Showing papers on "Magnetic circuit published in 1973"

The flux shuttle—A Josephson junction shift register employing single flux quanta

Abstract: A shift register is described which employs as information bits the flux quantum vortices occurring in Josephson junctions of extended dimensions. The positions of the vortices can be controlled and manipulated by an appropriately designed circuit geometry and by application of currents and magnetic fields. The time required for switching of the position of a vortex can approach the period of the Josephson plasma oscillation (∼10 ps) and the intrinsic energy dissipation is typically ≲ 10-18J/shift.

Collector-less D-C motor

Abstract: A permanent magnet rotor operates within the air gap of a stator magnetic circuit which has a stator winding. Current through the winding is controlled by a selectively energized semiconductor switch, which is energized over a portion of rotor rotation and in synchronism therewith. The air gap included in the magnetic circuit is non-uniform along its length, increasing to a maximum intermediate the extent of a pole, for example between 10 to 50 electrical degrees, and then decreasing to a minimum over the remainder to 180 electrical degrees over a pole. The winding is energized to cause rotation of the rotor while the permanent magnet is within a predetermined angular range, resulting in storage of magnetic energy which is released as torque upon further rotation of the rotor in another angular range. The timing of energization of the winding by a control circuit can be used to control motor speed.

Position control system using magnetic forces for correcting the inclination of a controlled member including a torsional mounting

Abstract: A position control system using magnetic forces, in which at least one pole of an electromagnet is opposed to a magnetic substance of a controlled object through an air gap therebetween so that a magnetic circuit including the magnetic substance, the air gap and the electromagnet is provided. The width of the air gap is preset to a value more than a predetermined width when the control curret is zero. The controlled object is supported by at least one spring so as to be movable along a direction in which the magnetic force functions between the electromagnet and the magnetic substance. The control current of the electromagnet is controlled for adjusting the magnetic force and also a width of the air gap so as to obtain a desired position of the controlled object along the above mentioned direction. The magnetic flux of the magnetic circuit is saturated at a condition where the air gap reaches the predetermined width. The elastic force of the spring is balanced with the magnetic force within the elastic region of the spring at the above mentioned desired position. The inclination of the controlled object with respect to the direction is detected by use of two light beams and compensated by controlling a controlled current applied to a correcting electromagnet, which is opposed to a corner of the controlled object received the tension of a torsion spring along the direction of the inclination.

Means for detecting fault current in a conductor and indicating same at a remote point

Abstract: The rectified output of one or more current transformers associated respectively with one or more conductors of a high voltage alternating current system is applied to a fault responsive winding on a magnetic circuit of a fault responsive device for magnetizing it with unidirectional magnetic flux in one direction. A normally open reed switch in the magnetic field of the magnetic circuit is closed on flow of fault current in one or more of the conductors and is connected to control signalling or control means located at a point remote from the fault responsive device. For demagnetizing the magnetic circuit, a reset winding is positioned on the magnetic circuit and is connected for energization to a direct current source under the control of a manually operable switch at the remote point.

Rotational position sensor utilizing a hall device and means to maintain the hall voltage constant

Abstract: A rotational position sensor is disclosed in which a Hall Effect device mounted within an air gap of variable size within a magnetic circuit is subjected to changes in magnetic flux density in direct relation to the rotational position of a cylindrical member forming a part of the magnetic circuit. The magnetic circuit includes a C-shaped permanent magnet having opposite pole pieces forming air gaps with the cylindrical member. The cylindrical member comprises a half cylinder in the region of the air gap containing the Hall Effect device so as to vary the effective area of the gap and thus the flux density as the cylindrical member turns. The voltage of the Hall Effect device is applied to a feedback circuit including a differential amplifier so as to vary the current through the device as necessary to maintain the Hall voltage constant and provide an output voltage which varies linearly with the rotational position of the cylindrical member.

Force on a Wire in a Magnetic Field

Abstract: MCCAIG1 has suggested that a shape factor might be involved in determining the force on a current-carrying wire in a magnetic field when there is a permeability contrast between the wire and its surroundings.

Adjustable-torque magnetic brake

Abstract: An adjustable-torque magnetic device for dynamically braking a reel, spool or other rotary element The device utilizes a multipole permanent magnet with poles in the form of circular sectors, and a pair of spaced magnetic circuit discs located oneon-each-side-of and coaxial with the permanent magnet, one of the discs being operatively connected to the rotary element The circuit discs provide flux paths between pole sectors of opposite polarity and thus cause a magnetic drag resisting relative rotation A flux gate is interposed between the permanent magnet and one of the circuit discs so that the braking torque may be adjusted by positioning the gate relative to the magnet between a maximum torque position wherein magnetic flux passes through the flux gate to and from the adjacent circuit disc, to a minimum torque position wherein a portion of the flux is shunted through the gate to bypass the adjacent circuit disc

Magnetic circuit device for a contactless switch or the like

Abstract: A magnetic circuit comprises a cylindrical disk permanent magnet having oppositely polarized end surfaces and a keeper of soft magnetic material The permanent magnet has an axial aperture which is cylindrical The keeper comprises a disk portion which bears on one end surface of the permanent magnet and a cylindrical pin which occupies the aperture of the magnet The pin terminates in a flat surface which is substantially co-planar with the second opposite surface of the disk magnet The magnetic circuit provides a high intensity localized magnetic field having field reversal properties for switching magnetic sensor devices such as a Hall effect cell

Short circuit sensing device for electromagnetic induction apparatus

Abstract: When an electromagnetic induction apparatus sustains an internal fault, such as shorted turns, a sensing device detects such fault and, in response thereto, disconnects the apparatus from a source of electrical power to thereby inhibit further damage to the apparatus. The apparatus, which may be a reactor or a transformer, includes a magnetic core, at least one winding disposed around the core and a yoke connected to the ends of the core for forming a low reluctance magnetic circuit. The sensing device includes at least one stray flux sensing coil and a relay which is activated by a voltage induced on the coil. The sensing coil is placed in relation to the magnetic circuit of the apparatus such that the coil is responsive to the stray flux. An internal fault within the apparatus, such as one or more shorted turns within the winding, creates a pattern of stray flux which is different from the flux pattern during normal conditions, and the coil has induced therein a voltage representative of this different stray flux pattern. This voltage then energizes the relay which disconnects the apparatus from the source of electrical power.

Saturating magnetic control valve

Abstract: An electromagnetic proportional ball type flow control valve is disclosed in which electric current supplied to the coil of an electromagnet produces a force to control a moving armature to which a ball valve is attached, the ball being seated on a port through which the flow of fluid is regulated. The armature and the ball valve are supported by four flexures to constrain movement in directions other than the desired direction and to eliminate friction. The magnetic circuit for the electromagnet is varied by means of saturating gaps made as annular grooves in the magnetic path to modify the shape of the force-displacement curve and produce improved control.

Induction heating apparatus for minimizing vibration and noise

Abstract: In an induction heating apparatus for induction heating a heated element by forming an alternating magnetic field, n groups (n>/=2) of magnetic circuits comprising said heated element are formed. The magnetic circuits are progressively excited by an excitation current having a phase difference in the range of 180 180 x 0.8 to x 1.2 degrees, n n SO THAT ALTERNATING COMPONENTS OF THE ELECTROMAGNETIC FORCE APPLIED TO THE HEATED ELEMENT ARE DECREASED OR REMOVED AND WHEREBY THE VIBRATION AND NOISE OF THE HEATED ELEMENT IS CONCOMITANTLY DECREASED. The present invention finds particular use with respect to an induction heating cooking apparatus run by standard line frequency current.

Stator for low-inertia dc machines

Abstract: This invention relates to a stator which forms the magnetic circuit of a DC machine, and provides a stator for a low inertia motor particularly adapted for the capstan driving of computors, in which the cross-sectional area of magnets is increased, whereby the interpole leakage flux is minimized and the effective flux density between the poles and the armature is increased and further the flux density is made largest at the contacting surface with the pole.

Ferro-resonant high voltage system

Abstract: A cathode ray tube high-voltage supply system is of the type in which sawtooth-shaped pulses are developed in a first transformer winding in order to produce a scanning waveform in a deflection yoke on the tube. So-called fly-back energy, developed as a result of magnetic field collapse in the yoke during retrace, is utilized, in turn, to produce high-voltage output pulses in another winding to which a load is coupled that requires a broad, generally-square pulse shape. The first winding is wound upon a first ferromagnetic core that defines a non-saturating magnetic circuit. The other winding is wound upon a second ferromagnetic core which, together with a portion of the first core, defines a second magnetic circuit that saturates in operation. A capacitor included in the load is coupled across the other winding and controls the energy in said second magnetic circuit in such a manner as to supply the load with pulses that are broad and have a generally-square shape.

Proportional solenoid actuator

Abstract: A solenoid device which provides an output force proportional to input signal amplitude regardless of the position of the solenoid plunger is disclosed. A flux measuring device is located in the magnetic circuit of the solenoid and provides a signal proportional to flux density. This flux density proportional signal is employed for control purposes to vary the solenoid coil excitation as a function of the input signal and the desired output force.

Weakly superconducting circuits

Abstract: An equivalent circuit has been developed for the time-dependent dissipating state of superconductivity which accompanies quantum phase slip. This equivalent circuit is used here to analyze the superconducting thin-film ring magnetometer and to determine its operating characteristics in terms of measurable circuit parameters.

Apparatus for measuring magnetic susceptibility

Abstract: Two magnetic circuits are provided with two gaps penetrated normally by similar magnetic fields and having similar zones of inhomogeneities as effective on two test bodies which are interconnected rigidly but in a manner permitting deflection, rotational or linear. The gaps are surrounded by gas, and one of the test bodies forms a combined system with an additional material as far as paramagnetically or diamagnetically produced deflective forces for that body is concerned. The gas may be a reference gas with the additional material being a liquid sample, or the gas may be a test gas to be investigated while the additional material is a reference gas, encapsuled in that one body; the other body is either hollow with access for the test gas to its interior or solid, but smaller. The interconnected bodies experience different deflections in the two gaps resulting in a deflection which is monitored and converted into an amplified control current which, in turn, is fed back to unbalance the magnetic fields in the gaps for returning the bodies to the equilibrium position. The current needed for unbalancing the fields is an indication of magnetic susceptibility of the sample.

Magnetic coupling for motor driven pumps and the like

Abstract: A magnetic drive coupling is disclosed which can be employed in motor driven pumps and for other purposes, which includes coupling members forming part of the magnetic circuit which can be isolated to prevent fluid communication therebetween and in which a plurality of stationary electrically activated flux sources are provided which also form part of the magnetic circuit and in which an improved flux path is provided.

A new technique for RF measurements using superconductors

Abstract: The quantization of magnetic flux in a superconducting circuit can serve for the measurement of electrical quantities in the same way that we use the wavelength of light to measure length. We report a demonstration of this function in the measurement of attenuation ratio at a frequency of 30 MHz.

Magnetic circuit having low reluctance

Abstract: A magnetic circuit which exhibits low reluctance on the path of a magnetic flux and comprises at least one anisotropic thin film formed of an iron-nickel-chromium alloy through which said magnetic flux passes in the hard direction of magnetization of the film.

Electrically actuated piezoelectric high voltage impact mechanism

Abstract: A piezoelectric high voltage impact mechanism is actuated electrically. The impact results from momentary actuation of a wire coil mounted in a magnetic frame. The force on the armature or hammer with electric power connected causes virtual closure of the magnetic circuit as the hammer strikes the adjacent end means of the piezoelectric element means. The resulting stress wave generates a high voltage transient which may be used to ignite gas appliances. The housing for piezoelectric element means is fastened to the magnetic frame. The coil is actuated from a relatively low voltage a-c or d-c power source. When the electric power source is disconnected from the coil the hammer or armature is returned to its initial position by a return spring or the force of gravity.

Electromagnetic suspension and guide system for suspended vehicles adapted to switch tracks

Abstract: An electromagnetic guide or suspension system for a magnetically supported vehicle having at least two rows of electromagnets extending along the vehicle in the direction of travel thereof and cooperating with respective armature rails upon the supporting track. Each row of electromagnets consists of two subrows of electromagnets, the electromagnets of at least one subrow being in a magnetic circuit with a respective armature rail at all times. The rows of electromagnets are designed to receive armature rails extending into the magnetic paths of the electromagnets symmetrically from opposite sides so that the vehicle may travel between a pair of outer armature rails along one track, can be switched to a second track in which the armature rails are flanked by the rows of electromagnets, or the electromagnets can be disposed to the same side of the respective armature rails in an asymmetrical arrangement.

Per-Unit System for the Dual-Excited Synchronous Machine

Abstract: The per-unit systems used for the conventional synchronous machine are not equally applicable to the dual-excited one when the field windings are not located on the rotor axes. This is because the mutual inductances between any of the two inclined field windings and the armature windings are dependent on the permeance in both the direct and the quadrature-axis. In this paper, a sound per-unit system, taking this dependence into consideration, is suggested for this machine. The system is derived in such a way so as to provide normalized equations representing the physical nature of the magnetic couplings between the different machine circuits.

Electromagnetic operated clutches and brakes

Abstract: In an electromagnetic clutch, stray magnetic fields on the axis of the clutch are minimized by arranging the poles of the magnet core radially and positioning the armature with respect to the core so as to complete a magnetic circuit of generally toroidal shape.

Electro-hydraulic servo-distributor

Abstract: An electro-hydraulic servo-distributor comprising a primary or pilot stage having a drive means constituted by a magnetic circuit which comprises two parallel polar cores, and two rectilinear magnets parallel to the cores and connected magnetically to one end of the cores by at least one metal plate. Two control coils are wound around the cores and a movable plate assembly is arranged opposite the other ends of the polar cores, forming therewith equal air gaps. The arrangement of the different components of the magnetic circuit is such that the flux produced by the control coils and the flux of one of the magnets pass across the corresponding air gap in the same direction, while the flux produced by the other magnet pass across the other air gap in the opposite directions. A support member is provided with a central part on which the movable plate assembly is fixed, and two lateral torsion rods which are each terminated by a lateral portion are engaged in the fixed structure of the servo-distributor. The support member also carries in its central part a hydraulic closure member which is substantially perpendicular to the plate assembly and which is intended to close according to the direction of magnetic turning moment to which the movable plate assembly is subjected, one or the other of two jets which are supplied with a hydraulic fluid, by a secondary or hydraulic stage controlling flow or controlling pressure.

Some measurements of inhomogeneous permanent magnets by the pole-coil method

Abstract: The pole-coil method for measuring demagnetization curves of permanent magnets is applied to inhomogeneous magnets. It allows the analysis of different causes of inhomogeneities: differences in the intrinsic magnetic properties within one test sample, in the degree of orientation of otherwise homogeneous material, in the effectiveness of magnetic heat and annealing treatment; inclusion of holes or nonmagnetic contaminations; unequal cross sections of the tested magnet, for example, with conical shape. By the pole-coil method inhomogeneities can be recognized by differences in remanence and coercivity. But in the case of serial arrangement of different components the resulting coercivity of an inhomogeneous sample is an average value of the coercivities of the components and nearly unaffected by the location of the measuring spot. The measurement of a magnet with different cross-sectional areas on both faces yields data for immediate magnetic circuit design.

Segmental readout device having improved magnetic circuit components

Abstract: A segmental readout device includes a support plate carrying seven rotatable magnetized indicator members in a spaced array adjacent to a front plate having openings to expose the indicator members. A magnetic back plate has forwardly extending magnetic cores integrally formed with the back plate and carrying cylindrical electromagnetic coils for actuating the indicator members. One group of lateral magnets in the array has diametrically opposite poles oriented oppositely from similar poles of another group of centered magnets. Coils associated with the lateral magnets are oppositely wound from the coils associated with the centered magnets. Rotational axes of the lateral magnets are perpendicular to the axes of the centered magnets. The orientation of the axes and poles winding of the coils effectively isolates adjacent magnetic circuits from each other so that it limits the ability of one magnet to cause rotation of any other magnet.

Mold assembly for making a magnetic base

Abstract: There is disclosed a magnetic printing base for one or more printing plates, a method of making the magnetic base, and a mold in which moldable,non-magnetic adhesive material is molded about various parts of the magnetic base. The base is structured to permit magnetic circuit devices and end plates to be interconnected by the non-magnetic material into a unitary arrangement. Each magnetic circuit device includes a flat magnet disposed between and in ccontact with a pair of flat magnetizable plates. The permanent magnetsextend short of the finaldesired dimension of the base. The plates and the molded material initially extend beyond the final desired dimension of the base, but are trimmed off by a cutter to the final desired dimension after assembly of the base. To obviate the tendency of the printing plate to creep or drift, the spacing between the magnetic circuits is such that the strength, at surface of the base, of the magnetic flux field between next adjacent pole plates of adjacent magnetic circuit devices is equal to the strength, at the surface of the base, of the magnetic flux field between the pole plates of a magnetic circuit device itself.

Voltage stabilizing transformer

Abstract: A voltage stabilizing transformer having a magnetic core formed of interleaved laminations defining a closed magnetic circuit and including a center winding leg and a pair of outer legs spaced therefrom. A first coil assembly, including at least a primary winding, is mounted on the center winding leg and a second coil assembly, including at least one secondary winding, is mounted on a center winding leg. Magnetic shunts are positioned between the first and second coil assemblies and extend substantially between the winding leg and the outer legs. A control winding is mounted on only a portion of the winding leg and is adapted to be short circuited for effectively removing that portion of the winding leg about which it is mounted from the magnetic circuit for the secondary winding.