Showing papers on "Magnetic core published in 1968"

Febrication of magnetic cores for electric rotating machines having axially-spaced air gaps

Abstract: THE SIDE SLOTS OF A WOUND TYPE MAGNETIC CORE FOR AN ELECTRIC ROTATING MACHINE HAVING AN AXIALLY SPACED GAP ARE MADE RADIALLY RECTILINEAR BY FIRST PUNCHING, IN THE STRIP TO A NUMBER LESS THAN, EQUAL TO, OR GREATER THAN THE NUMBER CORRESPONDING TO THE REQUIRED NUMBER OF SLOTS, AND AFTER COMPLETION OF THE CORE WINDING, THE WINDING TURNS OF THE CORE ARE DECREASED OR INCREASED TO OBTAIN THE REQUIRED NUMBER OF SLOTS.

Saturation current protection apparatus for saturable core transformers

Abstract: This disclosure describes a saturation current protection apparatus for saturable core transformers. A cut core (airgap) transformer detects the occurrence of rapidly increasing magnetic current in the saturable core transformer. When a rapidly increasing current condition occurs, the cut core

Linear induction motor

Abstract: Linear induction motor having a fixed elongated armature disposed along a linear path and cooperating with a movable magnetic core member. An electrical conductor disposed along said path energizes said core member by way of magnetic induction in order to produce a traveling magnetic field driving said core member.

Leakage current sensor

Abstract: A LEAKAGE CURRENT SENSOR FOR DETECTING LEAKAGE CURRENTS TO GROUND FROM THE CONDUCTORS OF AN ELECTRICAL NETWORK HAVING ONE OR MORE PHASES SUCH AS DUE TO INSULATION DETERIORATION, IS PROVIDED WHEREIN A FIRST MAGNETIC CORE SURROUNDS THE CONDUCTORS AND HAS ONE OR MORE WINDINGS FOR CURRENT DETECTION AND INITIAL PREMAGNETIZATION A SECOND MAGNETIC CORE, ALSO SURROUNDING THE CONDUCTORS OF THE NETWORK, IS LOCATED BETWEEN THE FIRST, DETECTION CORE AND THE CONDUCTORS TO SHIELD AGAINST STRAY FLUD FROM THE CONDUCTORS PREFERABLY, ALSO, A THIRD MAGNETIC CORE SURROUNDS THE DETECTION CORE TO SHIELD AGAINST EXTERNAL STRAY FLUXES BOTH THE SECOND AND THIRD, OR INNER AND OUTER, CORES ARE SHUNTED, IE, HAVE SHORTED TURNS THEREAROUND

Magnetic film memory systems

Abstract: The factors which must be considered in a magnetic film memory system design are enumerated. Particular attention is given to optimizing the amount of flux in a storage cell and the minimum signal requirements. The analyses performed indicate that memory size, memory speed, memory organization, and integrated circuit drive capability determine optimum requirements for storage flux in a magnetic cell. Thermal noise in the sensing system establishes a minimum signal level as a function of memory speed and amplifier bandwidth.

Magnetic shielding construction for electric transformers

Abstract: In an electric transformer, magnetic laminations for shielding the main magnetic core from leakage magnetic flux are positioned between the inner periphery of the coil and the portion of the main magnetic core which extends through the coil window. The shield laminations are arranged in closed magnetic loops, with the major surfaces of the shielding laminations lying in planes perpendicular to the major surfaces of the main core laminations, whereby only the edges of the shielding laminations are presented to the leakage magnetic flux, thereby minimizing eddy current losses and consequent overheating of the laminations.

Electric welder that uses magnetic amplifier to supply firing signals for controlled rectifier

Abstract: The high frequency voltages, that are customarily used to help initiate the arcs of electric welders, tend to cause premature and erratic initiation of those arcs where those electric welders use silicon controlled rectifiers to control the amounts of power supplied to those arcs and use transistor-type firing circuits to control the firing angles of those silicon controlled rectifiers; because transistor-type firing circuits are sensitive to high frequency voltages. The present invention provides an electric welder which utilizes silicon controlled rectifiers to control the amounts of power supplied to arcs and yet avoids premature and erratic initiation of those arcs by using a magnetic amplifier to control the firing angles of those silicon controlled rectifiers. Also, the present invention keeps that electric welder from supplying undesirably high amounts of power to those arcs, during the initiation of those arcs, by biasing the magnetic core of that magnetic amplifier downwardly at the conclusion of each welding operation. In addition, the electric welder of the present invention has a one-turn winding, on the magnetic core of the magnetic amplifier thereof, through which all of the welding current flows; and that one-turn winding is part of a feedback circuit for that magnetic amplifier which enables that electric welder to vary the amounts of power supplied to an arc over the full range of firing angles of the silicon controlled rectifiers thereof by merely adjusting a single control of that magnetic amplifier.

Long-wavelength response of magnetic reproducing heads

Abstract: The distribution of the long-wavelength magnetic flux in unshielded and shielded magnetic head cores is described and calculated. Two effects are found, depending on the path of the flux: the "secondary gap effect" and the "undulation effect." The secondary gap effect causes an increasing output level at long wavelengths; it occurs because of the finite permeability of the core. The undulation effect causes undulation in the reproducing-head wavelength response; it depends primarily on the dimensions of the core in the neighborhood of the tape. Experimental measurements confirm the validity of the calculations quite well.

Magnetic head assembly with sidebar

Abstract: A magnetic head assembly, useful for noncontact magnetic recording, is formed to provide an inner cavity, wherein a thin magnetic core is fixed against a cavity wall. A magnetic sidebar, to which electrical coils are mounted, is secured adjacent to the core to complete the magnetic circuit.

Phase splitting core for electromagnetic devices

Abstract: A MAGNETIC CORE CONSTRUCTION IN WHICH THE PHASE RETARDANT EFFECTS OF EDDY-CURRENTS AND HYSTERSIS IN A FLUX CARRYING CORE PORTION ARE EMPLOYED TO GENERATE AN ALTERNATING FLUX, LAGGING IN PHASE BEHIND THE FLUX WAVE FLOWING IN A NON-RETARDANT CORE PORTION.

A Square-Loop Magnetic Core Model for Computer-Aided Circuit Transient Analysis

Abstract: Square-loop magnetic core models presently used by automated circuit-analysis computer programs are inadequate. Instead, the effect of MMF F on flux ? is described by a more appropriate nonlinear core model, ? = ??(F,F) + ?i(F,?), based on the elastic and inelastic ? components. The core parameters may be measured or derived from a manufacturer catalog. The model has been incorporated into the automated computer-program TRAC (Transient Radiation Analysis by Computer), which was subsequently applied to transient analyses of several magnetic circuits. Machine-computed voltage and current waveforms agree satisfactorily with experimental oscillograms.

Modulating systems incorporating an electrically variable inductance as a modulating element

Abstract: Modulating systems in which modulation, either AM or FM is accomplished by use of an inductor, the impedance of which can be electrically varied. The inductor comprises a first winding wound on a magnetic core having four legs or common regions joined by end regions. A source of control current is connected to another winding wound on the core generally transverse to the first winding, the control current in the second winding controlling the inductance of the first. The variable inductor is used as a series impedance in AM modulation systems and as part of a tuned circuit in FM modulating systems.

Improved tunable ferrimagnetic filter using a magic-T

Abstract: A ferrimagnetic, bandpass filter configuration is demonstrated that permits dc magnetic field strengths to be substantially lower than those required with conventional geometries.

Analog-digital converter

Abstract: An analog-digital converter having a magnetic core, a plurality of windings wound on said magnetic core, said magnetic core being supplied with a multiphase alternating current to generate a rotating magnetic field, a magnetic path member disposed in opposite but spaced relation to said magnetic core and rotated in accordance with analog information, a detecting means for producing a pulse when said rotating magnetic field becomes aligned with said magnetic path member means for producing a reference pulse, and means for detecting the time difference between said pulse and reference pulse to convert analog information into digital information.

Magnetic Cored Coil Structure

Abstract: 1,187,738. Transformers and inductors. STANDARD TELEPHONES & CABLES Ltd. 14 Nov., 1968, No. 53992/68. Heading H1T. A magnetic cored coil structure includes two magnetic core members 1, 2 which provide a primary magnetic circuit and define a winding space 15 in which a coil (not shown) is positioned on at least member 1 (e.g. on a central hollow boss 3); and terminals 17 secured by insulating material 18 to member 1. The surface of the core member on which the coil is wound is coated with insulation 16. A tubular magnetic adjuster slug 9 is fastened to a self-tapping screw 8 which engages an insulating plastics nut 11 and has a head which is surrounded by an insulating head 10 which provides frictional engagement with the wall of a central bore 6 in the member 2. (An adjuster assembly of this kind is described in Specification 1,090,028.) The slug 9 may be moved longitudinally in the bores 6 and 4 in order to adjust the reluctance of the air gap 7 between members 1 and 2. The magnetic core members may be made of ferrimagnetic material (e.g. ferrite) or of compound powders of iron or nickel-iron alloys. A method of assembling the structure is disclosed. The insulating material may be epoxy resin filled for increased strength or colour coding; and the terminals may extend out of the moulding for insertion into a printed circuit board.

Improvements in and relating to high frequency apparatus

Abstract: 1,128,885. Radio receiving apparatus. MATSUSHITA ELECTRIC INDUSTRIAL CO. Ltd. 23 Feb., 1967 [24 Feb., 1966; 28 March, 1966], No. 8719/67. Heading H3Q. [Also in Division H1] In high frequency apparatus, e.g. a radio receiver, the aerial is provided with a magnetic core which is made hollow or in more than one part so as to contain other components of the apparatus. The core 21 for aerial winding 22 may be rectangular or alternatively cylindrical (Fig. 1, not shown) and provided with enclosing insulating end-plates (15) through which leads pass; an assemblage of individual components may be used, encapsulated by suitable means. Alternatively components may be mounted or formed on wafers 13 of insulating material which are joined together by longitudinal wires 14. The magnetic core provides a magnetic screen for the enclosed components and may have an insulating liner (25, Fig. 4, not shown). Adjustable components may be mounted on an enclosing end-plate (39, Figs. 5, 6, not shown) and the aperture in the core may also be used to accommodate a battery (34).

Head construction for multichannel magnetic recording and reproducing of data

Abstract: A MAGNETIC MULTICHANNEL HEAD FOR RECORDING AND REPRODUCING OF DIGITAL DATA, HAS SEPARATE POLE SYSTEMS, FOR TRACKS ON A MAGNETIC RECORD TAPE OR SIMILAR MEDIUM. EACH POLE SYSTEM HAS A SINGLE AIR-GAP AND TWO OPPOSITE SALIENT POLES. THE MAGNETIC CORE STRUCTURE OF THE HEAD IS COMMON TO ALL POLE SYSTEMS AND CONSISTS OF TWO SIMILAR HALVES EACH INCLUDING ONE OF THE TWO ARRAYS OF POLES AND CONSISTING OF AN INTEGRAL BODY. THE TWO HALVES ARE SCREWED TOGETHER INTO FIRM MECHANICAL AND MAGNETICAL CONTACT SUCH THAT THE TWO POLES OF EACH POLE SYSTEM FACE ONE ANOTHER ACROSS A SINGLE FINE AIR-GAP. THE CORE STRUCTURE HAS A THROUGH BORE, PREFERABLY A BORE OF SQUARE OR HEXAGONAL CROSS-SECTION. THE BORE EXTENDS PARALLAL TO THE TWO ARRAYS OF POLES AND IS SYMMETRICAL WITH RESPECT TO A PLANE OF THE JOINT ARE OF THE TWO HALVES AND WITH THE AIR-GAPS. THE MAGNETIC HEAD MAY BE CLAMPED ONTO A BAR OR ROD COAXIALLY EXTENDING THROUGH THE BORE, BY TIGHTENING THE TWO HALVES OF THE CORE STRUCTURE. THE AXIS OF THE BORE AND, THUS, OF THE ROD (IF ANY) IS ALSO THE AXIS OF CURVATURE OF THE SURFACE TO BE ENGAGED BY THE MAGNETIC TAPE SO THAT SAID SURFACE CAN BE MACHINED AND POLISHED BY ROTATING THE MAGNETIC HEAD AROUND SAID AXIS WITH RESPECT TO A TOOL. EVERY ONE OR EVERY SECOND OF THE INDIVIDUAL POLES IS PROVIDED WITH A WINDING SUCH THAT THE TWO HALVES ARE IDENTICAL AND EXCHANGEABLE. SAID ROD MAY SERVE AS A FIXTURE FOR MACHINING THE MAGNETIC HEAD AND AS A MOUNTING ELEMENT FOR THE HEAD IN A MAGNETIC RECORDER. THE MAGNETIC HEAD FORMS A SELF-SUPPORTING COMPACT UNIT EVEN WHEN NOT BEING CLAMPED ON THE ROD.

Hall-effect modulator including distortion suppression means

Abstract: In practical Hall-effect modulators, unwanted signal components, for example, carrier frequency harmonics and magnetic field components, appear in the output signal. These unwanted signal components are suppressed by selectively shaping a face of a magnetic core member of the modulator to introduce an inhomogeneity into the magnetic field applied to the Hall element. Further suppression of unwanted signal components is achieved by utilizing a potentiometer connected between output terminals of the Hall element and an additional terminal substantially in the center of the element.

Improvements in or relating to superconducting magnets

Abstract: 1,126,966. Superconductor magnets. GENERAL ELECTRIC CO. Ltd. 8 Feb., 1967 [10 Dec., 1965], No. 52565/65. Headings H1K and H1P. A superconductor device is produced by forming a sintered body of superconductor material in the form of a hollow cylinder the ends of which are bridged by at least one loop and cutting a helical slot in the wall of the cylinder to form a solenoid the ends of which are bridged by each of the loops. The device is produced by pressing and sintering a mixture of niobium and tin powders to form a rectangular plate with a solid circular cylinder extending along one edge. A pilot hole (34) is bored through the cylinder and a rectangular slot (12) is cut in the plate adjacent to the cylinder by spark erosion, Fig. 2 (not shown). The ends of the pilot hole are plugged and the body is electroplated with copper, the plugs are removed and the ends of the cylinder and plate, and that edge of the plate remote from the cylinder are machined to remove the copper layer. The bore in the cylinder is enlarged and a thread 38 is tapped in it. The thread is then deepened by means of a second tap so that it extends completely through the thickness of the niobium-tin cylinder to form a solenoid, the copper layer serving to support the turns, and a rectangular slot 13 is cut in the remainder of the plate by spark erosion, Fig. 4. Heating coils are wound round bridges 10 and 11 from which they are electrically insulated. The copper layer physically supports the solenoid and loops and also in use provides a low resistivity shunt path in the event of any localized part of the body turning normal. The end turns of the solenoid may be of reduced pitch produced by cutting the thread by spark erosion using a rotating electrode in the bore, the body being traversed at suitable rates. The device may be magnetized by placing the core of an electromagnet through outer slot 13, cooling the device to the superconducting state, energizing a first coil (17) to make arm 11 normal, energizing the electromagnet, deenergizing the first coil (17) to allow arm 11 to return to the superconducting state, slowly deenergizing the electromagnet to generate a circulating current, energizing a second coil (14) to transfer part of the trapped flux to loop 12 and the solenoid, de-energizing the second coil (14), and repeating the process several times to build-up the field, Fig. 1 (not shown). In an alternative method, Figs. 5 and 6 (not shown), a magnetic core is passed through the outer slot (13) and a rotating horseshoe type permanent magnet is provided so that when its poles are adjacent to the core a flux threads the slot (13). As the poles of the magnet move towards the core, the first coil (17) is energized until the magnetic flux in the slot (13) is a maximum. The magnet continues to rotate and when its poles are furthest from the core the second coil (14) is energized and then de-energized to transfer part of the flux trapped in the outer slot (13) to the solenoid, the first coil (17) is re-energized and the process is repeated several times to build up the required field. In a second embodiment, Fig. 7, only a single loop is provided and the part 21 lying parallel to the solenoid comprises a thin layer of soft superconductor material. This may be produced by using niobium powder for part of the plate when moulding the basic body or by bridging two arms of powdered niobium-tin with a thin foil of niobium and then sintering. The strip 21 is so thin that the flux of a permanent bar magnet 22 can penetrate it over a region, e.g. 24, smaller than the width of the strip 21. The solenoid is magnetized by moving the bar magnet in a loop across, and close to, the strip 21 and then across, but a large distance from, one of the side arms 9. This enables the flux due to the magnet to be threaded through the loop where it is maintained when the magnet is removed across the side arm. The required field can be built up by repeating the movement of the magnet. The penetration of the magnetic flux through the strip 21 may be aided by a radiation spot (not shown). The initial material may be powdered superconductor material rather than a mixture of its ingredients.