Showing papers on "Magnetic core published in 1977"

Experimental considerations on a new automatic cooling device using temperature-sensitive magnetic fluid

Abstract: An automatic cooling device to eliminate the waste heat of machinery has been made by utilizing a temperature-sensitive magnetic fluid. This cooler requires no pump for flowing the fluid, since a part of the thermal energy is converted to the kinetic energy. If a permanent magnet is used, power supply is unnecessary. The cooler is expected to be maintenance-free and simple in shape.

Stored field superconducting electrical machine and method

Abstract: Method and apparatus are provided for a stored magnetic field in a superconducting, rotating electrical machine. The apparatus includes a cylinder of superconductive material in which a magnetic field is trapped. The trapped magnetic field forms a magnetic circuit with an armature winding in the machine. The apparatus further includes means for generating a magnetic pattern field in the superconductive cylinder and means for cooling the cylinder so that a magnetic field can be trapped therein. The apparatus has application in both motors and generators and in both rotating and stationary magnetic fields used therein.

Magnetic head and method of making the same

Abstract: A thin film type magnetic head, in which a conductor is accommodated within a groove formed in part of a ferromagnetic substrate constituting part of a magnetic core, and a ferromagnetic film is disposed on the conductor to constitute part of the magnetic core. With this structure, it is possible to reduce the number of steps of layers constituting the magnetic head for reducing damage or breakage of the stepped portions of the layers and also increase the core gap in a central part of the core so as to reduce leakage flux even in the thin film magnetic head as well as bettering dissipation of Joule heat produced in the conductor.

Head arrangement for perpendicular recording information on a magnetic record carrier

Abstract: An arrangement for recording information on a magnetic record carrier, having at least one magnetic recording head which incorporates an electromagnet having a core, wherein said arrangement includes a magnetic shunt, said magnetic shunt and the magnetic core of the electromagnet being adapted to be arranged on either side of said record carrier and close thereto, so as to form a closed magnetic circuit in which the magnetic flux is substantially perpendicular to the surface of the carrier, the said core having a recording pole and a flux-closing pole and the cross-section of the recording pole being smaller than that of the flux-closing pole.

Superconductive winding for an iron core rotor of a dynamoelectric machine

Abstract: Iron or other ferromagnetic material is utilized in the rotor core of a dynamoelectric machine having a superconductive field winding. A parallel connection arrangement of the winding in combination with a plurality of current dividing resistance elements provides a sinusoidal distribution of current density across the circumference of the rotor. The magnetic field associated with the sinusoidal current distribution is reduced in critical interior regions of the winding by the demagnetizing field produced by the magnetic poles of the ferromagnetic core, thereby allowing a larger current to flow in the winding without destroying superconductivity. The two fields add in regions exterior to the winding, thereby providing a net increase in the useful external field obtained from a given amount of superconductive material.

Iron core assembly for magnetizing columnar permanent magnets for use in electrostatic developing apparatus

Abstract: Disclosed is an iron core assembly for magnetizing columnar permanent magnet, particularly columnar ceramic permanent magnets adapted for use in magnetic-brush type electrostatic developing apparatus. The invention is to clarify the magnetic pattern most effective for the development, as well as a construction for presenting such a pattern, and is aiming to provide a magnetizing iron core assembly having an improved construction of magnetic poles and magnetizing coil windings.

Micro stepping motor

Abstract: A micro stepping motor for use in compact electronic watches comprises a magnetic core, a coil winding wound on the magnetic core, and a one-piece stator connected to the magnetic core to define therewith a closed magnetic flux path. The stator has a necked portion defining a region of reduced cross-sectional area along its length, and a hole extends through the stator at the center of the necked portion. A rotor having at least one pair of magnetic poles is rotatably disposed within the stator hole with an air gap therebetween. The rotor rest positions are determined by either a pair of protrusions extending into the air gap at diametrically opposed sites about the stator hole, or a pair of recesses opening into the air gap at diametrically opposed sites about the stator hole.

Iron core manufacture

Abstract: PURPOSE: To obtain stably characteristic iron core without less dispersion in quality and to make easier the manufacture of stamp-out iron core by laminating and adhering a magnetic plate having a high bending strength on a noncrystal magnetic alloy plate. CONSTITUTION: A plural number of noncrystal magnetic alloy plates are laminated and adhered with the adhesive 3, and above these plates, the silicon steel plate 2 having a strong bending strength higher than the noncrystal magnetic alloy plate is adhered with the adhesive 3 to form the laminated plate 4. The laminated plate 4 is stamped out to the E-shape A and I-shape B to obtain the iron core of the transformer. Thus, in contrast to the conventional case in which only the noncrystal magnetic alloy plate 1 is stamped out to form the iron core, the bending of the end portion due to a force applied to the magnetic plate can be avoided at the time of the stamp-out processing, and thus the dimensional accuracy can also be raised. In addition, the butt joining of the E-shaped iron core and the I-shaped iron core can be completely performed without causing aperture and void, resulting in the enhancement of the characteristics of iron core COPYRIGHT: (C)1979,JPO&Japio

A Linear Position Transducer Using a Magnet and Hall Effect Devices

Abstract: Magnets and magnetic field sensing devices are often attractive in instrumentation because they are noncontacting, small, and independent of the media's dielectric constant. The nonlinearity of the magnetic field with distance is a problem, however. A circuit to remove this nonlinearity and also to reduce the effective temperature coefficient is described. The circuit is used in a clinical dental research laboratory to measure movements of the jaw.

Converter protection circuit operative to limit and counteract transformer saturation

Abstract: Primary and secondary currents of a converter transformer in a double-ended converter are continuously monitored to detect the onset of saturation in the magnetic core of the transformer. When the onset condition is detected, the conductive roles of the oppositely phased switching transistors in the converter are reversed to limit and counteract the onset of saturation in the magnetic core of the transformer.

Deflection device for use with in-line type color cathode ray tubes

Abstract: In a deflection yoke for use with an in-line color cathode ray tube in which a plurality of electron beams originating in a common plane, for example, a horizontal plane, within a tube envelope are directed forwardly along paths converging through the deflection yoke to impinge on a screen at the front of the tube envelope, and in which the deflection yoke is made up of vertical and horizontal deflection windings for producing magnetic fields by which the electron beams are deflected in vertical and horizontal directions, each of the vertical and horizontal deflection windings is of saddle form so as to have side portions connected by bent front and back end portions, the vertical deflection winding is disposed against the tube envelope and has its bent back end portion shaped to closely conform to the surface of the tube envelope, the horizontal deflection winding is disposed outside of the vertical deflection winding, and the bent back end portion of the vertical deflection winding is closer to the screen at the front of the picture tube than the bent back end portion of the horizontal deflection winding. Furthermore, the vertical and horizontal deflection windings are preferably arranged to produce barrel-type and pincushion type magnetic fields, respectively, and a toroidal magnetic core extends around the horizontal deflection winding. The use of the foregoing deflection yoke with an in-line color cathode ray tube makes it possible to eliminate or at least substantially simplify the usual dynamic convergence correcting device usually associated with the latter.

Flow control valve

Abstract: PURPOSE:To control the flow and completely close a fluid by sealing the mag netic fluid between a valve main body and an elastic body, pulling the magnetic fluid to the center of an electromagnetic coil with the magnetic force generated by the electromagnetic coil, pushing up the elastic body, and changing the dis tance between this elastic body and a mating valve seat. CONSTITUTION:When an electromagnetic coil 14 is excited to generate the magnetic field, a magnetic fluid 16 sealed in a diaphragm 12 is pulled to a fixed iron core 15 at the center of the electromagnetic coil 14 and gradually swollen, and it pushes up the diaphragm 12 to narrow the distance with a mat ing valve seat 18. When the excitation of the coil 14 is changed, the distance between the diaphragm 12 and the valve seat 18 is changed, and the flow of the fluid passing an inflow port 19 and flowing through an outflow port 20 via a gap between the diaphragm 12 and the valve seat 18 can be controlled intermittently or continuously. On the other hand, when the excitation is stopped, the magnetic field by the coil 14 is dissipated, the swollen magnetic fluid 16 is released from the magnetic field of the coil 14, and the distance between the diaphragm 12 and the valve seat 18 is made maximum.

Audio-frequency injection transformers for ripple control

Abstract: A coupling transformer for networks with superimposed audio frequency voltage, especially for ripple control systems, with primary and secondary windings rigidly coupled with each other and arranged about an iron core; the primary and secondary windings surround one another coaxially and are separated and insulated from one another by a cast resin insulation, whereby only one of the two windings is embedded in the cast resin insulation while the other, freely accessible winding coaxially surrounds the iron core constructed as rod-type core under formation of at least one cooling channel; an electric shield is additionally provided between the two windings.

Reducing method of iron loss of three phase transformer iron core

Abstract: PURPOSE:To intend to reduce iron loss at T shape joint part, by making surface treatment on a steel plate in the range which produces rotary flux of three phase transformer iron core. CONSTITUTION:Surface treatment by which minute local distortion caused by suitable drawn pattern is made on a steel plate on which rotary flux such as T joint part of three phase three legs type transformer iron core is existed, or iron loss at T shape joint part is intended to be reduced by removing surface film which is generally given on one directional steel plate product. For example, pattern on the upper part such as length 2 mm, interval 1.0 mm and space of line 2.5 mm are drawun on the T shape joint part in the right angle direction to rolled direction, and after this, perpendicular line 1 is drawn as T shape pattern of 2 mm in parallel to the rolled direction. Comparing with steel plate which has not drawn pattern, reduction rate of iron loss at T shape joint part is improved to 2.95%.

Vehicle electric current supply controller - has single magnetic circuit regulating two separate inductor systems

Abstract: The controller, is used for maintaining a constant electrical supply in a vehicle. It has a clock generator turning two semiconductor switches alternately on and off. The switches are connected to two inductor systems. The two inductor systems are each arranged in two different parts of a single magnetic circuit. The inductor systems (L1 and L2) are each arranged on one limb of a U-shaped iron core (K). Several configurations may be used but in all only one magnetic circuit is needed thereby reducing the space occupied.

Manufacturing method of magnetic heads

Abstract: PURPOSE:When sealing a ferrite core in a hole of ceramic body with glass, stress to the core is controlled by controlling glass cooling speed, and optimum value of magnetic core characteristics is obtained

Inductive position indicator with ferromagnetic core - has measurement winding with voltage deviations compensated by reference winding

Abstract: The magnetic core is movable between a primary winding supplied with a.c. at least one secondary winding. Secondary voltage corresponds to the core position. At least one turn of one or several secondary winding is so mounted in the path of an air-gap in the core, that a variable area is produced in the air-gap. A homogeneous magnetic field, independent from the core position is generated in it, so that a magnetic flux corresponding to the above area is linked with the turn. A further secondary (reference) winding (6) is in parallel with the secondary winding (4, 5) consisting of at least one turn and acting as the measurement winding. An independent from the core position part (A') of the surface (A) surrounded by the winding is linked with the magnetic flux in the core (1) air-gap.

Electrophotographic apparatus comprising improved bias source for magnetic brush

Abstract: A photoconductive sheet is wrappingly attached to an electrically conductive, grounded rotary drum so that part of the drum is covered by the sheet and another part of the drum is exposed. A magnetic brush developing member comprises a magnetic core and an electrically conductive sleeve surrounding the core. An electrically insulative layer is formed on the periphery of the sleeve. The core and/or sleeve are rotated to pick up toner particles which brushingly engage with the sheet to develop an electrostatic image formed thereon. A bias voltage is applied to the sleeve to prevent adherence of toner particles to white areas of the image. A regulator device maintains the bias voltage constant to prevent detrimental effects of charge buildup and dissipation across the electrically insulative layer on the sleeve of the magnetic brush.

Tunable inductor with core sleeve - may be screwed into ceramic tube and pressed radially to take up play

Abstract: The tunable inductor consists of a ceramic tube (1) with a cylindrical threaded plastic sleeve (5) screwing down inside it The sleeve contains the cylindrical magnetic core (6) The wire (3) is wound around the outside of the ceramic tube The outside diameter of the sleeve is less than the inside diameter of the tube so that there is considerable play between the two A curved proejection (10) projects radially from the sleeve's thread and presses the sleeve against the threaded surface of the tube (The end of the sleeve has a slot for the tip of a screwdriver)

Transformer or choke coil

Abstract: PURPOSE:The waste of a magnetic core is avoided and the leakage magnetic flux which occurs is decreased to the outside by taking the magnetic flux which occurred in each coil.

Electro magnetic pump

Abstract: PURPOSE:To make magnetic flux distribution uniform to improve efficiency by forming cylindrical inside yoke of magnetic pump by pressing side surface of layer-built iron core contained in radially provided grooves at magnetic iron core support by wedges.

Inductively heatable godet with insulating means

Abstract: An improved means for mounting the induction coil of an inductively heated godet about the magnetic core thereof so as to eliminate any movement or play therebetween in operation caused by heat expansion and vibration. The improvement comprises placing an elastic intermediate piece between the coil and magnetic core which compensates for any unequal thermal expansion of these elements. In the preferred embodiment of the present invention, the intermediate piece is constructed of a hose-like hollow chamber through which a coolant under pressure is circulated from an external source.

Assembling method for iron core of induced electric machine

Abstract: PURPOSE:An assembly method which facilitates the transport of a large capacitance transformer and is easy to be assembled and decomposed.

Load measuring apparatus

Abstract: PURPOSE:To improve linearity of load measuring apparatus which has iron core made by iron plate as a sash-shaped being shaped as toroidal, in a light load sphere.

Flaw detector for testing materials esp. tubes - has magnetic head with alternating field and tracking error compensation

Abstract: The flaw detector for testing material surface consists of a ferromagnetic probe head moved over the surface of the material under test The magnetic core carries three windings An exciter winding is driven from an AC generator A control winding provides a signal for maintaing a constant tracking distance between the head and the surface of the material A receiver winding produces a signal whenever a discontinuity is detected The detector signal is amplified and passes through a phase-sensitive detector The demodulated signal is filtered an amplified in an operational amplifier whose output can be displayed on an oscillograph Indicator lamps show variation of head-to-surface separation

Using an inverter to measure magnetic fields

Abstract: A toroidal core may be used with an inverter circuit to measure magnetic fields in the .8 to 80,000 A/m (.01 to 1.0 KOe) range. The sensor core may be the inverter transformer itself or may be coupled to a nonsaturating inverter transformer. The sensor is most sensitive to fields parallel to the plane of the sensor and the sensitivity is greatest for a core biased to near saturation. An empirical expression for the demagnetization factor is used in calculating the ambient field required to saturate the sensor core, making it possible to calculate the range of fields for which a given core could be used as a sensor.

The parametric transformer

Abstract: Although parametric devices have been known for many years, very little attention had been paid to the possibilities of exploiting the principles involved for low frequency power conversion purposes, until tfie recent advent of the parametric transformer. The theory of this device is developed in the thesis, and the unusual performance characteristics are explained. Possible application areas are discussed, for an assessment of the future potential of the device as a power-control element. The operation of the parametric transformer is considered initially on the basis of the Mathieu-Hill equations. The stability chart for these equations is extensively used to permit graphical interpretation of the behaviour and characteristics. As no complete theory exists for non-linear systems with time-varying parameters, other analytical methods are also considered, although since all of these regard the device as a parametric oscillator they throw little light an the inherent transformer action. By considering the parametric-transformer as a conventional saturable reactor with a capacitor connected across the load winding and the control winding driven from an alternating source, it can be placed within the perspective of non-linear magnetic devices already known. Many possible magnetic constructions with parallel and/or orthogonal flux. interactions are investigated, with special attention paid to the bridged magnetic core analogue of the two-C-core construction. The illustration of parametric coupling as a result of flux interaction in saturable reactor devices leads to a derivation of the overall equations directly from the physical system. The functions representing the magnetic structure of the parametric transformer are first evaluated graphically, ard using various analytical representations of the B/H curve their explicit expressions are then formulated for different magnetic configurations. The introduction into the study of the concept of a relative magnetisation curve is invaluable in explaining the current waveforms and many other aspects of the device. A mathematical model is established for the parametric transformer and the system equations are solved numerically by a digital computer. The voltage and current waveforms and performance characteristics are demonstrated, and the correctness of the theory is ascertained by comparison with experimental results. Based on considerations of losses and efficiency, the advantages and disadvantages of parametric transformers are discussed. Possible applications in such areas as power supplies, inverters and converters are viewed and examples are given.

METGLAS Alloys: An Answer to Low Frequency Magnetic Shielding

Abstract: The first commercial application of METGLAS° amorphous metal alloys*» a recently developed class of engineering materials, is magnetic shielding. As currently produced, these METGLAS alloys are directly cast into a ribbon combining excellent soft-magnetic prop­ erties with high strength. A readily handleable and efficient magnetic shielding wrap has been developed by weaving these ribbons into a flexible fabric, called METSHIELDTM magnetic shielding fabric.1 Experimental data are presented to com­ pare the magnetic shielding performance of METSHIELD fabric with conventional poly­ crystalline 80/20 Ni-Fe foils in cylindrical shields at power frequencies. Methods of fab­ rication and utilization of this material are illustrated. The excellent stability of shielding performance after fabrication and handling are discussed and documented with additional data.