A fluxgate detector for buried and abandoned chemical weapons is provided, comprising: a probe for sensing an external magnetic field, comprising a probe input and a probe output; an excitation module electrically connected to the probe input for inputting an excitation signal into the probe; a frequency selection module electrically connected to the probe output for isolating a second harmonic signal in an induced voltage generated by the probe; and a signal acquisition module electrically connected to the frequency selection module. The second harmonic signal in the induced voltage can be isolated by the frequency selection module, transmitted to the signal acquisition module, and converted to an intensity of the magnetic field by the signal acquisition module. The substance detected can be identified according to the intensity of the magnetic field, so that the buried ACWs can be found efficiently and accurately.

A current sensor includes core components that form a magnetic circuit and form a space where to dispose a probe coil on the magnetic circuit; and a clip that press-joins the core components with each other. Since magnetic reluctance decreases at a portion where the core components are press-joined by the clip, an amount of magnetic flux of an external magnetic field passing through this portion increases, and accordingly, an amount of magnetic flux interlinked with the probe coil decreases. This improves the immunity of the current sensor to an external magnetic field.

A current sensor includes core components that form a magnetic circuit and form a space where to dispose a probe coil on the magnetic circuit; and a clip that press-joins the core components with each other. Since magnetic reluctance decreases at a portion where the core components are press-joined by the clip, an amount of magnetic flux of an external magnetic field passing through this portion increases, and accordingly, an amount of magnetic flux interlinked with the probe coil decreases. This improves the immunity of the current sensor to an external magnetic field.

Apparatus features a signal processor configured to receive signaling from a flux sensor containing information about a residual field from an electrical supply to a motor of a driven machine and a magnetic field from one or more rotating magnets placed on a rotating component of the driven machine; and determine corresponding signaling containing information about the operation of the driven machine, based upon a difference between an electrical supply frequency and a slip frequency determined from the signaling received and processed. The signal processor also provides the corresponding signaling for further processing to determine further information about the operation of the machine.

The invention belongs to the technical field of current detection, in particular to a fluxgate current sensor and a current measurement method, wherein the fluxgate current sensor comprises a magnetic probe and an excitation and detection circuit, and the magnetic probe comprises an excitation iron core and an excitation coil, the excitation coil is connected to the excitation and detection circuit, the excitation and detection circuit is used to output alternating excitation voltages to the excitation coil, and the excitation coil is excited to generate alternating excitation currents and cause the excitation iron core to reach saturation alternately; the excitation and detection circuit is further configured to convert the excitation currents flowing through the excitation coil, into equivalent differences of two currents, so as to calculate average values of the excitation currents flowing through the excitation coil via differential equivalent currents, thereby calculating to-be-measured primary currents by the average values of the excitation currents. Technical solutions of the present invention can eliminate zero drift of the fluxgate current sensor, thereby improving small current identification and measurement accuracy thereof.

An electromagnetic sensing device with a package substrate, a first die mounted on the package substrate, and a second die mounted on the package substrate. The first die includes a first integrated circuit and a first magnetic core formed above the first integrated circuit. The first magnetic core has a first sensing axis parallel to a planar surface of the package substrate. The second die includes a second integrated circuit and a second magnetic core formed above the second integrated circuit. The second magnetic core has a second sensing axis orthogonal to the planar surface of the package substrate.

An electromagnetic sensing device with a package substrate, a first die mounted on the package substrate, and a second die mounted on the package substrate. The first die includes a first integrated circuit and a first magnetic core formed above the first integrated circuit. The first magnetic core has a first sensing axis parallel to a planar surface of the package substrate. The second die includes a second integrated circuit and a second magnetic core formed above the second integrated circuit. The second magnetic core has a second sensing axis orthogonal to the planar surface of the package substrate.

A calibration apparatus for calibrating a magnetic sensor configured to generate an output signal indicative of magnetic field strength when a bias signal is applied to it is disclosed. The apparatus includes a test magnetic field generator (MFG) to generate magnetic fields of known magnitude, and further includes a processor to control the MFG to generate a known magnetic field, control the sensor to generate a test output signal when the MFG generates the known magnetic field and a known bias signal is applied to the sensor, and determine how to change the bias signal based on a deviation of the measured test output signal from an expected output signal. Using a test MFG that produces known magnetic fields when known bias signals are applied to sensors allows evaluating and compensating for changes in sensitivity of the sensors by accordingly changing bias signals applied to the sensors.

An apparatus includes a magnetometer-based current sensor (e.g., a Hall-effect or fluxgate-based current sensor) configured to sense a magnetic field generated by a current in at least one conductor connecting a motor drive output to a motor and to responsively produce a first current sense signal and a magnetometer-based voltage sensor (e.g., a Hall-effect or fluxgate-based voltage sensor) configured to sense a magnetic field generated in response to a voltage of the at least one conductor and to responsively produce a first voltage sense signal. The apparatus further includes a signal conversion circuit configured to receive the first current sense signal and the first voltage sense signal and to generate a second current sense input and a second voltage sense input for provision to a current sense input and a voltage sense input, respectively, of a motor protection relay that protects the motor.

Measuring arrangement for detecting a magnetic unidirectional flux in the core of a transformer, wherein a sensor, formed from a ferromagnetic sensor core which is surrounded by a sensor coil, is arranged in a section of a core limb in a cooking channel, where the section is predefined by the width of the winding, or is arranged in an annular space, formed from an outer peripheral surface of the core limb and an inner peripheral surface of an associated transformer winding, such that a magnetic partial flux is diverted by the core limb and guided over at least one non-ferromagnetic gap.