30 results about "Coil geometry" patented technology

A time varying current sensor is constructed using surface coils uniformly spaced around a central cavity adapted to receive the conductor through which the current to be measured flows. Accurate and uniform coil geometry is achieved using printed circuit board technology, thereby eliminating the high cost of precision toroidal coil winding. An optional hinge in the housing can allow the sensor to be easily installed on existing conductors without the need to disconnect and reconnect.

A radio-frequency coil arrangement has a number of conductor traces forming basic coils and with capacitors interconnected in the conductor traces. Conductor traces of various basic coils intersect at node points. At least one switching arrangement for selective, reversible connection of the conductor traces to form different coil geometries is provided at least some of the node points.

An optimal design method of a superconducting magnet used for a magnetic resonance imaging (MRI) device comprises the following steps: obtaining current distribution maps of a primary coil and a screened coil according to magnetically confined conditions and then obtaining the initial cross section of the screened coil based on the current distribution maps; with the magnetic field of the screened coil as a background magnetic field, obtaining the current distribution map of the primary coil again according to magnetically confined conditions, thereby obtaining the initial cross section of the primary coil; based on the initial cross sections of the primary coil and the screened coil, optimizing coil section parameters by adopting hybrid genetic algorithm of simulated annealing to obtain the optimal coil geometries. By the method, the primary and the screened coil can be simultaneously designed.

Methods and apparatus are provided for fabricating and constructing solid dielectric “Coiled Transmission Line” pulse generators in radial or axial coiled geometries. The pour and cure fabrication process enables a wide variety of geometries and form factors. The volume between the conductors is filled with liquid blends of polymers and dielectric powders; and then cured to form high field strength and high dielectric constant solid dielectric transmission lines that intrinsically produce ideal rectangular high voltage pulses. Voltage levels may be increased by Marx and/or Blumlein principles incorporating spark gap or, preferentially, solid state switches (such as optically triggered thyristors) which produce reliable, high repetition rate operation. Moreover, these pulse generators can be DC charged and do not require additional pulse forming circuitry, pulse forming lines, transformers, or an output switch. The apparatus accommodates a wide range of voltages, impedances, pulse durations, pulse repetition rates, and duty cycles. The resulting mobile or flight platform friendly cylindrical geometric configuration is much more compact, light-weight, and robust than conventional linear geometries, or pulse generators constructed from conventional components. Installing additional circuitry may accommodate optional pulse shape improvements. The Coiled Transmission Lines can also be connected in parallel to decrease the impedance, or in series to increase the pulse length.

A metal detector (1) used for identifying contaminants (35) in products (35). The detector (1) includes an oscillator coil assembly (10) that may be formed as a combination of pairs of series wound coils (15, 18) and pairs of parallel wound coils (16, 17). A pair of input coils (13, 14) defines the boundaries of a region (39) within which the oscillator coil assembly (10) resides. A first signal (8) is generated by the first input coil (13) in response to the presence of a metallic object (35) while a second signal (24) is generated by the second input coil (14) in response to the presence of the metallic object (35). By measuring the ratio of the first signal (8) to the second signal (24) the physical location of a metal object within the metal detector cavity (7) can be determined.

A solenoidal induction coil with dynamically variable coil geometry is provided for inductively welding or heating continuous or discontinuous workpieces passing through the solenoidal induction coil in a process line. The coil geometry can change, for example, as the outer dimension of the workpiece passing through the solenoidal induction coil changes or as non-continuous workpieces pass through the solenoidal induction coil in an induction heating or welding process line.

A transceiver antenna has a transmit antenna coil defining a substantially closed transmit coil geometry circumscribing a transmit coil inner area. The transmit antenna coil is configured to conduct a current to generate a magnetic field. One or more receive antenna coils each define a closed receive coil geometry with a number of coil turns. The receive antenna coils are positioned to define one or more inner areas located within the transmit antenna coil inner area and one or more outer areas located outside of the transmit antenna coil. The inner areas and the outer areas of the receive antenna coil(s) are configured so that a first voltage induced by the transmit magnetic field into the outer areas of the receive antenna coils is attenuated by a second voltage induced by the transmit magnetic field into the inner areas of the receive antenna due to phase cancellation.

The invention relates to a parametric modeling method suitable for an end part coil of a generator stator winding. The parametric modeling method is characterized by comprising the steps as follows: step one, inputting geometric parameters of the coil; step two, defining the section shape of the coil; step three, modeling a geometrical model for the end part coil of the stator winding; and step four, establishing a finite element model of the coil. The parametric modeling method suitable for the end part coil of the generator stator winding has the advantages that stator winding end part coil modeling is parameterized, and the finite element model of the end part coil can be established simultaneously, so that the method can be applied to research on vibration characteristics of the stator winding end structure.

An electric joint design to be used in electromagnetic coils made with high-temperature superconducting tape, aspected wire, or cable. A terminal member contains an engraved twist-bend contour, which receives the coil and changes the direction of the coil by about 90 degrees without any hard-bends. A current lead is aligned with terminal section of the coil establishing an electric joint whose length is not limited by the coil geometry. Resistance is distributed along the length of the electric joint to reduce heat generation. The electric joint is placed away from the area where the magnetic forces are high to eliminate the problem of helium gas becoming trapped.

Musical instrument pickups and methods of constructing same to achieve a user-desired signal output level and a user-desired tonal characteristic from a stringed instrument are disclosed. The method may include steps for selecting a coil geometry, selecting a number of coils, selecting a coil wire gauge and number of turns for each coil and selecting a pole piece. In selecting the pole piece consideration may be given to pole piece composition, pole piece thickness, height and width, and pole piece response in terms of relative inductive and relative resonant frequency characteristics and/or the shape of the frequency response in the vicinity of resonance.

Low resolution image data from a whole-body coil (18) and each coil element (201, 202, 20n) of a parallel imaging coil are received in a memory or buffer (34). A reconstruction processor (36) reconstructs the low resolution whole-body coil data and the low resolution data from each of the coil elements into corresponding low resolution images (38). The low resolution from each coil element is divided (42) by the low resolution image from the whole-body coil to generate a corresponding sensitivity map (441, 442, 44n) for each of the coil elements. In areas where the low resolution body coil image has near-zero values or in areas where the values in the body coil or receive coil images are changing very rapidly, the sensitivity maps have defects. A sensitivity map or correction circuit or algorithm (50) determines regions of the sensitivity maps which are defective and interpolates/extrapolates adjacent portions of the sensitivity maps in accordance with (a) a coil geometry map (56) and (b) a wave-propagation model (58) to correct the defective regions, to propagate them into the outer regions of the field of view or to fully replace the measured sensitivity map and create a corrected sensitivity map for each coil element.

A coil arrangement for use in a magnetic resonance imaging system, the imaging system being for generating a magnetic imaging field in an imaging region, the coil arrangement including at least three coils for at least one of transmitting, receiving or transceiving an electromagnetic field, each coil being provided on a coil geometry and being substantially orthogonal.

A radio frequency (RF) coil array configured for use with a magnetic resonance imaging (MRI) system and that includes coil elements with a skewed coil geometry is provided. The coil elements are skewed with respect to a given direction, such as the slice-encoding direction of an MRI system, such that a variation in spatial sensitivity along that direction is provided. This spatial sensitivity variation allows for parallel imaging acceleration along the direction of the variation, which provides improved performance over standard rectangular geometries in performing acceleration along the slice-encode direction for three-dimensional axial acquisitions.

The invention discloses a three-degree-of-freedom position measuring device and method for a Y-shaped magnetic levitation planar motor rotor, and belongs to the technical field of magnetic levitation planar motors, the device comprises three linear Hall sensor groups, a stator and a rotor of a Y-shaped magnetic levitation planar motor, the rotor is suspended at a preset height above the stator, and the linear Hall sensor groups are connected with the stator and the rotor. Three linear Hall sensor groups are arranged below preset positions of geometric centers of three exciting winding coils on a stator, each linear Hall sensor group comprises two linear Hall sensors, and the distance between the two linear Hall sensors is equal to the width of magnetic steel in a Halbach magnetic steel array in a rotor. And the phase angle difference between each Halbach magnetic steel array in the rotor and the corresponding linear Hall sensor group is 90 degrees. The device is simple in structure, the cost is greatly reduced, additional devices such as a reading head, a reflecting mirror or an aluminum plate do not need to be installed on the motor rotor, and the motion performance of the planar motor is not affected.

The invention discloses a method for calculating the sensitivity of a single-ring Rogowski coil current sensor with any skeleton shape, and the method comprises the steps: building a three-dimensional rectangular coordinate system with a certain point in a Rogowski coil as a coordinate origin, and writing a parameter equation of a geometric center line of the Rogowski coil; when the measured wire is a straight wire, obtaining a unit vector of the current-carrying conductor; calculating the magnetic induction intensity generated by the current-carrying straight conductor at the point P according to the Biot-Savart law; calculating the magnetic flux passing through the section of the wire turn at the beta position; the magnetic flux of each wire turn is added to obtain the magnetic flux of the whole Rogowski coil, and the mutual inductance coefficient of the Rogowski coil and the direct current-carrying conductor is obtained; according to the basic working principle of the Rogowski coil current transformer, the sensitivity of the Rogowski coil can be obtained when wires with any positions and any shapes are measured. The method is high in universality and convenient to calculate, a program is easy to compile for calculation, and the design time is saved; no empirical formula exists in the calculation process, and the calculation precision is high.

The invention discloses a rapid calculation method for the sensitivity of a PCB Rogowski coil current sensor, and the method comprises the steps: setting one point in a PCB Rogowski coil as the original point of a three-dimensional rectangular coordinate system, setting the geometric center of the PCB Rogowski coil as the original point of the three-dimensional rectangular coordinate system if the PCB Rogowski coil is geometrically symmetric, and setting the point in the PCB Rogowski coil as the original point of the three-dimensional rectangular coordinate system; the geometric symmetry axis of the PCB Rogowski coil is the z axis of the coordinate system; wire turn section endpoint numbering is carried out on the intersection point of wire turn routing of the PCB Rogowski coil and the two endpoints of the coil in sequence; storing the serial numbers of the wire turn points and the coordinates of each wire turn point in a matrix; calculating mutual inductance between any two straight conductors in the space; calculating the mutual inductance between the PCB Rogowski coil and the current-carrying conductor; according to the basic working principle of the Rogowski coil current transformer, the sensitivity of the Rogowski coil is obtained when wires with any positions and any shapes are measured. The method is high in universality and convenient to calculate, a program is easy to compile for calculation, and the design time is saved; no empirical formula exists in the calculation process, and the calculation precision is high.