Showing papers on "Magnetic core published in 1979"

Magnetic thin film inductors for integrated circuit applications

Abstract: It is extremely difficult to fabricate small air-core inductors of sufficiently high inductance and Q for integrated-circuit applications due to the large number of turns required. Although the need for passive inductors can be circumvented by means of active filters at lower frequencies, such substitutes are difficult to realize at frequencies above 100 MHz. To drastically reduce the number of turns required thus rendering the fabrication of IC inductors feasible, we used anisotropic magnetic film cores of permeability as high as 104. In this paper, the design and fabrication of such inductors are discussed along with experimental results on their inductance.

Multipole electrical circuit breaker with improved interchangeable trip units

Abstract: A molded case multi-pole circuit breaker comprises an interchangeable trip unit having a magnetic circuit surrounding a main stationary conductor and provided with a U-shaped core secured to circuit-breaker assembly and a magnetic rod fastener to the trip unit. The rod is inserted between the legs of the core, and a single turn secondary winding surrounds the rod. A bimetal is attached to the winding, and the thermal tripping characteristics are independent of the relative position of the magnetic core and rod.

Measuring transformer for high-voltage switch-gear with metal encapsulation

Abstract: A measuring transformer for use with high-voltage switch-gear of a type which employs metal encapsulation. The transformer is retained between flanges at a joint of the metal encapsulation and includes a sealing and insulating spacing means. The latter forms a ring-shaped cavity with the flanges and seals such cavity from the interior of the metal encapsulation. In the ring-shaped cavity is disposed at least one iron core having a secondary winding placed thereon, the latter core together with the inner conductor of the high-voltage switch-gear forming a current transformer.

Magnetic core comprised of low-retentivity amorphous alloy

Abstract: An amorphous alloy core is converted into a crystalline state at least at one zone along the core body and such zone extends at least over a portion of the core cross-section at such zone. The zone converted into the crystalline state functions as an air gap of prior art crystalline low-retentivity alloy cores, because the permeability in the crystalline state is significantly lower than in the amorphous state. Magnetic cores formed in accordance with the principles of the invention are suitable in applications wherever a sheared hysteresis loop is required.

Low meter system provided with a pulse generator

Abstract: A flow meter comprises a fan wheel provided in a passage of a running fluid to be rotated thereby; a composite magnetic wire formed of a core and shell and fitted to the fan wheel; a pair of mutually facing permanent magnets arranged substantially in parallel above a plane through which the composite magnetic wire is rotated, with the poles of the opposite polarities set adjacent to each other; a magnetic core wound with a coil and disposed between the paired permanent magnets, and wherein, when the composite wire faces one of the paired permanent magnets, the alignment direction of the respective magnetic domains of the core of the composite magnetic wire is changed, and when the composite wire faces the other of the paired permanent magnets, the respective magnetic domains of the core of the composite magnetic wire regains the alignment direction before said change. Therefore, when the composite magnetic wire passes below the paired permanent magnets, pulses are generated in the coil; pulses thus generated are counted by a counter; a counted number of pulses is converted into a signal denoting a detected flow of a running fluid; and the converted signal is registered and indicated on a display device.

High frequency electrodeless lamp having a gapped magnetic core and method

Abstract: High frequency electrodeless (HFE) lamp has high-permeability core such as ferrite positioned in energy transferring relationship with respect to the phosphor-coated lamp envelope. The core forms a part of a tuned circuit output for a radio-frequency energizing source and during lamp operation, the resulting electromagnetic fields generated within the lamp envelope create a discharge which in turn generates radiations to excite the phosphor to produce visible light. The core is specially designed to include narrow gap means of low-permeability substance and this gap improves lamp performance by providing the dual function of stabilizing the output frequency of the tuned circuit to compensate for variations in permeability of the core and, in addition, the resulting increased Q of the tuned circuit substantially suppresses harmonics of the resonant frequency which are undesirable in such a lamp. There is also provided a method for assembling such a lamp as well as the finished lamp wherein the phosphor-coated envelope can be processed and sealed, and thereafter the core is assembled therewith so that the core is not subject to the temperature extremes required for proper envelope processing.

Transformer with gapped core

Abstract: In a transformer for use in a receiver set, a non-magnetic material arranged in part of a closed magnetic path established by a magnetic core is made of a plastic material such as paper mash or silicon putty. The non-magnetic material is pressurized and deformed so as to set the inductance of a coil mounted on the magnetic core to a predetermined value.

Magnetic field intensity measuring device with frequency change indication

Abstract: A device powered by a DC source produces an output signal the frequency of which changes as a function of changes in external magnetic fields sensed by such device. A pair of non-linear amplifiers are interconnected so that the output of one amplifier is the input of the other amplifier. An inductive sensor is connected between the outputs of the amplifiers. The inductive sensor has an elongated magnetic core and a coil is wound on the core. The voltages at the outputs of the amplifiers, across the inductive sensor, switch between zero and the full voltage of the DC source.

Amorphous metal lamp ballast having a capacitor integral with the magnetic core

Abstract: The magnetic core of a lamp ballast is bifilar wound from inherently thin amorphous metal strip and utilizes the laminations of the magnetic circuit as the plates of a capacitor. The outer yoke of the core encases the coils and is edge-wound from amorphous metal ribbon alternated with insulation to also be the power factor capacitor. The inner core is accordion-pleated or spirally wound and is electrically connected to be the starting capacitor. Cutaways in the inner core cause saturation and shape the lamp current waveform.

Magnetic work-holding device

Abstract: A magnetic work-holding device with at least two pole shoes defining a work surface, and a main magnetic core interposed between the two aforementioned shoes; the other sides of the pole shoes are fed by secondary magnetic elements whose poles facing the same pole shoe, have the same sign as the pole corresponding to the main magnetic core. A ferromagnetic yoke encircles the base and the sides of the equipment, short-circuiting the remaining poles of the secondary magnetic elements.

Magnetic core with magnetic ribbon in gap thereof

Abstract: A ferrite toroid has two radially extending gaps. Into each gap there is inserted an insulative shim having a magnetic metal ribbon folded over the shim. When current is applied to a winding on the core, the resultant magnetic flux is steered into the magnetic ribbons and around the gaps. For high frequency excitations eddy current losses in the ribbons are high and the windings have low Q but high inductance. At high winding currents, the magnetic ribbons are saturated, the inductance is reduced and the Q of the winding increases. In a switching voltage regulator, this inductor tends to generate only a small amount of ringing and electromagnetic radiation noise.

Manufacture of iron core

Abstract: PURPOSE:To enhance handleability and workability without causing the dislocation of iron core material during manufacturing process by stamping out a magnetic plate coated with s theremo-sensitive adhesive and then by laminating them in magazine during the period in which the stamped out plates are cured and blocked CONSTITUTION:The magnetic plate 1, eg, silicon steel plate, permalloy, noncrystal magnetic alloy, etc, the surface of which is coated with a thermo-sensitive adhesive 2 is continuously stamped out by means of the punch 3 and the die 4 The iron core material 5 is laminated while being charged into the magazine 6, inserted with the spacer 7, eg, paper, synthetic resins, etc, when a certain number of plates laminated is reached, and sent by turn on a pinch basis On its way, the thermo-sensitive adhesive 2 is melted by the heater 8 provided at the outside of the magazine 6, and at the same time pressurized to cure the adhesive 2 and then to make the iron core material 5 into blocks The blocked iron core 9 is separated by the taking-out tool 10 from the spacer 7 and then taken out of magazine 6

Family of magnetic flowmeters

Abstract: A family of magnetic flowmeters of different sizes ranging from at least as small as two inches in diameter to at least as large as twenty inches in diameter share a common low power coil driving circuit and a common signal processing circuit. The meters have coils which share proportional geometry and which have no magnetic core.

High magnetic flux amorphous iron alloy

Abstract: PURPOSE:To increase the permeability and to reduce the iron loss of an amorphous iron alloy by a method wherein the iron is incorporated with a limited amount of boron and carbon, and is annealed under the action of magnetic field and stress. CONSTITUTION:The iron alloy containing 11-17 atomic % of boron and 3-8% of carbon with the sum being 18-21% is annealed in magnetic field and non-oxidation atmosphere or vacuum at a range of temperatures below crystallization temprature (preferably, a temprature about 50 deg.C below crystallization temperature). Or, in this alloy, silicon is used to replace 5% or less of boron and less than 8% of carbon, and where necessary one of cobalt or nickel is added in 15% or less, with the total being 18-36%. This provides the amorphous alloy having a high permeability, low iron loss, and high flux densisty of 16,000 gauss or more, and as such capable of replacing silicon steel plate as magnetic core material. Also, magnetic properties are greatly improved by annealing treatment in this process.

Method of and apparatus for electrodynamic separation of nonmagnetic free-flowing materials

Abstract: Electrodynamic separation of nonmagnetic free-flowing materials is accomplished by feeding the flow of a material into a region of maximum intensity of a variable nonuniform magnetic field for inducing maximum eddy currents in electrically conducting particles of the material being separated and producing maximum electromagnetic forces which deflect the electrically conducting particles from the direction of feed of the material being separated. The variable nonuniform magnetic field is generated by an electromagnet having a closed magnetic core with a magnetic air gap defined by pole pieces. The electromagnet pole pieces are symmetrically divergent from the pole axes in a plane substantially perpendicular to the direction of feed of the material being separated.

AC Generator with low noise claw tooth rotor

Abstract: An AC generator for a vehicle comprises a rotor having a pair of finger magnetic poles and an armature iron core. By deviating pole pieces of the finger magnetic poles by predetermined angles relative to each of opposed tooth portions of the armature iron core, torque variation applied to each of the pole pieces during rotation is cancelled, and magnetic sound can be greatly decreased without reducing the output of the AC generator.

Permanenttmagnetttype synchronous motor

Abstract: PURPOSE:To provide a compact synchronous motor of high output, by using permanent magnets for a rotor, equalizing the number of the magnets to that (P/2) of the pairs of poles, rendering the direction of magnetization of the permanent magnets coincident with the radial direction of the rotor and producing image poles in the circumferential direction of the rotor. CONSTITUTION:A layer-built rotor iron core 2 is fixed on a rotary shaft 1. Numerous conductors 3 are provided in the form of a squirrel cage in the peripheral part of the iron core 2. The permanent magnets 11, which are shaped like an arc of angle equal to the quotient of division of the total central angle by the pole number P, and provided in the central part of the iron core 2. The number of the permanent magnets is equal to that (P/2 which is 3 because P=6 in the case shown in Fig.) of the pairs of the poles. The direction of magnetization of the magnets is rendered coincident with the radial direction of the iron core. The magnets have their N- poles on the outside and their S-poles on the inside. Slits 12 are provided between the poles of the iron core 2. The width of the iron core part 13 inside the magnets 11 is so set that the part 13 is not magnetically saturated when a half of flux of the magnet passes through the part.

Self excited saturatable core magnetic field detection apparatus

Abstract: A magnetic field sensing device comprising a magnetic rod which is direction sensitive relative to the field being measured. The rod is of such design that the magnitude or the strength of the field being sensed, significantly affects the magnitude of the excitation field required to produce a saturation of the magnetic core. An external field in the longitude direction of the core will require that the excitation field magnitude required to produce a given level of saturation will be different in one direction than in the other, by magnitude equal to twice the component of the external field acting upon the core. The excitation field is produced by current in the winding with the current changing at a given rate so that the induced or output voltage is greater than a specified value; as long as the core permeability is greater than a given specified value. Whenever the induced voltage drops below a given value, this situation is detected and the excitation field is reversed to give a constant rate of change of excitation in the opposite direction. A constant rate varying field is produced by an analog integrator used as a triangular voltage wave generator that is followed by a voltage-to-current converter with the current run through an excitational winding on a core. An external magnetic field acting on the core will cause the triangular voltage wave to be offset so that it is unsymmetrical, about zero. This average offset is detected and the value integrated in a second integrator. The outputs of the analog and second integrators are summed and the sum value is used to drive the voltage-to-current converter. The voltage value on the second integrator will be proportional to the component of the external magnetic field that is in the direction of the sensor.

Residual current transformer

Abstract: A residual current transformer comprises an annular magnetic core which has not a gap nor sectional part crossing said magnetic core but has one or more narrow sectional area parts.

Magnetic head for vertical recording

Abstract: PURPOSE:To produce the recording magnetic field with high efficiency, by providing the metallic magnetic layer in which the cross-sectional area is decreased to the tip, with the thick plate core side surface of the recording magnetic pole and giving winding on this magnetic pole. CONSTITUTION:On the surface of the thick plate core 12 at the magnetic pole side for recording of the magnetic head, the metallic magnetic substance layer 13 having high saturated magnetic flux density is formed with vapor deposition. This metallic magnetic substance layer 13 has a given thickness and small width to the tip, and the shrinked shape of the tip A is selectively formed according to the thickness (t) and the length D to obtain maximum magnetic flux density at the tip A. Winding is made on a part of the core 12 and the magnetic substance layer 13. Thus, the magnetomotive force caused from the winding can be used for the magnetization of the recording magnetic pole for recording with good efficiency, and without starting the saturation at the winding, the magnetic pole tip can effectively be magnetized to the saturated magnetic flux density of the raw material to strengthen the recorded magnetic field.

Circuit for the Dynamic Control of Magnetic Flux in Current Transformers

Abstract: Incorrect relay operation has often been related to saturation of current transformers. In many cases, the obvious solution to this saturation problem is an increased core cross-section of the current transformers, in order to allow a larger flux amplitude. In this respect, the transient asymmetrical component of fault currents is one of the most determining factors governing the dimensioning of the core cross-section of current transformers. A new technique using the characteristics of asymmetrical fault currents, has been developed in order to achieve a dynamic control of the core flux, thus allowing a significant reduction of the required cross-section. It is shown theoretically and experimentally that, taking into account all accuracy requirements and overvoltage limitations, the flux control circuit achieves a net reduction of the core crosssection by a factor of at least 3, even in the worst conditions imposed by C.T. or system parameters.

Enhancement of the magnetic permeability in glassy metal shielding

Abstract: An apparatus for shielding a time dependent magnetic field comprises a magnetic metallic glass element in which a magnetic biasing field is generated having higher frequency components than the major components of the time dependent magnetic field.

Device for transmitting signals by magnetic induction to projectile fuse

Abstract: A device for transmitting signals to a projectile fuse (1) by induction comprises a coil (5) for emitting an energy signal picked-up by a coil (3) inside the fuse. This coil (3) is wound on a first magnetic core (2). A second magnetic core (6) carries three receptive coils for information carrying signals. This information is emitted by three coils (19,20,21). This arrangement permits separating the transmission of the energy signals on the one hand and the information carriers on the other hand.

Roller magnetically compensated and adjusted for deflection

Abstract: A roller, magnetically compensated and adjusted for deflection, has a non-rotating axle with ends having a load imposed thereat and a cylindrical shell rotatably supported by bearings on the axle. A magnetic core is formed in the axle and has in transverse section a plurality of pole shoes spaced from the shell by an air gap. A plurality of electromagnetic windings, each wound on the core at a corresponding one of the pole shoes, produce a magnetic force in a manner whereby the magnetic flux through the air gap between the pole shoes and the shell produces a compensating force field between the shell and the core.

Apparatus for the contactless measuring of elastic stress in a ferromagnetic material

Abstract: 1. Apparatus for the contactless measuring of elastic stress in a ferromagnetic material, with - an exciter of magnetic field (6, 26) for producing an alternating magnetic field in the material (8) along a first direction, - a magnetic field detector (7, 27) for sensing and measuring in the material a magnetic flux appearing in a second direction which is nearly perpendicular to the first direction, as well as - a compensation device (28, 28A) for creating a configuration of the magnetic field in the material which compensates for contributions to the measurement result due to voltage-independent magnetic anisotropies in the material, characterised in that the compensation device consists of the following components : a) a direct current supply arrangement (18), b) two electromagnets (28, 28A, respectively) which are fed by the direct current supply arrangement (18) and which are constructed and arranged in such a way that the two static magnetic fields created by them in the material (8) are essentially perpendicular to one another and entail only a minimal coupling with the exciter (6, 26) of magnetic field and the magnetic field detector (7, 27).

The Calculation of the Deflection Magnetic Field and the Electron-Beam Trajectory for Color Television

Abstract: The practical calculation method for the magnetic field analysis of a saddle-shaped magnetic deflection coil with an iron core has already been reported. The authors used this calculation method to determine the deflection magnetic field. Further, by numerically solving the equation which was derived from the variation principle, the authors developed the program which determined the electron beam trajectory. By using this method, the deflection characteristics can be learned by using only the numerical values which show the physical position and the shape of the picture tube and deflection coils. In the past, the deflection system design was based on experience, but now it will be possible to depend upon theoretical analysis.

Magnetic head assembly for recording or reproducing vertically magnetized records

Abstract: A magnetic head assembly for recording and playing back information on a recording medium in a vertically magnetized mode. Main and auxiliary heads are provided opposite one another with the recording medium passing therebetween. The main head includes a core of material exhibiting a magnetoresistance effect to which core are attached leads which carry the output play back signal. The auxiliary head has a magnetic core around which is wrapped a winding carrying the recording current. The recorded information patterns have their primary magnetic field components perpendicular to the surface of the recording medium.

Miniature electromagnetic buzzer

Abstract: PURPOSE:To miniaturize products, and to shorten a manufacture process time by giving a bias to a magnetoelectric circuit after arranging a thin and miniature permanent disc magnet at the tip of a magnetic core.

Iron core of static induction electrical apparatus

Abstract: PURPOSE:To devise an improvement of magnetic characteristics by adhering end surfaces of legs and yoke irons piled up with sheet irons by adhesives containing magnetic powders. CONSTITUTION:End surfaces of legs 12a-12c piled up with sheet irons 12 respectively and yoke irons 13a, 13b piled up with sheet irons 13 respectively are butt jointed and these junction portions are adhered by adhesive 14 containing magnetic powders. Adhesives containing magnetic powders have a stability for a temperature rise of a junction portion and are used those having a desired permeability using such as epoxy-resin etc. of high adhering strength in which reduced iron powder of high purity, sprayed iron powder or magnetic powder such as of silicon containing iron are kneaded. In this manner magnetic reluctances are decreased than those of joints of sheet irons of legs and yoke irons simply butt jointed such as customary used general iron cores and together with improving characteristics, a noise due to a magnetic distortion is decreased as junction portions are adhered as one body.