Abstract: The objective of the present invention is to provide an information processing device that is operable by a battery and which suppresses the generation of standing waves and has little radiation noise. In the information processing device of the present invention having means for connecting to a battery pack that stores a battery for supplying power to the information processing device, there is one or more capacitive element (for example, a capacitor) in the proximity of the terminals of the positive and negative poles of the battery when the battery pack is connected to the information processing device, and it is possible for at least the terminal of the positive pole of the battery or the terminal of the negative pole of the battery to be connected electrically to the ground of the information processing device by way of this capacitive element.

Abstract: There is disclosed an apparatus and method that appear to alter the effects of gravity by generating a magnetic field that causes an upward/downward magnetic force to act on a substance in a container. This offsets or adds to the downward force of gravity, to simulate a low-gravitational or excess-gravitational environment inside the substance.

Abstract: A magnetization yoke having an exciting coil wound thereon is arranged to hold a magnetic member and a metal ring so that a magnetic flux passes through and magnetizes the magnetic member in the portion held by the magnetization yoke for successively magnetizing the magnetic member along the circumferential direction thereby multipolarly magnetizing the magnetic member in the circumferential direction. Thus, a magnetic encoder having large magnetization strength and a small magnetization pitch error, a wheel bearing employing the same and a method of manufacturing a magnetic encoder can be obtained.

Abstract: A sequential driving type degaussing circuit includes a rotation direction and angle detector for generating each pulse by using a pair of photo sensors and slits to detect a rotation angle and a rotation direction of a television set when it is rotated manually by a viewer; a microcomputer for judging the direction and the angle of the television as rotated manually on the basis of an output pulse of the rotation direction and angle detector, judging the rotation direction and angle of the television when it is rotated automatically by a motor, and outputting a control signal to sequentially drive the degaussing circuit if it is judged that the television set was rotated more than a predetermined angle; and a degaussing circuit unit for sequentially driving one by one a plurality of degaussing circuits under the control of the microcomputer and performing a degaussing function of a CRT.

Abstract: A bulk degaussing apparatus and method for erasing magnetic media of various sizes. A plurality of fixed magnetic poles are predisposed around a gap for projecting magnetic flux across the gap such that the spacing of the poles is provided at roughly equal intervals or sets of intervals across the gap to form sets of magnetic fields at the staggered intervals. A media passage is provided such that across the width of the passage at every point, media passing therethrough is linearly exposed to the magnetic fields provided through the gap. An adapter constrains location of the media passing through the gap by way of the media passage such that the plurality of magnetic poles effectively degausses regions formed between the poles. Placement of the magnetic poles is provided with partial overlap of facing poles on opposite sides of the pathway of the media passage. Two or more multi-pole degaussing regions provided with differing orientation avoid regional weaknesses or singularities in the magnetic field.

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: A compliant structure, such as a rubber pad, is used to simplify the resonance pattern of a vibrating object. According to one aspect of the invention, a support system is provided with a device for applying electromagnetic forces to the vibrating object, and the compliant structure is used to support the electromagnetic device. The electromagnetic device is positively controlled as a function of (A) the position of the vibrating object and (B) the position of the electromagnet. The compliant structure may also be used to further attenuate high frequency vibration transmission. According to one aspect of the invention, the compliant structure permits some rocking and/or rotational motion of the electromagnet to simplify the vibration transmission mechanism. According to another aspect of the invention, the compliant structure operates as a slightly-damped stiff spring in the axial direction of the electromagnet.

Abstract: A voltage source connected in the secondary circuit of a current transformer is controlled so as to provide a secondary current that is accurately and continuously proportional to a primary current that is either pulsed d-c electric current or pulsed a-c electric current. Similar to U.S. Pat. No. 6,180,697, the voltage source is controlled so as to compensate for the voltage drop caused by secondary current flowing through secondary circuit impedances, thereby reducing the effective burden of the secondary circuit. However, to prevent the accumulation of error when measuring pulsed currents that are not symmetrical, the present invention turns the burden-reducing compensation off whenever secondary current is near zero amperes, thereby providing for the decay of current error and magnetic flux, so that current error remains very small and the current transformer does not saturate.

Abstract: A system and method for removing unwanted magnetic flux from a superconductor. A device can generate a controllable electric field potential using an asymmetric electric field potential to efficiently remove the magnetic flux in different directions in the superconductor.

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: A rodent control device generates a pulsating, interrupted electromagnetic field via one or more coil(s) and induces it onto the power line wiring in a building via core(s) linked to the coil(s). The rodent control device circuit is microprocessor controlled which allows automatic sensing of line voltage cycle rates and precise control of coil switching circuitry. The coil(s) are connected to the microprocessor to provide a coil monitoring signal via which the microprocessor detects abnormalities in the coil(s) such as shorts or open circuits. Upon detection of such an abnormality, the microprocessor shuts off control signals to the coil and to an LED indicator until a normal coil condition is sensed. The microprocessor also provides a timed rest signal for shutting down the device for, for example, 2 minutes out of every 6 minute period as a power saving feature.

Abstract: An improved system and method for floating an object is disclosed by the present invention. The system includes an electromagnetic source for accommodating a wide weight-range of objects to be floated and for providing intelligent, responsive control of the system. The electromagnetic source includes a single Hall effect sensor for sensing the position change of the floating object and a microprocessor for intelligently controlling the floating object so that a better, simpler, and more stable operation is achieved. With the implementation of the microprocessor, a user friendly interface for initially placing the object on the system is achieved, and no complicate adjustments of the system are required to float a new object.

Abstract: There is disclosed an apparatus for generating gravitational force/gravitational field, which, for example, may be used in space and avionics applications, said apparatus comprising a capacito-inductor, constituted by at least two coils, made of two metal layers with two dielectric layers provided therebetween, said coils being wound in predetermined turns on a cylindrical core of an insulating material; a magnet placed at the center of said capacito-inductor for creating and passing radial magnetic field through the capacito-inductor; power supplies for applying equal and opposite current pulses at the end terminals of said two metal layers of the capacito-inductor, and also for applying predetermined voltage between the same end terminals of said metal layers; and a drive source for rotating the capacito-inductor, journalled between two covers.

Abstract: A method for starting up an electromagnetic actuator operating an engine cylinder valve. The actuator has two spaced electromagnets, between which an armature, connected to the cylinder valve, is reciprocated against a restoring spring from a center position to lie against a magnet pole face. An ECU alternatingly supplies the electromagnets with a capturing current, the level of which is regulated as a function of the approach of the armature toward a pole face, as detected by a sensor assembly. A reference temperature is detected for the magnets, and, at a normal temperature, the armature starts oscillating due to the alternating energization of the electromagnets, and is brought into contact with a pole face. Or, at a low temperature level, one of the electromagnets is supplied with a high current pulse.

Abstract: The device comprises means for detecting an unscheduled movement of the movable core of an electromagnet during a holding phase. For this, a control and regulation circuit monitors the current flowing in at least one coil of the electromagnet. When, during a holding phase, the current flowing in the coil is greater than a setpoint value and either remains so during a preset time or is increasing, an unscheduled movement is then considered as being detected and the device makes the electro-magnet switch to inrush phase with a much higher current.

Abstract: A combined externally pressurized gas and magnetic bearing assembly (3) includes an externally pressurized gas bearing (9) and a magnetic bearing (8) that are integrated together so as to have component parts common to both of the externally pressurized gas bearing (9) and the magnetic bearing (8). The externally pressurized gas bearing (9) or the magnetic bearing (8) may be disposed within an axial extent of the magnetic bearing (8) or the externally pressurized gas bearing (9), respectively. A spindle device (1) utilizing the combined externally pressurized gas and magnetic bearing assembly (3) is also provided which includes a housing (2) for supporting a main shaft (4) rotatably through the combined externally pressurized gas and magnetic bearing assembly (3). This combined externally pressurized gas and magnetic bearing assembly (3) can be applied not only to the radial bearing, but also to the axial bearing.

Abstract: An electrical circuit for producing a substantially constant pulsed magnetic field for repelling rodents includes an electromagnetic coil for generating a magnetic field in response to alternating current (AC) power applied to terminals of the coil and a gated triac connected in series electrical circuit with the coil for controlling application of AC electric power to the coil. A gating circuit develops a sequence of gating pulses for application to the triac with each of the gating pulses having a substantially constant voltage value extending for a time duration of a plurality of cycles of AC power for continuously exciting the coil with AC power during the extent of each gating pulse.

Abstract: An apparatus (10) for altering the magnetic state of a permanent magnet comprises a coil inductor (26) for generating and applying an induced magnetic field to the permanent magnet. The coil inductor (26) is provided in circuit between two charge storage elements (20, 24). The apparatus also comprises a discharge control circuit (28) for transferring charge alternately in opposed directions between the storage elements (20, 24) though the coil inductor (26) to generate a series of alternating polarity magnetic field pulses (167, 191) of decreasing magnitude in the coil inductor (26) or to generate a single magnetic pulse of relatively high strength. The apparatus (10) can be operated as either a magnetising or demagnetising device and is capable of demagnetising a column of 200 or more magnets.

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 suspension system for magnetically suspending an object O comprises an electromagnetic coil L having an axially extending core 13 of magnetically permeable material and a permanent magnet 14 disposed on its axis. A permanent magnet 10 is also provided in the object O and is arranged such that it is in attraction with the permanent magnet 14 on the coil L, and with the magnetically permeable core 13 so that the object O is suspended at a position below the coil L by the attractive force. Sensors 15,16 on the coil L detect the magnetic field of the permanent magnet 10 in the object O, and provide signals to a control circuit, which applies current to the coil L to attract the object O when the detected field is below a predetermined limit and to repel the object when the detector field is above a predetermined limit.

Abstract: In a method of magnetizing a cylindrical body comprising a substantially isotropically distributed material according to the present invention, the method comprises the steps of: applying a magnetic field to the body; and varying the magnetic field circumferentially around the body thereby to achieve at least over a part of the cylinder a generally sinusoidal magnetization circumferentially. Thus, can advantageously be achieved a sinusoidal flux density distribution for, in particular (though without limitation), rotors for electric motors in the air gap surrounding the rotor. The resultant sinusoidal back-emf waveform is ideal for high precision servo applications. In addition, when a high pole number is adopted, such bodies can be mounted on air cored rotor-hubs, which enable a substantial reduction in inertia, without substantial loss of performance.

Abstract: A method and apparatus for treating an object includes generating a magnetic field wherein at least some of the magnetic field is characterized by changes in amplitude of the magnetic field from an average non-zero value of the magnetic field. The object is placed in the influence of the magnetic field for a sufficient time to subject the object to the changes in amplitude of the magnetic field. A method and apparatus for determining a preferred field intensity of the magnetic field is also included.

Abstract: A magnetic switching device, includes a first electrode, a second electrode, and a nanoparticle having a magnetic moment and being disposed between the first and second electrodes. At least one of the first electrode and the second electrode includes a magnetic material which has a net spin polarization in its conduction band for injecting, into the nanoparticle, an electrical current including a net spin polarization for overcoming the magnetic moment of the nanoparticle upon selection of a predetermined magnitude for the electrical current.

Abstract: A method and apparatus for ramping current in an electromagnet in which a coil is used to generate the magnetic field provides rapid changes in the generated magnetic field. The method allows a change in current in the coil to be accomplished more rapidly than by applying a step change in voltage, when superconducting coils subject to quenching are used or when nonsuperconducting coils subject to other physical limitations are used. The method requires that both the current I(t) through the coil and the first derivative of the current vary with respect to time t during the ramping period, so that magnitude of the derivative of the current is higher when the magnitude of applied current is lower, lower when the magnitude of the applied current is higher. One variation of this method supplies (or removes) a constant amount of power from the magnetic field of the magnet, while another variation compensates for both self-generated eddy current losses and self-generated high field effects.

Abstract: An electromagnetic actuator has a large driving force and a good response speed and an image pickup apparatus obtains an image of a high resolution even by using a solid state image pickup device with a small number of pixels. The actuator comprises permanent magnetic field generating units for generating permanent magnetic fields and a current path forming unit which is relatively movable for the permanent magnetic field generating units and forms a current path which crosses the permanent magnetic fields by a current according to an input control signal. The permanent magnetic field generating units of the actuator generate two permanent magnetic fields in the directions which cross each other by, for example, two pairs of magnets. The current path forming unit has two coils each crossing the permanent magnetic field and winding shafts of those coils exist almost on the same line.

Abstract: An electronically controlled device, such as a fuel injector, includes a first solenoid and a second solenoid attached to the injector body. An electrical circuit is attached to the injector body, and includes a positive terminal and a negative terminal connected to the first solenoid and the second solenoid. The electrical circuit permits energization of one of the first solenoid and the second solenoid when electrical current flows in either direction between the first terminal and the second terminal. However, the electrical circuit permits energization of the other of the first solenoid and the second solenoid only when current flows in a single direction between the first terminal and the second terminal.

Abstract: Motion recognition processes are disclosed, in particular for regulating the impact speed of an armature on an electromagnetic actuator with at least one electromagnet having at least one pole face (4) and connected to a controllable power supply, and with an armature (5) connected to a regulating element to be actuated which when power is supplied to the electromagnet, is moved against the force of a restoring spring (7) in the direction of the pole face of the electromagnet from a first switching position to a second switching position in which it stops against the pole face. At least one sensor (11) detects in a defined air gap zone of the pole face a progressive attenuation of the magnetic field as the armature approaches and generates a corresponding signal.

Abstract: A magnetization magnet (11) is brought into contact with or close to the outer circumferential surface of a tire (12) that has a steel belt in its outer circumferential portion, and is relatively moved along the circumferential direction of the tire (12) so that the magnetic field generated by the magnetization magnet (11) runs in the circumferential direction of the tire. (12), thereby magnetizing the tire (12). The entire perimeter of the outer circumferential portion of the tire (12) is continuously magnetized in one direction along the circumferential direction. After the polarities of the magnetization magnet (11) are inverted with respect to the circumferential direction of the tire (12), an angle range smaller than 360.degree. on the outer circumferential portion of the tire is continuously re-magnetized in a direction opposite to the one direction.

Abstract: A rotor magnet of a three-phase reluctance magnet motor is magnetized by coupling two of the three outer terminals (RS), and feeding a positioning current between the outer terminals RS and a third terminal (T) for positioning the rotor at a magnetizing position with reluctance torque. Then, rotor is kept from moving by holding the shaft of the rotor with the rotor positioned at the magnetized position. Next, the outer terminals RS are separated and magnetizing current is fed between the outer terminals R and S to magnetize the rotor magnet.

Abstract: An apparatus for deactivating a surveillance tag comprising a first coil located in a first plane, a second coil located in a second plane, and a third coil located in a third plane such that the third plane intersects the first and second planes at an angle that is greater than zero degrees and less than ninety degrees.

Abstract: The arrangements essentially comprise an antenna element placed in the vicinity of a radiating conductor of the equipment in such a manner as to absorb the electromagnetic energy reaching it by coupling with the radiating conductor.

Abstract: A system and method for setting the activation state of electronic article surveillance markers, tags, and labels being transported on a conveyor system is provided. The system includes a pair of electromagnetic transmitting coils mountable on opposite sides of a conventional conveyor section, an electronic controller, and can include a remote external controller for manual operation. The electromagnetic transmitting coils are mounted within sensor housings that include one or more sensors to automatically sense an article traveling on the conveyor system and trigger the transmission of preselected activation or deactivation electromagnetic pulses when the article is in the proper location. The system can include an inhibiting sensor input to prevent the automatic transmission of an activation/deactivation pulse for specific preselected articles. The system includes a logic scheme to preselect and shape the activation or deactivation electromagnetic pulse.

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: Automatic gain control is provided for a control means for controlling a magnetic actuator for an elevator horizontal active suspension. The gain is varied depending on the drive current in the coil of the electromagnet of the magnetic actuator, the airgap of the magnetic actuator, or both.

Abstract: A lift pin 95 for dechucking a substrate 15 held to a chuck 50 by residual electrostatic charge, the substrate being processed in a plasma formed using RF currents, is described. The lift pin 95 comprises (a) a movable elongated member 110 having a tip 115 suitable for lifting and lowering the substrate 15 off the chuck 50, and capable of forming an electrically conductive path between the substrate 15 and a current sink 105. The electrically conductive path comprises at least one of the following: (1) a frequency selective filter capable of filtering RF currents flowing therethrough so that substantially no RF currents flow through the filter; or (2) a resistor having a resistance sufficiently elevated to reduce the voltage caused by RF currents flowing therethrough, by at least about 50%.

Abstract: A non-burnout controller for a switching coil is disclosed. The controller has a pulse timer, a relay switch, and an actuation switch. After being reset and actuated, the pulse timer defines a pulse having a predetermined pulse period. The relay switch has a switch actuation input for receiving the pulse and first and second switch outputs for being electrically coupled to first and second taps of the switching coil. The relay switch places a switching voltage across the outputs during the pulse period such that the switching coil has a switching current running therethrough. The relay switch places a substantially zero voltage across the outputs before and after the pulse period such that the switching coil has substantially no switching current running therethrough. The actuation switch has first and second positions. Upon being changed to the first position, the actuation switch resets the timer, whereby the switching coil has substantially no current running therethrough.

Abstract: This invention pertains to sensorless measurement of electromagnetically induced displacement in actuators and similar units. Primarily, the device imposes a constant frequency and amplitude excitation sine wave on a coil through a fixed impedance of a drive isolation network. The amplitude and phase of the voltage across the coil fluctuate depending upon the coil's inductance. This variation in the value of the inductance is dependent upon the change in magnetic flux density generated by the coil current and the displacement in air gap between the coil pole and armature. Accordingly, a measurable magnitude of displacement can be controllably imposed upon a system of solenoids. The displacement is thus measured and set without the use of extrinsic sensors.

Abstract: This invention provides a method and apparatus for agitating magnetic particles, suspended in a solvent using an alternating magnetic field gradient. The apparatus has a housing chamber capable of holding one or more vials containing suspended paramagnetic particles, one or more magnetic field generating devices surrounding the housing chamber and a controller device for controlling the length of time and position of the magnetic field generated.

Abstract: A method of adjusting the position of rest of an armature of an electromagnetic actuator, reciprocated against the force of resetting springs by an alternating energization of two spaced electromagnets; the position of rest being assumed by the armature in the de-energized state of the two electromagnets. The method includes the steps of detecting and determining actual values of an impact indicator representing an impact behavior of the armature as the armature impacts on the pole face of the capturing electromagnet; comparing the actual values derived from both electromagnets with predetermined desired values to form deviation values between the actual and the desired values; and, if deviation values are present, shifting the position of rest of the armature by an adjusting device until the actual values derived from both electromagnets correspond to a predetermined desired value.

Abstract: The arrangement for the control of an electromagnet is intended for an electromagnet consisting of a Stationary core 7, a pickup coil 1 through which current flows temporarily after the switch is closed, a holding coil 2 through which current flows during the operating state, as well as a moveable armature 8 moving in relation to the core 7. Within a magnetically responsive switching circuit 5, which is connected in series with the pickup coil 1, a coupling sensor 22 is included, consisting of at least one winding which is linked to at least a part of the magnetic field of the electromagnet at least then when the air gap is open. At the instant when the air gap is closed, the voltage spike induced in the sensor coil 22 switches a controllable semiconductor 11, connected in series with the pickup coil 1 into a state of high resistivity via an electronic switching circuit arrangement.

Abstract: An apparatus and a method for analyzing the physiological state of a sample of a living organism of eucaryotes and procaryotes, e.g.

Abstract: The control circuits for the electronic flow meter which are the subject of this invention and whose purpose is to meter with precision the flow through a pipe, eliminating disturbances caused by the metering procedure use, consist of an excitation block (2) of coils (B1 and B2) for the magnetic circuit and a processing block (3) for the metering signal which is captured through sensors (S) arranged orthogonally to the magnetic circuit pole components.

Abstract: A chucking magnet magnetizing method and magnetizing apparatus with which it is possible to carry out magnetization so that the magnetic attraction forces of chucking magnets are uniform even when there is some dispersion among products in the difference in height between the hub support and the chucking magnet are disclosed. Magnetization of a chucking magnet is carried out with the magnetizing power of a magnetizing device varied according to the difference in height between a hub support and the chucking magnet. There are provided a dimension measuring device for measuring the difference in height between the hub support and the chucking magnet and a varying device for varying the magnetization power from the magnetizing device based on measured values form the measuring device.

Abstract: A method and device for detecting full magnetization of an electro-permanent magnet which includes at least one permanent magnet part and at least one coil. Current is passed through the coil over a certain period of time in order to magnetize the electro-permanent magnet. The current through the coil of the magnet is measured during magnetization, and an increase of the derivative of the current curve is detected. A signal is given to an operator or computer if an increase in the current derivative is detected, which indicates full magnetization of the electro-permanent magnet.

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: 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: An apparatus for making permanent magnet material magnetizes a body of material including a primary winding which has portions wound on a first core carrying current in a first direction creating a first field of flux and a secondary winding having portions wound on a second core wherein the secondary winding carries current in a second opposing direction to create a second field of flux. Since the currents are flowing in opposing directions, the secondary field of flux is directed to oppose the first field of flux. The result of this is that the magnetizer is capable of controlling the width of the pole to pole transition region for matching the stator geometry and thereby nearly eliminating cogging torque and reducing ripple torque.

Abstract: An electric control circuit of an electromagnetic clutch includes a relay-controlled, two-position switch which operates, in response to a power source being disconnected from the switch relay and the clutch, to establish a path to ground through which the induced voltage of the clutch may be dissipated to thereby speed up the disengagement of the clutch once power thereto is discontinued. The control circuit may be that employed in a self-propelled forage harvester equipped with a metal detector, the latter including a normally closed relay switch which opens in response to metal being sensed to thereby de-energize the clutch and two-position switch relay.

Abstract: A marker for use in a magnetomechanical electronic article surveillance (EAS) system is made by mounting a magnetostrictive element in a housing adjacent to a biasing element that is magnetized to a degree of magnetization that is less than saturation. The resonant frequency of the marker is detected. If the detected resonant frequency does not match a predetermined operating frequency of the EAS system, the degree of magnetization of the biasing element is adjusted so as to tune the resonant frequency of the marker to the predetermined operating frequency.

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.