Abstract: In the inverter device of the invention, when a power source connected to an electrolytic capacitor 5 is interrupted, a switching control circuit 6a controls switching elements of an inverter main circuit 7a to operate to supply a current to a load, thereby discharging charges of the electrolytic capacitor 5, and an electrolytic capacitor electrostatic capacitance calculator 10a calculates the electrostatic capacitance of the electrolytic capacitor, on the basis of: a discharged charge amount which is obtained from an outflow current Ic from the electrolytic capacitor 5, and a discharge time; and a discharge voltage ?V which is a voltage drop from beginning of discharging of the electrolytic capacitor 5.

Abstract: In the inverter device of the invention, when a power source connected to an electrolytic capacitor 5 is interrupted, a switching control circuit 6a controls switching elements of an inverter main circuit 7a to operate to supply a current to a load, thereby discharging charges of the electrolytic capacitor 5, and an electrolytic capacitor electrostatic capacitance calculator 10a calculates the electrostatic capacitance of the electrolytic capacitor, on the basis of: a discharged charge amount which is obtained from an outflow current Ic from the electrolytic capacitor 5, and a discharge time; and a discharge voltage ?V which is a voltage drop from beginning of discharging of the electrolytic capacitor 5.

Abstract: A data output encoder capable of having its state of retaining internal error information and self-diagnostic information reset without recourse to removing power or furnishing a dedicated signal line. A reset pulse generator monitors the changing status of an externally provided output request signal. When the signal status reaches a predetermined pattern, the reset pulse generator generates reset pulses that cause an RS flip-flop circuit to reset the state in which the internal error information and self-diagnostic information are retained.

Abstract: A motor drive control apparatus for controlling an induction motor based on a primary current including a magnetic flux current and a torque current includes a circuit for determining air gap magnetic flux according to a first magnetic flux characteristic curve and a torque current limiting value according to a first torque current characteristic curve in a first speed range; and for determining the air gap magnetic flux according to a second magnetic flux characteristic curve and the torque current limiting value according to a second torque current characteristic curve in a second speed range. A motor driving circuit causes the magnetic flux current corresponding to the air gap magnetic flux and the torque current corresponding to the torque current limiting value to flow in the motor.

Abstract: The invention relates to a spindle speed/position control system for use in a numerically controlled machine tool such as a lathe. To improve the measurement of spindle speed and position, detected elements are attached directly to the rotatable spindle. A waveform shaping circuit takes the outputs of speed and position detecting sensors, and outputs a variety of sinusoidal and pulse signals. The sinusoidally varying signals are employed in speed detection while the pulse signals are used for position detection and control.

Abstract: The invention relates to a spindle drive controller for a machine tool such as a numerically controlled lathe of the two spindle type. According to the invention, a drive control unit is enabled to separately control the spindles, or jointly control both spindles simultaneously. A switchover unit controls whether one or both spindles is controlled, and changeover units are provided for selectively feeding back speed and position feedback signals from one or the other of the respective spindles, depending on which spindle is being driven at that time.

Abstract: A rotary shaft position control apparatus in which the rotary shaft is stopped in one revolution. After detection that a flux emitter on the shaft has passed a position detector, the shaft speed is set to a first speed. The first speed is continued until a product of the first speed and the elapsed time at the first speed after passing the position detector equals a predetermined constant. Then, the speed is reduced to a second speed. Finally, the shaft is stopped when the flux emitter again passes the detector.

Abstract: A speed detecting device for an electric motor in which the angular stopping position of a rotary shaft is controlled with a high precision. A magnet is mounted on a rotary shaft of the motor, and a position detector detects the position of the magnet as rotated by the motor, thereby producing an output signal having a linear region. A speed calculator samples this signal in the liner region at predetermined time intervals and performs a division operation whereby a difference between a present sampled value and a preceding sampled value of the output signal is divided by the time interval, thereby to produce a speed signal which is applied to the motor as a control signal.