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Showing papers on "Electromagnetic coil published in 1974"


Patent
16 Sep 1974
TL;DR: In this paper, a receiving coil is inductively coupled to the radiation over a given distance substantially less than a wave length of the high frequency signal to provide a received signal without the necessity of any electrical wires.
Abstract: A normal 117-volt, 60 cycle source is converted into a high frequency signal resulting in radiation of a substantial portion of the energy in the signal. A receiving coil is inductively coupled to the radiation over a given distance substantially less than a wave length of the high frequency signal to provide a received signal without the necessity of any electrical wires. The received signal in turn is converted into a D.C. signal and passed to a rechargeable battery for charging. The inductive coupling can be utilized for recharging portable electrical instruments having rechargeable batteries or for charging larger rechargeable batteries such as used in electrically driven vehicles.

207 citations


Patent
02 Jan 1974
TL;DR: In this article, a plug-in line protector for a communications circuit provides protection for over voltage and over current conditions of the line, where a cup and slug module containing carbon blocks provide an air gap for grounding high voltage transients.
Abstract: A plug-in line protector for a communications circuit provides protection for over voltage and over current conditions of the line. A cup and slug module containing carbon blocks provides an air gap for grounding high voltage transients. For an over current condition, a solder pellet melts causing the cup and slug to engage due to spring pressure and ground the line through a grounding strip. The grounding strip has plastic insulation bonded to a portion thereof and interposed between the line and ground. In an over current condition heat from one of the carbon blocks is transferred through the cup to the metalic strip. This heat may cause the plastic to melt to provide a back-up or secondary low resistance path to ground. The protector may also have a resettable over current responsive mechanism in the form of a heat coil in the line. When the heat coil breaks, a printed circuit board, on which the heat coil is mounted, is moved by a volute spring. In over voltage and in over current conditions, the volute spring conducts current from the printed circuit board to the slug and cup and to ground.

189 citations


Patent
25 Mar 1974
TL;DR: An apparatus for promoting healing of body tissue composed of a coil arranged to be applied to the affected body part and to be connected to a low frequency a.c. source to produce a magnetic field within the region to be treated, and at least two sheetlike electrodes associated with the coil and spaced from one another, the electrodes being arranged at respectively opposite sides of the region where the body tissue was treated and to connect to a source of low frequency voltage to produce an electric field in order to treat at the same time as the magnetic field.
Abstract: An apparatus for promoting healing of body tissue composed of a coil arranged to be applied to the affected body part and to be connected to a low frequency a.c. source to produce a magnetic field within the region to be treated, and at least two sheetlike electrodes associated with the coil and spaced from one another, the electrodes being arranged to be located at respectively opposite sides of the region to be treated and to be connected to a source of a low frequency voltage to produce an electric field within the region to be treated at the same time as the magnetic field.

168 citations


Patent
29 Jul 1974
TL;DR: In this article, a coil and magnet are implanted in the ear after removal of the incus, the magnet being fastened to the head of the stapes and the coil being energized by electrical signals from a sound transducer and producing a magnetic field which, interacting with the magnetic field of the magnet, causes movement of stapes.
Abstract: Problems of conventional hearing aids (low fidelity, poor frequency response and feedback) and of hearing aids employing implanted piezoelectric elements (high power requirements and microtrauma) are eliminated or attenuated by implanting a coil and magnet in the ear after removal of the incus, the magnet being fastened to the head of the stapes and the coil being energized by electrical signals from a sound transducer and producing a magnetic field which, interacting with the magnetic field of the magnet, causes movement of the stapes in the same manner as it normally is moved by the incus.

96 citations


Patent
29 Oct 1974
TL;DR: An induction cooking appliance for operation at ultrasonic frequencies and including an improved work coil coupled in a solid state inverter circuit to generate an ultrasonic frequency magnetic field which is coupled to a metallic utensil through a non-electrically conductive cooktop is described in this article.
Abstract: An induction cooking appliance for operation at ultrasonic frequencies and including an improved work coil coupled in a solid state inverter circuit to generate an ultrasonic frequency magnetic field which is coupled to a metallic utensil through a non-electrically conductive cooktop. Coil losses are minimized, and coupling efficiency increased by forming the coil of solid conductor wound in a loose spiral, with the pitch of the spiral being related to the radial thickness of the conductor by a factor falling within a predetermined range. The loosely wound coil is held in a grooved dielectric support which insures proper turn spacing for the life of the appliance and which is immune to high temperatures which may be developed during operation of the coil. Means are provided under the support to minimize stray radiation and limit inductance variations which might otherwise result from nearby metallic members. Means are provided for holding the coil adjacent the underside of the cooktop for optimum coupling and to utilize heat developed in the coil. The loosely wound configuration is advantageously fabricated by methods including interleaving the coil conductor with an insulative strip. Alternatively, an open coil may be formed by winding the conductor on a frusto-conical mandrel whose degree of taper is related to the desired pitch of the coil, and compressing the coil into a planar configuration.

91 citations


Patent
25 Jun 1974
TL;DR: In this article, a light emitting system consisting of an oscillator for generating oscillations at high frequency, a fixed coil adapted to be energized by the output of the oscillator, a movable coil electromagnetically coupled with the fixed coil and adapted to being energised by the intermittent energization of the fixed coils was presented.
Abstract: There is provided a light emitting system comprising an oscillator for generating oscillations at a high frequency, a fixed coil adapted to be energized by the output of the oscillator, a movable coil electromagnetically coupled with the fixed coil and adapted to be energized by the intermittent energization of the fixed coil, and a light emitting element connected to the movable coil to form a closed circuit and adapted to give light by an exciting current produced by the energization of the movable coil. The system thus eliminates the use of any mechanical sliding contact unit.

90 citations


Journal ArticleDOI
TL;DR: In this paper, the vector potential of a coaxial with an arbitrary number of cylindrical conductors is derived using an iterative process that has been adapted to computer programs.
Abstract: The vector potential has been obtained for a coil coaxial with an arbitrary number of cylindrical conductors. The derivation is quite general and employs an iterative process that has been adapted to computer programs. After the vector potential has been obtained, it is used to calculate the mutual and self‐impedance of multiple and single coils, the effect of defects in the conductors on the mutual and self‐impedances, and the induction heating density in the conductors.

90 citations


Patent
28 Mar 1974
TL;DR: An E-shaped magnetic core with a sensing coil wound around each outer leg, these coils being connected in series and the center leg made of a magnet to establish a symmetrical magnetic field as discussed by the authors.
Abstract: An E-shaped magnetic core with a sensing coil wound around each outer leg, these coils being connected in series and the center leg made of a magnet to establish a symmetrical magnetic field. When a conductive but non-magnetic material is passed through the flux field established in the air gap between the center and outer legs, eddy currents are induced in the material which oppose and momentarily change the magnetic field inducing a detectable voltage in the coils.

82 citations


Patent
18 Feb 1974
TL;DR: In this paper, the authors provided electrically conductive paths between the coil armor and the core laminations of dynamoelectric machines by placing a semiconducting elastomeric material between the coils sides and the walls of the core slots.
Abstract: According to the invention electrically conductive paths are provided between the coil armor and the core laminations of dynamoelectric machines by placing a semiconducting elastomeric material between the coil sides and the walls of the core slots. The elastomeric material is of a type which has a controlled resistance and will deform sufficiently under pressure to flow into the irregularities between the coil side and the slot walls, and in so doing provide conductive paths for electric charge to flow from the armor to the core laminations. This material must be capable of retaining its strength, elasticity, conductivity, etc., and remaining in place between the coils and core under vibration, coolant flow, electric stresses, repeated temperature changes, etc., for the operating life of the machine. Preferably, these paths will be heat conductors as well.

82 citations


Patent
01 Nov 1974
TL;DR: A metal-based cookware induction heating apparatus with an improved power supply and control circuit comprised of a chopper inverter including a gate controlled power thyristor coupled to and supplying an induction heating coil with periodic energization currents is described in this paper.
Abstract: A metal based cookware induction heating apparatus having an improved power supply and control circuit comprised of a chopper inverter including a gate controlled power thyristor coupled to and supplying an induction heating coil with periodic energization currents. A full wave rectifier supplies rectified, unfiltered, unidirectional high voltage excitation potential to the chopper inverter which converts the excitation potential to a comparatively high frequency of the order of 20 kilohertz for supply to the induction heating coil. A gating circuit is provided for driving the chopper inverter directly from the rectified high voltage excitation potential supplied by the rectifier.

76 citations


Patent
David L Lafuze1
30 Aug 1974
TL;DR: In this article, a dynamoelectric machine is driven as a brushless DC motor to start a dynamic load such as a jet engine and as a synchronous constant frequency generator after the jet engine is ignited and brought up to speed.
Abstract: The instant invention is an improvement of a starter-generator arrangement in which a dynamoelectric machine is driven as a brushless DC motor to start a dynamic load such as a jet engine and as a synchronous constant frequency generator after the jet engine is ignited and brought up to speed. A plurality of cycloconverters utilizing phase controlled rectifier banks are operated from a constant frequency supply source to supply current to the armature windings of the machine in the starting mode. Position sensing elements such as Hall generators sense the rotor position relative to the machine windings and generate enabling signals to control conduction of the phase controlled rectifiers to supply current to the proper armature windings so that the machine functions essentially as a DC brushless motor. The stator current conduction angle with respect to rotor position is varied as a function of speed to vary the phase angle of advance and provide for commutation of the SCR''s by the machine voltage at higher speeds. In addition, at machine speeds where the counter EMF generated in the armature windings rises sufficiently to reduce armature current, means are provided for reducing the counter EMF by further advancing the phase angle and providing additional torque to accelerate the engine. Specifically, a control signal proportional to the armature current is utilized to increase the phase angle between the armature current, the flux, and the machine voltage sufficiently to reduce the machine counter EMF thereby increasing the armature current and providing additional accelerating torque over an extended speed range to the jet engine.

Patent
07 Feb 1974
TL;DR: In this paper, a field excitation system is provided for a synchronous machine which is operated both as a motor and as a generator, by selectively switching the field winding connections of the exciter/transformer and by switching the voltage applied to the field windings from DC to AC.
Abstract: A field excitation system is provided for a synchronous machine which is operated both as a motor and as a generator. Field excitation is provided by a rotating machine which is connected as a brushless exciter when the synchronous machine is in the generating mode and connected as a rotating transformer when the synchronous machine is in the motoring mode. This conversion is achieved by selectively switching the field winding connections of the exciter/transformer and by switching the voltage applied to the field windings from DC to AC. When the main machine is to be operated in the motoring mode, a three-phase alternating voltage is applied to the exciter field winding and the field winding connections are switched so that the field windings are in a three-phase WYE connection and the machine functions as a rotating transformer. The alternating voltage induced in the rotor winding is rectified and provides field excitation for the main machine. As the main machine comes up to speed, a speed at which the machine is to be operated as a generator, the rotating machine is reconnected to operate as a brushless exciter generator. To this end, the field windings are connected in series, the three-phase alternating voltage is removed and a DC voltage is applied to the field windings. The exciter now operates as a standard inside-out synchronous exciter generator to generate a voltage in the armature rotor windings which is rectified to supply the DC field for the main machine rotor. In this fashion, DC excitation for the main synchronous machine is provided both when the machine is initially started from standstill in the motoring mode and when it switches to the generating mode.

Patent
12 Dec 1974
TL;DR: In this paper, an apparatus and method for placing magnet wire in the slots respectively defined by spaced, parallel blades of coil transfer apparatus which lie on an imaginary cylinder thereby to form a dynamoelectric machine field winding is presented.
Abstract: An apparatus and method for placing magnet wire in the slots respectively defined by spaced, parallel blades of coil transfer apparatus which lie on an imaginary cylinder thereby to form a dynamoelectric machine field winding. The wire is pushed and simultaneously guided with a motion having components in at least two mutually perpendicular directions in a path having sections respectively aligned with at least two of the slots thereby to push the wire into the slots, the path also having sections respectively within and outside of the cylinder.

Patent
David L Lafuze1
30 Aug 1974
TL;DR: In this article, a dynamoelectric machine is driven as a brushless DC motor to start a jet engine and as a cynchronous constant frequency generator after the jet engine is ignited and brought up to speed.
Abstract: The instant invention describes an improvement in a starter-generator arrangement in which a dynamoelectric machine is driven as a brushless DC motor to start a dynamic load such as a jet engine and as a cynchronous constant frequency generator after the jet engine is ignited and brought up to speed. A plurality of cycloconverters utilizing phase controlled rectifier banks are operated from a constant frequency supply source to supply current to the armature windings of the machine in the starting mode. Position sensing elements such as Hall generators sense the rotor position relative to the machine windings and generate enabling signals to control conduction of the phase controlled rectifiers to supply current to the proper armature windings so that the machine functions essentially as a DC brushless motor to drive a dynamic load such as a jet engine. The Hall sensors are so positioned that the enabling signals are generated so that stator current conduction in one winding may be terminated and current conduction switched to the next winding in such a fashion that commutation of the conducting SCR's by the machine counter EMF is made possible at high speeds while permitting maximum torque at standstill and low speeds. The stator current conduction angle with respect to the rotor position is varied as a function of speed. By varying the position sense advance and hence, the phase angle between the armature current and the machine voltage, maximum torque may be produced at the low speeds and maximum current may be commutated at the speeds where the machine voltage must be utilized to commutate the SCR's to transfer current flow from one winding to the other. The cranking time of an engine is thus substantially reduced since at low speeds, maximum torque is developed from the machine.

Patent
25 Nov 1974
TL;DR: In this article, a sampling type of metal detector is described in which an oscillator transmits an oscillators signal current through the transmit coil of the detector to produce an electromagnetic field in the region of a search head.
Abstract: A sampling type of metal detector is described in which an oscillator transmits an oscillator signal current through the transmit coil of the detector to produce an electromagnetic field in the region of a search head. A received signal is induced in the receive coil of the detector when a metal object is present within that portion of the electromagnetic field which is external to the search head. A sampling pulse generator produces sampling pulses, at a time related to the output signal of the oscillator, which are transmitted to a sampling circuit for sampling the received signal. In the preferred embodiment, the received signal is sampled at a time controlled by a phase shift adjustment means to produce an output sample voltage such that any indication due to mineral soils or other background conditions is excluded from the sample.

Patent
Takayuki Kato1
01 May 1974
TL;DR: In this article, the authors used a very compact structure for particular use in the vehicle brake system for detecting the amount of wear in the brake lining element and temperature rise in the braking system.
Abstract: Abnormality-detecting device of very compact structure for particular use in the vehicle brake system for detecting the amount of wear in the brake lining element and temperature rise in the brake system. Cumulative reductions in the effective thickness of the lining element are detected by measuring the coil inductance variation by a pick-up coil fixed to the brake shoe said coil also detects occurrence of a critical temperature rise in the brake system.

Patent
13 Mar 1974
TL;DR: An eddy current coil test arrangement comprises an excitation coil for producing over a portion of a workpiece to be tested for defects an alternating magnetic field which penetrates the workpiece in a direction perpendicular to the work piece surface to cause eddy currents flowing parallel to the surface as mentioned in this paper.
Abstract: An eddy current coil test arrangement comprises an excitation coil for producing over a portion of a workpiece to be tested for defects an alternating magnetic field which penetrates the workpiece in a direction perpendicular to the workpiece surface to cause eddy currents flowing parallel to the workpiece surface. A pair of sensing coils for detecting defects coupled electrically in opposition are disposed within the range of the magnetic field and have their axes oriented perpendicular to the direction of the alternating magnetic field. The spacing of the sensing coils along the direction of their coil axes is approximately twice the distance between the loci of the two maximum voltage signals occurring across the winding of one coil responsive to motion of the coil arrangement over the workpiece surface in the direction of the coil axes and passing over a defect extending transversely to the stated direction.

Patent
21 Oct 1974
TL;DR: In this paper, a displacement transducer with a movable magnetic core and a fixed magnetic core oppositely arranged so as to have predetermined gaps or clearances in at least two places is described.
Abstract: A displacement - electricity transducer contains a movable magnetic core and a fixed magnetic core oppositely arranged so as to have predetermined gaps or clearances in at least two places. Two substantially closed magnetic circuits, each including one of the gaps, are formed by both magnetic cores, so that when the movable magnetic core is displaced relative to the fixed magnetic core while maintaining a predetermined spacing therefrom, the substantially opposite area of the gap portion in one of the magnetic circuits increases, while the substantially opposite area of the gap portion in the other magnetic circuit decreases. A first coil is wound around a part common to the two magnetic circuits, while a second coil is wound around a part not common thereto. By applying an alternating current to the first coil, an output responsive to the displacement of the movable magnetic core is derived from the second coil.

Patent
24 Oct 1974
TL;DR: A heatable drawroll for drawtwisting, draw-winding and spin-draw winding machines includes a stationary induction heating coil having a core and mounted within a rotatable metal jacket.
Abstract: A heatable drawroll for drawtwisting, draw-winding and spin-draw winding machines includes a stationary induction heating coil having a core and mounted within rotatable metal jacket. A sleeve of heat and electrical insulating material is stationarily disposed inside the jacket in radially spaced relation to the jacket and the coil to circumferentially surround the coil and form an intermediate space therewith for receiving a coolant for cooling the coil. Means are provided for supplying coolant to and removing coolant from the intermediate space. A second coolant space can also be formed between the coil and the core and be connected with the first space via coolant ducts through the coil. The sleeve may be porous so as to allow some of the coolant to flow therethrough and impinge on the inner surface of the jacket.

Patent
19 Nov 1974
TL;DR: In this paper, a driving circuit for driving a coil of an electromagnet for the actuation of a hammer in a high speed impact printer of data handling systems is described.
Abstract: This disclosure relates to a driving circuit for driving a coil of an electromagnet for the actuation of a hammer in a high speed impact printer of data handling systems, which driving circuit includes first switching means upstream of the coil, second switching means downstream of the coil, current sensing means for sensing current in the coil, a closed unidirectional current path including the second switching means, the coil in a diode, first control circuit means for actuating the first switching means in response to an input control signal, second control circuit means for switching on the second switching means in response to the first input control signal and for the entire duration of the input control signal, and a bistable device triggered by the current sensing means to assume one of two electrical states when the sensed current reaches a predetermined value and to provide an output signal corresponding to that one state, the output signal being effective to switch off the first switching means even in the presence of the input control signal.

Patent
27 Sep 1974
TL;DR: In this article, a transducers of the resistance wire type are described, wherein strained resistance wires are adapted to function both as a sensor and load bearing member, in which the individual lengths of wire are mechanically parallel but are preferably connected in series electrically so as to form a continuous wire passing back and forth between and connecting the two load carrying or attaching elements.
Abstract: Transducers of the resistance wire type are described, wherein strained resistance wires are adapted to function both as a sensor and load bearing member. These transducers comprise a pair of spaced apart load carrying or attaching devices which are connected by a plurality of lengths of resistance wire or filament, such as a coil, belt or rope of wire construction, in which the individual lengths of wire are mechanically parallel but are preferably connected in series electrically so as to form a continuous wire passing back and forth between and connecting the two load carrying or attaching elements. In a preferred embodiment, the ends of a length of wire rope, constructed of insulated wire, are held in, but insulated from, a pair of wire rope terminal fittings such as sockets; the individual lengths of wire of which the wire rope is composed are connected in series at their alternate ends, and suitable means such as lead wires are provided to connect the two ultimate ends of the serially connected wire in a conventional four-arm bridge circuit, whereby changes in the resistance of the wire which are induced by dimensional changes therein caused by forces applied to the terminal fittings may be measured.

Patent
20 May 1974
TL;DR: In this paper, an apparatus and method for flaw detection in relatively moving elongated workpieces is disclosed, which includes an exciter circuit for producing an electromagnetic field in the region of the workpieces, and a detection circuit having a differential coil for producing flaw indicating signals in response to nonuniformities in the field caused by workpiece flaws.
Abstract: An apparatus and method for flaw detection in relatively moving elongated workpieces is disclosed. The apparatus includes an exciter circuit for producing an electromagnetic field in the region of the workpieces, and a detection circuit having a differential coil for producing flaw indicating signals in response to nonuniformities in the field caused by workpiece flaws. The apparatus includes use of the exciter circuit as an open weld detector, and tuning the exciter circuit to resonance in the presence of an unflawed workpiece for indicating detuning of the exciter circuit in response to open welds in workpieces subsequently passing through the region of the field. Balancing circuitry is disclosed for nulling the error voltage appearing across the entire differential detector coil due to slight nonuniformities in the windings of the differential coil. A specific end signal suppressor circuit is provided for sensing workpiece ends passing through the field and temporarily disabling the detector circuit from producing the flaw indicating signals for a predetermined time following passage of each workpiece end through the field.

Patent
William H Krug1
29 Apr 1974
TL;DR: In this paper, the authors describe a control for exciting the electromagnetic coil of a magnetic brake or clutch having two relatively movable parts normally physically engaged by the action of a permanent magnet in a flux path which passes through the members, but disengaged so long as a coil is excited by current to buck the magnet.
Abstract: A control for exciting the electromagnetic coil of a magnetic brake or clutch having two relatively movable parts normally physically engaged by the action of a permanent magnet in a flux path which passes through the members, but disengaged so long as a coil is excited by current to buck the magnet mmf. The control is characterized in that current through the coil is regulated according to changes in a weighted sum of feedback signals indicative of (i) coil voltage and (ii) coil current, in such fashion that exciting current tends to vary somewhat inversely with changes in the temperature of the brake or clutch, as a result of changes of coil resistance with temperature, so that the mmf of the coil is kept reliably within the ''''release band'''' of values (and the clutch or brake held released) despite not only drifting of the unregulated input voltage source, changes in coil resistance with temperature, but also - and very importantly - changes in permanent magnet mmf with temperature.

Patent
27 Nov 1974
TL;DR: A force cooled electrical transformer with a disc or flat coil winding conventionally has vertical duct walls and horizontal baffling to direct liquid coolant flow in a zig-zag path.
Abstract: A force cooled electrical transformer with a disc or flat coil winding conventionally has vertical duct walls and horizontal baffling to direct liquid coolant flow in a zig-zag path. The several disc coils in each coil section between horizontal baffles have a graduated, unequal coil spacing which decreases with height, to thereby achieve uniform velocity of the coolant flow radially between the coils for improved cooling.

Patent
13 Aug 1974
TL;DR: In this paper, a reciprocating motor compressor assembly includes a pair of opposed pistons or diaphragms actuated by an armature fabricated from laminations of ferromagnetic material.
Abstract: A reciprocating motor compressor assembly includes a pair of opposed pistons or diaphragms actuated by a reciprocating armature. The armature is fabricated from laminations of ferromagnetic material and includes a pair of electrically conductive induction rings disposed about the ends of the laminations in coaxial relationship with a longitudinal axis of the armature. A two coil stator is disposed in coaxial relationship with the armature and the coils are alternately energized by a multivibrator or a pair of oppositely poled half wave rectifiers connected to a source of alternating current voltage. In order to increase the duty cycle of the energizing current, each stator coil is provided with two coaxially wound parallel connected windings and a phase shifting capacitor connected in series with one of the windings.

Journal ArticleDOI
TL;DR: In this article, for a cylindric quadrupole coil, expressions for the components of the magnetic vector and for the gradient of its magnitude were given for diffusion studies and the influence of the iron pole pieces of the magnet on the field was considered.

Patent
18 Apr 1974
TL;DR: In this article, a transmitting-receiving coil configuration for a metal detector is presented, where a transmitting coil is located in the same plane as two receiving coils one of which is of greater diameter than the receiving coil and the other of smaller diameter.
Abstract: A transmitting-receiving coil configuration for a metal detector. A transmitting coil is located in the same plane as two receiving coils one of which is of greater diameter than the receiving coil and the other of which is of smaller diameter. The receiving coil of smaller diameter is elliptically shaped to provide a gradual null in the direction of the major axis of the ellipse. The receiving coils are connected in series opposition and initial balance is obtained by varying the diameter of the transmitting coil and final balance is obtained by varying the number of turns on the inside receiving coil. When in the vicinity of a metal object a current 90* out of phase with the alternating current fed to the transmitting coil is induced in the receiving coils. When the center of the coils is moved directly over the metal object a null is obtained. The areas bounded by the coils are adjusted to compensate for the background effect.

Journal ArticleDOI
01 May 1974
TL;DR: In this paper, the Fourier transform was applied to investigate magnetic levitation of proposed high-speed transportation, and extensive numerical data have been analyzed to determine the performance dependence of the system parameters such as velocity, coil shape, array configuration, clearance, and track thickness.
Abstract: The use of Fourier-transform techniques provides exact integral expressions for the forces on polygonal dc current coils moving over a conducting sheet. These expressions are applied to investigate magnetic levitation of proposed high-speed transportation. Extensive numerical data have been analyzed to determine the performance dependence of the system parameters such as velocity, coil shape, array configuration, clearance, and track thickness, conductivity and permeability. In terms of potential applications, a comparison between the superconducting repulsive and ferromagnetic attractive systems is given.

Journal ArticleDOI
01 Oct 1974
TL;DR: In this paper, it is shown how a rectangular plate, suspended by one such system, may also be propelled by the same system of currents which serve to suspend it, and that lateral guidance is then automatically built into the system.
Abstract: Conducting material, in both the solid and the liquid state, can be suspended above a.c. coil systems. It is shown how a rectangular plate, suspended by one such system, may also be propelled by the same system of currents which serve to suspend it, and that lateral guidance is then automatically built into the system. In early experiments which are described, over 90% of the input power to such a system was converted into heat in the process of suspension and guidance. Further inventions are then described, by means of which it is theoretically possible to convert the whole ofthe secondary input power to propulsion. It is concluded that such systems show promise for application to high-speed ground transport.

Patent
20 May 1974
TL;DR: In this article, an electric pulse is generated for every predetermined length of wire fed through a wire feeding mechanism; a predetermined number of these pulses, which are adapted for the production of the shape and dimensions of a coil spring, are applied at a time also adapted for forming the shape of the coil spring.
Abstract: In a method for producing coil springs, an electric pulse is generated for every predetermined length of wire fed through a wire feeding mechanism; a predetermined number of these pulses, which are adapted for the production of the shape and dimensions of a coil spring, are applied at a time also adapted for the formation of the shape and dimensions of the coil spring, to at least one of a pitch controlling circuit, a wire length controlling circuit, and a coil diameter controlling circuit all included in a control device; and the output of the control device is utilized for controlling at least one of a pitch forming device, a wire feeding device, and a coil diameter regulating device, and also a wire cutting device, whereby the shape and dimensions of the coil springs are controlled numerically.