Showing papers on "Magnetic core published in 1983"

Two-component, dry electrographic developer compositions containing hard magnetic carrier particles and method for using the same

Abstract: An electrographic, two-component dry developer composition comprising charged toner particles and oppositely charged, magnetic carrier particles, which (a) comprise a magnetic material exhibiting "hard" magnetic properties, as characterized by a coercivity of at least 300 gauss and (b) exhibit an induced magnetic moment of at least 20 EMU/gm when in an applied field of 1000 gauss, is disclosed. The developer is employed in combination with a magnetic applicator comprising a rotatable magnetic core and an outer, nonmagnetizable shell to develop electrostatic images.

Powdered iron core magnetic devices

Abstract: A compacted powdered iron core utilizes iron powder in the 0.002 to 0.006 mean particle size range which is first coated with an alkali metal silicate and then overcoated with a silicone resin polymer. The treated powder is compressed to approximately 94% of theoretical density and then annealed at approximately 600° C. This results in a core component characterized by overall core losses as low as in conventional laminated cores in A.C. operation.

Magnetic core and method of producing the same

Abstract: Disclosed is an magnetic core comprising a molded product made of an iron powder and/or an iron alloy magnetic powder having a mean particle size of 10 to 100 μm, and 1.5 to 40%, as a total amount in terms of volume ratio, of an insulating binder resin and an insulating inorganic compound powder. Also disclosed is a useful method of producing the magnetic core.

Thin-film magnetic head and method for fabricating the same

Abstract: A thin-film magnetic head having a magnetic core of double step structure and a method of fabricating it. A first magnetic core is formed on a substrate, which has a predetermined thickness at a pole chip region thereof and a thickness larger than the predetermined thickness at a back region thereof; a magnetic gap is formed thereon, a conductor coil is formed on the magnetic gap, which is encircled by an inter-layer, insulating film; a first magnetic film is formed thereon, which constitutes one layer of a second magnetic core and is connected with the first magnetic core at the back region; and a second magnetic film is formed thereon through an inorganic insulating film, which constitutes another layer of the second magnetic core and is removed at the pole chip region. When the second magnetic film is removed, the inorganic insulating film serves to protect the first magnetic film, and hence the thickness of the first magnetic film is maintained unvaried. Thus, there is obtained the thin-film magnetic head having a magnetic film which is of a predetermined thickness at the pole chip region and a thickness larger than the predetermined thickness at the back region. This structure enhances the conversion efficiency of the head as well as boosts the resolution for reproduction and relaxes the magnetization saturation for recording.

Toroidal electrical transformer and method of producing same

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 in substantial part over their length 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. Various components and sub-assemblies are also disclosed along with various apparatus and methods for producing such toroidal electrical transformer, its components and its sub-assemblies.

Discharge lamp lightening device

Abstract: Two fluorescent lamps are lightened by a single inverter circuit which provides switched power current to a single leakage transformer. The leakage transformer has a single primary winding coupled with said inverter circuit and a pair of secondary windings each coupled with a related fluorescent lamp. The core of said leakage transformer has a closed magnetic core with a pair of short legs each of which bridges across said closed magnetic path with a non-magnetic material so that said pair of short legs provides three windows and bypass leakage magnetic paths. The first window is defined by said pair of short legs, and each of the second and the third legs is defined by one of said short legs and said closed magnetic path. The primary winding is mounted in said first window, and each of said pair of secondary windings is mounted in said second or third window. The magnetic flux in said closed magnetic path provides high output voltage, which fires a lamp, then, the magnetic flux is switched to the leakage path which includes said short leg and the non-magnetic material, then, the output voltage is reduced but is enough to maintain the discharge current in the lamp.

New magnetic structures for switching converters

Abstract: In the past the majority of power processing applications have been centered around a very few standard switching converter topologies. Recently, a number of new converter topologies have been proposed in order to find the best possible electrical inter connection of power processing elements: switches, storage components, and transformers, that would yield the highest efficiency and best performance. However the equally important and complementary problem of their best magnetic interconnection has been completely overlooked. In some new converter structures, the nature of the switching process and existing waveforms allows integration of previously separate inductors and transformers into a single magnetic structure. Several such magnetic core structures are proposed and analyzed, which lead to further converter simplifications and performance improvements.

Magnetostriction and magnetic core loss at high frequency in amorphous Fe‐Nb‐Si‐B alloys

Abstract: Magnetostriction and magnetic core loss at high frequency up to 100 kHz were investigated together with crystallization temperature, saturation magnetization, and magnetic permeability for amorphous (Fe1−xNbx)zSi88−zB12 alloys. Crystallization temperature significantly rises with Nb addition, particularly in the high z region. Magnetostriction decreases with increasing Nb content and z value. Magnetic core loss decreases and magnetic permeability increases with decreasing magnetostriction. Magnetic core loss reduction due to Nb addition were analyzed to be mainly attributed to domain width reduction through the decrease of magnetostriction.

System for measuring torque and/or speed of rotating shaft

Abstract: A magnetic transducer (10) fits over a rotatable shaft (11) and has a multi-pole magnetic core (30), one primary winding (46) being wound on half of the poles while a second primary winding (47) is wound on the other half. Direct current pulses are alternately supplied to the two primary windings to provide a-c excitation for producing an alternating magnetic flux or field, adjacent to and within the shaft, which changes as the shaft is torsionally stressed when torque is applied thereto. This stressing causes compression and tension in the shaft which alter the shaft permeability and thus vary the magnetic flus pattern in the shaft. The resulting magnetic field is also a function of the shaft speed due to the shaft's armature reaction, eddy currents being generated in the shaft which develop a counter magnetic field that opposes and distorts the field produced by the two primary windings. A secondary circuit (51, 52) in the transducer (10), comprising a pair of secondary windings (38, 42) each wound on a separate magnetic core (31, 32), responds to the resulting magnetic field and provides information signals relative to the torque and speed characteristics of the rotating shaft.

Induction heating and fixing device for a copying machine

Abstract: An induction heating and fixing device suitable for a copying machine comprises a fixing roller, a first iron core, a second iron core, and two third iron cores. The first iron core inserted into the center of the fixing roller. The first, the second, and the third iron cores are magnetically and mechanically combined together to form a closed magnetic circuit. Magnetic blocks are provided for combining the first, the second, and the third iron cores. Each of these iron cores comprises a plurality of isolated thin silicon steel plates. At least one of the two of the third iron cores is disassembled to remove the fixing roller from the device for maintenance.

Coupled Inductor and Integrated Magnetics Techniques in Power Electronics

Abstract: Energy storage and power processing with magnetic devices is more efficient if the separate inductors and transformers are integrated into a single magnetic structure. The origins and main results of the coupled-inductor and integrated magnetics concepts are reviewed.

Inductive proximity switch having an oscillator magnetic core and a permanent magnet forming a saturation-sensitive magnetization area

Abstract: An inductive proximity switch including an oscillator a circuit of which has an oscillator magnetic core adapted to be influenced by a trip device for the purpose of actuating an electronic switch. The proximity switch is adapted to detect an approach of the trip device, of a permeable material, through a nonferromagnetic wall so as to enable a triggering of the switching process. A sensor field formed of a magnetic field of a permanent magnet or an electromagnetic, with the proximity switch having a saturation-sensitive magnetization area or region in which the magnetic fluxes of the permanent magnet or electromagnet and oscillator core heterodyne. The inductive proximity switch is adapted to be operated in saturation by a reduction in a magnetic resistance produced by introducing the permeable trip device into the sensor field, damping the oscillator circuit and causing a switching of the electronic switch.

Experimental Study on Magnetic Noise of Large Induction Motors

Abstract: This paper presents an experimental study on magnetic noise of an induction motor. The measurement of magnetic force wave was successfully accomplished by fitting flux-detecting coils on all stator teeth. Through the analysis of experimental results, a series of magnetic noise emitting mechanism and correlation among magnetic noise, vibration, frequencies and modes of both stator core and magnetic forces were found.

Magnetic reproducing system

Abstract: A magnetic material (1b-2) whose high frequency characteristics vary in response to a signal field recorded on a magnetic recording medium (1) is provided as a magnetic layer in a high frequency coupling circuit including the magnetic recording medium (1) and a reproduction head (5). The coupling degree of the high frequency coupling circuit noticeably varies with the change of the high frequency characteristics of the magnetic material (1b-2), thereby enabling the reproduction of the recorded signal by utilizing the change of the high frequency characteristics.

Stacked amorphous metal core

Abstract: A stacked magnetic core constructed from amorphous strip material. The legs and yokes of the core include first and second laminations formed from a non-amorphous magnetic strip material. The first and second laminations are spaced from one another to define a gap therebetween. A plurality of laminations formed from an amorphous magnetic strip material is stacked in the gap. Means are provided to join the first and second non-amorphous laminations so as to reinforce and support the core.

Magnetic field simulation from a voltage source

Abstract: A finite-element program has been developed to digitally simulate the dynamic response of solenoids to a specified voltage trace. The evolution of the magnetic field is modeled complete with eddy currents and saturation effects. The motion of the solenoid's plunger in response to mechanical and magnetic forces is incorporated into the solution for the magnetic field. Moreover, these effects are coupled with the electrical driving circuit whose inductance is unknown (and varying).

Energizing circuit for magnetic valves

Abstract: In the case of magnetic valves in metering devices which are excited by pulses, on the one hand rapid opening and closing of the valve is required, and on the other hand a power consumption and heat dissipation which are as low as possible are demanded. For this purpose, the energising coil (L) of the magnetic valve can be connected via two switch paths (T3, T5), connected in series, initially to a higher voltage trigger current source (U1) and, once the valve has opened, to a maintaining current source (U2) at a lower voltage. The changeover takes place either by means of a timer (R, C, T1) or by means of a sensor circuit sampling the position of the moving magnetic core of the magnetic valve, or its closing body. If a timer is used, this can be connected upstream of a switching transistor (T5), connecting the energising coil (L) to the trigger current source (U1), as an individual pulse transmitter. (Fig. 4):

Alternating electromagnetic field computation in laminated cores

Abstract: A finite element method is developed to compute alternating electromagnetic fields in laminated cores. The method is applied to a simplified model problem in order to evaluate power losses in mitered overlap joints. The influence of eddy currents on the magnetic field distribution in the neighborhood of the mitered joints is discussed. The power losses ate evaluated for cores with different overlap lengths.

Magnetic transducer head having series connected magnetroresistance effect sensing element with head output connected between the sensing elements

Abstract: A magnetic transducer head utilizing magnetoresistance effect having a circuit for applying a constant voltage to outer ends of at least one pair of magnetoresistance effect elements provided in series on a discontinuous portion other than a magnetic gap of a magnetic core forming a magnetic gap and a conductor arrangement for applying bias magnetic fields opposite in polarity to the magnetoresistance effect elements, respectively wherein an output is derived from a connected point between the pair of magnetoresistance effect elements.

Magnetic core for choke coil

Abstract: PURPOSE: To obtain a magnetic core enabled to prevent inductance from a sudden fall to be generated following the increase of a current, and moreover having large inductance at low current time by a method wherein the magnetic core forming a closed magnetic path and constructed by using an amorphous material having positive magneto-striction is impregnated with resin. CONSTITUTION: A magnetic core forming a closed magnetic path and constructed by using an amorphous material having positive magneto-striction is impregnated with resin. For example, a material consisting of composition of FebalNi 7.5 Si 16 B 9 is selected as the amorphous material, and after it is molten according to high-frequency melting, a mother alloy is manufactured, and after the mother alloy thereof is heated to be molten, the molten metal is ejected on a copper roll rotating at a high speed, and an amorphous ribbon of about 20μm thickness, about 6.5mm breadth is produced. The ribbon thereof is wound round to manufacture a toroidal core, epoxy resin is incorporated therein, and after deaeration is performed in a vacuum, it is thermoset. COPYRIGHT: (C)1984,JPO&Japio

Effects of magnetic characteristics of materials on the iron loss in the three phase transformer core

Abstract: The finite element method has been applied to clarify the relation between magnetic characteristics of the electrical steel and power transformer iron losses. Three material constants which represent the magnetic characteristics are used for this study. The computed results have contributed to understanding of factors which increase the transformer iron losses.

Magnetic transducer heads utilising magnetoresistance effect

Abstract: A magnetic transducer head utilising magnetoresistance effect comprises means for applying a constant voltage (V1, V2) to both ends of at least one pair of magnetoresistance effect elements (MRn1, MRn2) connected in series on a discontinuous portion other than a magnetic gap of a magnetic core forming a magnetic gap, and means for applying bias magnetic fields (HB, -HB) of opposite polarity to the respective magnetoresistance effect elements, an output being derived from a connection point between the pair of magnetoresistance effect elements.

Loop antenna containing magnetic core

Abstract: PURPOSE:To obtain a loop antenna containing a magnetic core which is flexible and hard to break with high effective permeability and a low loss, by putting a magnetic core formed with lamination of plastic films coating materials of high permeability into a tuning coil. CONSTITUTION:A magnetic layer 1 of the Mn-Zn or Ni-Zn ferrite, etc. for example, having high permeability is coated on a plastic film 2 to form a laminated magnetic core 3. This core 3 is put into a tuning coil 4. The effective permeability of the core 3 can be increased by increasing the permeability of the layer 1 and forming the core 3 into an oblong and flat shape. The eddy current loss of the core 3 which contributes to the effective Q of a tuning circuit is extremely reduced since the core 3 is laminated to an extremely this magnetic matter with the electric insulation applied by the film 2. Thus a loop antenna containing a magnetic core can be made to have the flexibility with a small loss and high effective permeability.

Self-holding type solenoid

Abstract: PURPOSE:To obtain a self-holding type solenoid powerful and low power consumptive, by a method wherein permanent magnets are fixed to both sides of an axis of a movable iron core symmetrically facing with each other, movably yokes are disposed on the outsides of the magnets facing a fixed yoke, and a fixed iron core and a movable iron core are disposed also facing with each other. CONSTITUTION:A fixed iron core 41 is caulked inside of a U-shaped fixed yoke 40, an electromagnetic coil 42 is fitted therein, a non-magnetic mounting plate 43 is caulked to the fixed yoke 40, a square bar 45 is movably inserted to a square hole provided in the center of the electromagnetic coil 42, flat permanent magnets 47 are adhered to both sides of a head 46, a movable yokes 48 are adhered outside thereof. A movable iron core 44 is provided with a deep hole in the center thereof, to which a spring 49 is fitted, and is provided with a valve body 51 having a valve rubber 50 on the end surface of the head 46. 52 is a valve seat. The movable iron core 44 is adsorbed by magnetic force, when the electromagnetic coi 42 is excited instantaneously or the valve body is opened. The movalbe iron core 44 is released and the valve seat 52 is closed, when the magnetic coil 42 is instantaneously applied with the inverse exciting current, as it weakens the magnetic field, decreasing adsorbability.

Multi-stage wound iron core

Abstract: PURPOSE:To decrease the using amount of a ribbon-shaped magnetic material by a method wherein a multi-stage wound iron core is composed of blocks split along the width direction of the magnetic material ribbon. CONSTITUTION:The section of a wound iron core is composed of blocks 7, 8, 9 split into three along the width direction of the ribbon of a magnetic material. Namely, the central block 8 made by winding a ribbon-shaped magnetic material with width (b) and the blocks 7, 9 made by winding a ribbon-shaped magnetic material with narrower width are superposed on the upper and lower opposite sides of the block 8 to form the section of the wound iron core. The center of the laminated layers of the blocks 7, 8, 9 is aligned in a straight line in the part of the leg section 1 of each block. Meanwhile, in a yoke section 2 wound no coil, the end sections at the iron core window 3 sides of the blocks 7, 9 at the opposite sides are marginally drawn to the iron core window 3. Therefore, this method can shorten the circumferential distance of the upper and lower outside blocks and reduce the using amount of the ribbon-shaped magnetic material.

Horn speaker with reduced magnetic flux leakage

Abstract: By adding a secondary magnetic piece with a partially open magnetic circuit to the front surface of a yoke connected to a primary magnetic piece, the magnetic flux leakage from the main magnetic piece is reduced on one hand and the magnetic flux extending across a magnetic gap is intensified through formation of a favorable magnetic field. This horn speaker is particularly useful in a ship where a horn speaker as an alarm is often required to be placed near magnetically sensitive equipment such as a compass.

Manufacture of induction magnetic iron core

Abstract: PURPOSE:To obtain good occupation rate of iron core and obtain sufficient low iron loss characteristic by applying an insulating film with the specified interval to the amorphous magnetic material in the pre-processing where the thin plate is laminated or wound. CONSTITUTION:Only when a processing tank 13 is located at the upper part, the insulating processing liquid 13a is applied to the amorphous magnetic material 11. When the processing tank 13 is located at the lower part, the insulating processing liquid 13a is not applied. The extraction plates 15 are formed in such a manner that the amorphous magnetic material 11 is coated with the insulating film 16 or only the amorphous magnetic material 11 is used for every specified numbers. The insulation processing liquid 13a is, for example, an inorganic film such as magnesia or phosphate and must be sufficiently resistive to the annealing under the magnetic field in the post-processing. The iron core is laminated in such a condition that the extraction plate having insulating film 16 on the surface of amorphous magnetic material 11 is inserted into the extraction plates of only the amorphous magnetic material 11 for every constant sheets. In the laminated iron core consisting of amorphous magnetic material which is coated with interlayer insulating film 16 in every thickness of 0.5-6mm., iron loss value does not increase.

Manufacture of magnetic core

Abstract: PURPOSE:To partly remove metal magnetic powder, prevent drop of electrical resistivity of core and obtain best characteristic of core by placing a liquid dissolving metal magnetic powder in contact with the surface of dust core material having completed the cutting work of grinding work. CONSTITUTION:The Fe powder and Ni powder in average grain size and epoxy resin are mixed in the specified volume ratio, the mixed material is subjected to the specified heat treatment after it is molded through compression and thereby a cylindrical core material 2 is formed. This core material 2 is sent to the cutting work and thereby a plurality of slots 3 and a plurality of tooth 4 are formed alternately and radially. This core material 2 is immersed into the mixing solution of ferric chloride and hydrochloric acid, the rate surface is removed by about 30mum and thereby a core 5 for magnetic deflection is manufactured. Drop of electrical resistivity of core 5 is prevented by the contact with the mixed solution and the best characteristic of core material 2 can be obtained.

High speed rotating disc type generator for high magnetic field

Abstract: A high magnetic field generator based on a new idea is described in this paper. The principle of the generator is different from those of previously published or tested. The fundamental principle of generating a high magnetic field is that the magnetic flux induced by an electromagnet with an iron core is concentrated by eddy currents on a rotating conductive disc and is compressed to high magnetic flux density on the hole surrounded with four discs. The energy for concentrating a magnetic flux is fed from the kinetic energy of rotating discs. Therefore, the generator is non-destructive and has only a relatively small electric source. The high magnetic field has a long pulse duration.

Manufacture of rotary transformer

Abstract: PURPOSE:To cut down the number of manhours required for manufacture of the titled rotary transformer as well as to contrive accomplishment of miniaturization and improvement in efficiency by a method wherein, after a resist mask has been formed on the region other than the coil pattern part on the surface of a plated base, a coil is formed by performing a conductor plating, and said coil is adhered to the wiring groove of a magnetic core. CONSTITUTION:A resist mask 14 is formed on the surface of the plated base 7 consisting of conductive material excluding a coil pattern part 8', a coil 8 is formed by performing a conductive plating on the coil pattern part 8', and a coil 8 is adhered to the winding groove 3 formed on a magnetic core 1. As a result, the manhours for the manufacture of the rotary transformer can be reduced, its cost can be cut down, and miniaturization and improvement of efficiency of the rotary transformer can also be contrived.