inductive coupler and method for a downhole tool such as a drill pipe comprising an electrically conductive ingot cast into a magnetically conducting electrically insulating (MCEI) annular mold. The MCEI mold may comprise an annular channel comprising a first perforation and one or more second perforations. The ingot may comprise first and seconds with sockets proximate the respective ends. The first perforation may comprise an electrical connection to a ground pin in the downhole tool. The one or more second perforations may comprise electrical connections to a similarly configured ingot within the downhole tool and to electrical equipment within the drill pipe. The ingot may further comprise cleats and flutes. The ingot may comprise an annular passageway around the interior of the ingot. The ingot may be sealed within the channel and each of the perforation may comprise a seal insolating the electrical connections from the downhole environment.

Abstract: A downhole tool and a wired drill string assembly including a downhole tool. The downhole tool includes a body having a first connector and a second connector. At least the first connector is configured to be connected to a wired drill pipe. The downhole tool also includes one or more electrical components coupled to the body and configured to receive a first signal and transmit a second signal. The downhole tool further includes a first transmission line extending along the body to the first connector and electrically connected to the one or more electrical components. The first transmission line is configured to be electrically connected to a transmission wire of the wired drill pipe when the wired drill pipe is connected to the first connector.

Abstract: A current transformer and a direct current source based on a current transformer are disclosed. In an embodiment, the current transformer includes two output ends; a first winding and a second winding connected in series between the two output ends; a main core; a bypass core, arranged to be magnetically coupled with the main core. The first winding is wound on a part of the main core and a part of the bypass core, and the second winding is wound on apart of the bypass core. In an embodiment, the current transformer also includes a high-frequency bypass, connected in parallel with the first winding, and used to filter a high-frequency signal. The high-frequency bypass provides a low-impedance path for a high-frequency signal in a primary conductor under measurement, such that the bypass core with the second winding presents less obstruction to the main core, thereby reducing heating.

Abstract: A drill pipe, particularly for a drill string, having an outer and an inner pipe (3), a female connector (4) with an internal thread at one end of the drill pipe (1), and a male connector (5) with an external thread at the end opposite from the female connector (4), wherein the inner pipe (3) is arranged substantially concentrically in the outer pipe (2) and the drill pipe (1) has a center region (8) with an internal diameter. The outer pipe (2) has an inwardly thickened wall portion at an end region (7) on the male connector side, having a smaller internal diameter than the internal diameter of the center region (8), and the internal diameter of the outer pipe (2) remains substantially the same at an end region (6) on the female connector side in relation to the internal diameter of the center region (8).

Abstract: An accelerometer as disclosed herein includes a support wafer, a bottom wafer, a top wafer, and an inductive pick-off. The support wafer may define a plane and may comprise a first side, a second side, and a proof mass. The proof mass may be configured to move in the plane defined by the support wafer. The bottom wafer may comprise a first side and a second side, and the first side may be positioned over the first side of the support wafer. The top wafer may comprise a first side and a second side, and the first side may be positioned over the second side of the support wafer. The inductive pick-off may comprise a near field resonant conductive coupling mechanism and may be configured to output a signal indicative of an amount of displacement of the proof mass to electronics.

Abstract: A downhole tool coupling (10) comprises first (11) and second (12) downhole tool elements that are securable one to the other in a releasably locking manner by moving the tool elements from a longitudinally relatively less proximate, especially overlapping position into longitudinally relatively more overlap with one another. The first downhole tool element (11) supports a first inductive, capacitative and/or magnetic energy coupler (23) and the second downhole tool element (12) supports a second inductive, capacitative and/or magnetic energy coupler (24). The first and second energy couplers (23, 24) are movable from an energetically uncoupled position when the tool elements (11, 12) are in the longitudinally relatively less overlapping position to an energetically coupled position when the first and second downhole tool elements (11, 12) overlap relatively more.

Abstract: An apparatus for performing a wellbore operation includes a drill string having a rigid tubular section formed of a plurality of jointed tubulars and a plurality of valves positioned along the rigid tubular section. Each valve may have a radial valve controlling flow through a wall of the rigid tubular section and a signal relay device configured to convey information-encoded signals. Wellbore operations may be performed by transmitting signals using the signal relay devices.

Abstract: A first housing portion of a split core sensing transformer includes a guide element arranged to engage a guide surface of a separable second housing portion and to control rotation and translation of the housing portions to align the housing portions during joining.

Abstract: A split core sensing transformer comprises a first core portion and a second core portion joined to the first core portion for pivoting relative to the first core portion about a first axis and for rotation relative to the first core portion about a second axis substantially normal to said first axis.

Abstract: An electrical assembly is provided. The electrical assembly includes a ring having at least two annular segments. Each annular segment includes a first portion and a second portion. The second portion tapers from the first portion toward an end of the second portion to define a circumferential cross-sectional area of the ring that is substantially constant along a radius of the electrical assembly. At least one winding is coupled about the ring.

Abstract: A rotary transformer includes a primary core having a primary coil wound thereon, and a secondary core having a secondary coil wound thereon, the cores being mounted for relative rotation about an axis of rotation. The transformer is characterized in that one of the cores includes a plurality of core segments arranged in spaced-apart relation relative to one another in a substantially circular array about the axis, and the other core has a substantially annular configuration. In a particular embodiment, the primary core is fixed and hence remains static during operation, and includes a plurality of spaced apart core segments arranged in a circular array around the axis.

Abstract: Axisymmetric solid of revolution derivable from section at FIG. 5 is generally toroidal with electric current(s) in windings 110, 160 preferably flowing circumferentially along major circle(s) during power coupling device operation. Current(s) in windings 110, 160; current(s) in half-shields 120, 170; and the volume of space swept out by shield airgap(s) 101 emerge from plane of paper perpendicularly at FIG. 5 but as these emerge therefrom they curve to follow toroidal major circle(s). Cores 115, 165 preferably shunt and align magnetic flux such that magnetic field lines escape therefrom primarily only in region(s) of core airgap(s) and such that magnetic flux loops lie in planes of toroidal minor circle(s).

Abstract: A Tran-Energy Machine is an energy conversion device to regain electric energy supplied to activated coils, from the total magnetic flux in the activated coils, and the rising and falling of magnetic flux lines of movable permanent magnets. The device may include one or more timing switches, electronic components in electric circuits, magnetic cores, permanent magnets, rotary parts, inductive coils, activation windings, rectifiers, and output switches. The one or more permanent magnets may be movably arranged with respect to the magnetic core for inducing alternating magnetic field upon movement, wherein activating and deactivating the windings attracts and repels the movable magnets generating regained energy from kinetic movement and changes in magnetic flux.

Abstract: A measurement and communication system for use with a tubular string, comprises a tubular string having a plurality of self-powered, autonomous telemetry stations disposed at predetermined locations along the tubular string. Each autonomous telemetry station is adapted to receive at least one first signal and transmit at least one second signal related to the at least one first signal. Power is extracted from potential energy sources proximate each autonomous telemetry station. A method of communicating information along a tubular string comprises, disposing an autonomous telemetry station at predetermined locations along the tubular string. A preferred transmission path is autonomously determined at each of the autonomous telemetry stations. Information is transmitted along the tubular string according to the autonomously determined preferred path.

Abstract: Provided is an inductor capable of adjusting an inductance in dozens of nH increments without requiring a large number of components. The inductor includes: a conductor; a first core body and a second core body each having an opposed surface, the opposed surface of the first core body and the opposed surface of the second core body facing each other so as to enclose the conductor; and a holding part provided with a slide surface for varying an opposed area of the opposed surfaces of the first core body and the second core body, for holding at least one of the first core body and the second core body at a desired position.

Abstract: The invention relates to an article of clothing (10) comprising at least one layer consisting of a flexible material and an inductive coupling device (20) for transmitting an electric current and/or data signals through the layer or layers of the flexible material. The invention also relates to an inductive interface for an article of clothing, which can inductively transmit an electric current and/or data between the interior and the exterior of an article of clothing, with which the interface is used. In addition, the invention relates to the use of an interface of this type for sending an electric current and/or data signals through a textile layer of an article of clothing.

Abstract: A magnet wheel and a stator winding which are necessary for an excitation device are included in a synchronous machine. Energy is transferred to the magnet wheel through inductivity, preferably, energy to a super-conductive coil, by the excitation device. Protection against the magnetic field produced by the current in the winding head is provided in the form of a specific system which is used to reduce the corruptions of the interfering fields of stator and rotor winding.

Abstract: A non-contact signal transmission apparatus transmits electric power and a signal in a non-contact manner via magnetic induction. The apparatus includes: a pair of annular electric power cores provided in opposing relationship to each other; a pair of electric power coils respectively provided in an annular form at one of the pair of electric power cores; and a pair of signal coils respectively provided in an annular form inside one of the pair of electric power cores. Relative permeability inside and around the signal coils is lower than relative permeability of the electric power cores.

Abstract: A downhole electrical transmission system having first and second tubular bodies coupled together by mating threads, each tubular body having a bore. An electrical conductor assembly is disposed within the bore of each tubular body. At least one end of each assembly has an electrical contact surrounded by a dielectric material, the electrical contact and dielectric material forming a polished, planar mating surface. The mating surfaces span an entire cross section of the end and are perpendicular to a central axis of the tubular bodies. The mating surfaces of each electrical conductor assembly are substantially engaged at a compressive load when the tubular bodies are fully mated.

Abstract: A method for manufacturing a magnetostrictive torque sensor having low nonuniformity of sensitivity characteristics. The residual austenite content in the rotating shaft of the torque sensor is measured first. A magnetic film is subsequently subjected to a heat treatment under heat treatment conditions that are different for each of the measured residual austenite contents, and magnetic anisotropy is imparted.

Abstract: A method for adjusting mutual inductance is adapted for use in a transformer including a main core and two windings that are wound on the main core and that have the mutual inductance established therebetween. The method includes the steps of: (A) disposing an adjusting core between the windings and adjacent to the main core, the adjusting core having a cross-sectional area smaller than that of the main core; and (B) without resulting in division of flux of the mutual inductance established between the windings, and division of an exciting magnetic flux into a plurality of independent magnetic paths, adjusting position of the adjusting core relative to the main core to vary the mutual inductance established between the two windings.

Abstract: A non-contact power system transfers power and signals simultaneously. The signals control the non-contact power system. And an operational frequency is operated on a resonant frequency so that there is no voltage alternating on power switch and power loss is reduced.

Abstract: An impedance matching network and network assembly employ one or more variable inductive elements, wherein one or more of the variable inductive elements includes a high temperature ferrite core, a helical coil, and a means for physically translating the magnetic core through the helical coil. An impedance matching network may alternatively or additionally employ one or more variable inductive elements, wherein one or more of the variable inductive elements is cooled using a fan assembly. Further, the impedance matching network and network assembly may alternatively or additionally employ one or more variable inductive elements, wherein the cooling of one or more of the variable inductive elements is facilitated by increasing the surface area of the variable inductive element core.

Abstract: An element for an inductive coupler in a downhole component comprises magnetically conductive material, which is disposed in a recess in annular housing. The magnetically conductive material forms a generally circular trough. The circular trough comprises an outer generally U-shaped surface, an inner generally U-shaped surface, and two generally planar surfaces joining the inner and outer surfaces. The element further comprises pressure relief grooves in at least one of the surfaces of the circular trough. The pressure relief grooves may be scored lines. Preferably the pressure relief grooves are parallel to the magnetic field generated by the magnetically conductive material. The magnetically conductive material is selected from the group consisting of soft iron, ferrite, a nickel iron alloy, a silicon iron alloy, a cobalt iron alloy, and a mu-metal. Preferably, the annular housing is a metal ring.

Abstract: Apparatus and methods to improve signal coupling in downhole inductive transmission elements to reduce the dispersion of magnetic energy at the tool joints and to provide consistent impedance and contact between transmission elements located along the drill string. A transmission element for transmitting information between downhole tools is disclosed in one embodiment of the invention as including an annular core constructed of a magnetically conductive material. The annular core forms an open channel around its circumference and is configured to form a closed channel by mating with a corresponding annular core along an annular mating surface. The mating surface is polished to provide improved magnetic coupling with the corresponding annular core. An annular conductor is disposed within the open channel.

Abstract: A robust transmission element for transmitting information between downhole tools, such as sections of drill pipe, in the presence of hostile environmental conditions, such as heat, dirt, rocks, mud, fluids, lubricants, and the like. The transmission element maintains reliable connectivity between transmission elements, thereby providing an uninterrupted flow of information between drill string components. A transmission element is mounted within a recess proximate a mating surface of a downhole drilling component, such as a section of drill pipe. To close gaps present between transmission elements, transmission elements may be biased with a “spring force,” urging them closer together.

Abstract: The invention relates to an apparatus with a device for simultaneous transfer of electrical power and information between two components being movable to each other and preferably comprising a stationary and a movable component. According to the invention the apparatus includes a transfer device for the common transfer of power and information, with a primary coil arrangement (5, 6) mounted on one of the components and a secondary coil arrangement (11) mounted on the other component, a power supply (35, 41, 59) connected to the primary coil arrangement (5, 6) and based on pulse width modulation, and means (71, 72) for modifying signals generated by the power supply in dependence on the information to be transferred. The information can be transferred both from the one component to the other component and vice versa (FIG. 6).

Abstract: A rotor transformer positioning mechanism permitting automatic positioning of a rotor transformer, having a first winding, relative to a rotor stack, having a second winding, mounted on a common rotary shaft to thereby permit a crossover having a predetermined length to be installed between the first and second windings includes a crossover positioning cutout disposed in a first flange of the rotor transformer. In an exemplary case, the rotor transformer includes the first flange and a second flange disposed on opposite ends of the first coil, and the second flange is proximate to the crossover. A method of assembling a rotating machine using the rotor transformer positioning mechanism is also described.

Abstract: The present invention includes a method of making an inductive coupler for downhole components. The method includes providing an annular housing, preferably made of steel, the housing having a recess. A conductor, preferably an insulated wire, is also provided along with a plurality of generally U-shaped magnetically conducting, electrically insulating (MCEI) segments. Preferably, the MCEI segments comprise ferrite. An assembly is formed by placing the plurality of MCEI segments within the recess in the annular housing. The segments are aligned to form a generally circular trough. A first portion of the conductor is placed within the circular trough. This assembly is consolidated with a meltable polymer which fills spaces between the segments, annular housing and the first portion of the conductor. The invention also includes an inductive coupler including an annular housing having a recess defined by a bottom portion and two opposing side wall portions.

Abstract: A system for transmitting data through a string of downhole components. In one aspect, the system includes first and second magnetically conductive, electrically insulating elements at both ends of the component. Each element includes a first U-shaped trough with a bottom, first and second sides and an opening between the two sides. Electrically conducting coils are located in each trough. An electrical conductor connects the coils in each component. In operation, a varying current applied to a first coil in one component generates a varying magnetic field in the first magnetically conductive, electrically insulating element, which varying magnetic field is conducted to and thereby produces a varying magnetic field in the second magnetically conductive, electrically insulating element of a connected component, which magnetic field thereby generates a varying electrical current in the second coil in the connected component.

Abstract: A system for transmitting data through a string of down-hole components. In accordance with one aspect, the system includes a plurality of downhole components, such as sections of pipe in a drill string. Each downhole component includes a pin end and a box end, with the pin end of one downhole component being adapted to be connected to the box end of another. Each pin end includes external threads and an internal pin face distal to the external threads. Each box end includes an internal shoulder face with internal threads distal to the internal shoulder face. The internal pin face and the internal shoulder face are aligned with and proximate each other when the pin end of the one component is threaded into a box end of the other component.

Abstract: A system for transmitting data through a string of downhole components. In one aspect, the system includes first and second magnetically conductive, electrically insulating elements at both ends of the component. Each element includes a first U-shaped trough with a bottom, first and second sides and an opening between the two sides. Electrically conducting coils are located in each trough. An electrical conductor connects the coils in each component. In operation, a varying current applied to a first coil in one component generates a varying magnetic field in the first magnetically conductive, electrically insulating element, which varying magnetic field is conducted to and thereby produces a varying magnetic field in the second magnetically conductive, electrically insulating element of a connected component, which magnetic field thereby generates a varying electrical current in the second coil in the connected component.

Abstract: An apparatus for generating electromagnetic pulses includes circuitry comprising an induction coil having a silver anode projecting into the coil. Moveable silver mass elements are adjustably mounted on the anode. The circuitry is immersed in liquid hydrogen and when energized produces electromagnetic pulses. If is believed that some of the anode material is consumed during the production of EMP converting the anode material into electromagnetic radiation energy. As the consumption continues the elongate anode assembly produces a composite wave form that equates to the size, shape and arrangement of the mass elements.

Abstract: A multi-dimensional position sensor includes at least three curved triangular-shaped sense inductors and a movable shaft that incorporates a conductive material. The distance of the movable shaft from the sense inductors varies as the shaft is moved in a two-dimensional plane. The variation in distance causes a variation in the inductance of each of the triangular-shaped inductors and this variation in inductance may be used to determine the physical position of the movable shaft through means of triangulation calculations.

Abstract: Disclosed is a method for adjusting the inductance of an inductor at least including a bobbin, a first magnetic member having a concavity on a side wall thereof, and a second magnetic member having a protrusion at a first end thereof for preventing the second magnetic member from being completely inserted into the bobbin so as to form a gap between the first and second magnetic members. The method includes the steps of selecting a reference piece with a suitable thickness to be disposed between the protrusion of the second magnetic member and the side wall of the first magnetic member with the concavity and closely attached to both of them t as said second magnetic member is inserted into said bobbin, and partially removing the second magnetic member from a second end thereof according to the thickness of the reference piece so as to obtain a predetermined inductance value.

Abstract: Variable reactances in an impedance-matching box for an RF coil, in a plasma deposition system for depositing a film of sputtered target material on a substrate, can be varied by rotating inductor cores during the deposition process so that the RF coil and substrate heating, and the film deposition, are more uniform due to “time-averaging” of the RF voltage distributions along the RF coil.

Abstract: A linear gauging head, or cartridge head, comprises a casing, a spindle movable with respect to the casing along a longitudinal axis, a feeler coupled to a first end of the spindle and a differential position transducer with windings, fixed with respect to casing, and a core coupled to a second end of spindle. The spindle is guided by recirculating ball bushings with rolling elements that cooperate with the spindle and thus allow its displacement with respect to the casing.

Abstract: A linear gauging head, or cartridge head, comprises a casing (1), a spindle (10) movable with respect to the casing along a longitudinal axis, a feeler (12) coupled to a first end of the spindle and a differential position transducer with windings (13, 14, 15), fixed with respect to casing (1), and a core (16) coupled to a second end of spindle (10). The spindle is guided by recirculating ball bushings (18, 19) with rolling elements (29) that cooperate with the spindle and thus allow its displacement with respect to the casing.

Abstract: A group of secondary windings are distributively provided on a stator over a predetermined range, and the respective inductance of the secondary windings in the group is set in such a manner to present predetermined inductance distribution. A rotor has an eccentric shape so as to cause variations in magnetic coupling at individual poles of the stator in response to its current rotational position. By combined use of the magnetic coupling variations between primary and secondary windings on the stator and the predetermined inductance distribution of the secondary windings, high-accuracy detection of a rotational position is achieved with a simple structure. A plurality of primary windings may be set so as to present predetermined inductance distribution.

Abstract: A Rotary Variable Differential Transformer, having a short axial length, small diameter, and a wide angle, linear output range, is provided. The Rotary Variable Differential Transformer (RVDT) comprised of a housing, a hollow cylindrical coil form made of non-magnetic, non-conductive material, about which a first and second secondary coils, adjacent to each other, are circumferentially wound. A primary coil is circumferentially wound about a segment of said first secondary coil, and about a segment of said second secondary coil.An elongated ferromagnetic core is disposed within the hollow coil form. The core is an axial section of a ferromagnetic cylinder which serves to couple said primary coil to said secondary coils.The output voltage measured across said secondary coils terminals is indicative of the angular position of said ferromagnetic core relative to the coil form assembly.

Abstract: An electrical fault limiter having first, second, third, and fourth magnetic cores. The first magnetic core opposes the second magnetic core and is adjacent to the third magnetic core. The fourth magnetic core opposes the third magnetic core and is adjacent to the second magnetic core. A rotor is disposed between the first and second magnetic cores, and the third and fourth magnetic cores. The rotor is rotatable about a rotor axis. The first and second magnetic cores are disposed on a first side of the rotor axis and the third and fourth magnetic cores are disposed on a second side of the rotor axis. Each core has a first arm, a second arm and a body to which the first and second arms are connected. Each body has a superconduction bias coil disposed about it. Each arm has a conduction mode coil disposed about it.

Abstract: A rotary transformer for aircraft deicing apparatus, the transformer including a primary winding adjacent a laminated primary core, and a secondary winding adjacent a laminated secondary core; at least one of the cores being rotatable with respect to the other core.

Abstract: A joystick for generating electric control signals comprises the following components: a housing, an operating rod, a universal joint for the operating rod, sensors and an element acting upon these in a positionally dependent manner. The distance of the element from the sensors can be varied by the operating rod. The sensors are in the form of induction coils through which alternating current circulates. The induction coils, in turn, are each part of an electric oscillatory circuit. It is adequate to provide only two such sensors. The element acting upon the induction coils is an induction body, more particularly, in the form of a spherical part which is rigidly connected to the operating rod. The center of the induction body is spaced from the center of the universal joint. By changing the distance of the induction body from the induction coils, the amplitude, frequency and/or phase of the respective oscillatory circuit can be changed in order to generate the electric control signals.

Abstract: A multi-phase electrical transformer includes a rotor-stator structure that provides varying-reluctance magnetic-field paths in which the magnetic fields pass through plural stator cores on which phased primary and secondary windings are mounted and through a rotor that includes two annular poles attached to cylindrical pole-connecting means. At least one of the annular poles includes at least one field concentrator member. An optional stationary field winding surrounds the pole-connecting means in the region between said pole-connecting means and the stator cores, and permits adjustment of power factor in primary or secondary windings. The structure permits separation of stator core and pre-formed windings for repair and permits the core and windings to operate at cooler temperatures without additional cooling apparatus. The device of this invention is capable of simultaneous operation as a transformer and a synchronous machine.

Abstract: Apparatus for testing for flaws in conductive objects which includes a coil of electrically conducting wire and an associated flux concentrator of electromagnetically active material which is disposed radially from the coil, sized and shaped to provide a desired resolution of flaw detection and provides close coupling between the coil and conductive object. An associated bridge circuit detects changes in the coil's impedance, caused by flaws in the object, and activates a display to visually indicate a change in impedance.

Abstract: The transmission system for transmitting direct current from an energy source on one side of an electrical and mechanical barrier to a load on the other side of the barrier utilizes a transformer comprising a primary core on one side of the transformer and a secondary core on the other side of the transformer. The cores are magnetically coupled selectively by moving a magnetic ferrite coupler in and out of alignment with the poles of the cores. The direct current from the energy source is converted to a time varying current by an oscillating circuit, which oscillating circuit is optically coupled to a secondary winding on the secondary core to interrupt oscillations upon the voltage in the secondary winding exceeding a preselected level.

Abstract: A resolver which in a preferred embodiment utilizes a stator member, preferably made of a single piece of ferrite material, which has active stator sine poles and active stator cosine poles and a rotor member which has passive rotor poles. The active stator poles have excitation voltage inputs supplied thereto and, as the rotor poles rotate relative thereto, the sine and cosine stator poles supply voltage outputs which vary sinusoidally and co-sinusoidally, respectively, as a function of the angular position of the rotor member relative to the stator member. Multiple stator and rotor pole combinations can be used to provide resolver operation at different speeds.

Abstract: A lifting electromagnet for ferromagnetic workpieces has two composite cores which extend downwardly from a yoke. Each core has a first section which is rigid with the yoke and is surrounded by an exciting coil, a second section which is connected with the respective first section, and at least one third section which is movable with reference to the second section, either up or down or horizontally. The poles at the lower ends of the third sections make an angle of 120 degrees, the same as the poles at the lower ends of the second sections. The second sections are surrounded by induction coils, and a further induction coil is disposed between each pair of neighboring third sections. The distance between the second sections is less than the distance between the first sections, and the distance between the second sections exceeds the distance between each pair of third sections.

Abstract: A non-contacting position sensor has an exciting coil in a plane and has a sensing coil in an intersecting plane so sensing coil portions are symmetrical around an exciting coil portion in mutually inductive relation to that portion of the exciting coil portions. A ferrite member magnetically shields those sensing coil portions from other portions of the exciting coil and a housing mount the sensor for relative movement with respect to magnetically permeable or electrically conductive inductance-modifier on an object whose position is to be monitored. Movement of the inductance-modifier as the object moves modifies mutual inductance between the respective sensing coil portions and the exciting coil portion so that, when the exciting coil is driven, the sensing coil provides a signal representative of the object position. If desired, an additional sensing coil is disposed in a third plane to provide X-Y position sensing.

Abstract: An angular displacement transducer of the variable reluctance type is disclosed. It utilizes two relatively rotatable rotors with two sets of magnetic circuits and a coil associated with each magnetic circuit. Each set of magnetic circuits has a set of magnetic cores, one-half the cores on one rotor and one-half on the other rotor. A pair of cores in the first set, one on each rotor, coact with each other to provide a first variable reluctance magnetic circuit which is magnetically linked with the first coil and which has a reluctance that varies with relative rotation of the rotors. A pair of cores in the second set, one on each rotor, coact with each other to provide a second variable reluctance magnetic circuit which is magnetically linked with the second coil and which has a reluctance that varies with relative rotation of the rotors.