Abstract: A thermal fluid generator utilizes a plasma energy heat source to generate steam, and combine the steam with nitrogen gas. Combined flow streams of steam and heated nitrogen are injected downhole into subterranean reservoir to thermally stimulate the flow of hydrocarbons (such as, for example, residual oil) from a reservoir, while also increasing fluid pressure in the reservoir. The thermal fluid generator can be located at the earth's surface, or positioned downhole within a wellbore.

Abstract: At least one exemplary embodiment is directed to a method of providing RF mitigation exposure to a user, more specifically an eartip that can provide RF mitigation. The eartip can be an elastic layer forming a cavity with a conductive medium within.

Abstract: At least one exemplary embodiment is directed to a method of providing RF mitigation exposure to a user, more specifically an eartip that can provide RF mitigation. The eartip can be an elastic layer forming a cavity with a conductive medium within.

Abstract: High temperature switch apparatus are disclosed. An example apparatus includes a ceramic contact base having an opening therein configured to removably receive a contact, a first ceramic plunger housing portion and a second ceramic plunger housing portion, the first ceramic plunger housing portion including a first protrusion, the second ceramic plunger housing portion including a first recess, the first recess to receive the first protrusion, and a first ceramic contact housing portion and a second ceramic contact housing portion, the first ceramic contact housing portion including a second protrusion and a first cavity, the second ceramic contact housing portion including a second recess and a second cavity, the first ceramic plunger housing portion, the second ceramic plunger housing portion, and the ceramic contact base configured to be coupled in between the first and second cavities when the second recess receives the second protrusion.

Abstract: A station building power supply includes: a power converter that converts DC power to AC power; a casing that houses the power converter; an AC system circuit that supplies the AC power output from the power converter to electrical apparatus outside the casing; and a filter circuit that applies a high-frequency current generated in the power converter from the AC system circuit to the casing. In the station building power supply, the power converter and the casing are grounded.

Abstract: A reduced-cost apparatus for calibrating the sensitivity and orthogonality of a triaxial magnetometer, and a method for adjusting the distance between the two coils of a Helmholtz coil and other related parameters are described herein. A method can include positioning a calibrated magnetometer within a mounting fixture between two coils of a Helmholtz coil, the two coils arranged in mutually parallel planes and separated by the radius of the Helmholtz coil, the mounting fixture mounted such that a position of the mounting fixture is adjustable along an axis orthogonal to the mutually parallel planes; adjusting the position of the mounting fixture over at least some of the positions and measuring the magnetic field at each position to generate a set of magnetic field measurements associated with the positions; and adjusting the first distance based on the first set of magnetic field measurements. Additional apparatuses, systems, and methods are disclosed.

Abstract: An apparatus for exciting a rotating field pattern in a cavity containing an object, the apparatus comprising a radiating element configured to excite an electromagnetic (EM) field pattern in the cavity, wherein the EM field pattern is excited with EM energy at a frequency in the radio-frequency (RF) range, a field rotating element configured to rotate the EM field pattern, wherein the field rotating element has an anisotropy, the anisotropy selected from magnetic anisotropy, electric anisotropy, and a combination of magnetic and electric anisotropies, and a controller configured to determine the EM field pattern according to value indicative of energy absorbable by the object and to control the anisotropy of the field rotating element in order to rotate the EM field pattern.

Abstract: Systems and methods for magnetic shielding are described. A magnetic shield formed of a material having a high magnetic permeability may be degaussed using a toroidal degaussing coil. The toroidal degaussing coil may enclose at least a portion of the shield. Magnetic field gradients may be actively compensated using multiple magnetic field sensors and local compensation coils. Trapped fluxons may be removed by an application of Lorentz force wherein an electrical current is passed through a superconducting plane.

Abstract: Residual magnetic locks, brakes, rotation inhibitors, clutches, actuators, and latches. The residual magnetic devices can include a core housing and an armature. The residual magnetic devices can include a coil that receives a magnetization current to create an irreversible residual magnetic force between the core housing and the armature.

Abstract: A system for compensating electromagnetic interfering fields is provided that includes two triaxial magnetic field sensors for outputting real sensor signals; six compensation coils, which are arranged as a cage around an object to be protected, and may individually be actuated; a control unit having six inputs, and six outputs, and a digital processor receiving the sensor signals on the input side, and processing the signals to control signals for the compensation coils. The real sensor signals are converted to virtual sensor signals by a first matrix multiplication for mapping the interfering fields at the location of the object. The virtual sensor signals are made to modified signals by an operator describing the controller structure. The modified signals are converted to real control signals by a second matrix multiplication, which control signals are individually fed to the six compensation coils.

Abstract: A method and apparatus provide an improved EM reverberation chamber which facilitates the dynamic three dimensional (3D) manipulation of EM field polarization within the chamber and produces a uniform field distribution inside the chamber. The chamber includes one or more walls with tunable lumped elements. A controller is provided to generate one or more control signals that are applied to the lumped elements and tunes their impedance in response to the one or more control signals. The result is to generate, within the chamber an electromagnetic field that appears to be random or pseudo-random in polarization, but which is sufficiently uniform in magnitude for EM testing.

Abstract: An integrated brushless DC motor and controller including a brushless DC motor having a rotating shaft with a 2 pole permanent magnet affixed to the shaft for rotation thereby in a plane orthogonal to the axis of rotation of the shaft. An X-Y Hall Effect Sensor is carried by a controller mounted on a circuit board attached to the motor and the Hall Effect Sensor is positioned proximate the magnet with the Hall Effect Sensor producing the Sine and Cosine components of the magnetic field as the magnet is rotated by the motor shaft. The electronic controller includes software for determining the motor angle and commutation logic from the Sine and Cosine components generated by the Hall Effect Sensor response to the rotating magnetic field.

Abstract: An internal combustion engine controller comprises a current or voltage source for controlling a potential at a diagnosis position in order to ensure a high-precision fault diagnosis, even if the drive cycle of the electromagnetic load (such as a fuel injector), in the internal combustion engine is shorted. Diagnosis timing is optimally set or the number of determinations for averaging is increased in order to ensure high-precision fault diagnosis without being influenced by unexpected disturbance such as noises. In fault diagnosis of a regeneration circuit into a booster circuit, either an input/output voltage or the regeneration current of a driver of the electromagnetic load is detected.

Abstract: An exciting voltage arithmetic portion calculates an exciting voltage of an electromagnet using a signal of a gap sensor. On the other hand, a sensorless exciting voltage arithmetic portion calculates an exciting voltage of the electromagnet using a signal of the current sensor. The exciting voltage adjusting portion adjusts a mixing ratio between an output value of an exciting voltage arithmetic portion and an output value of the sensorless exciting voltage arithmetic portion corresponding to a gap length. The excitation of the electromagnet is controlled according to an output value of the exciting voltage adjusting portion so as to reduce influences of noises on the gap sensors thereby always achieving a stable levitation control.

Abstract: A control system for controlling and synchronizing a plurality of medium-voltage vacuum contactors comprises a two-level network structure. A dedicated network includes a plurality of servant control units operably coupled to the vacuum contactors and configured to ascertain a plurality of different data and conditions thereof. In addition, the dedicated network includes a master control unit in serial communication with the servant control units and configured to send and receive communications therewith. The master control unit is operably coupled to a control network including a plurality of various control devices. The master control unit is configured to send predetermined data received from the servant control units to the control network. The two-level network structure enables relatively jitter free communication on the dedicated network while not overwhelming the control network with unnecessary data.

Abstract: A solenoid-operated valve device is provided which includes a valve, a solenoid actuator designed to be supplied with electric power from a battery to operate on voltage substantially identical with that outputted from the battery to move the valve, and a controller working to energize said solenoid actuator. Prior to entering a main energization mode to energize the solenoid actuator to open or close the valve, the controller works to supply a low current to the solenoid actuator to create magnetic field therein to assist in energizing the solenoid actuator in the main energization mode quickly at a high speed. The controller may alternatively be designed to step-up the voltage to be applied to the solenoid actuator initially prior to entering the main energization mode.

Abstract: For compensation of a magnetic field in an operating region a number of magnetic field sensors (S1, S2) and an arrangement of compensation coils (Hh) surrounding said operating region is used. The magnetic field is measured by at least two sensors (S1, S2) located at different positions outside the operating region, preferably at opposing positions with respect to a symmetry axis of the operating region, generating respective sensor signals (s1, s2), the sensor signals of said sensors are superposed to a feedback signal (ms, fs), which is converted by a controlling means to a driving signal (d1), and the driving signal is used to steer at least one compensation coil (Hh). To further enhance the compensation, the driving signal is also used to derive an additional input signal (cs) for the superposing step to generate the feedback signal (fs).

Abstract: In a control circuit for at least one actuator, in particular for a capacitive actuator of an injection system of an internal combustion engine, a control current can be applied to the actuator. The control circuit has an inductor, e.g., having a core and having multiple windings, the windings being designed and connected to the control circuit such that a control current flowing into the actuator and a control current flowing out of the actuator each flow through different windings of the inductor, and a magnetic flux induced in the inductor or its core by the control current flowing into the actuator and a magnetic flux induced in the inductor or its core by the control current flowing out of the actuator mutually compensate one another.

Abstract: A dynamic degaussing system includes a magnetic field sensor for generating a sensor signal in response to a sensed magnetic field. The magnetic sensor is coupled to a controller that produces an output signal based on the sensor signal. The controller may include feedforward and feedback control loops. The output signal of the controller controls a magnetic field generator which generates a magnetic field so as to attenuate the sensed magnetic field. According to one aspect of the invention, a vessel is provided with a reduced magnetic signature and a control system for controlling magnetic fields about a podded electric motor. The control system employs feed-forward and feedback control in tandem. The control system may be dynamically adapted to changing physical characteristics of the motor. Control signals are generated in response to sensed or predicted magnetic fields internal to, or external to, the motor.

Abstract: Method for piloting electromagnetic actuators for the control of the valves of an engine; each electromagnetic actuator is provided with at least one respective electromagnet, which is piloted by a common piloting device by means of the supply of an electric current wave which has two, initial and end control portions in which the intensity of the electric current varies rapidly and an intermediate maintenance portion in which the intensity of the electric current remains substantially constant; the method consists of supplying respective electric current waves cyclically to the electromagnets in order to control the valves according to the drive point, and to vary at a control portion of each wave the value of the intensity of the electric current supplied during the portions of maintenance of the other waves in order to limit the variation of the quantity of electric charge distributed overall by the piloting device.

Abstract: An electromagnetic mark device for any type of magnetism encoder applies the electric current magnetic field as the electromagnetic mark thereof. The electromagnetic mark device comprises an insulated base plate and a thin lead wire. The thin lead wire is fixed to the insulated base plate. It is characterized in that the thin lead wire is laid out on the base plate as a circuit in a way of providing a continuously twisted and turned shape with a constant pitch. Hence, alternate magnetic marks are formed with continuous magnetic poles N·S·N·S once the current passes the lead wire. The electromagnetic mark device can be adapted to a linear ruler or a rotary dial in the magnetism encoder to detect a relative displacement, velocity and angular velocity of a moving object so that the present invention can offer more stable signals and more accurate detection of location with being fabricated more easily.

Abstract: So that an actuator drive which holds an actuator element for actuating, for example, a charge cycle valve of an internal combustion engine, in a limit position by a coil, can be switched at the correct time into the other limit position, the energization of the coil is switched off a certain time period before the time at which the actuator element is to be released from the limit position. Here, the time period is selected as a function of the supply voltage of the actuator drive and/or of the coil current during the holding in the limit position. It is also possible to adapt the time period.

Abstract: A method and apparatus is provided for generating an artificial heat sink below ambient temperature for a cryogenic condenser by isothermally magnetizing a paramagnetic fluid and removing the magnetic field thereby creating a temperature drop in the fluid by the magentocaloric effect. The heat of magnetization is converted into mechanical work by initially placing the fluid inside a sealed chamber with a door that opens to a conduit leading into the bore of a superconducting solenoid. When the solenoid is energized with current, it creates a strong axial magnetic field that exerts magnetic attractive forces on the fluid inside the chamber. When the fluid is released by opening the door, it is accelerated through the conduit toward the superconducting solenoid where it becomes magnetized by the increasing strength of the magnetic field.

Abstract: A magnetic flux detector comprises a core member 12 and an armature member 11, and the core member 12 generates a magnetic flux by an exciting coil 13 when the exciting coil receives an excitation current controlled by an excitation current controller 30. The magnetic flux detector further comprises a search coil 14, which is provided in a magnetic path for the magnetic flux, and a magnetic flux calculator 40, which determines the magnitude of the magnetic flux by measuring an electromotive force induced in the search coil 14 by a change in the magnetic flux. The magnetic flux calculator 40 has a potential setup resistor 43, whose resistance B is sufficiently larger than the internal resistance A of the search coil 14 (approximately A=B/3˜B/30).

Abstract: The present invention involves a magnetic embolization apparatus for embolizing an aneurysm of a blood vessel. The apparatus includes a coiled element adapted for insertion within an aneurysm of a blood vessel, the coiled element shaped to be retained within the aneurysm, and one or more permanent magnetic segments carried by the coiled element to internally induce a magnetic field from within the aneurysm to control a magnetic field controllable embolic to embolize the aneurysm.

Abstract: A varying voltage is applied to a conductive winding (61) that magnetically interacts with a magnetic body (60). The varying voltage causes the voltage induced in the winding to have such waveform and magnitude that the integral over time of the induced voltage correlates to desired changes of the induction level (magnetic flux density). The induction level of a magnetic body may be controlled to transition from an initial induction level to a preferred induction level, to maintain a preferred induction level, to reduce fluctuations around a preferred induction level, or to vary with time in a preferred manner. The invention is especially applicable to ordinary current transformers, which may be demagnetized automatically while remaining in service. Once demagnetized, ordinary current transformers are able to accurately sense nonsymmetrical currents, including d-c currents and a-c currents that have d-c components.

Abstract: With the objective of preventing variations in sensitivity even if samples to be inserted between an upper coil and a lower coil opposite to each other are different in body frame, a pre-scan is effected on a sample in a state in which the sample is placed in a space defined between the upper coil and the lower coil, and reflected waves sent from the coils are detected by a directional coupler. Further, a comparison controller controls an attenuator so that the voltages of the reflected waves are equalized. Afterwards, a main scan is carried out.

Abstract: An electro-magnet (11) is spatially coupled with respect to a support armature (15) by an operational gap (16) and their relative movement is automatically compensated by controlling a current (14) supplied to the electromagnet (11). The current (14) and hence a magnetic field (F) are controlled by a current controller (13) which incorporates a transfer function and is operated in a feedforward path (19) by a signal (18) from a sensor (17) which detects variations in the gap (16) between the electro-magnet (11) and the support armature (12). The current controller (13) is also operated in a feedback path (22) by a signal (21) from a sensor (20) which detects variations in the flux intensity of the magnetic field (F).

Abstract: The invention relates to a manufacturing process of an electrical conductor or circuit compensated for radio interferences, including those from the electrical circuit itself. An application of a semi-conductor material (2) of resistivity coefficient allowing the external surface of the conductor (1) to the electrical circuit to be maintained at a static electrical potential near to that of the conductor (1) and the random electrical discharge currents to be absorbed is made to eliminate the interface micro-discharge interference phenomena. Application in the field of HiFi, home automation, instrumentation.

Abstract: An electro-magnet (11) is spatially coupled with respect to a support armature (15) by an operational gap (16) and their relative movement is automatically compensated by controlling a current (14) supplied to the electro-magnet (11). The current (14) and hence a magnetic field (F) are controlled by a current controller (13) which incorporates a transfer function and is operated in a feedforward path (19) by a signal (18) from a sensor (17) which detects variations in the gap (16) between the electro-magnet (11) and the support armature (12). The current controller (13) is also operated in a feedback path (22) by a signal (21) from a sensor (20) which detects variations in the flux intensity of the magnetic field (F).

Abstract: A method for initializing an actuator valve (12) and controlling the valve (12) using current command control (100) or voltage control including an estimate of back emf (200). A series of low voltage pulses (304) is applied to one of the solenoid coils (20, 24) in the actuator valve (12) according to the natural frequency of the armature (16) movement in the actuator valve (12). The current command control system calculates a desired force (Fem) and divides the force into closing and opening components Fem—c, Fem—o, for calculating a desired current command Ic_cmd, Io_cmd, for each of the solenoid coils. The back emf control system divides the current signal into close and open components, Io, Ic, that are individually processed and combined with a back emf estimate for each of the open and close solenoids, ec, eo. The result is a desired voltage command, vc*, vo*, for each of the solenoids that is communicated to the power stage (34) in order to operate the armature (16) as desired.

Abstract: A method for cleaning a solenoid-operated regulator valve wherein command current applied to a solenoid actuator establishes a defined response of a valve. Cleaning current pulses applied to the solenoid establish a response that does not interfere with the effectiveness of the valve function. The pulse width, pulse amplitude, pulse direction and pulse period are determined by the degree of contamination of the valve environment.

Abstract: A method and apparatus for establishing and maintaining a preferred induction level in a magnetic body. A varying voltage is applied to a conductive winding (61) that magnetically interacts with a magnetic body (60). The voltage is controlled during a first phase in such a way that the magnetic induction level of the magnetic body is changed from an unknown induction level to a known induction level. During a second phase, the induced voltage across the winding is controlled so that the induction level is changed from the known induction level to the preferred induction level. An optional third phase may be utilized, during which the average value of induced voltage is kept near zero in order to keep the induction level near the preferred induction level. The invention is especially applicable to ordinary current transformers, which may be demagnetized automatically while remaining in service.

Abstract: A current control system for a linear solenoid for feedback-controlling an output voltage value on the basis of a difference between a command current value to the linear solenoid, as set according to a vehicle running state, and a feedback current value, as produced by monitoring a current value to be really fed to the linear solenoid, including: a decision circuit that decides whether or not the resistance value of the linear solenoid can be calculated; a real resistance value calculating circuit that calculates a real resistance value on the basis of a signal coming from the decision circuit, the command current value and the output voltage value; a comparison circuit that compares the calculated real resistance value and a resistance value in a memory unit; and a correction circuit that corrects the resistance value in the memory unit on the basis of the comparison result from the comparison circuit. The output voltage value is outputted on the basis of the corrected resistance value.

Abstract: A coil for bucking out undesired ambient time varying magnetic fields in the region of the gap in an MRI magnet structure is energized by a servo loop controlled by a Flux Lock Circuit having, in turn, a closed loop circuit controlled by a magnetic sensor. The sensor has a pair of windings energized in parallel by a 2 KHz oscillator, the windings being oppositely poled to induce zero voltage in a third winding to which feedback signals are supplied. Extraneous fields cause an asymmetry in the current passing through the pair of windings which asymmetry is accompanied by the generation of second harmonic components which are detected and fed back to the third winding for restoring symmetry. The signal fed back to the third winding is also used for controlling the current supplied to the field bucking coil.

Abstract: A magnetically levitated vibration damping apparatus includes a table having a flat board of a magnetic material, an electromagnetic actuator for applying magnetic attractive forces to the flat board to levitate the table, a displacement sensor for detecting relative displacement between the flat board and the electromagnetic actuator, an acceleration sensor for detecting absolute acceleration of the table, and a control system for controlling a current supplied to the electromagnetic actuator based on signals from the displacement sensor and the acceleration sensor according to a first control rule for controlling a gap between the flat board and the electromagnetic actuator based on the signal from the acceleration sensor and a second control rule for controlling vibrations of the table based on the signal from the acceleration sensor, the second control rule including stability control of relative displacement of the table.

Abstract: A control method permits the operation of multiple superconducting magnetic coils so as to move a magnetic object to precisely specified locations within the body under command of a physician-operator observing the motion with live fluoroscopic imaging fused with more detailed preoperative imaging of some other kind. A computer contains the preoperative images and the fluoroscopic images, as well as the means to effect changes in the coil currents so as to accomplish the desired magnetic object motion and positioning. The control method operates the coils in pairs on opposite sides of the body in a manner to minimize the necessary current changes, thus avoiding the quenching of the superconducting coils. Combinations of these pairs can execute motion of the magnetic object in any direction in an impulsive manner and with high precision. The method should function well and provide advantages with coils which are not superconducting as well.

Abstract: An apparatus for monitoring the inductance of a coil (L1) which is not part of a resonant circuit including a second coil (L2) connected in series with the first mentioned coil and a resonant circuit which is formed by connection of a capacitor (C5) to the second coil, or optionally (C2) to a third coil (L3) which is in a mutually inductive relationship with the second coil so that the second and third coils act as the primary and secondary coils of a transformer (M), a device (1) for injecting into the circuit containing the first mentioned and second coils an a.c. signal of substantially constant peak voltage amplitude having a frequency within the resonance peak of the resonant circuit, and an amplitude detector (5) for measuring the amplitude of the voltage across a component of the resonant circuit. The apparatus may be employed as so-called integral control in closed loop control of the suspension of an object by the first mentioned coil.

Abstract: The present invention provides a magnetic compensation system and a method of utilizing a magnetic compensation system to neutralize magnetic fields in an environment of a magnetically sensitive instrument. A magnetometer is used to sense magnetic field components in the environment and convert them into a signal. The signal is filtered to remove frequency components associated with the resonant frequency of the compensation system. The filtered signal is amplified by a signal amplifier and amplified by a power amplifier to generate current to drive a semi-Helmholtz coil disposed in the environment of the instrument. Magnetic fields are produced by the semi-Helmholtz coil which neutralize the sensed magnetic fields. The filter may be implemented using either a low-pass filter or a notch filter with notch frequencies set to the resonant frequency and harmonics thereof.

Abstract: In a magnetic bearing apparatus, a rotating member having an axis of rotation along the horizontal direction is supported by a pair of radial magnetic bearings each including a plurality of electromagnets in the radial direction with clearances with the rotating member in two portions in the axial direction. The apparatus comprises a pair of position detecting sensors for detecting the displacement in the radial direction of the rotating member in the two positions in the axial direction of the rotating member and a control device for controlling magnetic attraction forces produced by the electromagnets on the basis of output signals from the respective sensors.

Abstract: A magnetic detector includes a magnetizer generating a magnetic field; a first magnetic sensor for detecting a leakage flux resulting from a magnetically defective portion of an object moving in and relative to the magnetic field; a low-pass filter for extracting a low-frequency signal component contained in the signal output by the magnetic sensor, the low-frequency signal component being indicative of a floating flux which crosses the magnetic sensor and is a result of the object moving through the magnetic field; an amplifier for amplifying the extracted low-frequency signal component; a compensating coil excited by the amplified low-frequency signal component output by the amplifier, for generating a magnetic flux which cancels out the floating flux crossing the magnetic sensor; a high-pass filter for extracting a signal resulting from the magnetically defective portion and contained in the signal that is output by the first magnetic sensor; an output amplifier for amplifying a signal output by the high-p

Abstract: Alternating current provided at an angular frequency (.omega.) for powering an electromagnet force actuator having a leakage inductance (L.sub.1) whereby the alternating current is controlled by a voltage reference and a feedback signal indicative of the controlled current and amplified at a gain factor (K.sub.1) having a magnitude greater than or equal to the leakage inductance (L.sub.1) times the angular frequency (.omega.), whereby the electromagnet has a flat or positive spring rate.

Abstract: The invention relates to a method and arrangement for reducing to a minimum the electrical alternating fields generated in the surroundings of a visual display unit (1). The visual display unit includes a voltage connected part (5), on which undesirable voltage variations occur. A smoothing high voltage capacitor (C3) of high capacitance is connected to the voltage connected part (5). Connected between the high voltage capacitor (C3) and earth is a compensating circuit (20) which functions as a negative capacitor whose capacitance is greater than the capacitance of the high voltage capacitor (C3) by a given factor.

Abstract: An arrangement for obtaining flux rate information in a magnetic: circuit including passive means connected across a flux rate sensor for implementing control of said flux rate. The passive means being a tuned magnetic flux rate feedback sensing and control arrangement wherein impedance is tuned and the energy loss characteristic is adjustable. The selection of inductance and capacitance values provides tuning and the selection of resistance affects the energy loss characteristics.

Abstract: An arrangement using sensing coils for obtaining flux rate of change information in a magnetic circuit. The arrangement can be used for vibration attenuation in a magnetic forcer system. Active (electric powered) circuitry is used to implement closed loop control of flux rate. The control loop is "tuned" for attenuating a narrow range of vibration frequencies. The arrangement can be applied to magnetic forcer/suspension systems in which vibrations due to magnetic, mechanical/magnetic runouts, system mechanical resonances, or external vibration sources are present.

Abstract: A magnetic levitation and transport system has a plate-like moving element (SFT) which is moved by a linear motor disposed in a stator (STT). The moving element is moved vertically by first through fourth electromagnetic devices (MGV.sub.10 -MGV.sub.41), and fifth and sixth electromagnetic devices (MGH.sub.10 -MGH.sub.21) exert forces on the moving element in a horizontal direction perpendicular to the direction in which the moving element is moved. Gaps between the moving element and the electromagnetic devices are detected by gap sensors which produce gap data. In the vertical direction, for example, attractive force commands (f.sub.V1 -f.sub.V2) are produced from the outputs from a circuit for calculating the amount of feedback (10) which is supplied with the gap data (XV.sub.1 -XV.sub.4) and also with the output from a variable gain g.sub.V (l) generator (60) to which the position (l) of the center of gravity of the moving element is supplied.

Abstract: An arrangement using sensing coils for obtaining flux rate of change information in a magnetic circuit. The arrangement can be used for vibration attenuation in a magnetic forcer system. Active (electric powered) circuitry is used to implement closed loop control of flux rate. The control loop is "broadband" since a broad range of vibration frequencies are attenuated. The arrangement can be applied to magnetic forcer/suspension systems in which vibrations due to magnetic mechanical/magnetic runouts, system mechanical resonances, or external vibration sources are present. The arrangement is particularly applicable for systems with a large number of varying vibration frequencies.

Abstract: Apparatus for selectively magnetizing and demagnetizing a small tool, such as a screwdriver, by providing an enclosure having a first opening to receive a tool for magnetizing a desired portion of the tool, and a second opening to receive a tool for demagnetizing a selected portion of the tool. The demagnetizing opening is surrounded by a demagnetizing coil that is directly connected through a first switch with a source of alternating current to provide an alternating magnetic field for demagnetizing a tool inserted into the demagnetizing opening. The magnetizing opening is surrounded by a magnetizing coil that is connected through a second switch with the source of alternating current and through a rectifier circuit to provide a continuous magnetic field for magnetizing a tool inserted into the magnetizing opening. Pilot lights are coupled with the respective magnetizing and demagnetizing loops to indicate when the respective loops are energized.

Abstract: A device for positioning a body (5) by means of at least two electromagnets (13, 15). A position sensor (29) measures the size of an air gap (23) between one of the electromagnets (13, 15) and a guide beam (1). An output signal of the position sensor (29) is applied to a linear electronic control unit (35) which passes a control current through the electromagnets (13, 15) in dependence on a difference between the measured and a desired size of the air gap (23). An electronic root extractor (37) is connected between the control unit (35) and the two electromagnets (13, 15). An output signal of the root extractor (37) has a value equal to the square root of a control signal coming from the control unit (35). In this way a force exerted by the electromagnets (13, 15) on the guide beam (1) is proportional to the value of the control signal, so that a control is obtained with the linear control unit ( 35) in which the stiffness and bandwidth are independent of the value of the control current.

Abstract: An AC electric field emission suppressor for use in a CRT imaging system cancels the ripple voltage on the ultor voltage that generates the undesired emission. Ripple-cancelling pulses are derived from the horizontal deflection circuit and are capacitively coupled through the CRT wall to cancel the ripple voltage and suppress the undesired emission.