Abstract: Apparatus and method for increasing sweep angle of a rotary actuator in a disc drive. The actuator supports a head adjacent a surface of a disc and an actuator coil adjacent a permanent magnet assembly. The actuator coil has first and second active lengths which magnetically interact with adjacent first and second magnet portions of the permanent magnet assembly, with the permanent magnet assembly generating a magnetic flux reversal at a transition zone between the first and second magnet portions. The head is moved by applying current in a first direction to move the actuator coil in a selected coil direction, thereby causing a selected one of the first and second active lengths to cross the transition zone. The polarity of the current is then reversed so that the current is applied in a second direction opposite the first direction, which causes the actuator coil to continue to move in the selected coil direction.

Abstract: A system that extends the life of bearings that support a primary payload and operate in oscillatory mode. The system integrates the primary payload, a reaction mass and the bearings into a single support structure so that constant hydrodynamic lubrication of the bearings is achieved even during stopping and reversal of the primary payload. This is accomplished by allowing the bearings to rotate continuously in one direction while the primary payload is oscillated. Torque compensation may be provided by applying an opposite torque to the reaction mass to minimize the torque disturbance experienced by the support structure.

Abstract: A system for controlling the movement of a movable member with respect to a stationary member, such as is found in a vibration welding apparatus. The system may include a force controller that converts desired force command signals into desired flux command signals and a flux controller that controls the flux in a magnetic core of the stationary assembly to effect the desired movement of the movable member. The stationary assembly may include a plurality of magnetically uncoupled E-cores of paramagnetic material.

Abstract: Motor driven adjustment device with a control unit (2; 2') for controlling a motor driven unit (4) wherein an acoustic signal generator (6, 6') which produces an acoustic signal upon activation of the motor driven unit (4) is coupled at an output (21, 23) of the control unit (2; 2').

Abstract: Disclosed is the drive apparatus for the powder feeder, which has; the duty ratio control circuit 12 which applies the alternating voltage with the resonance frequency to the vibrator 10 during a time corresponding to the duty ratio; the current monitor 15 which detects the residual frequency of the electro motive force produced due to the residual oscillation of the vibrator 10 when the alternating voltage with the resonance frequency is not applied from the duty ratio control circuit 12 and feeds back the detected residual frequency to the PLL control circuit 11 through the zero-cross comparator 17.

Abstract: A method of monitoring of the level of compaction of a soil surface undergoing compaction by an impact compactor which includes a rotatable, multi-sided compactor mass that applies periodic impact blows to the soil surface when rolled over that surface. In accordance with the invention, data related to the level of compaction of the soil surface is derived, during compaction of the soil surface, from the deceleration of the compactor mass as it impacts the soil surface. This is achieved using one or more accelerometers mounted on the impact compactor.

Abstract: Provided is a mechanical-vibration detecting apparatus in which not only adjustment is easy but also mechanical vibration can be taken out with high accuracy, and a vibration-reduction control apparatus by which reduction of mechanical vibration can be achieved. In a motor control apparatus for controlling the torque of a motor, provided are an equivalent rigid body model 103; a proportional operation means 104; a high-pass filter 105; and means for adding a torque signal and an output of the proportional operation means to supply a resulting addition signal to the equivalent rigid body model, and for subtracting an output of the equivalent rigid body model from a velocity signal of the motor control apparatus to supply a resulting difference signal to the proportional operation means and to the high-pass filter so that an output of the high-pass filter is used as a mechanical vibration control signal.

Abstract: Apparatus for controlling vibratory machines of the type having at least one electromagnetic drive coil to drive a member at a resonant frequency includes a DC power supply; a programmable controller that produces PWM control signals that when applied to the drive coil cause vibrating motion; a switching driver circuit that applies a drive waveform to the drive coil by switching DC power to the drive coil in response to the PWM control signals; and a motion sensor that detects vibration amplitude; the controller tracking resonant vibration frequency as a function of an amplitude signal related to the drive waveform. The motion sensor preferably produces a signal related to vibration velocity.

Abstract: A noise masking device for a low-cost laser beam printer, a copier or the like for performing a noise masking with respect to a noise of a drive motor of an image forming apparatus while affording no psychological unpleasant feeling due to a frequency fluctuation thereof. The noise masking device of the image forming apparatus having the drive motor which becomes a source of the noise upon operation thereof includes signal generating means for generating a correlation signal which correlates with the noise, a speaker for generating a masking sound which masks the noise and masking sound control means for controlling the speaker to vary the masking sound corresponding to the variation in the correlation signal.

Abstract: A method and apparatus for operating a positioning device for an adjustable device. The positioning device is mechanically actuated by a bearing connected to a pivotable armature that interacts magnetically with an electromagnet. The electromagnet is energized by current pulses generated by a computer program. The current pulses cause the air gap between the pivotable armature and the electromagnet to vary between open positions where the electromagnet is not magnetized, and a closed position where the electromagnet is magnetized. Several bearings and associated electromagnets may be arranged to operate the positioning device in one or more directions and at different torques and operating speeds for different directions of operation and different positions of adjustment.

Abstract: Disclosed is an AC electric motor with oscillating rotary output, a permanent magnet rotor having radially magnetized magnets, and feedback control of oscillation amplitude. Amplitude control is accomplished without a separate amplitude sensor by using an accurate model of the motor as a basis for calculation of amplitude from measurements of motor voltage and current. The motor has high efficiency, low inertia, and uses a relatively small volume of permanent magnet per unit power output.

Abstract: A linear oscillating motor capable of assuring a consistent and effective feedback control of keeping a constant oscillation amplitude with varying load conditions. The linear oscillating motor comprises an oscillator carrying a permanent magnet, and a stator with an electromagnet. The electromagnet is supplied with an electric power to develop an electromagnetic drive force of moving the oscillator in a linear direction relative to the stator. A spring is provided to apply a restoring force to the oscillator for providing a linear oscillating motion to the oscillator. A photo-sensor monitors the linear motion of the oscillator and outputs a signal to a reverse-point detector which determines right and left reverse points of the oscillator. A controller applies the electric power to the electromagnet at the drive points respectively defined subsequent in time to the reverse points and in a varying amount for keeping a constant oscillation amplitude of the oscillator.

Abstract: A method of recognizing armature impingement in an electromagnetic actuator having an electromagnet including a solenoid, an armature movable toward and away from the electromagnet and return means for exerting a force on the armature. The method includes the steps of maintaining a solenoid current at a predetermined magnitude I.sub.max during a predetermined period T.sub.A for capturing the armature at the electromagnet; switching off the solenoid current at a moment t.sub.1 upon lapse of the period T.sub.A ; upon lapse of a period T.sub.1 running from moment t.sub.1, oscillating the solenoid current between a lower holding current threshold I.sub.H1 and an upper holding current threshold I.sub.H2 ; detecting a current course from moment t.sub.1 ; and deriving a signal from such current course.

Abstract: A method of switching an electromagnetic actuator which includes an armature movable along a path of travel and two electromagnets having respective solenoids, disposed at opposite ends of the path of travel for alternatingly attracting the armature. The method includes the steps of alternatingly applying a supply voltage to the electromagnets for alternatingly causing a supply current to flow therethrough for effecting a reciprocating motion of the armature; and applying an induced current, generated by an induced voltage appearing across one of the solenoids upon removal of the supply current from the one solenoid, to the other of the solenoids until the supply voltage applied to the other solenoid is greater than the induced voltage and the supply voltage across the other solenoid is capable of maintaining an attained current flow therethrough.

Abstract: A method of attenuating vibrations, and a vibration attenuating actuator for attachment to a vibration transmitting structural member include an annular proof mass for attenuating vibrations. The proof mass is concentrically mounted without bearings on the strut so as to attenuate vibrations being transmitted therethrough without imparting a moment to the strut, and without affecting the structural integrity of the strut. The annular proof mass is moved parallel to the strut's longitudinal axis so that the actuator imparts a vibration attenuating force coaxial with the strut's longitudinal axis. The actuator may be used with feedforward and feedback controllers.

Abstract: There is provided a vibration eliminating apparatus utilizing a magnetic suspending system which achieves zero power control. The vibration eliminating apparatus includes a table on which equipment to be installed, magnetic yokes fixed on the table, control magnets for suspending the magnetic yokes from an installation floor, displacement sensors for measuring gaps between the control magnets and the magnetic yokes, power amplifiers for supplying exciting currents to the control magnets, and compensation circuits for controlling the exciting currents of the control magnets by supplying outputs from the displacement sensors to the power amplifiers. Each control magnet includes a permanent magnet for generating a bias magnetic flux and an electromagnet for generating a control magnetic flux to form a magnetic circuit. An integrated value of the exciting current fed to the electromagnet is fed back to the power amplifier.

Abstract: In a control system for an actuator applicable to a servo system in which a low resolution sensor and/or an operation detection signal having noise components is used as a feedback signal, a low-pass filter is disposed in a feedback loop of the servo system whose cut-off frequency is varied according to an operating condition of the actuator, e.g., an operation speed of the actuator.

Abstract: A method of the present invention for stabilizing the resonant frequency of a resonant scanner is that thermal energy of the same amount as the heat generated in an optical scanning mode is applied to the scanner section in a non-scanning mode to insure that the variation of the temperature of the resonant light deflector will lie within a predetermined range, whereby the resonant frequency of the oscillation of the reflecting mirror is stabilized. The resonant scanner of the present invention in which the scanner section is heated in the non-scanning mode by supplying the drive coil with an electric current that has a non-resonant frequency or with the heater is constructed. The resonant scanner using the method is capable of achieving precise optical scanning that has an improved dimensional precision in the sub-scanning direction.

Abstract: An acoustic compressor is disclosed for generating a high pressure acoustic waveform within a chamber containing a working medium. The compressor comprises an actuator body solidly mounted to the chamber with a vibrating armature spring-mounted within. The chamber and actuator body are resiliently mounted so as to be vibratable. Owing to reaction forces, vibration of the armature causes vibration of the chamber which generates an acoustic waveform in the medium. By matching the resonant frequency of the armature to the acoustic resonant frequency of the chamber and driving the armature at that frequency, extremely high pressures within the chamber may be obtained.

Abstract: An electromagnetic actuator is disclosed which is especially suitable for active vibration control applications. The actuator may be either of the moving coil or moving magnet type so that a moving element undergoes reciprocal motion in response to an electrical input signal. The invention allows the force of the moving element to be linearly related to the amplitude and direction of the input current with a high degree of efficiency. In one embodiment, the moving element is decoupled from any mechanical load so as to produce reaction forces which may be used to cancel vibrational forces.

Abstract: A compact system specially adapted for optical scanning in microscopes, substantially eliminates vibration associated with scanned elements which are rapidly reciprocated through relatively large angular arcs at substantial distances from a pivot axis by providing a counterrotating counterbalancing element and a second counterbalancing element rigidly connected to the scanned element in which the centers of mass of both the counterrotating counterbalance and the counterbalanced scanned element are placed on a single rotational axis about which the two counterbalanced systems oppositely rotate, thereby eliminating unbalanced momentum vectors to reduce transmission of vibration to the stationary supporting structures.

Abstract: The present invention relates to apparatus for stabilizing the operation of rotational machinery, particularly machinery which uses magnetic bearings. Accelerometers sense various vibrations within the machinery. The outputs of the accelerometers are analyzed by a Fast Fourier Transform algorithm and multiplied by an array of influence coefficients to calculate desired stabilizing forces to be applied to the rotating machinery. Compensating analog voltage signals are generated in accordance therewith and transmitted to magnetic control coils within the rotating machinery.

Abstract: A camera using film with a magnetic recording portion, is provided with a magnetic head for effecting the writing or reading-out of information onto or from the magnetic recording portion of the film during feeding of the film, and a motor for feeding the film. The motor has a commutator and brushes contacting with the commutator, and is disposed so that the tangential direction of brushes with respect to the commutator may be substantially parallel to a line linking the output shaft of the motor and the head gap of the magnetic head together.

Abstract: An apparatus 400 and a method are provided for increasing the density of a compactible material 10 while continuously evaluating the density of the material. The evaluation of material density is carried out by calculating the total of the static, dynamic and centrifugal forces applied by a vibrating tool 102 l to the compactible material 10. The total applied force calculation includes measuring the vertical acceleration of the material contacting member 102 and the position of an eccentric mass 206 mounted on the material contacting member 102. The acquisition of these parameters is carried out simultaneously, and the calculation of the dynamic and centrifugal forces is made when the material contacting member 102 is at its lowest position.

Abstract: An active vibration control device for controlling vibration in a cantilevered member and a method for the same are disclosed. The device is comprised of a cantilevered member having a longitudinal axis comprising a sensor mounted near the free end of the member to measure motion of the member in a transverse direction and to produce a corresponding signal. A force generating assembly is mounted to the member near the free end to oppose the measured motion with a force thereby minimizing subsequent motion along the transverse axis caused by vibration.

Abstract: A lithographic system, having a stepper and exposure station built on a block of granite attached to the ground using isolation legs, includes a servo control system for providing signals a motor associated with the stepper to control the movement of the stepper. The control system includes means to calculate a filter formula used to generate the control signals, which formula is calculated in response to the initial velocity, the movement of the stepper and a certain time between discrete movements, so that a minimum amount of energy is utilized. The filter formula requires that the difference in the velocity of the base and the stepper be zero at the time the stepper reaches the final position. Where time is short, both the base and the stepper initially move with the same velocity and end with the same velocity, and an array processor calculates the time varying filter formula.

Abstract: An apparatus and a method are provided for controlling the frequency of vibration of a compacting machine. The frequency control is carried out by the apparatus which determines the actual time at which a ground contacting member of the compacting machine is at its true vertically lowest position. This is determined by measuring the time at which the vertical acceleration of the ground contacting member has a maximum value during one rotation of an eccentrically mounted, vibration inducing mass. The time difference between the time at which the vibration inducing eccentric mass is at predetermined position and the time at which the acceleration of the ground contacting member is at the maximum value is used to calculate a phase angle relationship (.phi.) between the ground contacting member and the eccentrically attached member. This method of determining the phase angle relationship (.phi.

Abstract: A bidirectional variable reluctance linear actuator and force control system by which one or more bidirectional linear actuators can be operated to produce a linear relationship between the net force on the armature structure and an applied flux linkage variation signal, as well as an actuator system by which the transmission of vibration through a structure can be blocked by applying forces and/or moments to the structure so as to cancel out its vibratory velocity. An adaptive control system, which is synchronized to machine speed, is able to determine the proper forces that will cancel the vibration of the structure and automatically null out each harmonic of the structure vibration, and cancels the vibration in up to six degrees of freedom of structural motion. The system can provide active attenuation system with a variety of noise sources and transmission paths, i.e.

Abstract: A unit for attenuating frequency components generated in a sideband of a frequency of an AC voltage applied to an electro-mechanical energy conversion element. This attenuation is achieved by modulation performed in a speed control apparatus for a vibration driven motor. The control apparatus includes a filter for cutting frequency components of a smaller frequency difference (fd) or more of an absolute value of a frequency difference between a natural frequency of an n-th order vibration and a natural frequency of an (n-1)th- or (n+1)th-order. A filter output is input to a modulator in a driving circuit, and noise of the vibration driven motor can be greatly reduced.

Abstract: An apparatus for cancellation of vibrations in a device. A first matrix (51) combines the vibration signals from a plurality of locations to produce mode signals indicative of individual modes of vibration of said device. An adaptive element in response to said mode signals generates mode vibration attenuation signals corresponding to said mode signals. A second matrix (56) combines the mode vibration attenuation signals to produce vibration attenuation signals for generating vibration attenuation forces.

Abstract: A vibration control system for damping vibration of an body to be isolated against vibration. The body is supported on a movable base through the medium of vibration-damping supporting structure. The control system comprises a vibration sensor for detecting vibration of the movable base. An inverse vibration signal generating circuit includes a digital sensor and in supplied with a detection signal outputted from the vibration sensor for generating a signal with a waveform to cancel out the vibration of the body through interference therewith. An actuator is connected operatively to the movable base and the inverse vibration signal generating circuit for converting the signal derived from the latter into a mechanical vibration to be applied to the body.

Abstract: A vibrating type transducer wherein an H-shaped vibrator, formed integrally with a silicon substrate and having a hollow chamber provided therearound, is kept self oscillating at its natural resonance frequency together with an amplifier. A physical quantity, such as force, pressure, differential pressure, or the like, which is applied to the silicon substrate is detected by a change in the natural frequency arising at the vibrator corresponding to the physical quantity. The invention also includes a method for manufacturing such transducer using a semiconductor technique, including steps for keeping a vacuum internally in the hollow chamber, imparting an initial tension to the vibrator, and then operating the amplifier to have stable self oscillation.

Abstract: A high precision linear actuator for compensating short stroke, high frequency vibrations in a space deployed structure comprises a set of cylindrical magnetic pole pieces affixed to respective ones of a pair of graphite flexures, that are mounted to a thermally conductive cylindrical housing, which is to be affixed to the space deployed structure. Reaction against the "proof mass" pole pieces is achieved by a magnetic field produced by set of stationary magnetic coils that surround the pole pieces and are energized by a vibration compensation reaction current supplied from a sense/control processor. Coaxial with and mounted integrally with the cylindrical pole pieces of the proof mass is an internal accelerater, which generates an output signal representative of the force to which the proof mass is subjected.

Abstract: The electrical termination impedance of a variable reluctance electro-mechanical transducer is changed automatically in response to the frequency of vibration applied to the transducer, to provide the optimum electrical termination impedance which produces the highest effective mechanical impedance at said frequency. The transducer includes magnetic cores interconnected by a spring formed by cutting a relatively thin medial annulus in a relatively thick flat disk. A digital logic circuit uses a signal counter and NAND gates to determine the frequency and close the appropriate fast-acting relay in a parallel array of capacitor-relays. A negative-impedance electrical termination provides a high mechanical impedance over a broad band of frequencies. A shunting circuit eliminates spurious resonances by providing substantially no shunting in the transducer-terminating circuit at resonant frequency, and substantial shunting in the terminating circuit at other frequencies.

Abstract: The present invention provides an optical scanner including a horizontally arranged base plate, a light source unit rigidly mounted on the base plate and adapted to emit a beam of light, an optical scanning unit for scanning the light beam in a repetitive cycle and an optical system unit for conducting the scanning beam to a desired surface to be irradiated, the optical scanning unit including a unit base, a torsion bar rigidly supported on the unit base at the opposite ends, a rotor rigidly mounted on the twistable portion of the torsion bar and having a mirror for reflecting the light beam, an electromagnetic drive mechanism for applying a rotational drive force to the rotor and a unit-side mirror for further reflecting the reflected light from the mirror, the optical scanning unit being arranged such that the torsion bar is disposed parallel to the base plate, the light beam being scanned along a plane perpendicular to the base plate on the rotation of the rotor and the reflected beam being scanned along a

Abstract: Mechanical resonance of the vibratory feeder is maintained by minimizing a phase angle difference between substantially sinusoidal drive voltage and current wave forms. The mass flow rate of material being fed is controlled by controlling the electrical power applied to the vibratory feeder compared with a desired electrical power computed from a desired flow rate. The preferred embodiment includes synthesized drive wave forms which are variable in frequency and amplitude in order to maintain the vibratory feeder in mechanical resonance at the desired flow rate. Resonant operation and accurate material flow are accomplished without use of electromechanical vibration sensors and control is accomplished using the magnitude and phase relationships between the applied voltage and current drive wave forms.

Abstract: A rotary actuator in which there is a freely rotatable permanent magnetic armature between two stators. At least one of the stators produces an asymmetrical magnetic flux field that acts upon the magnetic field of the armature to cause the same to rotate.

Abstract: A control device (30) for controlling the supply of power to the coils (16A, 16B) of a drive motor (3) for a compressor unit of the resonant-piston type (1). The control device comprises a power-supply circuit (44) for energizing the motor coils from a direct voltage source (45), means (46, 47, 48; 46, 60) for determining a measure (P, .phi.), which indicates whether the power consumption of the motor as a function of the frequency of the energizing current is at least approximately maximal, and means (40, 42, 43; 61, 42, 43) for adjusting the frequency of the energizing current, depending on the derived measure (P, .phi.), to a value for which said measure indicates that the power consumption of the motor (3) is maximal.

Abstract: An apparatus comprising a rocker with a curved base, and an activating base supporting and continuously activating the rocker. Two magnets, whose north poles point in opposite directions, one upward and the other downward, are respectively disposed on either side, towards which rocker rocks, of the center of gravity of the curved base. A first induction coil is set within the activating base and under the rocker so as to produce induced a current when the rocker is rocking in the direction of one of the two magnets. An operational amplifier integrated circuit (OP AMP IC) is provided within the activating base so as to amplify the induced current. A second induction coil, which is connected to the output of the OP AMP IC, is provided so as to induce a magnetic field. This magnetic field applies an attractive force on the magnet when it moves closer to the activating base, and a repelling force on the other magnet moving away from the activating base so as to activate the rocking means.

Abstract: A solid state amplifier for driving a shaker is described. The amplifier is comprised of a circuit which generates a pulse-width modulated drive signal for driving an armature of a shaker. The circuit includes an oscillator, power supply, wave-shaping generator, error detection network, comparator modulator and drive amplifiers. The oscillator generates a base waveform which is shaped by the wave-shaping generator. This signal is compared with error signals and the resulting signal is used to provide the pulse-width modulated driving signal to the shaker.

Abstract: A method of and apparatus for measuring the vibration amplitude of an electromagnetic vibratory motor is disclosed in which the current induced in the coils of the motor is rectified and sensed and applied to a current signal conditioning circuit to produce an average current signal. The voltage across the coils is sensed and is applied to a voltage signal conditioning circuit to produce a peak voltage signal. First and second predetermined scale factor signals are generated. The average current signal is divided by the peak voltage signal and the result is multiplied by the second scale factor signal. The scaled divided signal is subtracted from the first scale factor signal to yield the desired signal representative of the vibration amplitude of the vibratory motor.

Abstract: A method of and apparatus for measuring the vibration amplitude of an electromagnetic vibratory motor is disclosed in which the current induced in the coils of the motor is sensed and differentiated and applied to dividing means where it is divided by the sensed induced voltage induced in the coils to produce a signal proportional to the instantaneous reluctance of the coils of the vibratory motor. The instantaneous reluctance signal is filtered to remove the line frequency harmonic therein, and this filtered signal is peak detected to produce the vibration amplitude signal. Means are also provided to eliminate the problem associated with the dividing means if the sensed induced voltage approaches zero.

Abstract: A controlled force variable reluctance actuator. A variable reluctance actuator having a moving element operated by a solenoid is provided in which the current in the solenoid is controlled by a signal representative of the flux density in the magnetic circuit of the actuator. The signal is produced by a Hall effect device placed in the magnetic circuit. Preferably, the Hall effect device controls the current in the solenoid by controlling its duty cycle; however, continuous control of the current may also be employed. Alternative embodiments are provided for a constant force actuator, an actuator whose force-displacement characteristic is altered, and an actuator in which the force may be selectively controlled. An embodiment is also provided for selectively controlling the position of the moving element based upon measured electric and magnetic parameters of the actuator.

Abstract: An electric starter motor and generator is integrated into the structure of an internal combustion engine by making the ferromagnetic pistons of the engine the relatively moving elements in the starter and generator. A coil is solenoidally wound around each sleeve of the engine. An electronically controlled switch sends battery current into an appropriate coil inducing a powerful magnetic field therearound. The magnetic field and piston interact resulting in a powerful magnetic force which moves the piston and thus cranks the engine. At appropriate times in the operation of the engine, fuel to the same can be shut off and the engine run as a high speed electric motor.

Abstract: A motor drive assembly includes a stationary housing, a shaft rotatably carried by the housing for driving a load, a gear box rotatably carried by the shaft, and an electric motor in the gear box having a rotor coupled by a gear train to the shaft. A switch in the housing near the gear box is operated when the gear box rotates against a spring bias in response to the rotor's exerting an increased predetermined torque. The motor may have an auxiliary winding in circuit with the switch to reduce power consumed by the motor when the switch is operated. Alternatively, a solenoid may be connected to the switch to hold the rotor stationary when the motor stops. The motor may have a main drive winding which is de-energized by the switch.

Abstract: An electrical drive circuit arrangement to control the energization of a reactive load with a high voltage including a control stage, an electrically isolating control signal transformer and an output stage including power control semiconductor devices and having an energization input for a high voltage electrical supply and an output for the connection of a reactive load, the high voltage being prevented from reaching the control stage via the input of the output stage by the isolating transformer, the control stage including a noise-resistant guard responsive to circuit condition signals to permit or prevent generation of the control signal, the transformer restricting the signal to the output stage to a permitted control signal and the output stage generating a protection signal on a current surge in a connected reactive load, the protection signal being a potential low enough for direct application to the control stage without the need for isolating transfer to protect against the high voltage reaching th

Abstract: An automobile fan controller comprises: a fluctuation signal generator for generating a fluctuation signal; a pulse-width-modulation circuit including a triangle generator for generating a triangle-waveform signal having a constant amplitude and a constant period, and a comparator connected to the fluctuation signal generator and the triangle generator, for comparing the fluctuation signal with the triangle-waveform signal, thereby producing a pulse signal having a pulse width variable dependent on the fluctuation signal; and a driver circuit, including a switching power transistor connected to the pulse-width-modulation circuit, a fan motor mounted on an automobile, and an air flow switching unit mounted on the automobile for energizing and de-energizing said fan motor with a variable pulse width in response to the pulse signal.

Abstract: An electronic motor includes a shaft mounted for rotation about a rotational axis. A plurality of radial lever arms are mounted with respect to the shaft. Each lever arm has an inner end connected to the shaft by a one-way clutch. The clutches allow the shaft to rotate in only a first circumferential direction with respect to the lever arms. An electrically conductive element is attached to an outer end of each lever arm. A drive coil is positioned adjacent to each electrically conductive element. A drive circuit periodically and sequentially energizes each drive coil with current pulses. Each drive coil is oriented to produce a first pulsed magnetic field in a direction generally tangential to the circumferential direction when energized. The first magnetic field induces circulating currents within the electrically conductive element. The circulating currents in turn produce a second magnetic field about the electrically conductive element.

Abstract: A linear electric motor having an oscillating linear armature disposed in proximity to a stationary stator and provided with an output member which can be directly coupled to a load. A power supply and control circuit is provided for matching the power input to the linear motor according to changing load conditions at the output.

Abstract: There is disclosed a drive regulation and control circuit for a tuning fork resonator also adaptable to other electrical devices wherein an approximately sine wave signal from a motion sensor is applied to an instantaneous level detector which causes a variable width pulse signal to be on during that portion of the sine wave signal where the instantaneous level exceeds an adjustable reference level; a control signal is generated with a magnitude varying as a moving average of the width of the variable width pulses; the control signal causes the reduction of current to the tuning fork drive to cause reduction of motion amplitude. An optional feature provides rapid response by activating a motion braking signal having a duration approximately equal to the variable width pulse "on" period.