Showing papers on "Magnetic core published in 1975"

Electrical machine stator

Abstract: An electrical machine stator comprising a laminated iron core, with magnetic steel clamping plates installed on both ends of the core for clamping the core sheets by nonmagnetic steel clamping fingers rigidly attached to the clamping plates, with slots in said plates extending from top to bottom and used to accommodate the clamping fingers.

Electrodeless fluorescent lamp having a radio frequency gas discharge excited by a closed loop magnetic core

Abstract: An electrodeless fluorescent lamp adapted for economical substitution in place of existing incandescent lamps comprises an ionizable medium contained within a phosphor coated globular envelope. A closed loop, magnetic core, which may be ferrite, is contained within the ionizable medium to induce an electric field, ionize the medium, and stimulate visible light output. The core, which may be coated with glassy material, is energized by a radio frequency power source in the lamp base structure. Current from the power supply is transmitted to the core by means of a metal rod structure which also serves to transfer heat from within the envelope. A secondary winding on the core provides high starting voltages to initiate a glow discharge.

Astigmatic focus correction circuit

Abstract: A cathode ray tube employing magnetic deflection coils for deflecting the electron beam in the horizontal and vertical directions, is corrected for the astigmatism error created by the non-uniform magnetic deflection field which causes a predictable elliptical distortion of the electron beam, through the use of two sets of correction coils mounted on a common annular magnetic core located on the neck of the CRT, which distorts the electron beam prior to its entry into the magnetic deflection field in a manner that is complementary to the distortion created by the non-uniform magnetic deflection field. The excitation currents for the correction coils are derived from the horizontal (Vx) and vertical (Vy) beam deflection voltage signals, in such a manner that the excitation current for the first correction coil is proportional to Vx2 - Vy2, and the excitation for the second correction coil is proportional to 2.sup.. Vx.sup.. Vy.

Electrically driven high voltage ozonator

Abstract: A method and apparatus for generating high concentrations of ozone using a solid state high voltage power supply and a specially designed ozonator. The power supply comprises a rectifier and voltage doubler to which commercial AC line current is applied to produce a 300 volt DC output which, in turn, is applied across a solid state switching device to chop the DC output at an adjustable high frequency rate. The switch means is controlled by a timing and trigger circuit and the output of the switch means is applied to the input of an auto-transformer of the automotive ignition coil type which raises the high frequency output of the switch to a very high voltage level in the range of 30,000 to 50,000 volts peak to peak. This is applied to the high voltage electrode of each cell of a concentric electrode type ozone generator. The heat limiting problems encountered in the prior art are ameliorated both by elimination of iron core transformers or choke coils and by utilizing a counter-flow gas feed principle in the ozonator to cool the inner high voltage electrode by the incoming air or oxygen flow before it is passed through the corona discharge gap. This counter flow is achieved by passing the feed gas through the inside of the hollow inner electrode before entering the gap. The AC field of the inner core thus also deionizes the gas before it is passed through the corona discharge thereby achieving further energy savings. Power consumption in the power supply may be further reduced by using a single limiting impedance to drive a plurality of similar output channels, each of which is connected to its corresponding ozonator generator in a manner such as to achieve maximum power transfer. The combined effect of these features is to minimize electrical power consumption per pound of production of ozone.

Method and apparatus for detecting direct currents in a transmission line

Abstract: An electromagnetic sensing apparatus includes one or more magnetic cores coupled by windings to a pair of transmission line conductors for sensing the presence, and in some cases the magnitude and direction of loop currents flowing in the transmission line, without interfering with the transmission of signal information therealong. In one embodiment, the direction of loop current flow in the transmission line conductors is detected by applying a steady-state electromagnetic bias to the magnetic core to cause a polarity or direction determining asymmetrical response in a sense circuit that is electromagnetically coupled to the core by a sense winding. In another embodiment, a pair of separate magnetic cores are used, each having associated drive windings connected in series with the transmission line conductors, and associated sense windings. The various drive and sense windings are wound on the magnetic cores so as to cause detection of the direct loop current flowing in the transmission line conductors, and at the same time to cause self-cancellation of any electromagnetic coupled of the sensing signal to the drive windings which would otherwise appear as interference or noise on the transmission line.

Outer locking turn for precut core

Abstract: A precut nested magnetic core having a locking outer turn. The locking turn is formed of magnetic core steel and has a pair of locking slots in one end and a single locking tab in the opposite end. The precut annular core is locked by using the second or inner slot with the locking tab while the formed annealed core is locked by using the first or outer slot with the locking tab.

Three phase alternators

Abstract: A three-phase alternator, particularly suited for automotive use, having three stator winding sections each including a given number of coils, with each coil encompassing two stator poles and separated from the next coil in the section by an unwound pole. The rotor poles are of tapered construction, each having an effective width of two stator poles. In a preferred "brushless" construction, a D.C. excitation coil encompasses a tubular center leg of a stationary magnetic core of E-shaped cross-sectional configuration, with flux of one polarity going to the rotor partly through a shaft journalled in the center leg of the core and through a radial air gap of substantial surface area, and flux of the opposite polarity going to the rotor through a large-area radial air gap adjacent the outer flange of the core.

Multi-tracks magnetic head with single turn winding structure

Abstract: A multi-tracks magnetic head has a first conductor utilized as the bias winding, and a second conductor as the winding for the signal to be recorded. Only the first conductors of the respective unit magnetic heads are connected in series. By making use of the multi-track magnetic head constructed in this way, electrical power consumption by the amplifiers supplying the recording currents to drive all the composing unit magnetic heads is minimized, and the magnetic cross-talk between the unit magnetic heads is reduced.

3-dimensional computation of transformer leakage fields and associated losses

Abstract: Numerical methods, based on a magnetic scalar potential function, have been used to compute three-dimensional leakage fields and leg-plate losses in large power transformers. Fast convergence is obtained. The currents induced in the leg-plate are calculated by a simple modification of the static scalar-potential formulation. This includes three-dimensional, flux perturbation, and plate edge effects. The results show that two-dimensional approximations are unsatisfactory.

Improved manganese-zinc ferrites for power transformers

Abstract: Manganese-zinc ferrites of relatively high iron content were prepared. The content of ferrous iron was controlled by suitable substitution, thus shifting the second permeability maximum and the minimum of the losses into the range of 60 to 120 °C. These ferrites were found to exhibit high Curie temperature and saturation polarization.

Magnetically shunted current transformer

Abstract: A magnetically shunted current transformer for use with a current carrying conductor, and being of the type having a non-distributed secondary winding is disclosed. The transformer includes a magnetic core comprising first and second separable core sections adapted for placement about the conductor wherein the ends of the sections abut one another to form a substantially continuous core about the conductor. The secondary winding is carried by the continuous core and surrounds a portion of at least one of the sections. A spring bail clamps the core sections together. First and second magnetic shunt members are respectively disposed on opposite sides of the continuous core. Each shunt member comprises a plurality of stacked steel lamina forming a lamination having an elastomeric housing or a jacket molded thereover. The shunt members are provided with a geometry substantially conforming to the continuous magnetic core except at their end portions which confront the secondary winding. Fastening means are provided to removably fasten the shunt members to the continuous core to provide a substantially unitary assembly. Accordingly, the leakage flux is captured by the shunt members thereby allowing a higher conductor current to flow before the transformer saturates; and, thereby, to provide a distributed transformer type operation to closely simulate an ideal current transformer.

Magnetic transducer for narrow track recording and playback

Abstract: A transducer core having a magnetic core defining a non-magnetic gap and being integrally joined with a superposed composite body. The composite body has a nonmagnetic front portion spanning the nonmagnetic gap and a contiguous magnetic back portion. The superposed core and body are provided with overlapping grooves forming a window adapted to receive transducer windings. A method of manufacturing a magnetic transducer is provided wherein two complementary blocks of magnetic material are bonded together to define a nonmagnetic gap therebetween. A confronting surface of one of the blocks is grooved prior to bonding. The resulting magnetic block is sliced into a plurality of magnetic cores. A second magnetic block is provided with a longitudinal groove along one side thereof which side is bonded to a nonmagnetic block. The resulting composite block is sliced into a plurality of composite bodies, each comprising a nonmagnetic front portion and a magnetic back portion. Each magnetic core is superposed with a composite body and bonded thereto with the nonmagnetic gap spanned by the nonmagnetic front portion and with the respective grooves overlapping. The exposed planar surface of the superposed magnetic core is lapped until its width is reduced to a desired track width.

Static inverter with controlled core saturation

Abstract: A static inverter is disclosed for d.c. to a.c. conversion comprising a pair of switching semiconductor devices and a power transformer having primary, secondary and control windings associated with a double apertured linear magnetic core. Each aperture partitions the core cross section in a localized region into two branches. The primary and secondary power windings encircle the full core, which has a closed magnetic path, while the control windings are associated with only a branch. Means are provided to cause one branch to saturate before the other branch and before full core saturation. Saturation of one branch is used to reduce the regenerative feedback and increase the degenerative feedback to provide an advance turn off, allowing charge stored in the switching device to dissipate prior to the end of each conduction period. This mode of the feedback control avoids full core saturation and avoids overstressing the switching devices that full core saturation would produce. The arrangement permits one to develop high power outputs from relatively inexpensive power transistors.

Differential pressure transducer

Abstract: An improved differential pressure transducer includes a chamber divided by a non-magnetic, electrically conductive measuring diaphragm supported between two support members each of which has a cavity covered with a seal diaphragm. Differential pressure of an incompressible fluid medium to be measured and transduced is applied to the measuring diaphragm, the displacement of which is detected by magnetic core detection coils. The detection coil magnetic cores are joined to the support members through spaces of magnetic material having temperature dependent characteristics opposite to that of the cores to thus neutralize temperatures induced effects. The inductance change in the detection coil upon displacement of the measuring diaphragm provides an electrical signal corresponding to the differential pressure through the provision of an oscillation circuit supplying AC signals to the coils, a control circuit controlling, to a constant value, the sum of the currents in the coils and a circuit for deriving the current differences as an output signal. Advantageously, the oscillation frequency of the output signal of the oscillation circuit is selected to be approximately the reasonant frequency of the detection coils.

Signal transmission system

Abstract: A signal transmitter supplies a contact closure type signal having a DC level to an electromagnetic coil inductively disposed around a magnetic core. The coil produces a corresponding magnetic flux which is, in turn, detected by a flux detector such as a Hall effect semiconductor element. The detector applies a signal corresponding to the detected magnetic flux to a signal receiver.

Iron core for induction apparatuses

Abstract: An iron core for induction apparatuses is constructed of at least one main leg and yokes including side yokes comprising laminations of magnetic material. The magnetostriction of the yokes is smaller than that of the main legs, so that the vibration of the inductors is easily suppressed without any special means. Noise, which otherwise might arise from the vibration is thus reduced sharply.

Thin film magnetic head and its production

Abstract: PURPOSE:To increase recording magnetic fields and improve recording density by forming an auxiliary magnetic core on the outside of a main magnetic core thereby reducing magnetic resistance

Toroidal resistance welding transformer

Abstract: A transformer for application in portable resistance welding machines assembled from toroidal sections of iron core, primary and secondary windings arranged concentrically one with another. The primary is constructed from copper plate modules so as to form a continuous single layer winding of toroidal form in which the separate modules are electron-beam welded one to another in order to form the continuous primary winding. A single turn secondary completely encloses the primary winding and iron core so as to form a compact cylindrical electrical transformer structure. A liquid electrical insulating material is sealed within narrow gaps between iron core, primary winding and secondary winding to allow good thermal transfer from these elements to a cooling medium and at the same time stabilize the relative position of these elements against the dynamic forces developed by the high currents passing through the secondary.

Intruder detection system

Abstract: An intruder detection system comprising a line adapted to be located substantially at ground level and consisting of an elongated high permeability magnetic core on which is wound a coil in the form of successive sections of respectively opposite winding handednesses, a high gain low noise amplifier coupled to the line and a detector coupled to the amplifier and adapted to be coupled to an alarm system.

Saturation adjustable transformer - uses magnetic conductive screws in core recesses to alter effective core cross-section

Abstract: The saturation transformer, i.e. a current transformer with linear transformation to secondary current up to twice nominal current, esp. for application as saturation relay for heavy-load-start motors, has a ring shaped preferably laminated iron core which surrounds the primary conductor. The secondary is wound round the core. The iron core has at least oen recess producing a reduced cross-section of the core. Into the recess a magnetic conductive part can be inserted to alter the core cross-section and thus the saturation point. The core may have two independent recesses. The magnetic conductive part may be a screw e.g. sheet metal tapping screw, which may be turned from outside the transformer housing for purposes of adjustment.

Magnetic circuit and method of making

Abstract: A low cost magnetic circuit and method of making the same are disclosed. The magnetic circuit comprises an integral magnetic core having at least four legs in a closed magnetic path, at least one leg thereof with a circular cross section and a bobbin rotatably disposed about the circular portion for containing a coil winding. The coil is formed by rotating the bobbin while holding the core stationary.

Magnetic core assemblies with adjustable reluctance as a function of temperature

Abstract: A metal strip on a magnetic core body, provided with an air gap, for a coil means, is connected to a surface of the magnetic material such that an assembly similar to a bimetal is formed. Variations in temperature then cause variations of the length of the air gap.

Electromagnetic system for shaft monitoring - employs toothed disc rigidly coupled to shaft for monitoring angular position and speed

Abstract: The toothed disc is made from ferromagnetic material, and rotates with the shaft relative to a magnetic field, set up between two electromagnets, the variations in the magnetic field strength caused by the movement of the disc teeth through the latter being detected and converted into an electric pulse signal. The first electromagneti is supplied from a constant current source, both electromagnets having a U-shaped magnetic core with these being placed on either side of the toothed disc in mirror symmetry to each other, so that a tooth and then a space alternately pass through the magnetic field between them, the resulting pulses being supplied to a counter.

Single-wire transformer for HV switchgear - has adhesive layer between secondary windings and tube around wire

Abstract: The single-wire transformer for gas or liquid insulated high voltage switchgear has the single wire passing through a metal tube (4) which has a metal disc (10) attached to its outside, top and bottom, for support from ring- shaped flanges (11) also at top and bottom of the encapsulating tube (1) around the outside. The bottom supporting disc (10) which carries sets of windings (15, 16, 17) each around an iron core (12, 13, 14) has a resilient washer under the bottom coil (17) and further resilient washers (19, 20) between the coils. These coils are attached to the inside tube (4) by an adhesive cast resin which is poured in while liquid and allowed to set. In an alternative method, adhesive strips are inserted between the tube and the coils.

Voltage regulating transformer

Abstract: A voltage regulating transformer is disclosed which includes a magnetic core and a primary winding connectable to an alternating current source for inducing an alternating magnetic flux in the magnetic core. The secondary winding comprises a plurality of paired sectioned windings responsive to the magnetic flux in the magnetic core. Each pair of the plurality of paired sectioned windings has a first and a second foil with a dielectric interposed between the first and the second foils thus creating a plurality of capacitors. One pair of the plurality of paired sectioned windings has a different number of turns than the other of the plurality of paired sectioned windings creating a potential imbalance upon interconnection of the paired sectioned windings. The potential imbalance produces an oscillation within the secondary winding at a frequency which is an odd harmonic of the frequency of the alternating current source providing a reinforcement of the magnetic flux during a portion of each cycle producing a greater peak output voltage. The invention is suitable for use with high-intensity discharge lamp regulators or ballasts which require a substantially high starting voltage in order to ignite the lamp. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

Flux penetration and core loss in solid iron

Abstract: A steady-state solution for the electromagnetic field in solid iron including both hysteresis and eddy-current effects is obtained by considering only fundamental components of flux density and magnetising force, expressed in terms of phasor vectors, and related by complex permeability. Static B/H loops for a material are used to give the complex permeability characteristic as a function of magnetizing force permitting a nonlinear magnetization characteristic to be represented. Computed results together with some measured values are given for the surface loss and the distribution of flux in mild steel subjected to traveling-wave or pulsating excitation.

Wheel velocity sensor with exciter ring runout compensation

Abstract: A single-core wheel velocity sensor which is substantially immune to exciter ring or wheel runout is provided by a toroidal-shaped magnetic core, a winding on the core, a bias magnet placed adjacent to the core, an oscillator which supplies a high-frequency signal to the core winding and a sensing circuit comprising a differential input amplifier which has a first input terminal coupled to receive the output signal from the winding of the core through a circuit path which has a relatively low value capacitor coupled from the first terminal to ground and a second terminal which has a circuit path which has a relatively high value capacitor coupled from the second terminal to ground, wherein a relatively low value resistor shunts the low value capacitor and a relatively high value resistor shunts the high value capacitor.

Polyphase frequency converter

Abstract: The interphase reactors of an unrestricted static frequency changer are mounted on a common multilegged magnetic core without affecting the individual quality of each reactor in the operation of the frequency changer.

Micro motor for a timepiece

Abstract: A micro motor for a timepiece comprises a curved magnetic core, a coil winding wound on the magnetic core, a stator connected to the magnetic core to define therewith a closed magnetic flux path and having an opening therein in which a rotor is rotatably disposed. The stator comprises a pair of stator pieces each connected at one end to a respective end portion of the curved magnetic core and the stator pieces have curved portions extending at least partly along the curvature of said curved magnetic core to thereby form a compact overall assembly.

Polarised electromagnetic telephone relay - has cylindrical magnetic core and parallel rectangular return flux yoke

Abstract: Electromagnetic relay for telephone systems has a cylindrical magnetic core and a parallel, rectangular shunt yoke. The magnetisable armature is in the form of a two-shank fork without a recessing spring, held in rest position by the contact springs only. The relay has a permanent magnet at its front end opposite the armature in the region between the magnetic core and the shunt yoke, together with magnetic flux conducting parts, of which one connects a pole of the permanent magnet with the shunt yoke, and the other one the other pole of the permanent magnet with magnetic core and simultaneously with the moving end of the armature. The flux conducting part connecting magnetically the permanent magnet, the magnetic core and the armature may form simultaneously an abutment for the armature in its rest position.