Abstract: A microscope with an automatic sweeping device which automatically sweeps a preparation, membrane filter, etc. for observing subjects, such as cells, microbes or others, existing thereon, is offered. The automatic sweeping device has the following functions: a control mechanism drives a transfer mechanism for moving a holder containing subjects according to the instructions from a control console to perform automatic sweeping by stepped or continuous movement of the holder, and at the base time a printer, memory and display are so controlled that they respectively print, store and display position and other various data. Manual operation is also possible immediately after suspension of automatic operation. Positions of subjects detected by a position detector are stored in the memory.

Abstract: A header apparatus for a flat IC pack having at least one conductive terminal includes a header housing which includes an IC pack chamber, an opening communicating with the IC pack chamber, the IC pack being inserted into and extracted from the opening, and a pair of actuation means, each of which includes drive member having a first surface formed inside the IC pack chamber of the header housing and a first rack, operation member which includes a second rack positioned to face the first rack of the drive means and an operation portion formed outside the IC pack chamber, and a pinion engaged with the first and second racks, wherein the first surface of the drive member is moved in an insertion direction of the IC pack by inserting the IC pack into the IC pack chamber, and pushes the IC pack inserted into the IC pack chamber in a direction opposite to the insertion direction of the IC pack by moving the operation portion of the operation means in the insertion direction of the IC pack.

Abstract: A connector unit is provided which includes a housing having connection terminals in its opening, and a movable member adapted to be inserted into the opening of the housing. The movable member has cam projections each extending from one end, where the movable member is inserted into the housing, toward the other end, over a proper length. When the movable member is partially inserted into the opening of the housing, an elastic contact portion of the connection terminal is pressed by the cam projection to provide such a clearance as to allow the conductor to be inserted there.

Abstract: From the peripheral velocity v.sub.M of a driving wheel and vehicle velocity v, the changing rate .DELTA.v.sub.s /.DELTA.t of the relative velocity v.sub.s therebetween with respect to time is obtained. The changing rate .DELTA.f/.DELTA.t of the traction force f produced in the driving wheel at that time is obtained from a detected armature current of a motor driving the driving wheel. A driving torque produced by the motor is so controlled as to be decreased when polarities of the changing rate in the relative velocity and that in the traction force are different from each other.

Abstract: An apparatus for sealing the skirt of a converter waste gas recovery system is disclosed, which includes an annular flange that is mounted about the outside surface of the converter adjacent to its mouth at a point clear outside the reach of the molten slag and metal that might spill over the rim of the converter mouth during the process of blowing. An annular sealing band is provided at the lower peripheral portion of the skirt, which runs surrounding the mouth. The annular sealing band is divided into multiple arcuate segments of a whole bandage, each pivotally disposed on a horizontal pin and connected to a separate hydraulic cylinder through its axially movable piston rod. It is so designed that the segments of the annular sealing band are individually yet simultaneously swung about their respective pins by their hydraulic cylinders into abutting contact with the external periphery of the flange providing a tight leakproof seal.

Abstract: A power converter such as an inverter or chopper using self-turn-off type semiconductor devices supplies power to an inductive load and free wheel diodes are provided so that the current flowing through this load circulates not through the power supply but through the free wheel diodes. When it is detected that the load current exceeds a predetermined value, the self-turn-off-type semiconductors which are conductive are turned off. At this time, the self-turn-off-type semiconductors which are turned on and immediately thereafter cause the recovery current to flow in the free wheel diodes are turned off not immediately but after the recovery current disappears.

Abstract: A method for operating a converter on the basis of a direct observation of the slag-forming conditions in a vessel interior.A device for observing the vessel-interior light is disposed in a throughhole extending through the side wall of a top-blowing or top- and bottom-blowing converter to reach the vessel interior. The converter operation can be carried out at a high accuracy of the slag-amount control on the basis of this observation.

Abstract: For controlling the rotational speed of an induction motor, an inverter is provided which converts direct current to alternating current and feeds the converted current to the motor. The output voltage and frequency of the inverter is controlled by a pulse-width modulated control device. The number of pulses contained in a half cycle of the inverter output voltage are changed every time the inverter output frequency reaches one of plural predetermined reference values. The plural predetermined reference values are adjusted in accordance with the DC supply voltage and/or with the motor current.

Abstract: A sine wave of a frequency to be generated in an inverter is compared with a triangular wave having a frequency N times (N: 15, 9, 3, 1) the frequency of the sine wave, so that a modulated pulse train is generated thereby to control the inverter. This inverter supplies power to an induction motor. With the increase in motor speed, N is reduced until it finally becomes 1. When the inverter transfers from an idle state to an active state, N is inhibited from becoming 1 but set to 3 even if the motor is running at high speed.

Abstract: A control system for an electric motor vehicle adapted to be driven by a group of induction motors, comprises a converter for producing an a.c. output to energize the group of induction motors, a frequency command circuit for producing a value representing a minimum number of rotations among those of at least two induction motors of the group added with a slip frequency in a power running mode of the vehicle on one hand and a value representing a maximum number of revolutions among those of at least two given induction motors of the group subtracted by the slip frequency in a regenerative braking mode, respectively, the values being utilized as frequency control commands, and a frequency control circuit for controlling the output for controlling the output frequency of the converter in dependence on the frequency control commands, thereby to improve the adhesion performance of the electric motor vehicle.

Abstract: A control apparatus is disclosed for an electric car having an induction motor supplied with polyphase AC power of variable frequency from a power converter so as to drive a driving wheel. This control apparatus comprises a detector for detecting the actual running speed of the electric car irrespective of whether the driving wheel causes adhesion or non-adhesion, a device for establishing a slip frequency of the induction motor, and a device for generating a frequency command based upon a signal of the actual running speed and the slip frequency, this frequency command being used to control the output frequency of the power converter.

Abstract: A control system for an electric car driven by an induction motor which is supplied with electric power of a variable frequency and a variable voltage from an inverter comprises means for detecting the car speed, means for setting a slip frequency of the motor, a frequency command generator, control means for controlling the output frequency of the power converter in accordance with the frequency command and controlling the output voltage of the power converter, a current command generator, and a voltage command generator. The output voltage of the power converter is controlled in accordance with selected one of the current command and the voltage command while being limited by the other command.

Abstract: A motor control apparatus to supply current from a D-C source to an electric motor has a thyristor chopper circuit, the duty factor of which is controlled depending on a current instruction signal. The thyristor chopper circuit is provided between the terminals of the D-C source in series with an electric motor, and has main and auxiliary thyristors. A series connection of a capacitor and a reactor, forming commutating elements, is connected across the auxiliary thyristor and oscillates to generate a pulse of current through a forward diode in order to turn off the main thyristor when the auxiliary thyristor is turned on. In addition, a saturable current transformer having first, second and third windings is provided. Through the first winding chopper current flows, and the second winding operates as the reactance of the commutating elements.

Abstract: A chopper and a series circuit of a dynamic braking resistor and a thyristor are connected in parallel with a d.c. motor which is operated as a generator during braking operation. A series circuit of a diode and an inductance element is connected in series with the d.c. motor. A condenser connected between the ground and the junction of the inductance element and the diode forms a filter circuit together with the inductance element. Current generated by the d.c. motor flows into a d.c. source through the diode and the inductance element during regenerative braking operation. An over-voltage detector fires the braking thyristor when the voltage across the condenser becomes greater than a predetermined limit value, as a result the dynamic braking operation is performed.A chopper controller varies the interval between an ON pulse to turn the chopper into ON state and an OFF pulse to turn the chopper into OFF state for adjusting ON time and OFF time of the chopper in response to the current through the d.c.

Abstract: A motor control apparatus to supply current from a D-C source to an electric motor has a thyristor chopper circuit, the duty factor of which is controlled depending on a current instruction signal. The thyristor chopper circuit is provided between the terminals of the D-C source in series with an electric motor, and has main and auxiliary thyristors. A series connection of a capacitor and a reactor, forming commutating elements, is connected across the auxiliary thyristor and oscillates to generate a pulse of current through a forward diode in order to turn off the main thyristor when the auxiliary thyristor is turned on. In addition, a saturable current transformer is so provided that through a primary winding thereof chopper current flows, and the secondary winding operates as the reactance of the commutating elements. Current flowing through the secondary winding therefore depends on the chopper current flowing through the primary winding.

Abstract: In an electric car, wherein the powering drive and the braking drive are executed by on-off controlling a current through a d. c. motor by means of a chopper, when the electric car is below a predetermined speed, a field coil of the d. c. motor is put into a series winding connection so as to carry out full field control, and when the car is above the predetermined speed, the field coil of the d. c. motor is changed-over to a shunt winding connection so as to carry out weak field control.The duty cycle of the chopper is controlled with the running state of the electric car taken into consideration in order that the field current at the time when the series winding connection has been changed-over to the shunt winding connection may become substantially equal to a value before the change-over, whereby the transient change of the current between before and after the change-over of the field coil is suppressed.

Abstract: A magnetic phase shifter control system comprises a magnetic phase shifter for producing an output signal in accordance with a control command at a predetermined amplification degree, a circuit for suppressing the output signal of the magnetic phase shifter to a level lower than a predetermined level on command, and a circuit for reducing the amplification degree of the magnetic phase shifter when the suppressing circuit is operative, whereby a delay for response due to a dead time which the magnetic phase shifter inherently has is eliminated.

Abstract: In order to effect regenerative brake control from a high speed with a chopper, a resistor is inserted in a motor circuit. The duty cycle of the chopper is reduced before the resistor being shorted, thereby dampening the increase of the voltage across a filtering capacitor which otherwise might occur at the time of the resistor being shorted.

Abstract: Regenerative brake control system for DC motor, in which a resistor is inserted in the motor circuit to effect regenerative brake control from a high speed by use of a chopper. In the voltage control region where the motor voltage less the voltage drop across the inserted resistor is controlled below an equivalent source voltage, the inserted resistor is not short-circuited, thus improving the efficiency of the regenerative brake.

Abstract: An electric braking control apparatus for the DC motor comprises; a DC power supply; a series circuit including the field winding and armature of a DC motor a smoothing reactor and a resistor connected to the DC power supply; a chopper connected in parallel to the series circuit, and a diode inserted between the DC power supply and the parallel circuit including the series circuit and the chopper. The field winding and the resistor are regulated in effecting regenerative braking of the DC motor by turning on and off the chopper.