Abstract: A laser discharge tube having electrodes the peeling of which is reduced and a method of manufacturing electrodes of a laser discharge tube by which the peeling of the electrodes is reduced. The electrodes are adhered to the outside periphery of the tube wall of the laser discharge tube. The electrodes contain as components an electric conductive substance, an inorganic binder and boron nitride as a thermal expansion preventing substance for suppressing a coefficient of thermal expansion. When a silica glass tube is used as the laser discharge tube, the laser discharge tube has a coefficient of thermal expansion of +0.5.times.10.sup.-6. When the electrodes are mixed with boron nitride, the electrodes have a coefficient of thermal expansion of +2 to +7.times.10.sup.-6 and the coefficient of thermal expansion of the electrodes can be brought close to the that of the laser discharge tube by mixing boron nitride with the electrodes.

Abstract: A laser discharge tube for preventing the flow out of an electrode material, deterioration of electrodes, and the like, caused by corona discharge, as well as for increasing power to be supplied to the laser discharge tube by improving the heat-dissipating property and insulating property of the electrodes. The laser discharge tube is a tube of a dielectric material (e.g., silica glass) with a circular cross section and two electrode units are helically disposed on the outside periphery thereof at the same pitch. The electrode units include electrodes and dielectric layers, respectively, and each of the electrodes is formed by depositing silver as an electric conductor on the outside periphery of the tube wall by metalizing.

Abstract: A spindle motor control method capable of high-accuracy contour machining uses a vector control processor executing a speed loop process to obtain a torque command (Tc). Vector control is performed (S4, S7) in accordance with a magnetic flux command (.PHI.c) set at a predetermined fixed value (CF.PHI.) when a spindle motor is being driven in a contour control mode. This prevents irregularity in motor speed and motor vibration attributable to a delay of the actual magnetic flux of the spindle motor behind the magnetic flux command, thus enabling high-accuracy contour machining. In a normal speed control mode or an orientation mode for tool replacement, the vector control is effected (S4 to S6, S8) in accordance with the magnetic flux command (.PHI.c), which is obtained on the basis of the torque command (Tc), its maximum value (Tcmax), maximum magnetic flux command (.PHI.cmax) set in dependence on the rotating speed of the motor, and minimum magnetic flux (NR.PHI.cmin, OR.PHI.min).

Abstract: The invention relates to a motor output changeover control apparatus used for the spindle motor of machine tools. Conventionally, since a constant output over a wide range is realized by gears, a spindle motor is constituted by a single winding. The amount of heat produced by the winding is great, and a speed-change mechanism employing the gears is large in size.With the motor output changeover control apparatus of the invention, output characteristics over a wide range from high to low speeds is stabilized by changing over the connection of the power lines of an AC motor.

Abstract: An amplifier unit for an AC spindle, comprising a casing (10) and an amplifier integrally contained in the casing (10) and electrically interposed between an AC motor for driving the spindle of a machine tool and a power source.

Abstract: An instruction decode method and arrangement suitable for a high-speed microprocessor are disclosed. The instruction decode arrangement comprises a high-speed PLA decoder of small capacity for decoding an instruction word having a small execution cycle, a low-speed PLA decoder of large capacity for decoding an instruction word having a large execution cycle, and a circuit for activating the low-speed PLA decoder to cause it to execute instruction decoding when the high-speed PLA decoder is not permitted for the execution of instruction decoding. Instantaneous current noises generated in the PLA decoders can be mitigated to avoid erroneous operations without degrading averaged decoding performance, thereby permitting the microprocessor to operate at high speeds.

Abstract: In a circuit board device for a magnetic circuit and a method of manufacturing the same according to the present invention, there is a printed circuit board on which electric circuits are arranged by use of copper foil portions (3, 4) formed by an etching process on the outer surfaces of an insulating plate (2) made of an electric insulator blank. On this printed circuit board, short bars (5) to serve as conductor pieces for high currents are clinched by burring onto the copper foil portions (3) for passing the high currents, whereupon electric components or the like are fixed to the burred portions by bolts (7), etc.

Abstract: A power supply regenerating circuit according to the present invention is used in an inductor motor drive circuit which performs motor drive control and regenerative control. The induction motor drive circuit has a parallel circuit including a reverse connected diode (D10) and a resistor (R1) connected between a circuit (C2), which rectifies and then smoothes the induced electromotive force of an induction motor (M) during deceleration, and a bridge circuit (Tr1-Tr6) which effects a conversion into AC power. Regenerative power blocked by the diode (D10) is supplied to the bridge circuit (Tr1-Tr6) as a current limited by the resistor (R1), and the regenerative power is regenerated only during a predetermined interval of a three-phase period.

Abstract: A control unit according to the invention has a plastic case (v) housing only power components (v), such as transistors for an inverter, among components constituting a control circuit. Other circuit components such as resistors are mounted on a printed circuit board, and the case and circuit board are secured to each other by fasteners allowing the case to be made light in weight. Screws for mounting the power components to the case are of the same size, and so are the energizing terminals. This makes possible automated assembly by robot.

Abstract: A motor velocity control apparatus according to the present invention has at least one of the following is included with a servoamplifier: a current feedback gain changeover circuit; a velocity feedback gain changeover circuit; a velocity loop gain changeover circuit; a changeover circuit for a current loop amplitude and phase table storage circuit. Accordingly, the invention is well-suited for changeover control of a plurality of spindle motors of different ratings in a machine tool.

Abstract: A method for emulating programs in a system includes a plurality of first and second data processors having different instruction word sets. An instruction which interrupts the operating system on the first data processor is defined. When the instruction is detected in a program running on the first data processor, it is determined whether or not the instruction is an instruction associated with an input/output macro instruction. If it is found, as a result of the determination, that this is the case, an interrupt is caused in a program running on the second data processor which controls the emulation, and the input/output macro instruction output from an emulated program is translated into an input/output macro instuction for the operating system, thereby implementing an emulation with a minimized overhead.

Abstract: A three-phase induction motor control method according to the present invention subjects a three-phase induction motor to vector control by an output from an inverter which is supplied with a direct current obtained by conversion from an AC input. The method includes sensing a DC-converted voltage at a DC link section, varying a flux command in dependence upon the sensed DC voltage, and controlling the motor to obtain a constant output irrespective of a fluctuation in power supply voltage.

Abstract: An induction motor torque control system is provided for resolving an excitation current command and a secondary current command into an excitation flux vector component and electromotive force-direction (torque direction) vector component, respectively, based on a torque command for the motor and an excitation flux command, decided for the motor, in such a manner that a linear output torque is obtained in response to these commands. A primary current command for the motor is obtained by combining these vector values.

Abstract: A magnetic sensor system for spindle orientation in which a magnetic body is attached to a rotating spindle and a magnetic signal from the magnetic body is detected by a sensing unit arranged on a mechanically stationary member to detect the rotational position of the spindle. A pair of wedge-shaped, annular fastening elements are fitted onto the circumferential surface of the spindle in such a manner that tapered portions thereof oppose each other, thereby rigidly securing an accommodating ring and a cover body together on the spindle.

Abstract: An AC motor control panel includes a short bar substrate (10) which is placed on a connection terminal (14) of an electronic component of an inverter control circuit arranged in a housing. A tubular connection member (17) is inserted into a hole (10b) provided in the short bar substrate 10. A screw (13) is inserted into holes provided in the tubular connected member (17), short bar (15) and connection terminal (14), and the end of the screw (13) is screwed into a nut (18) provided on a lower portion of the connection terminal (14). The connection terminal (14), short bar (15) and tubular connection member (7) are thus electrically interconnected.

Abstract: An induction motor control system in which the actual velocity of an induction motor follows a commanded velocity by correcting a difference between actual velocity and commanded velocity, and possesses a current negative feedback loop.

Abstract: A high-frequency noise absorbing circuit in a control circuit of a loading device having a power supply section (I), a converter circuit section (II), a DC link section (III) and an inverter circuit section IV, with capacitors C3 and C4 being connected between ground and respective positive and negative terminals of the DC link section (III) and a smoothing capacitor C1 connected between the positive and negative terminals of the DC link section (III). The high-frequency noise absorbing circuit includes a zero-phase reactor L1 arranged in the power supply section (I). Further, the high-frequency noise absorbing circuit includes a zero-phase reactor L1 arranged in the power supply section (I), and capacitors C5 arranged between the lines of the power supply section (I).

Abstract: A plural motor changeover control system for using a plurality of motors (1a, 1b), the power outputs of which differ, by successively switching among the motors. A conversion table (32a, 32b) corresponding to a motor designated for operation from among the plurality of motors (1a, 1b) is selected, and an amplitude command is fetched from the selected conversion table, which command corresponds to a velocity error, which is a difference between an actual velocity of the designated motor and a commanded velocity. The amplitude command is applied to the servo control circuit to control the designated motor.

Abstract: A method of controlling an AC motor which exhibits a constant torque characteristic at a rotational speed N below a base speed Nb and a constant output characteristic at a rotational speed N above the base speed Nb, comprising the steps of finding a base speed N.sub.L after limiting the output power of the AC motor, N.sub.L being derived from the base speed Nb and the ratio .eta. between maximum output power Pmax.sub.1 and maximum output power Pmax.sub.2 before and after the output power of the AC is limited, respectively, rendering the slip frequency of the AC motor constant until the rotational speed N of the AC motor reaches the base speed N.sub.L, varying the slip frequency in inverse proportion to the rotational speed N for N between N.sub.L and Nb (N.sub.L <N.ltoreq.Nb), and varying the slip frequency in proportion to the rotational speed N for N above Nb (Nb<N), whereby the output power of the AC motor is rendered constant at a rotational speed N above N.sub.L.

Abstract: An automatic tool changing mechanism includes a spindle mechanism (11) having at least a spindle (11a) and a first gear (11b) rotatable in unison with the spindle; a spindle motor (12) for rotating the spindle; a tool magazine (20) having at least a storage unit (20b) for storing a plurality of tools (21), a second gear (20c) rotatable in unison with the storage unit, and a slider (20e) slidably mounted on the spindle mechanism; a Z-axis motor (19a) for moving the spindle mechanism in the direction of a Z-axis; a constraining member (23) for constraining the tool magazine against movement thereof in the direction of the Z-axis and a control circuit (102, 103) for controlling the indexing. During machining operation, the first and second gears are brought out of mesh with each other, and the spindle is rotated by the spindle motor at a prescribed speed to enable a tool mounted on the spindle to machine a workpiece.