Abstract: There is provided a detecting apparatus including one or a plurality of magnetic coupling elements that include a plurality of coils, a positioning unit disposed near at least one coil from among the plurality of coils included in the one or plurality of magnetic coupling elements, and a detector that measures an electrical parameter related to the one or plurality of magnetic coupling elements or to a circuit that at least includes the one or plurality of magnetic coupling elements, and determines from a change in the electrical parameter whether a foreign matter capable of generating heat due to magnetic flux is present.

Abstract: A method and apparatus for the inspection of electrically conductive components is described. The described apparatus comprises a sensor module having a magnetiser unit suitable for generating a variable DC magnetic field within the test component and an eddy current probe. The variable DC magnetic field and eddy current probe are configured to perform a partial saturation eddy current test upon the test component. The eddy current probe further comprises a magnetic field sensor that provides a means for measuring the permeability within the test component. Employing the magnetic field sensor provides apparatus that is more accurate and flexible in its modes of operation since such sensors provide a means for the actual permeability of a material being tested to be measured. The described methods and apparatus find particular application in the inspection of tubular components used in the oil and gas exploration and production industries.

Abstract: A method for nondestructive and noncontact detection of faults in a test piece, with a transmitter coil arrangement with at least one transmitter coil, a receiver coil arrangement with at least one receiver coil for detecting a periodic signal which has a carrier oscillation whose amplitude and/or phase is modulated by a fault in the test piece. A signal processing unit producing a useful signal receiver coil signal, and an evaluation unit evaluating the useful signal for detection of a fault in the test piece. A self-test unit automatically or upon an external request undertakes systematic quantitative checking of signal processing functions of the signal processing unit and/or systematic quantitative checking of the transmitter coil arrangement and/or of the receiver coil arrangement and/or upon external request undertakes calibration of the signal processing unit using a calibration standard which replaces the transmitter coil arrangement and/or of the receiver coil arrangement.

Abstract: An apparatus, system, and method are disclosed for maintaining normalcy of a sensor with respect to a structure. The apparatus includes a driving member, a driven member, and a sensor. The driving member includes a first engaging element and a second engaging element. The driven member includes a third engaging element and a fourth engaging element. The third engaging element of the driven member is engaged with the first engaging element of the driving member. The fourth engaging element of the driven member is engaged with the second engaging element of the driving member. The sensor is coupled to the driven member, which is rotatably drivable by the driving member. Engagement between the first and third engaging elements facilitates three-dimensional adjustment of the driven member relative to the driving member. Engagement between the second and fourth engaging elements facilitates co-rotation of the driving member and the driven member.

Abstract: Calibration of a non-contact current sensor provides improved accuracy for measuring current conducted through a conductor such as an AC branch circuit wire. In a calibration mode, a predetermined current is injected through a voltage sensing conductor integrated in the non-contact current sensor. The magnitude of the magnetic field is measured using a sensing element of the non-contact current sensor. Then, when operating in measurement mode, a current conducted in a wire passing through the non-contact current sensor is determined by correcting the output of the non-contact current sensor using the result of the measurement made in the calibration mode. The voltage sensing conductor is used to provide an indication of the magnitude and/or the phase of the electrostatic potential on the wire. The calibration current may be a DC current, and calibration may be performed while the conductor is carrying an AC current.

Abstract: An apparatus, system, and method are disclosed for scanning metallic surfaces. The apparatus, in one embodiment, comprises a shaft and a rotating member. The rotating member may comprise a sensing end and a featuring engaging element. The shaft further comprises a first coupling element and the rotating member further comprises a second coupling element. The first coupling element may be coupleable with the second coupling element such that the rotating member is pivotable at any three-dimensional angle with respect to the shaft to orient the sensing surface parallel to the scanned surface.

Abstract: A force measurement sensor for measuring an applied force onto an object is provided. The force measurement sensor includes a first sensing unit which comprises a first flux concentrator having a first facing orientation pointing towards a surface of the object, a first magnetic field generating unit being adapted for generating a magnetic field, a first magnetic field detector unit being adapted for detecting a first magnetic field which field being generated by the first magnetic field generating unit and being influenced by the applied force to be measured, wherein the first magnetic field detector unit is further adapted for outputting a first signal being representative for the detected magnetic field, and an evaluating unit being adapted for evaluating a signal strength of the first signal and determining the applied force based on the first signal.

Abstract: Present embodiments include eddy current array probes having differential coils capable of detecting both long and short flaws in a test specimen and, additionally or alternatively, multiplexed drive coils. For example, an eddy current array probe may include a first plurality of eddy current channels disposed in a first row and a second plurality of eddy current channels disposed in a second row. The first plurality and second plurality of eddy current channels overlap in a first direction but do not overlap in a second direction. The probe also includes a semi-circular drive coil disposed proximate to the first plurality and second plurality of eddy current channels and configured to generate a probing magnetic field for each sense coil of the eddy current channels.

Abstract: Disclosed is a method of appropriately and easily selecting a combination of two different frequencies of an AC exciting signal used for eddy current measurement while decreasing or removing the dependence of the measurement accuracy on temperature. Three or more AC exciting signals of different frequencies are applied to an object under measurement by an exciting coil, and an induced current is produced. Detection signals corresponding to the frequencies are detected by a detection coil, and the phase difference between each detection signal and the AC exciting signal corresponding to each frequency is calculated from the detection signals corresponding to the frequencies. From the phase differences, a combination of two frequencies the phase differences of which are within a predetermined range is extracted. The lower frequency of the extracted combination is used for a first frequency, and the higher one is used as a second frequency. Thus, the combination of two frequencies are selected.

Abstract: A method and apparatus for determining and for reducing magnetism in a generator stator core (20). The method includes extending one or more conductors (38) proximate the core, applying a polarity-reversing excitation voltage to the one or more conductors, and reducing an amplitude of the voltage over time, wherein the voltage causes current to flow in the conductors, the current generating a magnetic field that demagnetizes the core. The method and apparatus are useful for determining hot spots in the core.

Abstract: A current probe enabling measurement of current of a signal in a circuit includes a ferrite core defining a gap, a wire wrapped around the ferrite core and a magnetic field sensor. The wire is configured to receive the signal from the circuit, where the current of the signal flowing in the wire generates a magnetic field in the ferrite core. The magnetic field sensor is positioned in the gap of the ferrite core, the magnetic field generated in the ferrite core flowing through the magnetic field sensor, which produces a voltage proportional to an intensity of the magnetic field. The current is measured based on the voltage produced by the magnetic field sensor.

Abstract: A device for detecting metal elements in slab form such as metal plates or sheets, includes an emission coil powered by suitable control elements and generating a magnetic field, a reception coil placed so as to enable generation via induction of a voltage across the terminals of the coil under the action of the magnetic field, and elements for processing and evaluating the voltage signal delivered by the at least one reception coil, enabling delivery of an information signal indicating the absence or presence of one or more metal elements near the coils. The emission coil (3) and the reception coil (5) are both mounted in a housing or a sensor head having an active detection face having an associated detection region, and are positioned at a defined inclination one relative to the other and relative to the face.

Abstract: A method and system for inspecting components, such as a rotating component of a turbomachines having one or more slots along a perimeter thereof. The method entails mounting to a robotic apparatus a probe assembly that includes a holder assembly to which a probe tip is mounted, an eddy current coil within the probe tip and adjacent a first face thereof, a touch probe contact located at a second face of the probe tip, an element for enabling relative movement between the probe tip and holder assembly, and an element for biasing the probe tip relative to the holder assembly in a direction parallel to the movement. The probe tip is then placed in a slot and caused to travel along the surface of the slot to electromagnetically inspect the slot for cracks in its surface while the first face of the probe tip is maintained in contact with a slot surface.

Abstract: An inductive sensor with coils arranged substantially in layers on a flat circuit-carrier. The edges of the flat circuit-carrier are metallized obliquely so that an upper side, a lower side, an intermediate layer and/or a plurality of intermediate layers of the flat circuit-carrier are interconnected with one another via the edges in a conductive manner.

Abstract: An extensible frame adapted to receive and maintain a rectilinear container applied upon an interior ledge extensible frame. Two or more orthogonally aligned sensor assemblies are provided to measure deflection of panels forming the container when a static or dynamic load is applied upon an uppermost panel. Each sensor assembly outputs a signal corresponding to a deflection of a panel induced by the load applied upon the uppermost panel. Signals output from the sensor assemblies are received and processed by an output processing unit in either a human cognizable or machine readable format. The amount deflection measured by the sensor assemblies corresponds to an amount of bulge of a panel when a defined load is applied.

Abstract: A metal detection apparatus that uses one or more operating frequencies. The metal detection apparatus comprises, among other things, a transmitter unit that provides transmitter signals to a transmitter coil that is coupled to a receiver coil, which is connected to the input of a receiver unit. The transmitter unit comprises a frequency generator that provides an operating frequency to the input of an amplifier stage, whose output is connected via a transformer to the transmitter coil. The amplifier stage is connected to a first tap and the transmitter coil is connected to a second tap of the same transformer winding of the transformer. A resonant circuit is formed that is tuned to the operating frequency, and can be tuned optimally and independently of other parts of the transmitter unit.

Abstract: A method of non-destructive testing that employs composite systems that include a curable resin and detectable particles that have a property that can be distinguished from a property of the resin is disclosed. Array probes useful in the method also are disclosed.

Abstract: An eddy current measuring sensor including a probe which is configured as a regular triangle and is provided with an excitation unit for applying a given AC excitation signal to a workpiece and a detection unit for detecting a detection signal occurring in an object to be measured responsive to the applied AC excitation signal, wherein the excitation unit is provided with exciting coils which are arranged on each side of the probe, while the detection unit is provided with detection coils which are arranged at each vertex of the probe.

Abstract: A well (2) doped for a conductivity type and provided as the sensor region is formed in a substrate (1) made of semiconductor material. Contact regions (4), arranged spaced apart from one another and doped for the same conductivity type as the well (2), are formed in a cover layer (3) that delimits the region with the conductivity type of the well. The contact areas (4) are electroconductively connected to the well (2) and provided for terminal contacts (6).

Abstract: A segmented magnetostrictive patch array transducer capable of generating a high frequency shear wave in a structure such as a rod or a pipe, a structural fault diagnosing apparatus including the segmented magnetostrictive patch array transducer, and a method of operating the segmented magnetostrictive patch array transducer are shown. The segmented magnetostrictive patch array transducer includes a plurality of magnetostrictive patches attached along a circumference of a rod member; a plurality of insulators that are disposed on the magnetostrictive patches; a plurality of meander coils, each of the meander coils comprising a plurality of coil lines extending along the circumference direction of the rod member on each of the insulators, wherein a current flows through adjacent coil lines in opposite directions to one another; and a plurality of magnets that respectively form a magnetic field along the circumferential direction of the rod member on the magnetostrictive patches.

Abstract: A vibration and condition monitoring system and the parts thereof with a true digital signal processing based design, with very limited analog based general signal conditioning. Specifically a method of driving and a driver of eddy current probes that have a simple highly accurate analog part and a unit and a method of enabling efficient vibration monitoring in hazardous areas. This is achieved by an eddy current probe oscillator unit having independent control of an amplitude gain and control of an impedance measurement sensitivity, i.e. amplitude gain linearity in relation to probe impedance.

Abstract: A method and apparatus for the inspection of electrically conductive components is described. The described apparatus comprises a sensor module having a magnetiser unit suitable for generating a variable DC magnetic field within the test component and an eddy current probe. The variable DC magnetic field and eddy current probe are configured to perform a partial saturation eddy current test upon the test component. The eddy current probe further comprises a magnetic field sensor that provides a means for measuring the permeability within the test component. Employing the magnetic field sensor provides apparatus that is more accurate and flexible in its modes of operation since such sensors provide a means for the actual permeability of a material being tested to be measured. The described methods and apparatus find particular application in the inspection of tubular components used in the oil and gas exploration and production industries.

Abstract: A linearly polarized eddy current sensor including a source antenna and a parasitic antenna coupled to the source antenna, serves as a high sensitivity tool for the measurement of the surface impedance of sheet goods without requiring contact with the sample. Sheet goods can have an anisotropic, frequency-dependent surface impedance that is sensitive to minor changes in configuration of the sample. Because the electric field induced by the sensor is linearly polarized, measurement of directionally dependent sheet impedance can be achieved. The measurement is performed with the resonant device operating in resonance mode whereby the immediate proximity of the material to be measured causes damping and shifting of the coupled loop resonance. The resonant frequency of the sensor can be tuned by making changes to its geometry.

Abstract: A system for underwater communications through a region between a transmit antenna and a receive antenna using electromagnetic signals. When the system is in an inactive mode, the region is occupied by water. When the system is in an active mode, fluid having a reduced conductivity is introduced into the region to provide transmission of electromagnetic signals with a lower attenuation and thereby facilitate a higher data transfer rate for a given range of communication between the transmit antenna and the receive antenna.

Abstract: A pipeline inspection tool includes two pole magnets oriented at an oblique angle relative to the central longitudinal axis of the tool body. An array of sensor coil sets is located between opposing edges of the two pole magnets and oriented perpendicular to the central longitudinal axis. Each sensor coil set includes a transmitter coil and two opposing pairs of receiver coils that are gated to receive reflections from the wall of a tubular member. Because the line of sensor coils is rotated relative to the magnetic bias field, the receiver coils are in-line with, and have the same angular orientation as, the transmitter coil. The tool provides improved sensitivity to small defects, substantial decrease in RF pulser power requirements, full circumferential coverage, self-calibration of the transmitted signals, and less interference between transmitter coils caused by acoustic ring around.

Abstract: There is provided a magnetic force sensor including: an action unit elastically supported by a supporting member; a magnetic-flux generating source including two or more magnets which are disposed so that a polarity of each of the magnetic-pole faces of the magnets is opposite to a polarity of a corresponding one of the magnetic-pole faces of the adjacent magnets in a particular direction; first magnetoelectric transducers that are individually provided at positions, the positions being positions at which the first magnetoelectric transducers oppose the magnetic-pole faces of the magnets in the action unit; and a second magnetoelectric transducer provided between the first magnetoelectric transducers. Vertical-direction components of a force are detected on the basis of outputs of the first magnetoelectric transducers, and a horizontal-direction component of the force is detected on the basis of an output of the second magnetoelectric transducer.

Abstract: An eddy current probe includes an excitation coil for coupling to a low-frequency alternating current (AC) source. A magnetoresistive sensor is centrally disposed within and at one end of the excitation coil to thereby define a sensing end of the probe. A tubular flux-focusing lens is disposed between the excitation coil and the magnetoresistive sensor. An excitation wire is spaced apart from the magnetoresistive sensor in a plane that is perpendicular to the sensor's axis of sensitivity and such that, when the sensing end of the eddy current probe is positioned adjacent to the surface of a structure, the excitation wire is disposed between the magnetoresistive sensor and the surface of the structure. The excitation wire is coupled to a high-frequency AC source. The excitation coil and flux-focusing lens can be omitted when only surface inspection is required.

Abstract: A method and apparatus to determine a parameter of a metal-containing film are provided herein. In some embodiments, a method of determining a parameter of a metal-containing film may include generating a first magnetic field by flowing an alternating current through a coil disposed adjacent to and spaced apart from the metal-containing film, wherein the first magnetic field induces a second magnetic field proximate the metal-containing film; heating the metal-containing film from a first temperature to a second temperature; measuring a response of the first magnetic field to the second magnetic field as the metal-containing film is heated from the first temperature to the second temperature; and correlating the response with a rate of temperature change of the metal-containing film as the metal-containing film is heated from the first temperature to the second temperature to determine a parameter of the metal-containing film.

Abstract: An electromagnetic detection system comprising: a transmitter loop for generating a primary magnetic field, and spaced apart receiver coils for measuring a secondary magnetic field generated in response to the primary magnetic field.

Abstract: A vibration and condition monitoring system with true digital signal processing based design, with very limited analog based general signal conditioning and integrated specific sensor conditioning and sensor power supply options. The device supports direct connection of eddy current probe systems to the module, due to a built-in driver and linearization functionality. Linearization and compensation of a specific eddy current probe/cable system is done by measuring its far/infinite gap response. This response is then according to the invention recalculated into a linearization curve/transfer function. Specific sensor signal conditioning is not dependent on hardware, but only on embedded software (firmware). There is full sensor input support in an I.S. environment. Not only the common sensor input types from accelerometer, velocity sensor or eddy current probe system for both vibration and/or speed measurements.

Abstract: The systems and methods of detecting a change in object presence in a magnetic field disclosed herein inject a low amplitude signal near the resonant frequency into the coil until the system comes to equilibrium. At this point the feedback is measured. The feedback signal can be measured as at least one of several signals, for example, but not limited to the voltage on the resonant capacitor, the current in the coil, and the voltage between the resonant capacitor and the coil. A change in the steady state response indicates a change in device presence.

Abstract: A method for operating of a metal detection system may comprise a balanced coil system with a transmitter coil that is connected to a transmitter unit, which generates transmitter signals having a transmitter frequency that is selected from a group of at least two transmitter frequencies, and with a first and a second receiver coil that provide output signals to a signal input of at least one amplifier unit included in a receiver unit, wherein the output signals compensate each other so that the system is in balance. A system adapted to operate according to an exemplary method is also provided.

Abstract: The invention concerns a method for producing an assembly of at least one transmission coil (B1) and one reception coil (B2) for eddy current testing, the reception coil receiving in the absence of fault a complex amplitude signal VR, subject to a variation ?VR in the presence of a characteristic fault to be detected. The method consists in selecting the distance ?ER between the axes of the transmission coil and the reception coil so as to maximize the ratio I?VR/VRI.

Abstract: A device for nondestructive and noncontact detection of faults in a test piece, with a stationary measurement device (16) for taking an eddy current or a magnetic stray flux measurements on a test piece (10) continuously advanced relative to the measurement device; and a device (12) for positioning the test piece with respect to the measurement device in a plane perpendicular to the direction of movement of the test piece. The device also has a monitoring unit (20) with at least three distance sensors (22) arranged distributed around the test piece in the peripheral direction for contactless detection of the distance between the surface of the test piece facing the respective sensor and the respective sensor, as well as a unit for evaluating the signals from the sensors.

Abstract: An automated, non-destructive anhysteretic magnetization characterization method for studying and modeling soft magnetic materials. This measurement method employs a “reading-waveform” that allows multiple points of reference to be established in tracing out the B waveform. In using the reference values from this waveform, the components of B that cannot be measured directly may be calculated with precision. In turn, the initial magnitude of the B waveform is identified as the unknown component of the anhysteretic state. The processes can be repeated for different values of static fields as well as a function of temperature to produce a family of anhysteretic magnetization curves. The core characterization was performed without physically altering the core, so that the true anhysteretic magnetization curve, and the true B-H loop under applied bias H, is measured.

Abstract: It is an object of the present invention to provide an eddy current testing method capable of securely detecting a high hardness part locally occurring in a metal material having magnetism, and capable of securely checking whether the high hardness part has been removed after execution of a repairing treatment for removing the high hardness part. In the eddy current testing method according to the present invention, a frequency of the AC current for energizing the differential coil 1 is set so that a phase difference between a magnetism variation signal of the metal material P and a liftoff signal detected by the differential coil is equal to or larger than 135°, and a local high hardness part occurring in the metal material is detected based on an amplitude and a phase of a detection signal outputted from the differential coil.

Abstract: The method for detecting at least one structural defect in a spherical particle (33) comprises at least the following steps of passing the particle (33) into at least one induction coil (15); exciting the induction coil (15) in order to induce Foucault currents in the particle (33); acquiring an output signal at the terminals of the induction coil (15); and analyzing the signal in order to establish whether or not the particle (33) comprises a structural defect. A plurality of output signals are acquired by passing the particle (33) successively into one or more induction coils (15) with different positions of the particle (33), the or each induction coil (15) being excited at least each time the particle (33) passes in order to induce Foucault currents in the particle (33).

Abstract: The present device relates to a sensor capable of detecting changes in the electromagnetic field it generates when in proximity to either conductive or nonconductive materials. This occurs by way of oscillating a transmit coil with an electro motive force at a resonant frequency thus creating an electromagnetic field. The magnetic field passes through a target of either conductive or nonconductive material and is then intercepted by a receive coil which likewise oscillates at a resonant frequency, which when in proximity to the transmit coil and transmit coils resonant frequency produces an enhanced signal by way of the interaction of the respective resonant frequencies and receive coil output.

Abstract: A shielded eddy current coil probe is formed on a printed circuit board and comprises a first coil component forming a test coil and a second coil component forming an active shielding coil. The test coil and the active shielding coil are concentrically arranged and the number of coil windings in the active shielding coil and the field direction thereof are configured to limit the induced field or the sensed field in the test object to the footprint area of the test coil on the test object. Multiple sets of test coils with active shielding coils can be provided on the same or different layers of the printed circuit board to realize different driver, receiver and combined driver/receiver coil configurations.

Abstract: An electromagnetic system for biosensors including two independent electromagnetic units separated in the region of pole shoes of the electromagnetic units positioned under a gap, a cartridge positioned in the gap providing a sample volume and a biosensor having a sensor surface located at one or more inner surfaces of the cartridge proximate to the pole shoes.

Abstract: Disclosed is an eddy current flaw detection probe that is capable of pressing itself against an inspection target whose curvature varies. A flaw sensor is configured by fastening a plurality of coils to a flexible substrate that faces the surface of the inspection target. A first elastic body is positioned opposite the inspection target for the flaw sensor, is obtained by stacking two or more elastic plates, and has an elastic coefficient that varies in a longitudinal direction. A second elastic body is a porous body positioned between the flexible substrate and the first elastic body. A pressure section is employed to press the first elastic body toward the inspection target.

Abstract: An eddy current probe testing apparatus structured to operate concurrently in a driver pick-up mode and said impedance mode is provided. The eddy current probe has two coils. The eddy current probe testing apparatus also includes a signal producing device, an output device, and a switch assembly. The switch assembly is structured to switch how an input signal from the signal producing device is provided to the two coils.

Abstract: In an eddy current testing method which involves using a rotatable eddy current testing probe in which a detection coil is arranged within an exciting coil, a change in detection sensitivity (a deviation of detection sensitivity) which changes depending on the rotational position of the detection coil is reduced. The eddy current testing probe includes an exciting coil EC1, a detection coil DC1, an exciting coil EC2 and a detection coil DC2, which are mounted on a disk DS. The eddy current testing probe is placed so as to face a circumferential surface of an object to be inspected T, which is in the shape of a circular cylinder, and the disk DS is rotated. Then, the distance (liftoff) between the detection coils DC1 and DC2 and an inspection surface changes. Therefore, also the detection sensitivity to a flaw signal changes. To reduce the change in detection sensitivity, the detection sensitivity is adjusted by detecting the rotational position (rotational angle) of the detection coils DC1 and DC2.

Abstract: A sensor circuit is configured and operated in the presence of interference. In connection with various example embodiments, a stray magnetic field is sensed with current sensors that also respectively sense current-induced magnetic fields generated by current flowing in opposing directions through different portions of a conductor. The current-induced magnetic fields and the stray magnetic field are coplanar, and the current sensors are arranged such that a portion of the output from each current sensor corresponding to the stray magnetic field is canceled when the sensor outputs are combined.

Abstract: An object of the present invention is to provide a method for inspecting the presence or absence of a foreign metallic material mixed into an austenitic stainless steel material weld with more satisfactory accuracy. The method for inspecting an austenitic stainless steel weld of the present invention is characterized by comprises performing eddy current test of a weld portion of an austenitic stainless steel using a probe comprising an excitation and inspection coil and a permanent magnet disposed inside the excitation and inspection coil, and inspecting the presence or absence of a foreign metallic material mixed into the weld portion, and is also characterized in that magnetic flux density of magnetic field formed by the permanent magnet is from about 0.3 to about 1.5 tesla.

Abstract: This invention relates to a method of and apparatus for, measuring an object of interest. The apparatus (100) comprises an outer layer (102), an inner layer (101) which is intended to be attached to the object of interest, a coil arrangement comprising at least one transmitting coil (111) and at least one measurement coil (111?) arranged on the inner layer (101) obtains measurement signals, exciting circuits (112) and processing circuits (112?) are configured to cooperate with the coils (111, 111?) to get the measurement result. The inner layer (101) is movable together with the object of interest. At least part of the exciting circuits (112) and the processing circuits (112?) are arranged on the outer layer (102). In this way, the measurement error caused by movement of the object of interest can be avoided and the object of interest can feel comfortable by being mobile.

Abstract: Methods and apparatus for characterizing composite materials for manufacturing quality assurance (QA), periodic inspection during the useful life, or for forensic analysis/material testing. System are provided that relate eddy-current sensor responses to the fiber layup of a composite structure, the presence of impact damage on a composite structure with or without a metal liner, volumetric stress within the composite, fiber tow density, and other NDE inspection requirements. Also provided are systems that determine electromagnetic material properties and material dimensions of composite materials from capacitive sensor inspection measurements. These properties are related to the presence of buried defects in non-conductive composite materials, moisture ingress, aging of the material due to service or environmental/thermal exposure, or changes in manufacturing quality.

Abstract: Disclosed is a method of appropriately and easily selecting a combination of two different frequencies of an AC exciting signal used for eddy current measurement while decreasing or removing the dependence of the measurement accuracy on temperature. Three or more AC exciting signals of different frequencies are applied to an object under measurement by an exciting coil, and an induced current is produced. Detection signals corresponding to the frequencies are detected by a detection coil, and the phase difference between each detection signal and the AC exciting signal corresponding to each frequency is calculated from the detection signals corresponding to the frequencies. From the phase differences, a combination of two frequencies the phase differences of which are within a predetermined range is extracted. The lower frequency of the extracted combination is used for a first frequency, and the higher one is used as a second frequency. Thus, the combination of two frequencies are selected.

Abstract: An apparatus for calibrating a metal detecting device of a materials processing line. A placement arm is provided to control the path of a calibrating sample in order to simulate movement of tramp metal moving on a processing line along with materials being processed. Upper and lower arms of the placement arm are joined by an adjustable elbow which can be set to a maximum angle of extension in order to accurately place the calibrating sample at a preferred location in a detecting field of the metal detecting device.

Abstract: A magnetic field is generated by at least one coil in magnetic communication with at least a portion of a vehicle responsive to a first time-varying signal operatively coupled to the at least one coil in series with a sense resistor. A second signal is generated responsive to a voltage across the sense resistor and is response to a magnetic condition of the at least one coil, which is response to the magnetic communication of the at least one coil with the portion of the vehicle.