Abstract: Provided are an alternating current field based defect identification method and an array detection probe. The evaluation method includes the following steps: obtaining a magnetic field Bx signal in direction X and a magnetic field Bz signal in direction Z; removing a background magnetic field of each of the magnetic field Bx signal in the direction X and the magnetic field Bz signal in the direction Z, and obtaining a magnetic field Bx1 signal in the direction X and a magnetic field Bz1 signal in the direction Z without background magnetic fields; drawing an array image of the Bx1 signal and an array image of the Bz1 signal; and locating a distortion zone corresponding to disturbance at the same time and position in the array image of the Bx1 signal and the array image of the Bz1 signal.

Abstract: Apparatus and device for testing within a metal pipe are described. The apparatus includes an exciter for generating an electromagnetic (EM) field for exciting a wall of the metal pipe; an extendable and retractable sensor assembly comprising a plurality of sensor bars arranged in an angled manner with respect to an axis of the pipe for sensing residue EM field on a wall of the pipe; a plurality of guide wheel assemblies for supporting and moving the apparatus along the axis of the pipe; and a control unit for recording sensed data from the sensor assembly.

Abstract: An exemplary encoder assembly includes a substrate, a first encoder, and a second encoder. The substrate has two or more position sensors, each position sensor being configured for detecting a rotary position of a shaft or other rotating element of a machine. The first encoder includes at least one first position sensor of the two or more position sensors. The at least one first position sensor is disposed on the substrate for off-axis alignment with the shaft or other rotating element of the machine. The second encoder includes a second position sensor of the two or more position sensors, the second position sensor being disposed on the substrate for on-axis or off-axis alignment with the shaft or other rotating element of the machine. Each position sensor is configured to detect different or common signal types, and a signal type of the second position sensor excludes optical signals.

Abstract: Systems and method for a multi-array magnetic sensing component, which can include a circuit base platform; a set of magnetic sensors arranged on the circuit base platform; and a circuit system comprising intermediary circuit components, signal input, and a signal output, the signal input being an electrical oscillator signal input and being directable to each magnetic sensor in the set of magnetic sensors, the signal output including magnetic field measurements from the set of magnetic sensors, wherein each magnetic field measurement is individually selectable, the circuit system being configured to turn on or off subsets of the set of magnetic sensors, and the intermediary circuit components including a mixer.

Abstract: A leakage-flux flaw detection device includes a plurality of leakage-flux flaw detectors provided at positions not in contact with a steel strip and arranged in a width direction of the steel strip, wherein the leakage-flux flaw detectors each include a rotating disk that faces a surface subjected to flaw detection of the steel strip and that rotates, and a plurality of defect detection heads installed at different positions in a circumferential direction on the rotating disk, that perform direct-current magnetization of the steel strip, and detect leakage flux leaking from a linear defect due to the direct-current magnetization, wherein at least one of the plurality of defect detection heads has an inclination angle different from inclination angles of other defect detection heads, the inclination angle being defined by a tangent line of a rotation trajectory and the magnetization direction at an installation position of the defect detection head.

Abstract: An early sign detection device includes a plurality of sensors, a data acquisition unit configured to acquire time series variation data of a physical amount from each of the plurality of sensors, a computation unit configured to compute an occurrence probability of a vibration mode involved in a sudden variant vibration of a detection subject from an amplitude or a phase of the time series variation data of the physical amount at each of the plurality of positions, and a detection unit configured to detect an early sign of the sudden variant vibration on the basis of the occurrence probability of the vibration mode. The plurality of sensors are respectively disposed at a plurality of positions of the detection subject and are each configured to measure the physical amount at a corresponding position of the plurality of positions.

Abstract: A set of radial springs to bias the sensor arms of an inline pipeline inspection tool radially outward towards the pipe wall. The springs are resilient clips typically made of metal which bias adjacent sensor arms away from one another and radially outward. There are two sets of springs, a forward set and a rearward set which operate independent of each other. Each set of springs operates on a plane which is perpendicular to the axis of the body of the tool and perpendicular to the planes upon which the sensor arms extend.

Abstract: A magnetic detector includes permanent magnets that magnetize a wire rope W in the longitudinal direction, and a search coil that detects a change in the cross sectional area of the wire rope W magnetized by the permanent magnets. The magnetic detector is provided so as to surround a part of the wire rope W. Prior to inspection, the magnetic detector is moved back and forth at least three times across an inspection range of the wire rope W. After the magnetic detector is moved back and forth, the change in the cross sectional area, that is, damage to the wire rope W is inspected by using signals outputted from the search coil.

Abstract: A sensor assembly for monitoring a heater system for an aircraft probe sensor includes a current sensor module with a current sensor core and a high electromagnetically permeable enclosure around the current sensor core. An input wire pathway extends through the current sensor core and is configured to receive a heater input wire. A return wire pathway extends through the current sensor core and is configured to receive a heater return wire. A high electromagnetically permeable tube extends through the current sensor core and is configured to extend around one of the input wire and the heater return wire.

Abstract: Disclosed herein is a system for inspecting equipment and materials for quality. The system for inspecting equipment and materials for quality includes: a magnetic sensor configured to generate a magnetic field in an inspection target object, and to detect magnetic flux density; and a quality inspection server configured to determine the presence of a defect, a portion where the detect is present, and the type of defect for the inspection target object based on magnetic flux density waveforms over a range from one end of the inspection target object to the other end thereof that are generated via signals detected by the magnetic sensor.

Abstract: This magnetic body management system (100) includes: a first magnetic body inspection device (1) configured to acquire a detection signal (DS) before the magnetic body (MM) is installed at a location of use; a second magnetic body inspection device (2) configured to acquire a detection signal (DS) after the magnetic body (MM) has been installed at the location of use, the second magnetic body inspection device (2) having the same method as that of the first magnetic body inspection device (1); a server (3); a first transmission unit (4); and a second transmission unit (5). The server (3) is configured to estimate a deterioration state of the magnetic body (MM) based on at least the first magnetic body information (10) and the second magnetic body information (11).

Abstract: A device and a method for testing a steel defect based on internal and external magnetic perturbation. The device includes: a magnetizer comprising a magnetization source and a magnet yoke, arranged on a surface of a sample, and configured to generate two types of typical magnetic field regions applied to testing based on internal and external magnetic perturbation; a double-row magnetic sensor probe, configured to collect internal and external magnetic perturbation data; a master controller, configured to perform pre-processing on the internal and external magnetic perturbation data, and store the pre-processed data; scanner wheels, configured to generate a sampling trigger pulse during scanning to enable the master controller to receive the internal and external magnetic perturbation data from the probes; and a host computer, configured to analyze the pre-processed data uploaded by the master controller to obtain a defect quantitative result.

Abstract: A method and apparatus for detecting a discontinuity in the wall of a ferrous object is disclosed, which utilize a bank of sensors where each sensor is configured to detect a difference in magnetic flux across a predefined area. Sets of readings from the sensors are converted to images, from which the existence and location of a discontinuity can be detected.

Abstract: A one-step method of cleaning a girth gear set of a mill in preparation for inspection is provided, the method comprising: substantially emptying the mill; inching the gear; spraying a low, very low or non-Volatile Organic Compound (VOC) cleaning formulation at high pressure onto the gear, the cleaning formulation comprising a non-VOC aliphatic hydrocarbon solvent, an extreme pressure lubricant, a fretting wear lubricant, a non-ionic surfactant, and a mixture of non-VOC unsaturated fatty alcohols; and continuing to spray the low or very low VOC cleaning formulation on the gear for sufficient time for the formulation to clean the gear, thereby providing a so cleaned gear.

Abstract: A testing system for testing a device under test including a plurality of circuits under test includes a probe card, testing apparatus, and a controller. The probe card includes a plurality of probes temporarily coupled to the circuits under test. The testing apparatus holds the probe card and tests the circuits under test through tine probe card. The controller controls the testing apparatus and executes a testing procedure that includes: measuring the contact resistance values between the probe card and each of the circuits under test; determining a statistical value of the contact resistance values; determining whether the statistical value exceeds a first threshold; when the statistical value does not exceed the first threshold, setting a clean flag to be in a first state; otherwise, setting the clean flag to be in a second state; and performing a clean operation on the probes according to the clean flag.

Abstract: A method for determining a quantity of interest in a target comprises: providing simulated statistics of a deviation, caused by a boundary distortion in observations of the physical quantity; providing an approximate mathematical model of observations of the physical quantity, the approximate mathematical model defining the physical quantity to be dependent on the quantity of interest in the target domain, and on a deviation a boundary distortion causes in the observations, said deviation being determined to behave in accordance with the simulated statistics; receiving measured values of the physical quantity; determining an observation difference between the measured values of the physical quantity and corresponding observations according to the approximate mathematical model, and adjusting the approximate mathematical model to reduce the observation difference; and determining an estimate of the quantity of interest in the target domain on the basis of the adjusted approximate mathematical model.

Abstract: Described embodiments generally relate to a method of determining power delivered by a cable, the method comprising receiving data related to a residual magnetic field produced by the cable; determining a proportionality factor relating the received data to the power delivered by comparing the residual magnetic field data to independently measured reference data related to the power delivered by the cable; and based on the proportionality factor, determining the power delivered by the cable.

Abstract: Apparatuses and methods for inspecting a section of piping are disclosed. In one example embodiment, an apparatus includes first and second excitation coils, a plurality of magnetometers, and a data acquisition system. The first excitation coils are disposed at a first axial location and are energized with a first swept frequency waveform and the second excitation coils are disposed at a second axial location and are energized with the swept frequency waveform. The plurality of magnetometers are disposed at an axial location between the first and second axial locations and are positioned to detect magnetic fields generated by eddy currents induced in the section of piping by the first and second excitation coils. The data acquisition system is operatively connected to receive output data from the plurality of magnetometers.

Abstract: A high mast light pole inspection system includes a command center and a transport vehicle. The transport vehicle has a frame configured to be secured around a high mast light pole, and a plurality of sets of wheels. Each set of wheels has a spring mechanism that biases a respective set of wheels inward towards a center of the frame. The plurality of sets of wheels are wirelessly controlled from the command center. In addition, the transport vehicle includes a plurality of cameras mounted to the frame, a power supply coupled to each set of wheels and camera, and a RF digital video transmitter coupled to the plurality of cameras. The transmitter is configured to transmit a wireless multiplexed output of the cameras to the command center.

Abstract: A sensor system has an integrated sensor cartridge, and instrument, and an instrument side connector. The integrated sensor cartridge has a mechanical support, a flexible sensor array, and a rigid connector. The mechanical support is shaped to facilitate sensor measurements on a test object. The rigid connector has a mechanical connection and an electrical connection for simultaneous electrical and mechanical mating of the sensor cartridge to the instrument side connector. The flexible array has a connecting portion, a lead portion, and a sensing portion. The sensing portion is attached to the mechanical support, and the connecting portion interfaces with the rigid connector. The connecting portion may form the electrical connection of the rigid connector or may simply mate internally with the electrical connection. The instrument side connector is connected to the instrument which measures the response of the flexible sensor array.

Abstract: Apparatus and methods for sensing current carried by one or more planar conductors is described. A plurality of sensing coils may be fabricated adjacent to one or more planar, current-carrying conductors. The sensing coils may detect a magnetic field generated by time-varying current flowing through the one or more planar conductors. The sensing coils may be arranged to cancel uniform and linear-gradient magnetic fields.

Abstract: A method of examining a wheel or rim on site is provided using an eddy current array probe in electronic communication with a computer, the computer having a processor and a memory, the memory to provide instructions to the processor. The method involves standardizing the eddy current array probe with a reference standard, adjusting the eddy current array probe with a lift off screw to provide a suitable distance between the probe and a surface of the wheel or rim, scanning the wheel or rim with an alternating current, sending a data set to the computer, the computer analyzing the data set, and the computer displaying a three-dimensional image of the data set on a user interface. This method is particularly developed for off road vehicles at mining sites or any off road vehicle wheels and rims.

Abstract: A measurement system, its assembly and use are disclose. The system may include an instrument for making sensor measurements. The instrument has a substantially cylindrical housing. The shape and size allow the instrument to easily fit in an average hand enabling handheld operation. The housing houses a board stack of electronic boards. These electronics drive an electrical signal in at least one drive channel and measure responses from at least two sensing channels. These responses are provided to a processor for analysis. The instrument has a sensor connector that enables simultaneous electrical and mechanical attachment of an end effector.

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 method is provided for inspecting a prestressed concrete pipe (PCP). An impedance probe is passed along the PCP. As the impedance probe travels along the PCP, a magnetic field within the impedance probe is generated and the impedance of the impedance probe is measured. The measured impedances are analyzed for anomalies, which may indicate broken prestressed wires. RFT probes, which are what are typically used for inspecting PCPs, require axial separation of two coils, one being an exciter coil and the other being a passive detector coil. However, there is only a single coil in an impedance probe and so the apparatus used to inspect the PCP is not as large axially. The apparatus used to inspect the PCP is simpler to set up than if an RFT probe is used, and coupling between a transmitter and a receiver is not a concern.

Abstract: The present invention provides a partial-discharge measurement method in which a partial-discharge defect signal and noise are separated, a partial-discharge defect position is detected, and the risk of a detected partial discharge defect is diagnosed. Further, this method provides a highly reliable high-voltage device. An electromagnetic wave generated by a sample is simultaneously measured by a plurality of sensors. A partial discharge and noise are separated through the comparison of the spatial intensity distribution of measured signals and a spatial signal intensity distribution measured beforehand at the time of the occurrence of a partial discharge, and a defect position is detected using a peak position. Further, the risk of a defective site is diagnosed on the basis of a simultaneously measured charge amount signal.

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: The present invention relates generally to lifting gear such as cranes which use high-strength fiber ropes instead of steel ropes. In this respect, the invention in particular relates to an apparatus for recognizing the discard state of a high-strength fiber rope in use at such lifting gear comprising a detection device for detecting at least one rope parameter as well as comprising an evaluation unit for evaluating the rope parameter and for providing a discard signal in dependence on the rope parameter evaluation. In accordance with the invention, the detection device of the apparatus for recognizing the discard state comprises a plurality of differently configured detection means for a magnetic, mechanical, optical and/or electronic detection of a plurality of different rope parameters which can be evaluated by the evaluation unit individually and/or in combination with one another for recognizing the discard state.

Abstract: A leakage flux probe for non-destructive leakage flux-testing of magnetizable bodies comprising a plurality of coils for detection of near-surface flaws in the body, wherein the coils have a degree of sensitivity which is dependent upon the orientation of the flaws in the body, and wherein coils having a different degree of sensitivity are disposed in the leakage flux probe with a first type of coil having a high degree of sensitivity for longitudinal flaws or transverse flaws and a second type of coil having a high degree of sensitivity for oblique flaws.

Abstract: An eddy current object testing system includes an EC probe and an acquisition channel which is configured to receive an EC signal from the EC probe and to generate a visual output, namely an impedance plane representation, of the output. A display is coupled to the acquisition channel to display the visual output. The at least one probe is provided with a test loop substantially surrounding it and has a series switch which can be selectively closed or opened to thereby cause the image plane to assume a state that is indicative of a fault, if any, in the EC probe.

Abstract: A method of magnetizing a multi-pole magnet includes the steps of obtaining a magnetization coil having a magnetization zone and a central axis, and positioning a magnet within the magnetization zone. The method also includes positioning at least one pair of shield bodies including a conductive material proximate the first and second surfaces of the magnet, with the shield bodies being aligned together to cover both sides of at least a first region of magnet and expose both sides of at least a second region of the magnet. The method further includes energizing the magnetization coil to generate an applied magnetic field within the magnetization zone that is sufficient to induce eddy currents in the at least one pair of shield bodies and to magnetize the exposed second region of the magnet.

Abstract: A projected artificial magnetic mirror (PAMM) includes conductive coils, a metal backing, and a dielectric material. The conductive coils are arranged in an array on a first layer of a substrate and the metal backing is on a second layer of the substrate. The dielectric material is between the first and second layers of the substrate. The conductive coils are electrically coupled to the metal backing to form an inductive-capacitive network that, for a a selected frequency band, substantially reduces surface waves along a PAMM surface, the PAMM surface residing within the substrate or above the substrate. The PAMM surface may be substantially adjacent or coexistent with the first layer.

Abstract: Disclosed is an ECA probes assembly capable of providing reliable and durable ECA inspections of dovetail slots without the use of an external guiding mechanism. The design combines a novel universal probe manipulator with a probe support suited for a wide range of probe supports which fit a rage of turbine disks. The probe support embodies a rigid yet expandable core, exerting a force pushing the array probe against the inner cavity of the dovetails. The pushing force is strategically located in critical areas of the dovetail leading to array probe to be self-guiding into the dovetail, and to provide optimum performance with consistent and stable lift-off.

Abstract: Disclosed is a sensor and housing assembly for a single-use bioreactor system, including a device for operatively associating a sensor with a flexible wall, the device comprising an internal housing portion that is removable and variably positionable on an internal surface of the flexible wall, the internal housing portion comprising a chemical detector sensor, which may be an optical chemical detector sensor.

Abstract: A method and apparatus for the non-destructive testing of electrically conductive components such as wellbore tubulars, which is suitable for testing the components in situ a wellbore installation. The method comprises the steps of performing a remote field eddy current test phase and at least one of a conventional direct-field eddy current test phase and a partial saturation eddy current test phase. A measurement data set from each of the test phases is obtained and the combined measurement data is processed to evaluate a condition of the test component.

Abstract: A multi-layer eddy current sensor includes a sense coil for detecting an eddy current, and a drive conductor for inducing the eddy current. The drive conductor comprises a substantially straight conducting portion that traverses the entire width of the sense coil.

Abstract: A method and apparatus for inspecting a metallic structure. A first signal is sent into a first location in the metallic structure and a second signal into a second location in the metallic structure at substantially a same time. A first response to the first signal is received. A second response to the second signal is received. The first response is compared with the second response to form a comparison. A determination is made as to whether an inconsistency is present using the comparison.

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: A method for monitoring local defects in a rotating engine component such as a gear uses one or more eddy current sensor(s) arranged to interact with the engine component as it is rotating during service. The eddy current sensor(s) may be carried by one or more teeth of a monitoring gear. A device is arranged to measure an output signal from the eddy current sensor(s) resulting from interaction with the rotating engine component. The output signal is processed so as to detect a change in shape of the output signal indicative of a local defect.

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 water-chamber working apparatus 1 according to the present invention includes a movable body that can move along a tube plate 12 of a steam generator 10, an extendable member 21 that extends and retracts in a direction in which a first coupling portion 21d approach each other and a direction in which these portions move away from each other, where the first coupling portion 21d is attached to a maintenance hatch 15 via a first joint 23a including two rotation axes intersecting with each other, and the second coupling portion 21e is attached to the movable body via a second joint 23b including two rotation axes intersecting with each other, which are different from the rotation axes of the first joint 23a.

Abstract: A device and method of eddy current based nondestructive testing of tubular structures made of electrically conductive materials is disclosed. The device includes a plurality of excitation electromagnets having an axis of symmetry and magnetoresistive sensors having an easy axis for magnetic field sensing; wherein the magnetoresistive sensors are arranged in a circular array on a single plane with the easy axis aligned radially with respect to the circular pattern and wherein the electromagnets are arranged in a circular pattern on both sides of the plane with their axes of symmetry being arranged parallel to the plane and orthogonal to radii of the circular pattern on which the electromagnets are placed.

Abstract: The present inventions provides a magnetizing apparatus 100 for magnetic particle testing of a wheel 7 that includes a hub 71, a plate 72, and a rim 73 in sequence from inward to outward in a radial direction of the wheel. The apparatus includes: a conductor 1 inserted through a bore 711 of the hub 71; and a pair of auxiliary conductors 2 connected to respective opposite end portions of the conductor 1, and so disposed as to face respective opposite side surfaces of the wheel 7, and to extend from the hub 71 to the rim 73 outwardly in a radial direction of the wheel 7, wherein the pair of auxiliary conductors 2 and the conductor 1 are energized with alternating current.

Abstract: A semiconductor device having a lateral semiconductor element includes a semiconductor substrate, a first electrode on the substrate, a second electrode on the substrate, and an isolation structure located in the substrate to divide the substrate into a first island and a second island electrically insulated from the first island. The lateral semiconductor element includes a main cell located in the first island and a sense cell located in the second island. The main cell causes a first current to flow between the first electrode and the second electrode so that the first current flows in a lateral direction along the surface of the substrate. The first current is detected by detecting a second current flowing though the sense cell.

Abstract: A probe for detecting distortions in a material includes a probe body, a ferrite core in the probe body, an excitation coil encircling the ferrite core and adapted to generate eddy currents, further magnetic shielding surrounding the excitation coil, and at least one giant magnetoresistive (GMR) sensor disposed in magnetic field-communicating relationship with the excitation coil and off-center with respect to the excitation coil's axis.

Abstract: A current sensor arrangement comprises plural sensor elements arranged around a center point, each of the sensor elements having a plane of zero sensitivity to uniform magnetic fields. A first one (202) of the sensor elements has a first angular separation (X1) relative to the center point from a second, adjacent sensor element (204) and a second angular separation (X2) relative to the center point from a third, adjacent sensor element (206). The first angular separation is less than the second angular separation. An intercept (I13) of the planes of the first and third sensor elements is located outside a triangle formed by the center point and the first and third sensor elements and an intercept (I12) of the planes of the first and second sensor elements is located inside a triangle formed by the center point and the first and second sensor elements.

Abstract: A semiconductor device having a lateral semiconductor element includes a semiconductor substrate, a first electrode on the substrate, a second electrode on the substrate, and an isolation structure located in the substrate to divide the substrate into a first island and a second island electrically insulated from the first island. The lateral semiconductor element includes a main cell located in the first island and a sense cell located in the second island. The main cell causes a first current to flow between the first electrode and the second electrode so that the first current flows in a lateral direction along the surface of the substrate. The first current is detected by detecting a second current flowing though the sense cell.

Abstract: Inspection systems provided herein include drive coils capable of being excited to generate a substantially uniform magnetic field about an object. The object includes a ferromagnetic adhesive adhered thereto. The inspection systems may also include an array of sensor coils adapted to detect the magnetic field from the drive coils after the magnetic field interacts with the ferromagnetic adhesive and to produce a voltage output corresponding to the detected magnetic field.

Abstract: The present invention discloses an eddy current probe and an eddy current inspection device including the eddy current probe for inspection of surface defect of a rotor wheel including a dovetail coupling part in which a hook is formed. The eddy current probe in accordance with an embodiment of the present invention includes: a main body, a contact part coupled to the main body and having a convex part and a concave part formed thereon corresponding to the hook, and an eddy current sensor being coupled to an end part of the convex part of the contact part. Accordingly, the detectability of a defect and the permeation depth can be enhanced, and the inspection procedures can be simplified.

Abstract: The device comprises a magnetization unit, which generates a constant magnetic field, to which the test specimen (12) is exposed so as to magnetize it. The magnetization unit and test specimen (12) carry out a relative motion to each other, thereby inducing eddy currents in the test specimen (12). The magnetization unit has at least one yoke (10) projecting in the direction of the relative motion. In addition to a probe (14), which is offset toward the back with respect to the magnetization unit in the direction of the relative motion and which is suited to detect damage based on the influence of the damage on the induced eddy current, the device comprises at least one further probe (16) between the yoke limbs of the magnetization unit.