41 results about "Search coil" patented technology

An apparatus and method for determining a condition of an electric machine. Search coils are wound around stator teeth and the induced voltage is used to decouple stator and rotor fluxes. The decoupled fluxes allow for machine condition monitoring and fault diagnosis.

Provided is a contactless power transfer device for a moving object. Each of a power transmission coil and a power receiving coil comprises an H-shaped core, and first, second and third search coils are installed on a magnetic pole object of the H-shaped core of the power transmission coil. A y-direction positional deviation between the power transmission coil and the power receiving coil is detected using voltages measured at the first and second search coils, and an x-direction positional deviation is detected using voltages measured at the third search coils.

The present invention discloses a magnetic clamping device having at least one magnetic holding unit comprising a switchable magnet generating a magnetic clamping force at a workpiece and a sensing means, wherein said sensing means comprises a search coil adapted to provide a detection signal indicative of a magnetic flux being applicable for at least approximately determining a clamping force exerted on the workpiece to be clamped and a method for detecting an operating state of a magnetic clamping device.

The invention discloses a device and a method for monitoring and protecting a series reactor. A search coil assembly is arranged inside or outside a dry type air core reactor coil body; one side of the search coil assembly corresponds to the reactor; the other side of the search coil assembly is correspondingly provided with an isolation transformer; one end of the isolation transformer is grounded; the other end of the isolation transformer is connected in series with a filter module; the filter module, a resistor and a TVS (Transient Voltage Suppressor) are connected in series in sequence and then grounded; the filter module and a data acquisition module are connected in series in sequence and then grounded; and the data acquisition module is connected with a control computer. The device and the method for monitoring and protecting the series reactor have the beneficial effects that the occurrence of serious accidents such as reactor firing is prevented, and the operation safety coefficient of a current limiting reactor is improved, so that the safe operation of the transformer is guaranteed.

The invention discloses a linear induction accelerator test platform and a double-coil detection structure. The structure comprises: a PCB, a detection coil A, organic glass, and a detection coil B. The organic glass is fixed to the wall of a beam pipe. The PCB is fixed to the organic glass. The detection coil A and the detection coil B are fixed to the PCB and have opposite grounding direction. The double-coil detection structure solves a technical problem that a conventional detection structure is complicated and high in industrial requirements, is simple in structure and low in process requirement, has no influence on the transmission of beams, and improves the diagnostic efficiency of the beam radius.

A portable metal detection system that includes a hand / wrist mounted metal detector with two search coils mounted on the palm side of the detector. The mounted metal detector includes a wireless transmitter and a small rechargeable fuel cell. The detection system also includes a separate housing that contains a wireless receiver, a small rechargeable fuel cell and an adjustable vibration or audio alert circuitry. The separate housing may be worn anywhere on the operator of the system. Once the hand / wrist mounted metal detector detects a metal object, the wireless transmitter sends a signal to the wireless receiver in the separate housing that activates the vibration or audio alert circuitry. The separation of the detection device and the alert circuitry prevents a metal detection detainee from hearing or feeling a metal detection alert.

A new dual field search coil for pulse induction metal detectors has multiple coplanar wire coils of different diameters connected in series with the output of a pulse source, overcoming the loss of target size resolution associated with a single coil search loop. Small objects are sensed by an internal small coil and larger objects are sensed by the larger outside coil, and the overall depth of target sensing remains similar to that of a single coil construction. The smaller coil is isolated from the pulse source by the inductance of the larger coil and will ring at a frequency determined by its own parameters. To prevent the smaller coil from ringing, a second damping resistor is connected across the terminals of the smaller coil at the junction of the large and small coils making up the modified search loop.

An apparatus and a method for controlling operation of a reciprocating compressor is capable of reducing a stroke estimation error by eliminating an error that occurs due to resistance and inductance of a compressor motor by estimating a stroke with a counter electromotive force induced by a searching coil. Furthermore, by leaving errors of inductance and resistance, among all motor parameters, out of consideration in stroke estimation, a stroke estimation error can be reduced.

A search coil assembly comprises a transmit coil operable for radiating a magnetic field in response to a time varying current. The transmit coil comprises a conductive path being disposed at least within a transmit plane for radiating the magnetic field. At least one receive coil is operable for inducting a current in response to a time varying magnetic field. The receive coil comprises a conductive path being disposed within a receive plane for inducting the current. The receive coil is positionable to place the receive plane and the transmit plane in a substantially orthogonal orientation with the receive plane being substantially within null regions of the transmit coil's magnetic field, in which a metallic object, at a distance from the search coil assembly, reacts to a radiated magnetic field from the transmit coil, and the receive coil inducts a current in response to the reaction.

The invention discloses an open-type magnetic field shielding device capable of adjusting at full frequency band, and belongs to the technical field of electromagnetic compatibility. The magnetic field shielding device comprise a magnetic field searching coil, a magnetic field detection oil, a driving circuit, a magnetic field adjustment coil and a corresponding matched sample table, wherein the magnetic field detection coil is used for monitoring change of an environmental magnetic field, the magnetic field adjustment coil is driven to offset with an external magnetic field by the driving circuit after a power is amplified, the magnetic field searching coil is placed right above the device, the sample table is placed in the center of the magnetic field adjustment coil, the magnetic fielddetection coil is connected with a magnetic field detection probe and is placed on the sample table, the driving circuit is placed at an outer side of the magnetic field adjustment coil, and a shielded magnetic field is arranged above the driving circuit. The magnetic field shielding device capable of adjusting at full frequency band is more beneficial for engineering practice.

The invention provides a device and a method for detecting winding inter-turn short-circuit fault of a fraction-slot concentrated winding permanent magnet motor. The method comprises the following steps: placing search coils at winding ends of the fraction-slot concentrated winding permanent magnet motor; combining measurement values of search coils corresponding to different phase windings into aset of detection signals; and determining whether a motor has an inter-turn short-circuit fault by comparing a detection signal of a group of search coils with a threshold value. The method does notneed to perform Fourier transform on detected values, and does not need to add an additional data collection device, which is simple and convenient and has low-cost.

Embodiments of the present invention provide for a system and apparatus for mobile device integration of a portable metal detector. In an embodiment of the invention, a portable metal detector includes a shaft, a handle attached to shaft, a mobile device housing attached to the handle, and a search coil attached to a distal end of the shaft. The search coil includes a search coil configured to wirelessly transmit a signal detected by the search coil.

The invention relates to a device and method for detecting sparse pulse by utlizing a vortex finder, exactly, the induced flux caused by pipeline defect is preferentially detected by utlizing the vortex finder, a search coil and a Hall sensor, so that the general pipeline defect and the specific pipeline defect can be simultaneously detected. According to the invention, the average thickness of a pipeline coverd with a thermal insulation material or thick pipeline is measured by a large diameter induction coil, and any local defect of the pipeline can be detected by the Hall sensor located in the central part. The quantitative measurement of pipeline wall thickness reduction can be improved, and any defect can be detected in a simple processing manner without professional operation.

A power converter including: a transformer; a primary-side full-bridge circuit including a primary-side coil of the transformer and a magnetically-coupled reactor, in which two reactors connected to both ends of the primary-side coil are magnetically coupled; a first port connected to a positive electrode bus bar of the primary-side full-bridge circuit; a second port connected to a tap of the primary-side coil; a secondary-side full-bridge circuit including a secondary-side coil of the transformer; a third port connected to a positive electrode bus bar of the secondary-side full-bridge circuit; a first search coil wound around a core of the magnetically-coupled reactor; a second search coil wound around a core of the transformer; and a detection circuit detecting voltages of the first port and the third port by measuring a variation in a sense voltage generated by combining voltages of the first search coil and the second search coil.

The invention provides a multifunctional magnetometer with combination of a searching coil type and a flux-gate type. The multifunctional magnetometer comprises a feedback winding, a coil and a magnetic core, wherein the multifunctional magnetometer is provided with a sensitive shaft for measuring three magnetic-field components of one space point; the sensitive shaft adopts a thin-long space structure with integration of an X axis, a Y axis and a Z axis; the thin-long space structure can be provided with one section of Z axis, two sections of Z axes, three sections of Z axes or N sections of Z axes. The feedback winding adopts a Helmholtz coil structure and comprises a middle coil and an internal magnetic core. The invention also provides an application of the multifunctional magnetometer. The multifunctional magnetometer has the characteristics that the loop-opening sensitivity is high, the direct-current magnetic field is accurately measured, the weak alternating-current magnetic field overlaid in the direct-current magnetic field is accurately measured, the amplitude amplification factors of alternating-current magnetic fields with all frequencies are equal, and the alternating-current magnetic fields work in the flux-gate mode or the searching coil mode in a time division way.

The invention discloses a self-starting method of a bi-directional wireless power transmission system based on the detection of a searching coil. The method is suitable for the self-starting of a noncontact power bi-directional transmission system. Taking the power flowing from a side 1 to a side 2 as an example, at the starting stage of the system, the phase information of a high-frequency inversion voltage at the side 1 is acquired by using a sampling resistor at the side 2 and used as an input of a controller at the side 2, so that the controller at the side 2 outputs a control pulse meeting the phase requirement of the system. After the self-starting process of the system is completed, the controller at the side 2 generates a turn-off signal to cut off the sampling resistor, so that the consumption on the sampling resistor when the circuit works normally can be eliminated; meanwhile, the input voltages at the side 1 and the side 2 are converted to a normal voltage stage so as to execute the high-efficient wireless bi-directional transmission of the energy.

A mount is for installing a probe, such as for example, a search coil, in a variety of locations and orientations within an electrical generator, without requiring the rotor of the generator to be removed. The mount includes a block having a longitudinal hole and a plurality of transverse slots intersecting the hole. A plurality of wedges are disposed within the slots. A wedge pin inserted into the longitudinal hole engages the wedges forcing the wedges outward in order to secure the mount and search coil thereon in the desired position within the generator, such as for example, in the air gap between the rotor and stator. A fastening mechanism further secures the mount in place.

A method for measuring an apparent density of a metal powder includes holding a metal powder in a vessel, applying an alternating magnetic flux to the metal powder using an exciting coil disposed outside the vessel, detecting the alternating magnetic flux passed through the metal powder using a search coil disposed outside the vessel, and determining an apparent density of the metal powder from an amplitude of the detected alternating magnetic flux using a calibration curve representing a correlation between the apparent density of the metal powder and the amplitude of an alternating magnetic flux prepared in advance. The method enables to measure the apparent density of a metal powder with a high precision in an on-line and non-contact manner without stopping a process of producing a mixed powder or a process of producing a powder compact.

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.

A method for parameter estimation in an electromagnetic actuator having a main coil and a search coil includes driving a current through the main coil, determining a main coil voltage, determining a search coil voltage, determining a main coil current, and estimating at least one parameter of the actuator based on the main coil voltage, the search coil voltage and the main coil current.

Provided is a wire rope flaw detector including a magnetizer configured to form a main magnetic flux in a part of a wire rope in a longitudinal direction thereof. A plurality of search coils are configured to detect a leakage flux that occurs from a damaged part of the wire rope in a segment in which the main magnetic flux is formed. A control unit is configured to detect induced voltages generated in the plurality of search coils. Further, the control unit is configured to superimpose voltage waveforms of the plurality of search coils on one another while shifting the voltage waveforms by a time calculated based on an interval between the plurality of search coils adjacent to each other and on a relative moving speed of the wire rope with respect to the magnetizer, to thereby amplify a peak of the induced voltage.

The invention relates to the technical field of superconducting quantum interference devices (SQUID). The invention adopts double closed-loop detection coils, makes the current of the common part of the two closed loops proportional to ΦA-2ΦB+ΦC, couples with SQUID, and obtains a second-order magnetic field gradiometer. The present invention has a simple structure; as long as the SQUID can be coupled with the line 1, the present invention has no strict requirements on the position of the SQUID; multiple SQUIDs can be coupled with the line to improve the yield.