Showing papers on "Electromagnetic coil published in 1976"

Single coil probe with transmission‐line tuning for nuclear magnetic double resonance

Abstract: First we discuss a method of tuning NMR probe circuits and matching impedances which employs a variable length transmission line as one of the tuning elements. This method is useful for high voltage circuits where, due to space considerations, suitable tuning elements may not be placed adjacent to the rf field‐producing coil. Second, we describe the design of a single coil double resonance probe which uses λ/4 transmission lines as filters as well as tuning elements. This double resonance probe is useful when the two frequencies of interest are widely separated.

Charging system and method for multicell storage batteries

Abstract: A battery-charging system includes a first charging circuit connected in series with a plurality of battery cells for controlled current charging. A second charging circuit applies a controlled voltage across each individual cell for equalization of the cells to the fully charged condition. This controlled voltage is determined at a level above the fully charged open-circuit voltage but at a sufficiently low level to prevent corrosion of cell components by electrochemical reaction. In this second circuit for cell equalization, a transformer primary receives closely regulated, square-wave voltage which is coupled to a plurality of equal secondary coil windings. Each secondary winding is connected in parallel to each cell of a series-connected pair of cells through half-wave rectifiers and a shared, intermediate conductor.

Control system for driving a capacitive display unit such as an EL display panel

Abstract: A coil is serially connected to a capacitive display unit, such as an EL display panel, which includes an insulating display element sandwiched between a pair of electrodes. The coil and the electrostatic capacitance of the display unit function, in combination, to form an LC resonance circuit, which limits transient current flowing through the insulating display element and enables the display unit to operate in a low power dissipation mode. An alternating driving signal to be applied to the display unit has an intermediate potential period on which a writing pulse is superimposed, thereby to minimize high voltage requirement of the writing circuit.

Bearing and drive structure for spinning turbine

Abstract: A bearing and drive structure for the funnel-shaped spinning element of an open-end spinning turbine, composed of a stator with a projecting portion carrying an elastically mounted bearing and a rotor with a cup-shaped portion into which the projecting portion of the stator extends, the rotor being carried by the bearing and having its center of gravity at least approximately in the region defined between the axial ends of the flexible bearing, the stator carrying electrical windings cooperating with the cup-shaped rotor portion to form an electrical drive for the rotor

Switch control system

Abstract: A switch control system particularly well suited for use in a electromechanical vibrator drive. Solid-state switches and diodes are used in combination with a DC power supply to alternately switch energy between the electric field of the power supply filter capacitor and the magnetic field of the actuator coil of a vibrator in a power resonant mode. The control system includes a variable frequency oscillator and a controllable pulse generator which respectively provide signals for controlling the closing and opening of the switches whereby the frequency and amplitude of movement of a vibratory feeder may be adjusted.

Eddy current gauge for monitoring displacement using printed circuit coil

Abstract: A proximity detection system for non-contact displacement and proximity measurement of static or dynamic metallic or conductive surfaces is provided wherein the measurement is obtained by monitoring the change in impedance of a flat, generally spiral-wound, printed circuit coil which is excited by a constant current, constant frequency source. The change in impedance, which is detected as a corresponding change in voltage across the coil, is related to the eddy current losses in the distant conductive material target. The arrangement provides for considerable linear displacement range with increased accuracies, stability, and sensitivity over the entire range.

Conical compression spring

Abstract: A conical compression spring having the characteristics of a cylindrical spring of much greater free length. The spring is characterized by wire whose diameter diminishes from base to apex end and by coils whose pitch diminishes from base to apex end such that the ratio of mean coil diameter to wire diameter is constant from coil to coil. Further, each coil diameter is preferably dimensioned to fit within the next larger coil permitting a spring to be designed which exhibits a small solid compressed height.

Tire pressure indicator

Abstract: An improved system is disclosed for electro-magnetically monitoring the condition of a vehicle tire which has a plurality of possible states, such as an internal air pressure which can fall within predetermined limits. The system is of the type which comprises a transmitter which serves to transmit to the monitored vehicle tire an interrogation signal composed of a carrier wave modulated at a predetermined modulating frequency. The tire to be monitored carries a transponder device which is operable in response to the state of the tire for passively detecting the modulating frequency of the interrogation signal and retransmitting an information signal at the modulating frequency. A receiver is provided responsive to the retransmitted information signal so as to provide an output which is indicative of the state of the device being monitored. The transponder includes an improved signal coil, embedded within the body of the vehicle tire and disposed as a circular loop about the tire, coaxial with the axis of rotation thereof. This improved coil configuration enables a continuous and more uniform display of the condition of the tire when the vehicle is in motion.

Helical coil dispensing machine apparatus

Abstract: Improved dispensing apparatus for dispensing machines of the type having at least one dispensing tray containing a dispensing unit which dispenses articles from the machine by the use of a helical dispensing coil. Improved mounting apparatus is provided for supporting both the forward and back end portions of the dispensing coil. A cross-bracket member having a portion extending across the diameter of the coil, is mounted to the back portion of the coil. A cross-bracket holding device, connected for rotation by appropriate motor means, releasably accepts the cross-bracket for mounting the back portion of the coil in elevated position above the shelf surface of the dispensing tray. The cross-bracket holding device is configured to matingly accept differently sized cross-bracket members, to enable rapid interchangeability of differently sized dispensing coils in the machine. Coil support apparatus mounted to slidably engage the outer circumference of the dispensing coil near its forward end supports the forward end of the coil in elevated spaced-apart manner above the tray surface, and supports the coil in a manner which minimizes jamming of the items being dispensed at the forward end of the coil. Coil compression means mounted adjacent the forward end of the dispensing coil causes the coil to positively eject or to impart dispensing motion to the item being dispensed from the convolutions of the coil, during the dispensing rotation movement of the coil.

Limit control apparatus

Abstract: An actuator control system includes a ballscrew type actuator for controlling the positioning of a valve device. A processing circuit is responsive to direction and drive signals for driving a synchronous stepper motor which is operatively coupled to the actuator. The processing circuit includes a switching device which applies a DC voltage to the motor windings to hold the valve position when it is not being driven. A limit sensing device provides a limit signal when the movable member of the actuator approaches a limit of travel. A limit control circuit responds to the limit signal to alternately reverse the direction signal applied to the processing circuit so long as that signal is representative of the direction in which the limit is being approached.

Split core current transformer having an interleaved joint and hinge structure

Abstract: A split core current transformer for coupling monitoring apparatus to a current carrying conductor includes a two-piece annular core structure formed by first and second arcuate core assemblies having windings, connectable to the monitoring apparatus, wound on laminated core sections, the laminated core sections each including a plurality of flat lamination elements arranged in a stacked configuration with alternate elements having generally circular end portions which project beyond the main body portion of the arcuate core section at each end thereof defining generally circular gaps, permitting interleaving of the projecting end portions of the core sections of the two core assemblies providing an annular core structure having two interleaved joints which are held together by way of removable hinge pins which permit separation of the interleaved projecting end portions at either one of the joints to facilitate coupling to the current carrying conductor.

Stator coil winding and lead wire connection

Abstract: Method and apparatus for connecting stator coil lead wires to terminal connection means mounted on a 2-pole stator core at a coil winding station. Also disclosed is an improved lead loop hook assembly.

Electromagnetic actuator, notably for hydraulic servo-control valve

Abstract: Electromagnetic actuator, especially for actuating a hydraulic servo-control valve, which comprises a magnetic shell constituting a body of revolution and a concentric armature-forming permanent magnet, at least one annular field coil, the field coil and the armature being adapted to move axially in relation to each other The movable member (field coil or armature) is caused to move by the resultant electromagnetic force resulting from the energization of the field coil to which a control direct current is applied and by the antagonistic force of a repulsion member incorporated in the magnetic shell The field coil is longer than the armature so that the electromagnetic force is independent of the movement of the movable member and proportional to the control direct current The movable member is caused to perform simultaneously a cyclic motion superposed to the axial movement in order to eliminate the friction hysteresis of the hydraulic valve

Method of making a self-supporting wire coil

Abstract: A wire is wound on a coil body form about a removable mandrel in a first layer in which the turns abut one another. A guide ring reverses the direction of lead of the wire to form a second, overlying layer in which the turns are spaced a short distance apart from one another. The final turns of the outer layer engage about the coil form. A casting agent applied to the coil penetrates the turns of the second and first layers and is hardened. The mandrel is removed and the coil is self-supporting, for use as in a moving-coil motor. A fiberglass sheet may optionally be applied about the first layer before the second layer is wound thereover to increase the strength of the coil.

Electronic monitoring system and responder device

Abstract: An electronic monitoring system for monitoring the passage of objects, such as persons, past a monitoring station. An antenna is provided flat on the floor of the station to generate electromagnetic fields in the vicinity of the station and to generate electrical alarm signals whenever the electromagnetic fields are disturbed by the passage of an object carrying a special responder device. The responder device comprises an elongated bar of ferromagnetic material about which is wound the coil of a resonant electrical circuit. A mounting strap is provided to mount a responder device the leg of each object to be monitored such that the elongated bar is held perpendicular to the floor whereby maximum electrical interaction is provided between the antenna and the resonant electrical circuit.

Eddy-current test probe utilizing a combination of high and low reluctance materials to optimize probe sensitivity

Abstract: A coil of insulated wire surrounds a low reluctance core A combination of low reluctance and high reluctance materials positioned adjacent said coil: (1) control the spatial extent of the magnetic flux and, (2) concentrate the total reluctance of the magnetic circuit of the exciting coil into a volume of controlled size and shape within the material being tested The magnetic flux is controlled, and the reluctance is concentrated, in such a manner as to optimize the sensitivity of the eddy-current generator to variations in the material being tested; at the same time, the coil impedance is maintained at a value which is optimum for the performance of any selected precision electrical impedance measuring device

Printed circuit coils

Abstract: The conducting path width of a spiral printed circuit coil is reduced for the inside of the spiral coil to obtain more inductance in the same space without substantial sacrifice in Q. In another form of spiral coil with non-constant path width, the path width is reduced in a sector of the coil located between the inner and outer terminals to reduce the distance between terminals with minimum sacrifice in inductance or Q.

A new method of high magnetic field generation and its applications

Abstract: A new method of generating high pulsed magnetic field up to about 1 MOe without destroying coils is described The magnet consists of multi-layer coils which were designed so as to share the strong Maxwell stress within their tensile strength A small 4-layer model magnet was tested and the maximum field of 107 MOe with the pulse width of 018 m sec was obtained without destroying the coil A three-years project of constructing a high magnetic field laboratory based on the new idea is proceeding in Osaka University A 15 M Joule energy source is used to produce up to 1 M0e within a volume of 20mmD × 20 mm and low temperature experiments will be possible after two years At present, however, the experiments at liquid helium temperature are limited up to 05 MOe The submillimeter electron spin resonance experiments under the strong field were done using HCN and H 2 O lasers and the determination of exchange constant between dissimilar spins was done New terms, H2S2, H2SI and H3S in the spin Hamiltonian are also discussed Magnetization measurements in metals and compounds are reported

Wheel slip correction method, system and apparatus

Abstract: The following specification described a method or system of correcting locomotive wheel slip in which each driven wheel provides a wheel velocity signal proportional to its angular velocity. This signal is compared in a wheel slip detection circuit for each wheel with a train speed signal to derive a signal corresponding to the difference in the event of wheel slip. This difference signal is differentiated to provide a signal corresponding to the acceleration and multiplied by a signal corresponding to the slipping wheel speed to provide a correction signal corresponding to the power lost in the slipping wheel. The wheel velocity signals are compared in a "less than" and a "greater than" circuit respectively to derive the train speed signal and the slipping wheel signal. The correction signal is utilized for controlling the current in the field windings of the main generator of a diesel electric locomotive to reduce the power by a factor corresponding to the power lost in the wheel slip and to initiate the application of sand to the track in the event the train speed is low or the slip is repetitive. An override relay is also operated by the correction signal to control the conventional override solenoid to reduce the generator output and thereby enable the governor to reduce the engine fuel supply. The correction signal is also used for controlling the storage of the train speed signal to retain a record or memory of the train speed so that the correction signal is always properly derived irrespective of the number of slipping wheels.

Reactively decoupled dual channel keying circuit for wide-band frequency modulated keyable control circuit

Abstract: A keyable control circuit, has sensing coils located in the vicinity of a plurality of locations where lock control is desired. At least one swept high-frequency oscillator, which is connected to each sensing coil, generates an rf signal, rapidly swept over a wide frequency band. When an external keying circuit, containing more than one resonant circuit, each correctly tuned to a predetermined keying frequency, is inductively coupled to a sensing coil, each resonant circuit absorbs rf energy as the oscillator frequency is swept past its resonant frequency. Electrical interaction between the resonant circuits is accomplished by reactive cancellation. Energy absorption in the external keying circuit induces corresponding reductions in rf energy in the sensing coil as the oscillator frequency is swept past the keying frequencies. Tuned detectors within the keyable control circuit produce a control signal when energy reduction is sensed at each of the predetermined keying frequencies. If correct absorption fails to occur at any one or more of the predetermined frequencies, the control signal is withheld. A time-gating system enables selective direction of the control signal to one or more using locations while excluding others. This function finds convenient application in automotive use where it is frequently desired to enable simultaneous unlocking of one or more doors while excluding unlocking of the deck lid. A dead-oscillator detector averts attempted actuation of the unlocking function by the coupling of untuned energy-absorbing material, such as iron, to a sensing coil.

Electromagnetic fuel injection valve

Abstract: An electromagnetic fuel injection valve which exhibits faster opening and closing times as well as being more linear in flow characteristics than prior art valves. The fuel injector valve of the invention accomplishes these desirdata by providing a combination of design improvements over prior art electromagnetic fuel injector valves. Most notable among the design improvements are: a lighweight plunger, a flat-faced armature, dual adjustment of the valve seat and biasing on the plunger, and a wet coil construction whereby the electromagnetic coil is cooled by fluid flowing through the valve.

Ultrasonic transducer power output by modulated radiation pressure

Abstract: We have set up and are using an apparatus for the measurement of total sound power output of a piezoelectric transducer radiating into water. This apparatus combines the better features of previously used methods which depend on radiation pressure. The input is modulated at a low frequency and the output power is intercepted by a target which experiences a force at the modulation frequency. The target is mounted on the armature of an electromagnetic receiver provided with an independent coil through which a current at the modulation frequency is adjusted in amplitude and phase, either manually or automatically by feedback, to arrest the motion of the armature. When the armature is stationary the force depends only on the current, and the apparatus can be calibrated using direct current and dead weights. It is thus absolute. In practice, the carrier frequency is swept over any part of the range 0.1–15 MHz while a recording of power output versus frequency is made. The results of comparisons made with those of other mehtods are encouraging. Examples of curves from normal and defective transducers are shown.

Helical compression spring made of wire of circular cross section, especially for use in motor vehicles

Abstract: A helical compression spring having a partially progressive characteristic which has a cylindrical portion of constant wire thickness coterminously and integrally joined to a truncoconical portion whose coil of greatest coil diameter is disposed away from the cylindrical portion. The truncoconical portion has inconstant wire thickness with the coils of largest wire diameter being positioned between coils of smaller wire diameter.

Coil with protection against overheating

Abstract: A plastic coil bobbin has a recess with the precise dimensions of a thermal fuse. On one side, the recess is open so that, as the coil is wound on the bobbin, successive layers of coil wire form a wall-like surface closing that open side. As the fuse is press fit into the recess, it is also forced into intimate contact against the wall of wire. Thus, the only material between the fuse and wire is a thin plastic shell forming the fuse housing. Since the fuse rating takes this wall thickness into account, there is effectively no thermal insulation between the coils and the fuse. Accordingly, under overheating conditions, the fuse opens a circuit when there is overheating and before a fire can start.

Hydrogen-purification apparatus with palladium-alloy filter coil

Abstract: A hydrogen-purification filter has a closed chamber with a pure-hydrogen outlet. A coil made of thin palladium-alloy tubing is contained in this chamber and has an inlet end and an outlet end accessible from outside the chamber. This coil is of D-section so that in case a leak forms the turn of the coil containing the leak can be excised by cutting at the straight sections on both sides of the leak and the remaining coil rejoined at the straight sections.

Transient suppression circuit for push-pull switching amplifiers

Abstract: A protective coupling circuit is located between the D.C. supply voltage the amplifier components of a push-pull switching amplifier to suppress transients created during switching. The coupling circuit comprises a power supply filter with an inductor coil and capacitor, and circuitry for limiting the voltage on the individual switching elements and the output coil. Excess voltages caused by transients are fed to the power supply filter. In an alternative embodiment the power supply filter inductor coil is actually an auxiliary winding on the amplifier output transformer rather than a separate coil. This allows for use of some smaller capacity circuit elements.

Method for making loudspeaker with magnetic fluid enveloping the voice coil

Abstract: A method for the manufacture of loudspeakers having a ferromagnetic fluid contained in the voice coil magnetic air gap and being confined by the loudspeaker magnet field thereby enveloping the portions of the voice coil that are within the magnetic air gap. A critical viscosity range of the ferromagnetic fluid is required, the viscosity determined by the viscosity of the liquid phase and the concentration of the colloidal ferromagnetic particles which provide the viscous damping forces on the voice coil effective at low and high frequencies. The damping forces are due to shearing stress set up in the fluid by motion of the voice coil in response to electrical excitation and result in surprisingly improved acoustical performance, higher electrical output and freedom from hiss in the loudspeaker. The ferromagnetic fluid also provides an improved heat sink for the voice coil thus improving the electrical power dissipation capability of the voice coil. An opening in the cap over the voice coil permits entrapped air under the cap or dust cover to escape thereby eliminating a noticeable hiss.

Superconducting dipole electromagnet

Abstract: A dipole electromagnet of especial use for bending beams in particle accelerators is wound to have high uniformity of magnetic field across a cross section and to decrease evenly to zero as the ends of the electromagnet are approached by disposing the superconducting filaments of the coil in the crescent-shaped nonoverlapping portions of two intersecting circles. Uniform decrease at the ends is achieved by causing the circles to overlap increasingly in the direction of the ends of the coil until the overlap is complete and the coil is terminated.

Method for checking coins and coin checking apparatus for the performance of the aforesaid method

Abstract: A method of, and apparatus for, checking coins, wherein the coin to be checked is moved through a constantly regulated alternating-current field of a measuring coil. The influence of the coin upon the alternating-current field produces a regulation magnitude formed from the difference between a reference voltage and the rectified oscillator-measuring voltage. The regulation magnitude readjusts, by means of the oscillator circuit, the oscillator-measuring voltage at the measuring coil to a constant value. During coin checking the regulation magnitude is employed as the coin checking criterion in a manner such that it is possible to determine by means of an evaluation circuit whether this regulation magnitude has reached a value falling within an upper and lower boundary. The time-constant of the regulation circuit is chosen such that slow changes can be controlled, but the oscillator-measuring voltage is also maintained constant during relatively rapid passage of the coin through the measuring coil and there is obtained as high as possible amplitude of the regulation magnitude.