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Showing papers on "Magnetic core published in 1990"


Journal ArticleDOI
TL;DR: In this paper, the authors compared conventional techniques and new techniques based on digitizing instruments for making high-frequency B-versus-H loop and core-loss measurements on magnetic cores.
Abstract: Conventional techniques and new techniques based on digitizing instruments for making high-frequency B-versus-H loop and core-loss measurements on magnetic cores are presented and compared. Potential sources of measurement errors and their magnitudes, limitations imposed by the instrumentation, and thermal considerations are discussed. Circuits suitable for high-frequency sine-wave or square-wave core excitation are also discussed. The utility of such measurements is illustrated with sample data. >

164 citations


Journal ArticleDOI
Roger Wood1, M.L. Williams1, J. Hong1
TL;DR: In this article, a reluctance model is developed to explore the relationship between the geometry of a head and its inductance, and the model is extended to include the effects of eddy currents, and to allow the frequency-dependent efficiency to be calculated.
Abstract: The significance of head inductance and eddy currents in limiting field rise times is discussed. Poor rise times can cause severe distortion and loss of performance at high data rates. A simple reluctance model is developed to explore the relationship between the geometry of a head and its inductance. The model is extended to include the effects of eddy currents, and to allow the frequency-dependent efficiency (hence the field rise time) to be calculated. Based on this rise time, a geometric model is used to calculate the positions of the recorded transitions and the resulting transition-shift distortion. Experimental results at transition separations down to 6 ns reveal a strong write current dependency which is not seen in the model. This dependence is, however, clearly seen in a simple domain wall model which implicitly includes magnetic saturation. Transition shift distortion can be mitigated by the use of precompensation. It is found that it is possible to successfully recover data at 180 Mbit/s using a conventional thin-film head. >

78 citations


Proceedings ArticleDOI
11 Jun 1990
TL;DR: In this paper, the authors investigated various design considerations for high-power (multikilowatt), high-frequency transformers for DC-DC power converters and investigated the influence of leakage flux distribution in the window region on the copper losses.
Abstract: Various design considerations for high-power (multikilowatt), high-frequency transformers for DC-DC power converters are investigated Although Ferrite (PC40) is lossier than Permalloy80 (05 mil) at the frequencies of interest (25-50 kHz) the use of the former is justified on the basis of cost, weight, and wide ranges of shapes The influence of the leakage flux distribution in the window region on the copper losses has been demonstrated for various conventional winding arrangements However, it is seen that in conventionally wound transformers a considerable amount of leakage flux enters the core, resulting in localized core saturation and hot-spots This becomes a very critical issue for high-power, high-frequency transformers Coaxially wound transformers are seen to be a viable alternative, in that the leakage flux is contained with the interwinding space, with very little or none of it permeating the core Such transformers can also realize multiple benefits of a low distributed and controllable leakage inductance, robust construction, low electromechanical forces, and low core and copper losses Test results on two coaxially wound transformers with different tube geometries, designed for 50 kW, 50 kHz, primary voltage of 200 V, and secondary voltage of 1000 V (two windings), are presented Finally the concept of coaxial winding technique for three-phase transformers is also presented >

77 citations


Journal ArticleDOI
17 Apr 1990
TL;DR: A thin-film cloth-structured inductor for MAGIC (magnetic integrated circuit) operation in the high-frequency range is described in this paper, where magnetic core arrays with low demagnetizing factor are utilized.
Abstract: A thin-film cloth-structured inductor for MAGIC (magnetic integrated circuit) operation in the high-frequency range is described. To achieve high inductance in a small area, magnetic core arrays with low demagnetizing factor are utilized. To increase the frequency, which is limited by the resonant frequency, the magnetic-strip core arrays are divided into three parts and each core array is excited out of phase; that is, the inductor is composed of three unit inductors connected in series with low mutual coupling. Thus, the resonant frequency of the integrated inductor is high, and high-frequency operation is possible. The experimental inductor is 3*3 mm/sup 2/ in size. The inductance is about 300 nH at 100 MHz, which is about eight times as large as that of the air-core inductor. High inductance can be easily achieved by increasing the number of strip cores with high permeability. >

68 citations


Journal ArticleDOI
TL;DR: In this article, the gap element, the expanding element, and the shielding element have been conceived for discretizing narrow gaps in an iron core, the long legs of a transformer core, and thin shielding plates.
Abstract: Three-dimensional special elements, called the gap element, the expanding element, and the shielding element, have been conceived for discretizing narrow gaps in an iron core, the long legs of a transformer core, and thin shielding plates. The concept of the 3D special element and its finite-element formulation are described. The special elements are applied to several models, and the effects of the elements on accuracy and CPU time are discussed. It is shown that CPU time can be reduced by using the special elements. >

61 citations


Journal ArticleDOI
TL;DR: In this paper, a spiral windings sandwiched between top and bottom-plane thick magnetic plates is investigated theoretically using the method of current images, and it is shown that the inductance depends only on the net distance between the top-and bottom magnetic plates and is independent of the position of the spiral wires within the gap, whereas in contrast to open planar structures, the sandwich inductor can yield large values of inductances with the enhancement over air core values limited only by the permeability of the magnetic plates.
Abstract: Inductors with spiral windings sandwiched between top- and bottom-plane thick magnetic plates are investigated theoretically using the method of current images. Expressions are obtained for the inductances, and magnetic fields of these planar structures assuming infinite plane thicknesses. The dependence of the inductance on the permeability and the distances between the spiral windings and the top and bottom plates is studied by numerically evaluating the inductance expressions. It is shown that, except for some limiting cases, the inductance depends only on the net distance between the top and bottom magnetic plates and is independent of the position of the spiral windings within the gap. Furthermore, it is found that, in contrast to open planar structures, the sandwich inductor can yield large values of inductances with the enhancement over air-core values limited only by the permeability of the magnetic plates. Numerical evaluation of the formulas for magnetic fields both inside the magnetic plates and in the gap are used to calculate energy density variation in the device, to estimate lateral dimensions of these sandwich inductors, to discuss construction of multiple devices in a single-sandwich structure, and to discuss calculation of losses in the sandwich inductors. >

61 citations


Patent
26 Feb 1990
TL;DR: In this paper, a continuous casting method was proposed to secure the sufficient performances in an electromagnetic brake and an electromagnetic stirring, related to a method for continuously casting steel while controlling the flowing of molten steel in a mold by using an electromagnetic coil unit.
Abstract: PROBLEM TO BE SOLVED: To secure the sufficient performances in an electromagnetic brake and an electromagnetic stirring, related to a method for continuously casting steel while controlling the flowing of molten steel in a mold by using an electromagnetic coil unit useable for the electromagnetic brake together with the electromagnetic stirring, for example, when a slab is continuously cast. SOLUTION: This continuous casting method is the one, with which the electromagnetic brake or the electromagnetic stirring is selectively acted to the molten steel 2 by making to flow a direct current or multi-phase alternating current having ≥3 phases to coils arranged at the outer circumference of the long wall sides 3b. The coils are arranged to the same pieces on each long wall side and (2n+2) (n is natural number) in the total in the mold. Each coil set has two pieces of coils wound on the outer circumferential part in the respective magnetic pole iron core and one piece of coil wound on the outer circumferential part with two pieces of magnetic pole iron cores together. At the electromagnetic stirring time, in the adjacent coils at each long wall side, the multi-phase alternating current having 90° to 120° current phase difference is made to flow. Further, at the electromagnetic braking time, the direct current is made to flow to the one piece of coil wound on the outer circumferential part to each coil set with two pieces of magnetic pole iron cores together, or the direct current is made to flow three pieces of coils. COPYRIGHT: (C)2007,JPO&INPIT

56 citations


Journal ArticleDOI
11 Jun 1990
TL;DR: In this paper, an electronic technique which greatly increases the apparent permeability of a magnetic core of a current transformer without a galvanic connection to either of the usual primary or secondary winding circuits is described.
Abstract: Summary form only given. An electronic technique which greatly increases the apparent permeability of a magnetic core of a current transformer without a galvanic connection to either of the usual primary or secondary winding circuits is described. The number of turns and the turns ratio can be selected independently as desired. Means are available for examining the waveform of the magnetizing current for the presence of even harmonics, thus indicating possible remanence or direct currents in the windings. Application of the technique to transformer voltage dividers is also discussed. >

52 citations


Patent
17 Jul 1990
TL;DR: In this article, a magnetic shielding material is described which has a laminate structure comprising a ferromagnetic sheet having a high saturation magnetic flux density, an amorphous alloy foil and a non-magnetic sheet.
Abstract: A magnetic shielding material is described which has a laminate structure comprising a ferromagnetic sheet having a high saturation magnetic flux density, a ferromagnetic sheet having a high magnetic permeability and a non-magnetic sheet. The high saturation magnetic flux density sheet includes a sheet of mold steel, silicon steel or an iron-cobalt alloy. The high magnetic permeability sheet includes an amorphous alloy foil or a laminate thereof. The magnetic shielding material may further have at least one foil of an electromagnetic wave-shielding material.

49 citations


Proceedings ArticleDOI
11 Mar 1990
TL;DR: In this article, a multidimensional minimum search algorithm was used to design the smallest transformer and determine the optimum number of turns, winding space allocation, and size of the magnetic core.
Abstract: A computer-aided tool for design and analysis of high-frequency power transformers has been developed The program uses a multidimensional minimum-search algorithm to design the smallest transformer and determine the optimum number of turns, winding space allocation, and size of the magnetic core The design specifications include current and voltage waveforms, desired core shape and material, type of winding (Litz wire, solid wire, or foil), and primary and secondary winding arrangement The program also calculates the core loss and computes the winding loss distribution, taking into account proximity and skin effects An experimental transformer was designed for a 75 W offline zero-current quasi-resonant converter to verify the calculations >

39 citations


Patent
25 Jul 1990
TL;DR: In this paper, the authors describe a thin-film magnetic head for magnetic recording and reproducing apparatus, which includes a lower insulating layer, an intermediate layer, and an upper layer.
Abstract: A thin-film magnetic head for magnetic recording and reproducing apparatus includes a lower insulating layer deposited on a substrate and including a lower magnetic core, an intermediate insulating layer deposited on the lower insulating layer and including front and rear intermediate magnetic cores, and an upper insulating layer deposited on the intermediate insulating layer and including an upper magnetic core. The magnetic cores make up a magnetic circuit which has a magnetic gap defined between the lower magnetic core and the front intermediate magnetic core or between the front intermediate magnetic core and the upper magnetic core. A multiturn coil is embedded in the intermediate insulating layer to surround the rear intermediate magnetic core. The lower, intermediate, and upper insulating layers have respective flat surfaces including respective surfaces of the lower, intermediate, and upper magnetic cores. The lower, intermediate, and upper insulating layers are joined to each other through the flat surfaces.

Journal ArticleDOI
TL;DR: In this paper, a 2D magnetic field calculation method that takes into account the nonlinear anisotropic property in the grain-oriented steel was proposed, where the magnetic permeability was represented by a tensor with field-dependent components.
Abstract: The authors propose a 2-D magnetic field calculation method that takes into account the nonlinear anisotropic property in the grain-oriented steel. An elliptical model is used; the magnetic permeability is represented by a tensor with field-dependent components. This model is applied to a finite-element method using a scalar potential. The iron nonlinearity is considered and a Newton-Raphson method is applied to a family of B-H curves to improve convergence. To minimize variation of flux density between elements, an auto-adaptive process has been used. This modelling of nonlinear anisotropic magnetic fields is applied to a three-phase transformer core. >

Patent
16 May 1990
TL;DR: In this paper, the end point of polishing for removing a surface layer during the processing of semiconductor substrates is detected by measuring the induced voltage in the polishing wheel.
Abstract: The present invention relates to a method and apparatus for remotely detecting impedance. It is specifically adapted for use on a polishing machine wherein the end point of polishing for removing a surface layer during the processing of semiconductor substrates is detected. A first, or stationary coil having a high permeability core is wound having an air gap and an AC voltage is applied to the stationary coil to provide a magnetic flux in the air gap. A second coil is mounted for rotation on the polishing table, in a position to periodically pass through the air gap of the stationary coil as the table rotates. The second coil is connected at its opposite ends to contacts which are embedded in the surface of the polishing wheel. The contacts are positioned to engage the surface of the substrate which is being polished and provide a load on the second or rotating coil. The rotating coil, when it is in the air gap of the stationary coil, will perturb the flux field therein as a function of the resistance of the load caused by the contacts contacting either a conducting surface or a non-conducting surface. This perturbance of the flux field is measured as a change in the induced voltage in the stationary coil which in turn is converted to a signal which is processed to indicate the end point of polishing, the end point being when a metallic layer has been removed to expose a dielectric layer therebeneath or, conversely, when a dielectric layer has been removed to expose a metallic layer therebeneath.

Patent
30 Jul 1990
TL;DR: In this paper, a cylindrical central iron core is formed using wire materials composed of a magnetic substance and an insulating layer is applied to the outer circumference of the wire materials.
Abstract: PURPOSE:To efficiently and easily insert an ignition coil into a cylindrical space such as a plug hole into which the ignition coil is inserted by a method wherein wire materials composed of a magnetic substance are bundled and a cylindrical central iron core is formed CONSTITUTION:Wire materials are composed of a material whose flux density is at 13 tesla or higher when a magnetic field is at 8 oersted The wire materials are wound to be a cylindrical shape at a space factor of 525% or higher; a central iron core is formed In addition, an insulating layer is applied to the outer circumference of the wire materials; the wire materials to which the insulating layer has been applied are pressurized, brought into close contact and bundled to be a cylindrical shape at a space factor of 85 to 95%; a central iron core is formed A central iron core 20 is formed in the following manner: many wire materials 30 to which an insulator has been applied on their surface are cut to prescribed lengths; the individual wire materials 30 are bundled; they are filled into the space formed by an upper metal mold and a lower metal mold which can make the external shape of a product round and on which a mold-releasing agent has been coated; and they are pressed and shaped while being heated from the outside An insulating layer 31 is formed of a thermoplastic resin When a saturation flux density can be made large and the wire materials can be insulated in this manner, it is possible to obtain a high secondary generation voltage

Patent
21 May 1990
TL;DR: In this article, a thin film magnetic head has a first magnetic core member carried by a substrate, a gap layer formed on the first core member, and a second core member formed in a spaced relation with the core member.
Abstract: A thin film magnetic head has a first magnetic core member carried by a substrate, a gap layer formed on the first magnetic core member, and a second magnetic core member formed in a spaced relation with the first magnetic core member. The second magnetic core member is coupled to the first magnetic core member to form a magnetic path and to have an end portion of the gap layer sandwiched by gap defining portions of the first and second magnetic core members. A coil conductor is wound about the magnetic path. In one embodiment, the first magnetic core member includes a first magnetic layer made of a magnetic material having stable magnetic properties during heat treatment and the second magnetic core member includes a second magnetic layer made of a material having a saturation flux density higher than that of the material of the first magnetic core member.

Patent
02 Aug 1990
TL;DR: In this paper, a permanent magnet field pole is made to have an unequal pitch and a skew structure in an armature iron core and an equal gap structure is employed to compensate for the cogging torque generated at both end extending portions in the magnets.
Abstract: A permanent-magnetic motor employs a skew structure in an armature iron core and an equal gap structure. A center line of a permanent magnet field pole is disposed to be shifted against a mechanical center line of the motor or a center line of the iron core. The magnet field pole is made to have an unequal pitch. A cogging torque generated at both end extending portions in the magnets is cancelled out. The cogging torque of the permanent-magnetic motor in power steering assistance such as for the automobile yields a smooth steering feeling sensitivity during the operation of the automobile.

Patent
26 Jul 1990
TL;DR: In this article, an electromagnetic disc brake for an elevator lifting apparatus comprises a disc spline-coupled with a rotational shaft, and braking springs press the armature against the disc.
Abstract: An electromagnetic disc brake for an elevator lifting apparatus comprises a disc spline-coupled with a rotational shaft. Braking body and an armature disposed to clamp the disc; braking springs press the armature against the disc, and an iron core is provided which includes inner and outer magnetic poles each facing the armature and concentrically formed with respect to the rotational shaft. An electromagnetic coil generates magnetic flux to pass through the inner and outer magnetic poles as magnetic paths. In addition, at least one of the pole face of the outer magnetic pole and the facing portion of the armature where it faces the pole face is provided with an arrangement for increasing a magnetic gap, and the braking springs are disposed in portions of the outer magnetic pole. Further, the braking body is supported through a sound absorbing member or one side of the armature facing the disc is formed of a sound absorbing member.

Patent
17 Jan 1990
TL;DR: An Fe-Si alloy powder magnetic core comprises an alloy powder of an average particle diameter of 10-100 μm, produced by water atomization, in which the composition by weight of the alloy powder is 2-12% silicon and 0.05-0.95% oxygen with the balance being essentially iron as discussed by the authors.
Abstract: An Fe-Si alloy powder magnetic core comprises an alloy powder of an average particle diameter of 10-100 μm, produced by water atomization, in which the composition by weight of the alloy powder is 2-12% silicon and 0.05-0.95% oxygen with the balance being essentially iron. The process of manufacturing the powder magnetic core is also disclosed.

Patent
Tokihiro Umemura1, Abe Keiichi1
24 Jan 1990
TL;DR: In this paper, a partial discharge detecting device for transformers is described, which includes an antenna disposed in a metallic insulation gas filled tank enclosing a core and coil assembly and a signal processing circuit for processing an output signal from the antenna.
Abstract: A partial discharge detecting device for transformers includes an antenna disposed in a metallic insulation gas filled tank enclosing a core and coil assembly and a signal processing circuit for processing an output signal from the antenna. The antenna includes a magnetic core and a single coil or two coils differently operated. An electromagnetic wave due to the partial discharge is detected by the antenna. A detection signal from the antenna is supplied to the signal processing circuit, which determines whether or not the partial discharge has taken place, based on the detection signal.

Patent
22 May 1990
TL;DR: A thin film magnetic core array has a large number of individual thin film core memory elements arranged on a substrate with X, Y, Z and SENSE conductor leads reeving through the core elements between contact pads arranged about the periphery of the array.
Abstract: A thin film magnetic core array has a large number of individual thin film core memory elements arranged on a substrate with X, Y, Z and SENSE conductor leads reeving through the core elements between contact pads arranged about the periphery of the array. Each thin film magnetic memory element includes a bottom pole, a top pole forming a closed magnetic path with the top pole, the structure surrounding the leads passing through the core, and insulation material for electrically insulating the leads from each other and from the pole pieces. The SENSE lead from the array is coupled to a miniature thin film transformer which amplifies the signals read from the individual core elements. The transformer has a bottom pole, a top pole forming a closed magnetic path with the bottom pole, including a central leg extending between the top and bottom poles, and a pair of electrically conductive coils mutually spaced in the region between the top and bottom poles.

Patent
16 Feb 1990
TL;DR: In this paper, a transducer includes a uniform pitch winding wound on a hollow bobbin with several continuously variable concentric coils wound over it with layers of insulation in between.
Abstract: A variable transformer is disclosed. The transducer includes a uniform pitch winding wound on a hollow bobbin with several continuously variable concentric coils wound over it with layers of insulation in between. The variable coils are wound in accordance with true trigonometric functions by adjusting the pitch between adjacent turns and reversing the direction of winding at each maximum pitch point corresponding to the zero crossover. The variable pitch coils are physically wound in quadrature with respect to a reference point on the bobbin. The transducer is finished by placing a magnetic shield over the bobbin which may include magnetic end washers. Lead wire connections are made and the entire unit is placed in a suitable housing. A moveable core, made from a highly permeable material, is placed inside the unit for slidably engaging the bobbin in its hollow. The variable pitch coils may then be excited by separate trigonometric function generators operating in quadrature and the output signal from the secondary has a constant amplitude which changes in phase with respect to one of the excitation sources in direct proportion to the position of the moveable magnetic core. Alternatively, the uniform pitch coil may be excited by a single phase AC source and the amplitude of the output signals from the variable pitch coils in conjunction with their phase relationship to the AC excitation source will indicate displacement of the core.

Patent
14 May 1990
TL;DR: In this article, the authors proposed to make the whole inexpensive in addition to high performance by installing an inductor in an elevator shaft and simultaneously setting up a magnetic field and an armature both in a lifting body so as to be opposed each to this inductor.
Abstract: PURPOSE: To make the whole inexpensive in addition to high performance by installing an inductor in an elevator shaft and simultaneously setting up a magnetic field and an armature both in a lifting body so as to be opposed each to this inductor. CONSTITUTION: An inductor 21 extending in the vertical direction is attached to the wall surface of an elevator shaft 6. In addition, each of section U-shaped magnet cores 23 is attached to both sides of a cage 4 as opposed to the inductor 21. A lot of magnetic pole-formed projections 21a are installed in the inductor 21 at regular intervals in a symmetrical alternate manner in the vertical direction. A field coil 24 and an armature coil 25 both are attached to the magnetic core 23, thereby constituting a magnetic field 26 and an armature 27. When a DC magnetic field in the field 26, there are produced magnetic poles (N or S pole) in the magnetic pole-formed projection 21a, so that there is produced a thrust owing to a traveling magnetic field in the armature 27 in combination, thus the cage 4 is lifted up and down. With this constitution, it is good enough to attach the inductor to the elevator shaft, thus cost is reduced, while any drop in a power factor is kept back, and the whole elevator system can be made inexpensive in addition to high performance. COPYRIGHT: (C)1992,JPO&Japio

Journal ArticleDOI
TL;DR: In this paper, a description of soft magnetic powder composites, such as sinters, dielectromagnetics, and magnetodielectrics, and the problems associated with their application as magnetic cores in electrical converters is presented.
Abstract: A description of soft magnetic powder composites, such as sinters, dielectromagnetics, and magnetodielectrics, and the problems associated with their application as magnetic cores in electrical converters is presented. Typical magnetic properties and methods of processing are reviewed and criteria for choosing the type of composite for a particular magnetic core are discussed. Dielectromagnetics can be divided, both in terms of their present status and for future development, into conventional and special types. The problems associated with both these types are described. A brief review is given, based on the authors' experience with these problems, of the present status of and the prospects for soft magnetic powder composites. PM/0519

Patent
21 Aug 1990
TL;DR: In this paper, the leads are arranged so that they extend through a generally axially extending hole in the rotor with their free ends being connected in a parallel splice configuration which extends radially outward from the hole.
Abstract: An electric generator and a method of securing a connection between flexible electrical leads from a rectifier and a main field winding in a rotor of the generator wherein the leads are arranged so that they extend through a generally axially extending hole in the rotor with their free ends being connected in a parallel splice configuration which extends radially outward from the hole with the connected free ends being secured with respect to the rotor so as to remain in the radially outward extending position during rotation of the rotor. The rectifier is located at one end of the magnetic core and field winding of the main generator with the rectifier leads extending through a hole in the magnetic core and a field winding insulator to the opposite end of the magnetic core and field winding for connection with the field winding leads. Rotational forces will not pull the lead wire connections apart and the connections are readily accessible for repair.

Patent
12 Jun 1990
TL;DR: In this article, a magnetic core with high magnetic permeability and in the form of a surface film on a substrate, and at least two coils magnetically coupled to the magnetic core is described.
Abstract: A device for measuring a weak magnetic field is disclosed. The device includes a substrate, a magnetic core having a high magnetic permeability and in the form of a surface film on a substrate, and at least two coils magnetically coupled to the magnetic core. A pulse generator is connected to one of the coils and is used to drive the magnetic core into intermittent saturation. The other coil is used to generate an output signal. The device can be used for measuring the weak magnetic fields associated with bank notes for identifying the values of the bank notes.

Patent
28 Sep 1990
TL;DR: In this paper, a superconducting magnetic shield and a magnetic shielding apparatus were provided to measure an extremely weak magnetic field such as magnetoencephalographic waves by reducing the influence of magnetic field of the earth or magnetic noises.
Abstract: This invention provides a superconducting magnetic shield and a magnetic shielding apparatus including the same, thereby accurately measuring an extremely weak magnetic field such an magnetoencephalographic waves by reducing the influence of magnetic field of the earth or magnetic noises.

Journal ArticleDOI
Abstract: We have developed an all solid‐state exciter consisting of a magnetic pulse compressor with a transfer energy of 10 J/pulse approximately for KrF discharge lasers. The magnetic pulse compressor was operated with an energy transfer efficiency of 65% at a repetition rate frequency of 40 pps. A KrF excimer laser excited by the all solid‐state exciter was operated with an average laser power of 2.7 W. Four types of amorphous metals as a magnetic core material were experimentally compared in terms of their magnetic induction and magnetic loss so as to be used in the all solid‐state exciter.

Patent
09 Oct 1990
TL;DR: In this paper, a magnetic ribbon on at least one surface of which fine particles formed of a nonmagnetic inorganic substance having insulating properties are attached and a magnetic core around which this magnetic ribbon is wound or on which it is laminated.
Abstract: Disclosed are a magnetic ribbon on at least one surface of which fine particles formed of a nonmagnetic inorganic substance having insulating properties are attached and a magnetic core around which this magnetic ribbon is wound or on which it is laminated. The fine particles serve as a spacer to form a layer of air between adjacent layers of the magnetic ribbon.

Patent
20 Jul 1990
TL;DR: In this article, a magnetic core main body composed of flat-shaped soft magnetic alloy material and insulator and a metal outer pipe accommodating said core is provided, and the flat surface of the soft magnetic Alloy material is orientated in the axial direction of the outer pipe.
Abstract: PURPOSE: To reduce magnetic gap, and improve magnetic characteristics, by providing a magnetic core main body composed of flat-shaped soft magnetic alloy material and insulator and a metal outer pipe accommodating said core, orientating the flat surface of the soft magnetic alloy material in the axial direction of the material outer pipe, and substantially constituting the soft magnetic alloy material in an amorphous state. CONSTITUTION: Magnetic core main body composed of flat-shaped soft magnetic alloy material and insulator and a metal outer pipe accommodating said core are provided, and the flat surface of the soft magnetic alloy material is orientated in the axial direction of the outer pipe. The soft magnetic alloy material is amorphous alloy expressed by Fe 100-a-b M a Y b . M is at least one kind of element selected out of group IV a , group V b elements in periodic table, and Mn, Co and Cu. Y is at least one of Si, B, P and C. The notations (a) and (b) represent at%, and adjustment is performed so as to satisfy 0≤a≤8 and 10≤b≤30. COPYRIGHT: (C)1992,JPO&Japio

Patent
14 Mar 1990
TL;DR: In the case of the known magnetic core materials with a high nickel content of the permalloy type, this requires a special additional anneal as discussed by the authors, which can be dispensed with if the magnetic core material used is an iron-based alloy with an iron content of more than 60 atomic %.
Abstract: In magnetic core materials for fault current protective switches, a high constancy of the magnetic properties is required over the entire application temperature range from -25 DEG C to +80 DEG C. In the case of the known magnetic core materials with a high nickel content of the permalloy type, this requires a special additional anneal. This can be dispensed with if the magnetic core material used is an iron-based alloy with an iron content of more than 60 atomic %, more than 50% of whose structure consists of fine crystalline grains having a grain size of less than 100 nm and which has a saturation induction of more than 1.1 T and also a remanence ratio of less than 0.7.