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Showing papers on "Magnetic core published in 1986"


PatentDOI
TL;DR: In this paper, a direct contact hearing aid is described, including an output electromechanical transducer for converting audio output signals into mechanical movement of an output coupling element without the production of discernible sound waves to prevent acoustic feedback.
Abstract: A direct contact hearing aid apparatus adapted to be mounted deep within the ear canal is disclosed, including an output electromechanical transducer for converting audio output signals into mechanical movement of an output coupling element without the production of discernible sound waves to prevent acoustic feedback. The coupling element is supported for magnetic engagement with a contact element mounted on the tympanic membrane by a metal clip attached to the malleus bone to provide direct electromechanical coupling to the ossicles through the tympanic membrane. Alternatively, the contact element may be attached to the malleus bone by a clamp whose jaws are lined with bioactive ceramic. A pair of magnetic switches is provided within the hearing aid housing for mechanically switching the connections of the battery and a volume control while the hearing aid is mounted in the ear canal in response to changes in the polarity of a remote external magnetic actuator located outside of the housing. An external magnetic attachment device is used for insertion and removal of the hearing aid, radio or other electronic apparatus into and from the ear canal by magnetic engagement with a magnetic holder member on the electronic apparatus. The magnetic attachment device may be unipolar or bipolar and has a permanent magnet which is rotated between an attraction position and a release position by a selection knob. The output transducer of the hearing aid may be a piezoelectric plastic film transducer in the form of a flexible diaphragm or a folded sheet bender of the bimorph type, or it may be an electromagnetic transducer. The electromagnetic transducer may have an external magnetic coupling element mounted outside the hearing aid housing and spaced from the magnetic core of such transducer but coupled to the contact element. Also, a reverse bias permanent magnet may be provided at the end of such core to repel a movable permanent magnet which is mounted on a resilient coupling member to form the external magnetic coupling element.

128 citations


Proceedings ArticleDOI
23 Jun 1986
TL;DR: In this article, a new modeling method for magnetic circuits with any number of windings is presented, which incorporates adequate information about the correct distribution of leakage energy, the presence of gaps throughout the core, the arrangement of the windings, and the type of core used.
Abstract: A new modelling method for magnetic circuits is presented. The method can be used to model magnetic circuits with any number of windings. The models incorporate adequate information about the correct distribution of leakage energy, the presence of gaps throughout the core, the arrangement of the windings, and the type of core used. Several commonly used arrangements such as toroids with uniformly distributed turns, and bobbin core structures with multiple windings were modelled with the new technique. The measured electric circuit model values always compared favorably with the predicted physical values derived with the new method.

89 citations


Patent
30 Jun 1986
TL;DR: In this paper, a method of manufacturing a chip coil, including a magnetic core, a winding wire, and internal terminal electrodes, a fired mass of magnetic material surrounding and encapsulating the coil element, and external terminal electrodes electrically connected to the internal terminals, is presented.
Abstract: A method of manufacturing a chip coil, including a coil element which includes a magnetic core, a winding wire, and internal terminal electrodes, a fired mass of magnetic material surrounding and encapsulating the coil element, and external terminal electrodes electrically connected to the internal terminal electrodes. The winding wire is coated with a heat-resistive electrically insulating film and is wound around the magnetic core. The internal terminal electrodes are electrically connected to opposite ends of the winding wire and are exposed to the exterior of the mass at opposite ends of the core where they are electrically connected to the external terminal electrodes.

45 citations


Patent
23 May 1986
TL;DR: In this paper, the reluctance control regions where the control cores intersect the principal core are selected such that the degrees of influence of the individual control cores are in a binary sequence, and additional control windings may be coupled to respective additional control cores (13a, 13b, 13c) which intersect the primary core, so that selective control of the currents in the various control woundings enables selective controlling of the degree of interference with the principal cores, and hence the reluctance thereof.
Abstract: An inductive device includes a principal magnetic core (11) having a principal winding (10) coupled therewith so that the reluctance of the principal core influences the inductance of the principal winding. A control winding (12) is coupled to a control magnetic core (13) so that the current in the control winding influences the magnetic flux in the control core. The control core intersects the principal core so that magnetic flux produced in the control core interferes with the principal core. Selective control of current in the control winding influences the magnetic flux in the control core, which in turn interferes with the principal core so as to influence the reluctance thereof and thereby vary the inductance of the principal winding. Additional control windings may be coupled to respective additional control cores (13a, 13b, 13c) which intersect the principal core, so that selective control of the currents in the various control windings enables selective control of the degree of interference with the principal core, and hence the reluctance thereof. The dimensions of respective reluctance control regions where the control cores intersect the principal core may be selected such that the degrees of influence of the individual control cores are in a binary sequence.

39 citations


Patent
02 Sep 1986
TL;DR: In this paper, a flux gate magnetic sensor with an excitation coil and a sensing coil wound around an annular magnetic core made of high permeability material is used for detecting an external magnetic field and an operation circuit for operating the geomagnetic direction.
Abstract: Electronic equipment has, in its case, a flux gate magnetic sensor with an excitation coil and a sensing coil wound around an annular magnetic core made of high permeability material, an integrated circuit including a magnetic field detector, cooperating with the magnetic sensor for detecting an external magnetic field and an operation circuit for operating the geomagnetic direction, a display device for displaying at least the geomagnetic direction, and a power source battery. The flux gate magnetic sensor is arranged along the inner surface of the case and the battery is arranged within the annular magnetic core of the magnetic sensor.

37 citations


Patent
06 Nov 1986
TL;DR: In this article, a variable-ratio transformer for arc and plasma setups, comprising a magnetic core made up of a main part composed of two yokes and legs in accordance with the number of phases and an additional part disposed on the side of the yoke of the main part of the magnetic core, is presented.
Abstract: A variable-ratio transformer for arc and plasma setups, comprising a magnetic core made up of a main part composed of two yokes and legs in accordance with the number of phases and an additional part disposed on the side of the yoke of the main part of the magnetic core. The additional part of the magnetic core is made up of a yoke and legs whose number is equal to the number of the legs of the main part, at least one leg being placed with a gap in relation to the first yoke of the main part. The primary winding of each phase comprises two series-connected parts, the first part being located on the main part of the magnetic core, while the second part is located on the additional part thereof. A controlled electronic switch which regulates the load current flowing through the secondary winding of each phase, disposed on the main part of the magnetic core, is connected in parallel to one of the parts of the primary winding of each phase.

36 citations


Patent
15 May 1986
TL;DR: In this paper, a toroidal transformer with a low voltage coil, a high voltage coil and an annular magnetic core is described, where the preferred low voltage and high voltage coils are each continuous and form an arcuate elongated passage.
Abstract: A toroidal electrical transformer having a low voltage coil, a high voltage coil and an annular magnetic core is disclosed. The preferred low voltage and high voltage coils are each continuous and form an arcuate elongated passage therethrough. The preferred annular magnetic core is wound in place in said arcuate elongated passage substantially from a continuous strip of magnetic material resulting in a toroidal transformer with continuous windings and a continuous wound core. Various components and sub-assemblies are also disclosed along with various apparatus and methods for producing such toroidal electrical transformers, its components and its sub-assemblies.

35 citations


Patent
20 Mar 1986
TL;DR: An apparatus for nuclear magnetic resonance scanning and imaging which employs a primary magnetic field, an rf field, and a detector for detecting a nuclear magnetic signal is described in this paper.
Abstract: An apparatus for nuclear magnetic resonance scanning and imaging which employs a primary magnetic field, an rf field, and a detector for detecting a nuclear magnetic resonance signal, the primary magnetic field being produced by an assembly of relatively low energy flux magnetic material combined with an assembly of relatively high energy flux magnetic material. The magnetic flux of the relatively low energy flux magnetic material is concentrated in a magnetic flux conductor means which is in turn combined with the magnetic flux of the relatively high energy flux magnetic material and is concentrated at a pole piece.

34 citations


Patent
08 Apr 1986
TL;DR: In this article, a process for producing a magnetic core, comprising the first step of bringing magnetic powder of a metal into contact with a polymer dispersion, followed by drying, to form an insulating layer on the surface of the magnetic powder and the second step of compression molding, is described.
Abstract: Disclosed is a process for producing a magnetic core, comprising the first step of bringing magnetic powder of a metal into contact with a polymer dispersion, followed by drying, to form an insulating layer on the surface of the magnetic powder and the second step of compression molding the magnetic powder. Also, disclosed is a magnetic core produced by the above process. A magnetic core according to this invention has, since good insulation between magnetic powder particles can be ensured with a small amount of an insulating material, high magnetic flux density, small core loss and excellent frequency characteristics of magnetic permeability and is particularly suitable for use in high frequency range of some 10 KHz or higher.

32 citations


Journal ArticleDOI
TL;DR: In this article, the model is applied to inductors and transformers made from a variety of core materials, and procedures are given for determining the model parameters directly from magnetic core catalog data.
Abstract: Magnetic saturation and hysteresis are simulated on SPICE2 using a model containing two nonlinear controlled sources. The model is applied to inductors and transformers made from a variety of core materials, and procedures are given for determining the model parameters directly from magnetic core catalog data. Four examples of circuit applications are given: a saturating instrumentation transformer, a saturating snubber inductor, a ferroresonant regulator transformer, and a Royer saturation oscillator.

31 citations


Patent
12 Jun 1986
TL;DR: In this article, a resonant vibration-transmitting apparatus, including a yoke, a magnetic coil attached on the bottom of the yoke and a vibrant leaf spring attached to it, is described.
Abstract: A resonant vibration-transmitting apparatus, including a yoke, a magnetic coil attached on the bottom of the yoke, a vibrant leaf spring attached to the yoke, and an iron core attached to the leaf spring in a manner that a substantial part of the iron core is placed inside the magnetic coil so as to resonate the leaf spring to the frequency of a power source.

Patent
18 Mar 1986
TL;DR: In this article, an inductor structure is combined with a ferroresonant regulator as a filter inductor in one instance, and as a regulating inductor as a regulator in another.
Abstract: An inductor structure is combined with a ferroresonant regulator as a filter inductor in one instance, and as a regulating inductor in another. In one example, a ferroresonant voltage regulator includes a pair of shunt filters at its output to reduce the low order odd harmonic content of the AC output. The filtering arrangement includes two LC shunt filters having their independent inductor windings wound on a single magnetic core unit. Auxiliary windings coupled to each of the inductor windings are placed in series with the output to buck any remaining harmonics. In a second instance, independent regulating inductors in a multiphase ferroresonant regulator are also realized on a single magnetic structure.

Patent
09 Jun 1986
TL;DR: In this paper, a magnetic core for a transformer or for high-frequency welding of a laminated tube and a process for producing a magnetic molding from the magnetic composition is described.
Abstract: A magnetic composition to be used as a magnetic core for a transformer or for high-frequency welding of a laminated tube and a process for producing a magnetic molding from the magnetic composition. The magnetic composition comprises 80 to 95 wt % of ferromagnetic powder, 5 to 20 wt % of highly heat-resistant thermosetting resin powder, and 0.1 to 1 wt % of a metal chelate compound. All of these powers are mixed together and molded under heat and pressure to produce a magnetic molding. The composition enables molding of materials of complicated form at low tempertures, and the obtained moldings have excellent heat resistance, mechanical strength, mechanical workability, and initial magnetic permeability.

Patent
17 Apr 1986
TL;DR: In this paper, an electromagnetic pile driver has an elongated guide in which a magnetic core is permitted to fall by gravity to impact against an anvil transmitting the impact energy to the pile.
Abstract: An electromagnetic pile driver has an elongated guide in which a magnetic core is permitted to fall by gravity to impact against an anvil transmitting the impact energy to the pile. The core is raised by a coil in a ferromagnetic sheath disposed at an upper portion of the guide and an upper anvil can be provided and coupled to the pile when the apparatus is used for withdrawing piling. The coil is energized by the control discharge of a capacitor.

Patent
10 Sep 1986
TL;DR: In this paper, a flexible circuit is inserted into the window of an integrally formed core member for a magnetic or ferrite head assembly, which is easily adapted to an automated assembly line.
Abstract: A flexible circuit (20), sufficiently rigid for easy handling, is inserted once into the window (91) of an integrally formed core member (81)for a magnetic or ferrite head assembly. This flexible circuit contains a pattern of several parallel conductors. When the flexible circuit is bent around the core member, the ends of the parallel conductors come together. When respective ends are soldered together, a continuous multi-turn winding is created. Only one insertion is required, the flexible circuit is less prone to breakage, the electrical characteristics are repeatable, and the turns are inherently shielded and insulated from each other. Most importantly, the flexible circuit is easily adapted to an automated assembly line.

Patent
Toshihiko Ohta1, Fumio Izawa1
20 Nov 1986
TL;DR: In this paper, a thin-film type electromagnetic transducer is constructed such that a leakage flux generated along the plane of the substrate is greater than that generated in a direction intersecting with the plane, the leakage fluxes being generated from the core when a current is supplied to the coil.
Abstract: A thin-film type electromagnetic transducer formed on a nonmagnetic substrate by a thin-film forming process. The transducer includes a magnetic core formed on the substrate by the thin-film forming process, and a conductor coil formed on the substrate by the thin-film forming process, so as to be wound around the core. The core is shaped so that a leakage flux generated along the plane of the substrate is greater than that generated in a direction intersecting with the plane of the substrate, the leakage fluxes being generated from the core when a current is supplied to the coil. In a method for transferring signals from the thin-film type electromagnetic transducer described above, a magnetic head is located so as to face that region of the core of the transducer where the maximum leakage flux is generated. The magnetic head has a magnetic gap such that the direction of a leakage flux generated in the gap is coincident with that of the maximum leakage flux from the core, and whereby magnetic signals are transferred between the magnetic head and the maximum-leakage-flux generating region of the core.

Patent
10 May 1986
TL;DR: In this paper, a magnetic gap is formed by symmetrically butting upper and lower click-like edges of two long magnetic core rods against each other with thin films made of a nonmagnetic substance in between.
Abstract: PURPOSE:To simplify the manufacturing process of a magnetic head by symmetrically butting upper and lower click-like edges of two long magnetic core rods which are made of a soft magnetic substance and have bracket-like cross sections against each other with thin films made of a nonmagnetic substance in between. CONSTITUTION:A magnetic gap 3 is formed by symmetrically butting upper and lower click-like edges of two long magnetic core rods 1 and 2 against each other with thin films 4 and 4' made of a nonmagnetic substance, such as Ti, in between and pushing both rods 1 and 2 against each other, then, fixing the rods 1 and 2 to each other with the thin films 4 and 4' in between with a bonding agent. When the magnetic cores 1 and 2 thus formed are cut horizontally along the plane A-B and further cut by the track width T of a magnetic head in the longitudinal direction, plural magnetic head core elements 1' and 2' are obtained. The elements 1' and 2' are put in the angular holes of a holding plate 8 and a winding frame 6 which is already provided with a winding 5 and terminals 7 is inserted into the linear sections of the elements 1' and 2'. Then a magnetic head core 9 already provided with windings is housed in a sealed case 11 and the magnetic path is closed by closely putting a back plate 10 on and over the edges of the leg sections of the elements 1' and 2'. Finally, the sliding surface is R-polished.

Patent
05 Mar 1986
TL;DR: In this article, a flow control valve body is fitted to a rotatable iron core in an opened valve condition, and when a current passing through the armature coil is stopped, the energizing force of a spring 7 becomes greater than the magnetic force between the permanent magnet of rotatable IR core 3 and stationary magnetic poles to lower the open/close valve body.
Abstract: PURPOSE:To control the flow passage of fluid to open or close and at the same time to control variably the opening area of a flow passage by magnetizing stationary magnetic poles by an armature coil to slide a rotatable iron core in the axial direction, and further rotating the rotatable iron core in response to magnetizing conditions. CONSTITUTION:When a current is passed through an armature coil 1 so as to generate a magnetizing force that attracts a rotatable iron core 3 to stationary magnetic poles 2 under such a condition that the rotatable iron core 3 is not given a rotary motion, the rotatable iron core 3 is fitted to be held in an opened valve condition. At this time, a flow control valve body 6 closes almost fully the outlet 11 of the valve. Next, when a current is passed through the armature coil 1 so as to rotate the rotatable iron core 3 by an angle of 90 deg., the valve body 6 makes the opening area of fluid flow passage communicating with the valve outlet 11 in a half-opened condition. On the other hand, when a current passing through the armature coil 1 is stopped, the energizing force of a spring 7 becomes greater than the magnetic force between the permanent magnet of rotatable iron core 3 and stationary magnetic poles to lower the open/close valve body 5, so that a sheet 15 is seated on a valve seat 13 to fully close the fluid flow passage.

Patent
Masayuki Takagi1
11 Feb 1986
TL;DR: In this article, a thin-film magnetic head provided with a magnetic thin film having a magnetostrictive characteristic is disclosed in which a central part of magnetic core formed of the magnetic thin layer has a positive magnetostriction constants, and side parts of the magnet core on both sides of the central part have negative magnetstriction constants.
Abstract: A thin-film magnetic head provided with a magnetic thin film having a magnetostrictive characteristic is disclosed in which a central part of magnetic core formed of the magnetic thin film has a positive magnetostriction constants, and side parts of the magnetic core on both sides of the central part have negative magnetostriction constants. Thus, when a stress due to the patterning of the magnetic core varies the magnetic characteristic of the magnetic core, the permeability of the magnetic core becomes high, and the magnetic stability thereof is improved. Accordingly, a signal reproduced by this magnetic head has a high output level, and is low in noise level.

Patent
19 Mar 1986
TL;DR: In this paper, a transformer with a toroidal magnetic core is shown to have a top and bottom annular winding frames providing radial winding conductor grooves for guiding an interconnecting conductor to connect between the adjacent two unit coils.
Abstract: A transformer with a toroidal magnetic core. The toroidal magnetic core is housed in an insulating case. The insulating case has a top and bottom annular winding frames. These frames provide radial winding conductor grooves. The top annular winding frame provides a plurality of grooves for guiding an inter-connecting conductor therein each of which is formed between two adjacent winding conductor grooves. The inter-connecting conductor is guided through said guiding groove to connect between the adjacent two unit coils.

Patent
11 Jan 1986
TL;DR: In this article, the authors proposed a method to obtain a uniform adhesion state in the process for making to adhere the above powders to the surface of metal magnetic powder and then using a percussion-type mill or a counter jet mill, the mixture of these powders is filled in a metal mold and an iron core is manufactured by press-forming it under of less than 1000 MPa.
Abstract: PURPOSE:To easily manufacture an iron core which exhibits excellent frequency characteristics of magnetic permeability and has the high magnetic flux density by causing an iron powder or a ferro-alloy powder having each different particle diameter to collide with an inorganic compound powder or an organic resin powder and by making to adhere its compound and organic resin powders to the surfaces of the above iron powder or ferro-alloy powder and further by causing the obtained powders to be press-formed into the iron core CONSTITUTION:The raito of an average particle diameter of a magnetic metal powder to that of an inorganic compound powder or an organic resin powder shall be 5:1 so as to obtain a uniform adhesion state in the process for making to adhere the above powders to the surface of metal magnetic powder and, for example, the collision between these powders is carried out by using a percussion-type mill or a counter jet mill In this way, the inorganic compound powder or the organic resin powder which is usually in a state of flocculating is released from its flocculation and the above powder is driven in the surface of magnetic metal powder by colliding with the magnetic metal powder individually A mixing powder obtained in this way is filled in a metal mold and an iron core is manufactured by press- forming it under of less than 1000 MPa that is easily applicable to an industrial process This approach makes it possible to obtain easily an iron core which exhibits excellent frequency characteristics of magnetic permeability and has a high magnetic flux density

Patent
Takeshi Nakao1, Yutaka Akiba1
20 Nov 1986
TL;DR: In this article, a magneto-optical recorder is disclosed in which an external magnetic field required for recording and erasing can be produced by a small-sized electromagnetic coil having a small magneto motive force.
Abstract: A magneto-optical recorder is disclosed in which an external magnetic field required for recording and erasing can be produced by a small-sized electromagnetic coil having a small magneto-motive force. The electromagnetic coil is made up of a magnetic core and a coil winding, and the outer peripheral portion of the coil winding other than that peripheral portion thereof which confronts a recording medium, is covered by a core material. A magnetic field emanating from the electromagnetic coil spreads in a narrow space, and can be applied to the recording medium with large intensity even when the electromagnetic coil has a small magneto-motive force. In the recorder, a magnetic body is disposed such that the electromagnetic coil and the magnetic body face each other, to concentrate the magnetic field generated by the electromagnetic coil, to the vicinity of that portion of the recording medium which is irradiated with a light spot. The length of the electromagnetic coil is made equal to or greater than the length of the recording area of the recording medium, to apply a substantially uniform magnetic field to the whole recording area without moving the electromagnetic coil.

Journal ArticleDOI
TL;DR: In this paper, the power loss of each type of material in strip form was measured under controlled distorted magnetisation and it was found that the uniformity of the flux distribution and the variation in incremental eddy current loss determined the building factor.
Abstract: Magnetic measurements are reported on 3-phase transformer cores assembled from grain oriented silicon-iron, high permeability silicon-iron and laser scribed high permeability silicon-iron. The power loss of each type of material in strip form was measured under controlled distorted magnetisation. The core built from ZDKH had the lowest loss but the deterioration of losses due to building (the building factor) was lowest in the CGO core. The building factor reached a peak in each core at about 1.3T. It was found that the uniformity of the flux distribution and the variation in incremental eddy current loss determine the building factor. At low flux density ( 1.6T) the flux becomes more uniform in all the cores and their building factors drop. The ZDKH material was found to be most affected by the presence of distorted flux in single strip tests but this factor was not predominant in the built up transformers.

Patent
Kaoru Toki1
20 Feb 1986
Abstract: An apparatus and a method for recording, reading and erasing information, which use, as a recording medium, a magnetic film having vertical magnetic anisotropy characteristics and record, read and erase information by means of a laser beam and an external magnetic field applied to the magnetic medium. These are characterized in that the application of the external magnetic field to the recording medium is controlled by controlling the magnetic field provided by a permanent magnet put at a predetermined distance from the recording medium. For controlling the magnetic field, means for applying an external magnetic field to a recording medium is employed, which comprises a permanent magnet, a magnetic core of a high magnetic permeability material comprising a pole piece attached to at least one pole of the permanent magnet and a lag piece integrally connected to the pole piece and having a wire wound therearound, and an electric current source supplying electric current to the wire wound of the core.

Patent
15 Aug 1986
TL;DR: In this paper, a magnetic core is arranged in portions that may be secured around a cable so as to impede the flow of common-mode high frequency current, and the portions are aligned by clamps and secured by a strap.
Abstract: A magnetic core 1 is arranged in portions that may be secured around a cable 5 so as to impede the flow of common-mode high frequency current. The portions are aligned by clamps 2 and secured by a strap 3. A number of cores may be assembled together to provide increased impedance.

Patent
06 Aug 1986
TL;DR: In this paper, the authors proposed a method to make uniform the temperature distribution of each part of an iron core by a method wherein the generated heat corresponding to the quantity of radiant heat coming from the surface part of the iron core is added by increasing the generated loss of the surface parts of the wound core.
Abstract: PURPOSE:To make uniform the temperature distribution of each part of an iron core by a method wherein the generated heat corresponding to the quantity of radiant heat coming from the surface part of the iron core is added by increasing the generated loss of the surface part of the iron core. CONSTITUTION:Each of magnetic material bodies 13 is wound around between wound layers of the amorphous magnetic alloy thin plate 12 on the outer circumferential surface of a wound core 11 and the wound core 11 located adjoining to the outer circumferential surface of the wound core 11. The magnetic material body 13 has a large loss generating value, and a silicon steel plate (Curie point of approximately 700-800 deg.C, average thickness of approximately 0.35mm), which has the Curie point higher than that of the amorphous magnetic alloy thin plate 12 (Curie point of approximately 500-550 deg.C), can be used for said magnetic material body 13. Then, two wound cores 11 are arranged, and an exciting coil 14 is wound (temporary winding) on the leg part located outside each wound cores 11 in such a manner that their winding direction is reversed each other. When an annealing is performed for the purpose of removing the distortion of the wound cores 11, the exciting coil 14 is connected to a high frequency AC power source 16 using a change-over switch 15, and a high frequency AC current is applied to the exciting coil 14 by adjusting voltage using a voltage adjuster 18. When an AC current is applied to the exciting coil 14, heat is generated on the amorphous magnetic alloy thin plate 12 and the magnetic material body 13.

Journal ArticleDOI
TL;DR: A dc magnetic field of 33.6±0.3 T was produced in a hybrid magnet whose central field was enhanced by a 3.5 T contribution from holmium pole pieces as mentioned in this paper.
Abstract: A dc magnetic field of 33.6±0.3 T was produced in a hybrid magnet whose central field was enhanced by a 3.5 T contribution from holmium pole pieces. The working (sample) volume was a 2‐mm gap between the 19‐mm‐diam×32‐mm‐long pole pieces tapered to 12‐mm‐diam faces. The magnetic field was measured with high‐field/low‐temperature Hall‐effect sensors whose reproducibility and linearity made practical an extrapolation technique for fields above 30 T. Three superconducting samples with previously measured upper critical fields were used as calibration check points.

Journal ArticleDOI
TL;DR: In this paper, the design and characteristics of miniaturized magnetic device in cloth structure are discussed by using machine-made devices and the method of optimization of size of amorphous fiber and conductive fiber is made clear.
Abstract: Design and characteristics of miniaturized magnetic device in cloth structure are discussed by using machine -made devices. The method of optimization of size of amorphous fiber and conductive fiber is made clear. The inductor with quality factor Q\simeq20 and inductance per unit volume L d >10µH/mm3is realized.

Journal ArticleDOI
TL;DR: In this article, the three-dimensional magnetic flux distribution on the tank wall of a three phase transformer has been calculated using a finite element scheme to obtain a 2D solution at 15 meridian planes of the transformer coil of a single phase transformer for any arbitrary value of current density.
Abstract: Increases in the ratings of large power transformers have demanded more accurate methods of predicting leakage fields which give rise to excessive losses in the devices. This paper addresses the issue, giving the development of a technique which can be used with minimal computing power to determine the distribution of the magnetic fluxes. Estimates for the additional stray load losses in the iron parts can be calculated with reasonable accuracy after the flux distribution has been found. For developing large transformers and reactors, it is necessary to know the distribution of the magnetic leakage field to calculate the electro-dynamic forces and the stray losses due to eddy currents in the winding conductors and in steel parts such as core, tank, pressing beams, etc. In general, the magnetic field in the transformer is calculated using the assumption that the structure is two-dimensional. But actual transformers are three-dimensional. Thus, the customary two-dimensional approximations are inadequate. In this paper, the three-dimensional magnetic flux distribution on the tank wall of a three phase transformer has been calculated. In order to perform the calculation, a finite element scheme has been adopted to obtain a two-dimensional solution at 15 meridian planes of the transformer coil of a single phase transformer for any arbitrary value of current density. Using the actual values of current densities, the magnetic field has been computed for each phase at two selected instants of time in the cycle. Then, the results are manipulated to obtain an overall solution.

Patent
15 Aug 1986
TL;DR: In this paper, a U-shaped metallic frame is constructed for defining the window of a jointed magnetic core, which core is constructed of amorphous metal alloy, and methods of constructing such a fixture are described.
Abstract: A fixture for defining the window of a jointed magnetic core, which core is constructed of amorphous metal alloy, and methods of constructing such a fixture. The fixture includes first and second substantially U-shaped metallic frame members which are easily and quickly assembled with interlocking joints which positively maintain the desired geometric configuration of the core window, as well as the peripheral dimension thereof. Notwithstanding the high mechanical strength of the fixture, the interlocking joints are easily unlocked, which feature is necessary as the fixture will be required to be assembled, disassembled, and reassembled a part of the normal processing of the magnetic core. New and improved methods of constructing the fixture enable the same tooling to be used for different sizes of fixtures, which are required to cover the range of transformer ratings the magnetic cores will be an integral part of.