Abstract: A high-accuracy, 1X VR resolver includes a first rotor portion having (N?1) salient poles, where N is an arbitrary integer not less than 3, a second rotor portion having N salient poles, a first stator portion having an input coil and an output coil for a shaft angle multiplier of (N?1)X are provided, and a second stator portion having an input coil and an output coil for a shaft angle multiplier of NX. A first resolver unit composed of the first rotor portion and the first stator portion, and a second resolver unit composed of the second rotor portion and the second stator portion are disposed in front and rear stages, respectively. The output coil of the stator portion in the front stage is connected to the input coil of the stator portion in the rear stage in such a manner that the output coil of the stator portion in the rear stage outputs an output signal for a shaft angle multiplier of 1X.

Abstract: The invention finds application in the field of electric valve actuators. Particularly, the invention relates to a magnetic absolute angular position sensor for valves controlled by electric part-turn actuators, wherein the rotation ? of the valve shaft (10) induces a change in the direction along which the lines of the magnetic field generated by a magnet (8) integral therewith, pass through a stationary circuit board (7), containing two Wheatstone bridges arranged at 45° to each other, and made of a magneto-resistive material. Hence, two 90° electric signals X and Y are generated, having the same amplitude, which allow to uniquely determine the angle of rotation ? of the shaft (10).

Abstract: A magnetic rotational position sensor comprising a magnetic circuit including a loop pole piece and a magnet, and a magnetic flux sensor adapted to sense varying magnitudes of magnetic flux density associated with the magnetic circuit. The loop pole piece has a peripheral outer wall defining an inner air gap, with the outer wall including an inwardly projecting portion extending into the air gap. The magnet is positioned within the air gap generally opposite the inwardly projecting portion of the loop pole piece. The magnet and the loop pole piece cooperate to generate a magnetic field within the air gap. The magnetic circuit is rotatable about a rotational axis to correspondingly rotate the magnetic field about the rotational axis. The magnetic flux sensor is disposed within the magnetic field to sense a different magnitude of magnetic flux density in response to rotation of the magnetic field about the rotational axis.

Abstract: A method and apparatus to screen individuals specifically for paramagnetic or ferromagnetic objects they may be carrying or wearing, before they enter a controlled area. The device comprises a screening portal, including at least one magnetic gradiometer and its electronics. The device places all of the sensor arrays in close proximity to a subject's body, for screening purposes. The portal has at least one excitation coil oriented to cause the excitation field to have zero mutual inductance with the gradiometers.

Abstract: An eddy-current probe according to the present invention comprises: a substrate having a first surface facing to a subject to be tested and a second surface opposite to said first surface; an exciting coil formed on the second surface, having a pair of current lines in parallel with each other through which exciting currents flow in opposite directions to each other during testing, for generating an alternate magnetic field applied to the subject by the exciting currents; and at least one eddy-current sensor positioned on a central axis between the pair of current lines on the second surface of the substrate, for detecting a magnetic field generated newly from the subject by an eddy-current induced by the alternate magnetic field.

Abstract: A method and apparatus are provided for measuring a thickness of a nonconductive coating disposed over portions of first and second conductive surfaces that intersect at an intersection angle. The apparatus is a thickness measurement gauge having an eddy current sensor. The thickness measurement gauge includes an eddy current sensor and electronic analyzer. The thickness gauge may be provided with a pressure enclosure. A method of calibrating a thickness measurement gauge and a calibration stand are also provided. The calibration stand has third and fourth conductive surfaces intersecting at the intersection angle. The conductivities of the third and fourth surfaces correspond to the conductivities of the first and second surfaces.

Abstract: A method and system for inspecting a turbine wheel having axial slots along a perimeter thereof that are configured for mating with and securing airfoil members to the perimeter of the wheel, and an annular slot that intersects the axial slots. The method and system make use of one or more eddy current probes that are placed in the annular slot to electromagnetically inspect the annular slot and at least one of the axial slots for cracks in surfaces thereof. The probe is part of a probe assembly that includes a mounting member for engaging at least one of the annular and axial slots. The probe assembly is operable to maintain the probe at a fixed distance from surfaces of the annular slot as the probe travels through the annular slot.

Abstract: A system (90) for measuring the gap (16) between a rotating blade (14) and a stationary component (12) of a turbo-machine, including an eddy current coil (30) and an eddy current tester (91). The eddy current tester may excite the coil in a pulsed eddy current testing mode. The coil is positioned in a stationary portion (12) of a turbo-machine traversed by a rotating blade and the eddy current tester is coupled to the eddy current coil to provide an indication responsive to a distance between the blade and the stationary portion as the blade traverses the position. The coil may be mounted in a frangible ceramic pill (70) movably disposed in a housing (74). The coil is positioned near the turbine blade, the coil is excited with a voltage step function (120), and the response (122) of the coil to the step function is detected and processed to determine the proximity of the blade.

Abstract: A biomagnetic measurement apparatus having functions to detect the release of a magnetic field lock in a SQUID fluxmeter operation circuit due to the influence of a much greater noise level than that of a biomagnetic signal, to notify an operator of the release of the magnetic field lock, and to automatically or manually revert to a state for allowing magnetic measurement. The release of the magnetic field lock occurs when an integrator of the fluxmeter operation circuit is saturated. Thus, a high pass filter is provided at a subsequent stage of the integrator, and a function is provided to judge that the integrator is in a saturated state when the noise level of the output after passing through the high pass filter is lower than a pre-set threshold.

Abstract: The invention relates to a method and to a circuit for detecting the armature position of an electromagnet. The magnetic voltage is compared with a reference voltage. The reference voltage is used derived from the magnetic voltage by a filtration.

Abstract: An electromechanical rotation sensing device includes a mechanical sensing system for sensing a physical parameter; a rotational member rotated by the mechanical sensing system in response to the parameter sensed; a magnetic device movable with the rotational member and providing a magnetic field whose orientation changes with motion of the rotational member; and a magnetic field sensor providing an electrical signal responsive to the orientation of the magnetic field.

Abstract: A magnetic field measuring device useful for measuring a magnetic field associated with an electric current, including a bus section connectable into the path of the electric current, a first magnetoresistive (MR) bridge oriented to be sensitive to the magnetic field of a current in the bus section, a second MR bridge oriented to be substantially insensitive to the magnetic field of a current in the bus section, a biasing coil configured and positioned to apply a magnetic field to the first and second MR bridges, whereby the sensitivity of the first MR bridge can be controlled; and a signal processing device responsive to a voltage output of the second MR bridge to control the current through the biasing coil. The device exhibits good rejection of stray magnetic and electric fields, is convenient to use, and can be fabricated in a single chip, with or without associated signal processing and conditioning circuitry, using conventional IC processing techniques.

Abstract: Ramp arrangements and methods in accordance with the present invention can provide the position or velocity of an actuator assembly in a rotating media data storage device while loading or unloading a head connected with the actuator assembly from a disk. One such arrangement comprises a conductive ramp electrically coupled to a conductive suspension lift tab such that a closed circuit is formed when the head is unloaded from the disk. As the suspension lift tab slides along the ramp, the resistance of the circuit changes. By measuring multiple positions at multiple times, a head velocity can be determined. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.

Abstract: A method of orienting the axis of magnetization of a first magnetic element with respect to a second magnetic element uses a first element and a second element lying on a substrate. Each of the elements has a magnetic layer with an axis of magnetization. The method includes depositing a pattern of flux-concentrating material close to the first element and subsequently orienting the axis of magnetization of the first element in an applied magnetic field. The semi-finished article for measuring a magnetic field includes a substrate, a first magnetic element, a second magnetic element, a third magnetic element and a fourth magnetic element on the substrate in a bridge configuration. A first bridge portion is provided wherein the first element and the second element are electrically connected in series. A second bridge portion is provided wherein the third element and the fourth element are electrically connected in series.

Abstract: A sensing assembly senses angular speed and position of a device that rotates about an axis of rotation. The axis of rotation is defined with respect to a frame. The sensing assembly includes an encoder target wheel that is fixedly secured to the device. The encoder target wheel rotates about the axis of rotation with the device being measured. A first Hall effect sensor is fixedly secured to the frame at a predetermined distance from the axis of rotation. The first Hall effect sensor has a first output line and transmits a first output thereover. A second Hall effect sensor is also fixedly secured to the frame at the same predetermined distance from the axis of rotation. The second Hall effect sensor is offset from the first Hall effect sensor by ninety degrees. The second Hall effect sensor has a second output line and transmits a second output thereover. A controller is electrically connected to the first and second Hall effect sensors. The controller receives the first and second outputs.

Abstract: There is provided a compact, noncontact rotary position sensor that accurately detects a rotary position of a rotating object. A magnetism throttling portion is provided in a midway point of a magnetic path. Two magnetic induction elements are disposed adjacently each other at the magnetism throttling portion. This arrangement effectively allows a magnetic flux to converge at the location, at which the magnetic induction elements are mounted. A noncontact rotary position sensor offering high sensitivity and high accuracy can then be obtained. It is also possible to simplify routing of signal lines from the two magnetic induction elements, since the two magnetic induction elements are adjacent to each other.

Abstract: An inductive displacement sensor having a displaceable or rotatable, magnetically permeable measuring head, at least one measuring loop whose geometric shape varies in response to the longitudinal/rotary displacement of the measuring head, and at least one excitation loop by which a magnetic flux can be generated in the measuring head. The flux penetrates the at least one measuring loop at any point of the longitudinal/rotary displacement, essentially in the region of the measuring head, and inducing an electric measuring signal (i2). A resonant circuit, which is electrically decoupled from the outside, is arranged on the measuring head and is excited in correct phase relation by a short voltage pulse after a number of, preferably, 10 to 20 free oscillations.

Abstract: An angle transducer comprising a first disk, the rotor, with circularly arranged and radially directed receiver electrodes and a second disk, the stator, equipped with circularly arranged and radially directed transmitter electrodes arranged at the same radius as the receiver electrodes and with a fixed separation between the receiver and transmitter electrodes, whereby the disks are arranged coaxially and rotatable relative to each other, and the disks are further separated by a thin air-gap. The transmitter electrodes are each supplied with an alternating voltage with different phases for neighboring electrodes, whereby the number of supply phases, ?, is greater than two, and the separation of the transmitter electrodes=the separation of receiver electrodes/?. The transmitter electrodes of the stator are geometrically arranged such that errors in their geometry relative to the geometry of the receiver electrodes produce equal but opposite error signal in the receiver electrodes of the rotor.

Abstract: A magnetic detector capable of being easily assembled and diminishing fluctuation in magnetic detection accuracy includes: magnetic resistance elements whose resistance value changes according to change in magnetic field generated by rotation of a multi-polarized rotor; an IC formed by integrating a signal processing circuit section that outputs a signal corresponding to multi-polarization of the rotor based on change in resistance values of the magnetic resistance elements; a lead frame mounted with the IC and connected to an external output terminal for externally outputting an output signal from the signal processing circuit section; a magnet applying a bias magnetic field to the magnetic resistance elements; and a magnetic guide for correcting lines of magnetic force from the magnet. The IC, lead frame and magnetic guide are preliminarily assembled to serve as a first assembly, and the magnet and external output terminal are preliminarily assembled to serve as a second assembly.

Abstract: A configuration comprising a magnetic sensor and a pointing control circuit, for implementing a pointing device, is rendered compact in size. To that end, the pointing control circuit is formed in the central part of an IC chip, substantially square in shape, and Hall elements are provided in four corners of the peripheral region of the pointing control circuit, respectively, thereby forming the magnetic sensor, comprising the Hall elements, integrally with the pointing control circuit. Further, the Hall elements are formed integrally with the pointing control circuit in the step of fabricating an IC, thereby uniting the Hall elements with the pointing control circuit.