Abstract: An overcurrent detector realized by using a computer. The apparatus is provided with an overcurrent detector (5) which calculates the temperature rise .theta.(n) =K.sub.1 P(n)+K.sub.2 .theta.(n-1), based on a current (In) flowing in an electric machine, under the conditions that the machine has an electric resistance (r), the machine works in a known ambient temperature, the allowable temperature rise (.theta.(max)) of the machine is known, a first coefficient (K.sub.1) and a second coefficient (K.sub.2) are predetermined. The overcurrent detector (5) further compares the temperature rise (.theta.(n)) with a difference between the allowable temperature rise (.theta.(max)) of the machine and the ambient temperature at which the machine is used, and determines that the machine is in an overcurrent position, when the former exceeds the latter.

Abstract: A digital pulse circuit receives parallel N digital signals, assuming N is an even integer equal to or greater than 4, the levels of the signals inverted every time a constant quantity of change in an objective quantity to be measured occurs, any phase differences between the successive signals of the signals about 1/N of the constant quantity; has a logic circuit which enables only two signals which can change state in due process corresponding to the next change of the objective quantity to be measured, to enter the next stage; and synchronizes each of the N digital signals by a clock pulse, to make any phase difference among the N digital signals equal to or more than a predetermined phase difference, and the remove the influence of noise superposed on the digital signals (FIG. 10).

Abstract: A motor drive unit used in controlling an AC motor which drives the spindle or feed shaft of a machine tool is suitable for automatic assembly in which a plurality of electrical components are mounted and wired. In accordance with the motor drive unit of the invention, an upper frame (2) supporting a printed circuit board (1) having electrical circuitry which employs control semiconductors, and a lower frame (4) for mounting a heat radiating device (5), which mounts a rectifier or the like, as well as a power resistor (6), are constructed of synthetic resin. A power board (3) on which power circuit components are connected by soldering is sandwiched between the two frames (2), (4) and has the components on the heat radiating device (5) and the power resistor (6) mounted and connected thereto by screws. The two frames (2), (4) are fastened together by screws (25).

Abstract: A light receiving element (1) and an operation transistor (3) are connected in series, a plurality of signal output transistors (5a, 5b) are current-miller-connected to the operation transistors (3) in parallel, and photoelectrically converted output signals (O.sub.1, O.sub.2) are separately applied to a plurality of circuits in parallel from the plurality of the signal output transistors (5a, 5b). As a result, in the plurality of the circuits which receive the photoelectrically converted output signals (O.sub.1, O.sub.2) in parallel to carry out predetermined processes, interference will not occur, the signals are processed correctly, the power consumption is reduced, and the speed of responsitivity is improved.

Abstract: A pulse encoder has a motor detecting portion (1) which detects a motion of an object whose position should be measured and which outputs a signal having information regarding the motion. A clock generator (3) outputs a clock pulse. The pulse encoder processes the information regarding the motion synchronized by the clock pulse. The pulse encoder includes a clock malfunction detecting portion (4) which receives the clock pulse and at least a part of the signal having information regarding the motion showing whether the object, whose position should be measured, has moved or not. The clock malfunction detecting portion outputs a clock malfunction signal when motion is detected by the part of the signal having information showing whether the object has moved or not, when the clock pulse is not output.

Abstract: A connecting terminal for connecting an electronic component to a printed circuit board includes a rectangular metal plate and a leg provided at each of four corners thereof. The approximate center of the metal plate is provided with a screw hole through which a screw is passed that is screwed into a terminal of a screw terminal-type electronic component. The legs of the connecting terminal, which are passed through pin holes provided in the printed circuit board, are soldered to an electrical circuit and thereby fixed to the circuit board. A screw which is screwed into the terminal of the screw terminal-type electronic component is passed through the screw hole of the connecting terminal. When the screw is tightened, the electronic component is secured to the printed circuit board.

Abstract: Disclosed is a control method in which control errors, attributable to a change of the state of a transmission mechanism, disposed between a servomotor and a load driven thereby, are reduced in controlling a driving force to be applied to the load.A detected value (PH) of the driving force applied actually to the load is compared with a set value (PL') of the force to be applied to the load. The driving current of the servomotor is controlled in accordance with the result of such comparison. Thereupon, a change of the correlation between the servomotor output and the driving force applied actually to the load, which is attributable to the change of the state of the transmission mechanism, is compensated automatically. Thus, the driving force applied actually to the load is adjusted accurately to the set value.

Abstract: The drive system of an induction motor wherein the exciting current command value I.sub.o of the induction motor (14) is held constant and the rotational speed thereof is caused to quickly respond to a command speed by the vector control circuit the induction motor (104) has exceeded a predetermined speed, an exciting current amplitude-controlling circuit (51) increases the exciting current command value in accordance with the rotational speed. The level of the driving supply voltage of the induction motor is sensed by a supply voltage output circuit (52), whereupon the exciting current amplitude-controlling circuit (51) is controlled so that the predetermined speed serving as a threshold value for changing the exciting current command value may be increased in accordance with the sensed level.

Abstract: A discharging circuit for a power source device with a rectifier circuit used in an power source for driving a motor in which when the alternating current power source is turned off and the load is electrically separated, the voltage of a time constant selection circuit (22, 23) falls rapidly, the voltage across a diode (25) rises, a Schmitt circuit (24) is activated, the circuit consisted of a transistor (27) and a resistor (26) is conducted, and a smoothing capacitor (28) is discharged, and hence the heat generation at the resistor is decreased and the concern over unsafety due to delayed discharge of the capacitor is eliminated.

Abstract: A control system for a synchronous motor which is employed as a servomotor, wherein a pulse coder is employed for detection of the absolute position of one of the field poles of the motor, the absolute position being a component of the input signals for generating a poly-phase alternating current voltage which generates a rotating field maintaining a fixed amount of phase difference with respect to the absolute position of one of the field poles of the motor, thereby the synchronous motor is controlled to run maintaining a fixed amount of internal phase angle of e.g. .pi.

Abstract: A control circuit for driving an induction motor wherein an AC voltage is converted into a direct current by a rectifying circuit and the direct current is converted into a signal having a variable voltage and frequency by a transistor inverter connected in parallel with a smoothing capacitor, and a regenerative circuit is connected in parallel with the inverter, and a circuit is provided for comparing the terminal voltage V.sub.C of the smoothing capacitor and a reference voltage V.sub.r when braking is to take place is disclosed. When condition V.sub.C .gtoreq.V.sub.r exists, the transistor inverter is disabled but the regenerative circuit is allowed to operate; when the condition V.sub.C <V.sub.r exists, the transistor inverter is operated in the regenerative braking mode.

Abstract: A control circuit for driving an induction motor wherein an AC voltage is converted into a direct current by a rectifying circuit and the direct current is converted into a signal having a variable voltage and frequency by a transistor inverter connected in parallel with a smoothing capacitor, and a regenerative circuit is connected in parallel with the inverter, and a first monitoring circuit is provided for comparing the terminal voltage V.sub.C of the smoothing capacitor and a first reference voltage E.sub.1 when braking is to take place. When the condition V.sub.C .gtoreq.E.sub.1 exists, the transistor inverter is disabled but the regenerative circuit is allowed to operate. When the condition V.sub.C <E.sub.1 exists, the transistor inverter is operated in the regenerative braking region. A second monitoring circuit is provided for comparing the smoothing capacitor terminal voltage V.sub.C and a second reference voltage E.sub.2 (E.sub.2 >E.sub.1). When the condition V.sub.C .gtoreq.E.sub.

Abstract: An apparatus for preventing malfunctions in a phase control mechanism of the type in which the firing angle of thyristors in a thyristor bridge is controlled to regulate the rotational speed of a DC motor comprising the load of the thyristor bridge. Thyristor firing pulses are produced each time a rising analog speed command signal generated in response to the phases of a N-phase power supply intersects N-number of sawtooth signals. Immediately after the generation of each firing pulse, the thyristors are not supplied with firing pulses for a time interval at least equivalent to the thyristor commutation overlap time.

Abstract: A device for driving a DC motor with feedback control provides a circuit for judging whether the motor is in acceleration or in deceleration and a circuit for switching the gain modification signal, and said switch circuit is controlled by the output signals of said judgement circuit.

Abstract: In a DC motor control apparatus for driving a DC motor in accordance with a signal of the difference between a revolving speed signal from a speed detector coupled with the DC motor and a command speed signal so as to drive the DC motor at a revolving speed indicated by the command speed signal, when a voltage to be applied to the DC motor and the revolving speed signal from the speed detector are both detected, the operation of the DC motor control apparatus is decided as normal, and when the voltage to the DC motor is detected but the revolving speed signal from the speed detector is not detected, the operation of the DC motor control apparatus is decided as abnormal and an alarm signal is produced.