86 results about "Magnetic impedance" patented technology

A three-phase current limiter (30) for an alternating current system includes an AC magnetic circuit having at least one AC coil (35R1, 35S1, 35T1) for each phase of a 3-phase AC supply wound on a saturable ferromagnetic core and configured to subject respective AC coils for each phase to a common magnetic flux, and a DC magnetic circuit (34a, 34b) for biasing the AC magnetic circuit into saturation at normal conditions. In use the AC coils are connected in series with a load and during alternate half cycles of the AC supply at least one of the AC coils produces a magnetic field that opposes a magnetic field of the DC magnetic circuit. The AC coils (35R, 35S, 35T) for each phase are configured so that at least one of the AC coils exhibits unbalanced magnetic impedance relative to remaining ones of the AC coils for each phase.

The invention discloses a full-tensor magnetic field gradiometer based on the giant magnetic impedance effect. The full-tensor magnetic field gradiometer comprises an X-Y-direction gradiometer body, a Z-direction gradiometer body and signal leads. The X-Y-direction gradiometer body comprises a cross-shaped substrate and a giant magnetic impedance thin film, the Z-direction gradiometer body comprises a rectangular substrate and a giant magnetic impedance thin film, a junction point at the input end and a junction point at the output end of an electric bridge are connected with the signal leads, and the signal leads are arrayed symmetric with the geometric center of the whole gradiometer as the three-dimensional center. The full-tensor magnetic field gradiometer has the advantages of being high in accuracy, minimized, low in cost, wide in frequency response, rich in information and the like. Due to the design of preparing a three-dimensional structure through planar thin films, the problem of space consistency of the full-tensor magnetic field gradiometer based on the giant magnetic impedance thin films is solved, and the magnetic field gradient measuring sensor with the size at the chip level is designed for the first time.

A small, low-cost, wide-range current sensor excellent in environmental resistance and noise resistance and high in accuracy, and an application device, a DC magnetic field is applied to two magnetic elements (1a, 1b) having a magnetic impedance effect by means of a magnet (3), while a negative feedback magnetic field is applied to both elements by means of a coil (2). The variation of the magnetic field depending on the external magnetic field applied to the magnetic elements (1a, 1b) is detected by detection units (7a, 7b). The difference between the output is amplified by a differential amplifier unit (8). Thus, detection is achieved in a wide range while eliminating the influence of the noise.

A transducer of giant magnetic impedance field is prepared as applying transistor with cut ¿C off frequency of 3 ¿C 60 MH2 as kerr magnetic oscillation circuit, applying the same resistance value on two voltage ¿C dividing resistances between base electrode and ground as well as between base electrode and DC power supply, series ¿C connecting crystal oscillator with frequency of 1¿C 20 MH2 with vibration starting capacity between base electrode and ground, existing noncrystalling belt as part of radio electrode load.

The invention relates to a rapid deexcitation system for synchronous machines (1) with indirect excitation by means of an excitation machine (2) and rotating rectifier bridge (8) comprising:

• • a deexcitation impedance (10) connected between the field winding (5) of the synchronous machine (1) and the rotating rectifier bridge (8);
  • a controller (9) connected in parallel with the deexcitation impedance (10);
  • a control circuit (11) of the controller (9) configured to:
    • keep the controller (9) closed such that the rotating rectifier bridge (8) directly feeds the field winding (5) of the synchronous machine (1) during normal operation of the synchronous machine (1);
    • open the controller (9) such that the deexcitation impedance (10) remains in series with the field winding (5) and with the rotating rectifier bridge (8) when the synchronous machine is to be deexcited.

In an overload current protection device for cutting off power from a power supply to a load (3) such as a motor by means of a contactor (switch) (2) at overloading, an MI element having a magnetic impedance (MI) effect as current detectors (4a, 4b, and 4c) is installed at a position capable of detecting a current flowing through the secondary winding of power supply transformers (5a, 5b, and 5c) that generate a control power supply to thereby reduce costs without using a constant voltage power supply and expand a current detection range by eliminating magnetic saturation due to a core, a problem with a conventional current transformer, thereby providing at low costs a high-precision overload current protection device having a wide current detection range.

This invention relates to a manufacturing method for a huge magnet impedance effect magnet-sensitive device based on micro-electromechanical system (MEMS), which applies MEMS technology to process a double-face oxidized silicon chip to get an aligned symbol carved in double faces so as to increase the aligned accuracy when exposing, applies a quasi-LIGA photo etching technology and micro plating to prepare a zigzag sandwich structure FeNi/Cu/FeNi soft magnet multiplayer membrane material, applies physical etching to remove the substrate to avoid the erosion brought with wet etching and offsets the huge magnet impedance effective curves by selecting suitable magnets to make the magnet-sensitive device to work in the linear zone.

The invention discloses a system and a method for corrosion diagnosis of a grounding grid of a transformer substation on the basis of an inductive apparent magnetic impedance method. The system includes a transmitter that is connected between two down-lead conductors of the grounding grid of the transformer substation. The transmitter employs a sine excitation source and is used for injecting a frequency-adjustable excitation current into the grounding grid so as to excite a magnetic induction intensity signal of ground surface; the system also includes: a trolley arranged on the ground, on which two detection coils are arranged vertically to each other and are used for detecting the magnetic induction intensity signal and converts the magnetic induction intensity signal into an inductionvoltage signal; the detection coils are successively connected to a receiver and an upper computer, wherein the receiver is used for collecting and processing the induction voltage signal so as to acquire amplitude spectrum and phase spectrum, and the upper computer draws two-dimensional and three-dimensional figures of the amplitude and phase by means of Lab VIEW software. In the invention, by means of injection of the frequency-adjustable large excitation current and measurement of trapped wave circuits and wave filtering on hardware, the system can avoid intensive electromagnetic interference from the transformer substation and can provide more reliable measurement data.

A magnetic field detecting device which comprises a magnetic impedance sensor including a magnetic impedance element 1 in which a pulse electrical current or a high frequency electrical current is applied from an oscillator 2 to an amorphous wire 10 and an alternate current or AC damped oscillation voltage, which is induced in a detecting coil 11 wound around the amorphous wire 10 and has a magnitude corresponding to an external magnetic field, is output, and an arbitrary magnetic field is applied to the amorphous wire by means of the magnetic field generated on the detecting coil 11 energized by connecting the detecting coil 11 to a voltage source or to a current source E through an impedance network 3 comprising of a resistor R or a coil L or a condenser C or comprising a combination of the resistor R, the coil L, and the condenser C.

To provide a magnetism detection apparatus that is small and low in cost and power consumption, a biasing coil 4 and a negative-feedback coil are integrated with a magnetic impedance element having a magnetic impedance effect in a resinous structure. The magnetism detection apparatus has a reduced magnetic resistance between the magnetic impedance element and the coil, thereby making it possible to apply a bias magnetic field and a negative-feedback magnetic field to the magnetic impedance element with a reduced power consumption.

This invention relates to a huge magnetic impedance effect magnet-sensitive device based on a soft magnet multiplayer membrane composed of a SiO2 substrate, pins, a zigzag sandwich structure soft magnet multiplayer membrane and an offset magnet, among which, the pins are led out from the copper layers at both ends of the multiplayer membrane and set on the substrate, the entire multiplayer membrane is placed on the substrate. The offset magnet is prepared with fine process technology and adhered on the back of the device with epoxy glue.

The invention relates to a stress-torsion magnetic impedance integration test device of a metal fiber and aims at solving a problem that a test can not be directly and effectively performed in the prior art. The device comprises an integration test platform and an attached magnetic field generation apparatus. Integration test platform matching is used for collecting a four-terminal magnetic impedance test and analysis system of metal fiber impedance to be tested in the platform and magnetic field calibration and monitoring system. The magnetic field generation apparatus comprises a Helmholtz coil and a direct-current power supply which matches with and is connected to the coil. The integration test platform is a stress-free torsion platform which exerts torsion on the metal fiber to be tested or a stress-torsion combined platform used for exerting the stress and the torsion on the metal fiber. The magnetic field calibration and monitoring system comprises a single axis magnetometer and a probe arranged on one side of the torsion platform. An axial direction of the probe is parallel to an axial direction of the Helmholtz coil and an axis is parallel to and is consistent with a height of the metal fiber. The device has the following advantages that it is convenient to replace the test platform; the stress and torsion control is accurate; and the fiber is not easy to break and kink.

Solutions for non-invasively monitoring blood metabolite levels of a patient are disclosed. In one embodiment, the method includes: repeatedly measuring a plurality of electromagnetic impedance readings with a sensor array from an epidermis layer of a patient and one of a dermis layer or a subcutaneous layer of the patient, until a difference between the readings exceeds a threshold; calculating an impedance value representing the difference using an equivalent circuit model and individual adjustment factor data representative of a physiological characteristic of the patient; and determining a blood metabolite level of the patient from the impedance value and a blood metabolite level algorithm, the blood metabolite level algorithm including blood metabolite level data versus electromagnetic impedance data value correspondence of the patient.

An over-current protection device is constituted of a current detection unit for detecting a current from a power-supply source to a load having a magnetism detection element with a magnetic impedance (MI) effect, an AC-current supply device for supplying an AC current to the detection element, a bias-current supply device for supplying a bias current to a bias coil, a peak detection device for detecting a peak of impedance of the magnetism detection element as a variation of voltage, and a switch corresponding to a phase for selecting an output of the peak detection device. In the current detection unit, a holding device for holding a switch output and an amplifier are disposed in common for detecting the current in each phase, thereby expanding a current detectable range and reducing power consumption and cost.

This compressor includes housing members that form a body; a drive shaft linked to a drive power source via an electromagnetic clutch; movable members moving in cooperation with the drive shaft and carrying out the compression of a fluid; a detected body moving in cooperation with the drive shaft; a drain bolt screwed into a drain bolt hole provided in a housing member in proximity to the detected body; and a detecting device detecting the rotation state of the drive shaft by the detected body. The drain bolt is provided with a permanent magnet, the detecting device is structured by a magnetic sensor that includes a magnetic impedance element, and the magnetic sensor is provided at the head portion of the drain bolt. Thereby, it is possible to provide a rotation detecting mechanism by using an existing drain bolt, without requiring the machining of a hole in the compressor body.

The present invention relates to composite wire with barrier layer possessing giant magnetic impedance effect, and belongs to the fields of magnetic sensing, storing and information functional material and the preparation technology. The composite wire consists of metal wire, barrier layer and soft magnetic layer. The barrier layer of insulating material is attached to the surface of the metal wire, and the soft magnetic layer of GMI soft magnetic material is attached to the surface of the barrier layer. The preparation process includes painting barrier layer onto the metal wire, chemically plating the soft magnetic layer onto the barrier layer, and annealing. The composite wire with giant magnetic impedance effect has simple preparation process, relatively high giant magnetic impedance effect and low work frequency and may be used in device conveniently and reliably.