Abstract: An improved induction motor control system utilizes an inverter supplying a variable frequency AC voltage to drive the induction motor, and volt/frequency (V/F) control section controlling the inverter to produce a suitable voltage and frequency in a predetermined relationship therebetween. A power factor detecting section is included to detect a power factor phase angle between the motor current and the inverter output voltage as indicative of an amount of load imposed on the motor. The detected power factor phase angle is compared with a predetermined phase angle which is a frequency dependent angle indicative of a standard load at a given frequency, in order to provide a control output in response to which the V/F control section alters the inverter output voltage out of the predetermined relationship with the frequency for improving motor efficiency. Thus, the detected load (i.e.

Abstract: A pulse width modulation control circuit includes a pulse width modulator which supplies a signal to a power switch tying together a DC signal generator and a motor and various sensing circuit including a control voltage disabler circuit. All of the sensing circuits are appropriately designed to ensure that the various components of the circuit are not damaged under abnormal conditions whether due to motor loads heavier than rated or undesired changes in AC current input or control voltages.

Abstract: A device and associated method to control the electromechanical energy conversion process of a variable speed drive utilizing a doubly fed machine, which provides the mechanical energy as demanded by some mechanical load. Alternatively, a device and associated method is provided for a synchronous motor. The terminals of either the stator or rotor winding of the doubly fed machine are directly connected to a polyphase AC power grid of a certain grid frequency. The device establishes through electronic control a stable operation of the drive at a desired power factor at the terminals of these windings, irrespective of varying load conditions. This capability is provided without the need for computing or sensing this desired power factor and the subsequent feedback of its deviation from the desired value through a properly designed regulator.

Abstract: A system for driving a brushless motor comprises motor drive coils belonging to a plurality of phases respectively, a plurality of pairs of drive transistors connected to the drive coils respectively, a distribution circuit for sequentially distributing drive-coil energization switching signals to the plural drive transistors respectively, a slope synthesizer for smoothing leading and trailing slope portions of the drive-coil energization switching signals so as to apply the smoothed energization switching signals to the drive transistors respectively through the distribution circuit, a voltage-controlled oscillator for supplying a signal having a suitable frequency as an input to the slope synthesizer, a phase error detector for detecting the phase difference between counter-electromotive voltages induced in the drive coils and the drive-coil energization switching signals in a driver-coil energization pause period, and an error amplifier for amplifying the output signal of the phase error detector and apply

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: A magnetic or optical disk apparatus featuring a circuit for generating a dual implication MOTOR STATUS signal in response to a MOTOR SPEED signal representative of the speed of rotation of a disk drive motor and to a MOTOR ON signal dictating the rotation and nonrotation of the disk drive motor. The MOTOR STATUS signal indicates: (1) the rotation of the disk drive motor at a desired normal speed, enabling data transfer between the disk and a head; and (2) the slowing down of the motor to a predetermined speed close to zero. The two implications of the MOTOR STATUS signal can be distinguished from each other by reference to the MOTOR ON signal. The first implication may be used to enable reading or writing of data on the disk, and the second implication for disk ejection and for opening a power switch or switches, among other purposes.

Abstract: A resistor is provided in parallel with the capacitor of a phase compensating circuit in order that a rapid transition may be made to a steady velocity state when a motor is started, a target velocity (reference velocity) is changed, or a large fluctuation in load occurs. When the steady velocity state does not prevail, the capacitor is isolated from the circuit and the resistor is connected into the circuit in its place.

Abstract: The motor speed control circuit senses average back EMF as a measure of motor speed. The back EMF charges a capacitor circuit which accumulates charge and develops a voltage indicative of the motor speed. A sample and hold circuit may be used to sample the back EMF when the motor is switched off during each cycle. This voltage is compared with a reference voltage indicative of the desired motor speed. An error signal is generated by comparing the desired speed with the actual speed and this error signal is used to generate a variable duty cycle pulse train which gates the power controlling transistor on and off to control motor speed. A logic gated or SCR gated voltage boosting circuit operates in synchronism with the gating pulse train to drive the power transistor hard into saturation. This lowers the resistance of the power transistor, causing less energy dissipation as waste heat.

Abstract: A servo motor system for a transportation line with the travel distance of the article predetermined and with a relatively low positioning accuracy. Basically, the system is constructed as an incremental servo motor system in which an incremental movement of the motor is detected, and the incremental movement signal is fed back to a motor driver, which also receives pulse signals from a controller corresponding to a traveling distance to a destination. Only one time after starting the operation of the servo motor system with the article not at the destination point, a stop signal is fed from an external signal generator located at the destination point to the motor driver, which stops the motor there. At this time, a coordinate system of the movable space of the article is established in the controller and the servo motor system is operated as an incremental system from the second time on, without utilizing an external signal generator.

Abstract: A speed detector outputs a deviation, from a desired rotation speed, of the rotation speed of a capstan motor for driving a tape. A phase detector outputs a phase deviation, from a reference signal, of a reproduction control signal. When in a recording mode, in which only speed control is effected, the capstan motor is driven on the basis of a signal obtained by integrating the integration output of the speed detector. When in a reproduction mode, in which speed and phase controls are effected, the capstan motor is driven on the basis of a signal obtained by adding the deviation output of the speed detector to a signal derived by integrating the deviation output of the phase detector. Further, the capstan motor is driven on the basis of the integration data, which is stored in a data register in the reproduction mode, at the time of transition from the reproduction mode to the recording mode.

Abstract: A microprocessor based motor controller which provides open loop speed control at low conduction angles, closed loop speed control at high conduction angles, and a smooth transition between open loop and closed loop zones. In open loop, the motor speed is selected and is permitted to vary with applied load. In closed loop, the motor speed is held constant, substantially irrespective of load. In the transition zone, the motor is operated in a hybrid open loop, closed loop fashion.Anti-kickback protection is also provided based on a percentage change in the motor's rotational period.