Abstract: The servo amplifier is used for driving power transistors supplying current to a D.C. servo motor. The servo amplifier includes a control signal input; a tach signal input; circuitry coupled to the inputs for creating an error signal between the control signal and the tach signal; a triangular wave generator for generating a triangular wave form; a summing network for summing the error signal with the triangular wave; a modulator for modulating the resultanat signal; tri-state drive logic circuitry; and power transistor drive circuitry adapted to be coupled to the power transistors. The triangular wave modulator is coupled to the output of the summing network for supplying modulated signals to the tri-state drive logic circuitry and the drive logic circuitry having outputs coupled to the drive circuitry. The tri-state drive logic circuitry provides fast response to the error signals indicating a desired change in speed of the D.C. motor, and without over-shoot or hunting of the D.C. servo motor.

Abstract: A device for controlling the rotational speed of a motor carries out feedback control by a speed difference control signal and a phase difference control signal. A first time period from a reference time point to a time when a newest detection pulse is outputted is calculated every time a predetermined number of detection pulses are counted by detection pulse counters. A second time period from the reference time point to the time when a command pulse, which is assigned an ordinal number equal to the ordinal number of the newest detection pulse and which thereby corresponds to the newest detection pulse, is calculated on the basis of the total number of pulses counted by the detection pulse counters in the time period from the reference time point to the time when the newest detection pulse is outputted, and the period of the command pulse.

Abstract: A brushless motor comprises a rotor having multipolar magnets magnetized, a stator coil having a plurality of phases of winding, a rotor position detecting circuit to detect a specified position of the rotor and to output a signal having levels which alternately change in accordance with revolution of the rotor, and a phase changing circuit to output driving signals to the stator coil in accordance with the output of the rotor position detecting circuit, a stop time signal generating circuit to output a drive-stop signal for stopping the actuation of the stator coil for a predetermined time from the time when a level of the output signal of the rotor position detecting circuit is changed, a temperature detecting element to detect the temperature of an object to be cooled, an instruction value generating circuit to output to the stop time signal generating circuit an instruction signal in response to the output of the temperature detecting circuit so as to change the specified time, and an overheat detecting c

Abstract: A recording and/or reproducing apparatus in which a head is driven along a disk while the disc in rotated. A rotation speed control and a rotation phase control are provided to control the disc rotation. The apparatus is operated in a phase control mode until the phase of the disc rotation deviates from a reference phase by a predetermined amount. Then the apparatus switches to speed control a memory is used to store data concerning start up information to reduce the required amount of start up time required in future operations.

Abstract: A digital current control arrangement for optimizing the transport time delay of a thyristor power supply used as a source of armature current for a DC motor utilizes a coarse gate angle interrupt subroutine to perform a preliminary calculation of the gate firing angle for the next thyristor to be fired. The coarse gate angle calculation is performed at a predetermined time following the firing of a previous thyristor. A finite gate angle interrupt subroutine is also provided for recalculating the gate firing angle at a second predetermined time just prior to the firing of the thyristor. The finite and coarse gate angle interrupt subroutines both perform their respective calculations using the common parameters. A flag passing arrangement is also included in the current control arrangement and is effective to insure that the finite gate firing angle is the preferred calculation used in the firing of the next thyristor.

Abstract: A method of synthesizing a system which forces finite value of an impedance to zero comprising a positive current feedback of a prescribed functionalism and a negative voltage feedback to ensure stability of the system. The prescribed functionalism of the current loop uses arithmetic elements as well as voltage and current measurements to provide for a parameter-free synthesis of the converter whereby the converter operates in the measurement-based mode, the measured variables being the voltage and the current associated with the impedance of interest, without a need to supply values of both resistive and reactive components of the impedance of interest. The converter is used in synthesizing electric motor drive systems, incorporating any kind of motor, of infinite disturbance rejection ratio and zero-order dynamics and without specifying the resistive and the inductive values of the motor impedance.

Abstract: A rotation drive device for driving a rotator is disclosed, comprising an electric motor for driving the rotator, a phase detecting circuit for detecting the phase of rotation of the rotator, a reference signal source for forming a reference signal of a constant period, a phase control circuit for controlling the motor in such a manner that the phase difference between the output of the reference signal source and the output of the phase detecting circuit becomes a constant value, a detecting circuit for detecting a fact that the reading-out of the phase difference is not completed in the time interval between the successive two outputs of the phase detecting circuit, a control circuit for varying the number of cycles of phase difference computing operation of the phase control circuit depending on the time interval between the successive two outputs of the phase detecting circuit, another detecting circuit for detecting a fact that the phase detecting circuit has produced no output in one period of the refer

Abstract: The present invention provides a circuit for shaping ripple in the armature current of a D.C. motor. The circuit includes a phase-locked loop (100). In addition, the circuit preferably includes a back-e.m.f. circuit (300) suitable for generating a signal proportional to the back-e.m.f. of the motor and for controlling the frequency of the phase-locked loop (100) on the basis of the signal obtained in this way and/or the back-e.m.f. circuit (300) suitable for generating a signal proportional to the back-e.m.f. of the motor, a voltage controlled oscillator (500) controlled by the signal proportional to the back-e.m.f., and a switched capacitor filter (400) controlled by the output of the oscillator (500), the filter being connected upstream from the phase-locked loop (100).

Abstract: There is provided a motor control device comprising a motor; an apparatus for entering the number of revolutions of the motor; a detector that detects the number of revolutions of the motor; and a microcomputer for entering the output from the detector and a controlling the motor according to predetermined programs, wherein the microcomputer comprises a counter to which a count value is set according to a circuit from the input to form a reference frequency signal and a circuit for forming a phase error signal according to the reference frequency signal and the output of the detector and outputs a signal for driving the motor based on the phase error signal.

Abstract: A rotary body drive device for controlling rotation of a motor on the basis of the phase difference between a periodic signal produced in accompaniment with rotation of the motor and a reference clock signal so that their phase relationship becomes a prescribed one. When the phase difference between both signals detected in a certain state is largely different from that detected in the preceding time, a correction is given to the phase difference of both signals detected in the aforesaid certain state, so that the rotation of said motor is controlled in accordance with the corrected phase difference.