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: The present invention discloses a speed control apparatus for an AC motor which vector-controls, for example, a drive current of the AC motor such as an induction motor, synchronous motor and AC commutator motor with a feedback current control loop providing an inverter utilizing a semiconductor element for power amplification such as power transistor and compensates for non-linear current characteristic of the drive current generated by dead time resulting from ignition delay of a semiconductor element with a current compensation control element provided within the current control loop, thereby controlling the rotation speed and command response speed of an AC motor.