Abstract: In a computer network having a central computer, a plurality of peripheral computers, and a time-shared common memory accessible to the network computers over a single bus connected to the common memory, an electronic switch of the telephone type is connected to all of the computers so that direct links may be established between respective members of one or more selected pairs of computers. Data is transmitted between computers via the direct links effected by the switch, and the bus is thus primarily reserved for access to the main memory for each of the computers. Direct links for transmitting data from a peripheral computer and another computer are established in accordance with connection orders sent from the peripheral computer to the central computer via the common memory. If the other computer is available to receive data, the central computer instructs the electronic switch to connect the peripheral computer directly to the receiving computer.

Abstract: The invention concerns a control apparatus for an arc furnace (1) comprising at least one electrode (2), and powered with direct current from an alternating current electric power source (4), through the intermediary of a controlled-rectifier converter (3).According to the invention, this apparatus includes a loop (24) for rapid control of the reactive energy drawn from the alternating current power source (4), and a circuit (15) for limitation of the maximum intensity of the direct current flowing in the electrode (2). Preferably, the rapid control of the reactive energy is obtained by holding essentially constant the product of the intensity in the source (4) and the sine of the dephasing angle. It includes in addition a loop (13) for slow control generating a reference signal of the reactive energy applied to the said rapid control loop (24), and limiting the variation of the reactive energy.

Abstract: A two terminal control switch having a main switch and a saturable current transformer whose primary winding is series connected with the main switch. A center tapped full wave rectifier has a capacitor connected between its DC sides, such capacitor also being connected to a junction between the primary winding and the main switch.

Abstract: In accordance with the present invention, a signal generator providing multiple signals with different frequencies includes, in a combined form, a clock (1), an address counter (2), a memory (3), and a digital-to-analog converter (4), which are to be series-connected. Individual storage locations within the memory (3) shall be preloaded with amplitude samples for the entire group of signals with different frequencies, which are to be selected in such a manner that storage locations in use within the aforementioned memory (3) shall contain an integral number of cycles for each signal. The address counter (2), which is controlled by the clock (1), shall successively address each storage location within the memory (3), and a capacitor (5) connected to the converter output shall be used to smooth the resulting signal. Applicable for systems permitting prompt transmission of multiple messages within railway systems, by use of contact ramps.

Abstract: The invention pertains to a logic circuit with threshold and built-in safety such that any change in the characteristics of its components produces a relative increase of the threshold value. It comprises a comparator (7) one input of which receives a reference d-c voltage (VR) whereas the other input is connected to the junction point of a first and a second resistance (1, 2). A first d-c voltage (V1) of low relative value is applied to the free terminal of the first resistance (1), and a second d-c voltage (V2) of high relative value is applied to the free terminal of the second resistance (2) by means of a third resistance (3). According to the invention, there is applied at the junction point (A) of the second and third resistances (2, 3) a third d-c voltage (V3) of intermediate relative value by means of a fourth resistance (4) in series with a chopping commutator (6).

Abstract: A balancing circuit (2) comprising two windings (L1) and (L2) detects a current (Ids) between the common collector-to-emitter junction of two power transistors in series and the common junction of two balancing capacitors connected across the transistors in order to balance the collector-to-emitter voltages (VCE) of the transistors.

Abstract: An electrical passage for an hermetic enclosure including electronic elements comprises a conducting piece (2) traversing an insulating sleeve (3) bearing on the inner surface (1) of the enclosure. A ring (7) surrounds the conducting piece (2) and a portion of the insulating sleeve (3) projecting outside of the enclosure, and a nut (13) inserted onto the conducting piece (2) ensures fastening of the assembly. A full ring seal (10) disposed between the inner surface (11) of the ring (7) and the outer surface (12) of the insulating sleeve (3) is compressed longitudinally by the outer wall (8) of the enclosure and by a shoulder (6) of the conducting piece, thus ensuring the hermeticity of the assembly. The tightening of the nut (13) acts on the insulating sleeve (3) within the enclosure. The invention has application to the electrical connection of power semiconductors utilized within the domain of railway traction.

Abstract: This invention is concerned with an interface for a computer system. This interface is characterized in such a way that it includes an assembly of elements (C2, C2') capable of performing an AND function, controlling modules (K1, K1') for monitoring the function of these elements (C2, C2'), the outputs of which modules are tied to a command system associated with the computer system D1, D1'), and means (K2, K2') to test the monitoring modules (K1, K1'), the command sytem being equipped with means to compare the states of the elements (C2, C2') that perform and AND function, as indicated by the control modules (K1, K1') with the command state. The warranting, means to inhibit the sending of a command signal is inhibited when the two states do not match. The invention is applicable to situations where a security interface is required.

Abstract: The present invention pertains to a commutator containing a semiconductor operable with unidirectional current and bidirectional voltage and with controlled interruption and automatic ignition, and in which a semiconductor device with controlled commutation is utilized. In accordance with the invention, the commutator includes a logic gate (61) having an input which, when the anode-to-cathode voltage of the semiconductor device (2) is below a specific positive voltage close to zero, receives a logic signal from an adapting circuit (4) connected to the semiconductor anode. The other input of the logic gate receives a control logic signal, and the output of the gate is connected to another adapting circuit (5) which converts the logic signal output by the logic gate into a suitable control signal which is transmitted to a the control terminal of the semiconductor device (2).

Abstract: The present invention relates to supplying a load either from a direct-current source or from an alternating-current source. The power unit, according to the invention, is characterized in that it consists of a single conversion unit (CV) having unidirectional semi-conductor power components forming switches (I1, I2, I3, I4) controlled in appropriate fashion by a logic control in such a manner as to ensure the functioning of the conversion unit (CV) either in a chopper mode, or in a rectifier mode when the load functions to draw power, or to ensure energy regeneration when the load functions in a generating mode. The present invention has application particularly for supplying direct-current motors used in dual-current railroad locomotives.

Abstract: The invention involves an "AND" logic circuit with built-in safety comprising a first and a second input to which pulses can be applied, and respectively tied to the base of a first and a second transistor (1,2) each having a collector to which a reference voltage (5) is applied by means of a corresponding resistance (6,7), and comprising, in addition, a third transistor (3) having its base tied to ground by means of the secondary winding (15) of a transformer whose transforming ratio is less than unity, its collector tied to the positive terminal of the d.c. voltage supply by means of a resistance (13), and its emitter having the reference voltage (5) applied thereto. According to the invention, the first transistor (1) has its emitter tied by means of a first diode (8) and its collector tied by means of a capacitor (9) to ground, whereas the second transistor (2) has its emitter directly tied and its collector tied by means of a branch comprising a capacitor (10) and a second diode (11) in series to ground.

Abstract: In electrical apparatus of the type having a column of stacked semiconductors and interposed heat sinks mounted between a pair of end plates, a precalibrated clamping element is provided for applying a predetermined clamping force to one end of the column to secure the column between the end plates. A hollow cylindrical body of the clamping element threads into one of the end plates and houses a spring which has been placed in precalibrated compression by a press. The spring is retained in a precalibrated state between a shoulder portion of a piston within the body and a fixed inner surface of the body. A cap is secured to an end of the body and is positioned to abut the shoulder to retain the spring in the precalibrated state.

Abstract: The present invention is intended to reduce thermosiphon effects within the annular space (6) situated between the pump casing (1) and the vertical wall (9) of an opening situated within the slab (3) covering the vessel for a nuclear reactor immersed in liquid sodium (4), with an inert gas (15) filling the space situated between the surface of the sodium and the bottom portion of said slab (3).The device to which the present invention pertains consists of a floating ring (7) placed around the pump casing (1) and a disc (8) which is integral with the vertical wall (9) of the opening situated within the slab (3). The shape of the aforementioned ring (7) and the shape of the aforementioned disc (8) are complementary with one another.Nuclear plants application.

Abstract: A transmission configuration between a main station and a local station consists of a line which permits supplying of direct voltage power for stations from a source within the main station. A rectifier bridge is installed in such a manner that suitable polarization of the receiver can be achieved, regardless of the branching direction for wires comprising the line. Groups of unipolar current impulses are superimposed upon the supply voltage along the line by two generator units (K.sub.44, 40 and K.sub.50, 46) within the main station and a generator (K.sub.102, 100) within the local station. The respective polarities of impulses sent to and from the main station and the local station are such that said impulses can flow through rectifier bridges within local stations.

Abstract: A safety device to be applied to the vertical displacement of, for example, the control rods of a nuclear reactor, comprises the combination of a stator placed on the outside upper part of an impervious, nonmagnetic cylinder within the inside of which a rotor is mounted about its shaft, free in axial translation, with the shaft rotatable with the rotor but fixed in translation, and with the rotation of the shaft transferred to a hollow threaded rod which will transfer rotation to a nut slidable vertically inside the cylinder, supporting the control rods therebelow; the rotor also controlling the opening and closing of a jaw for holding and releasing the hollow threaded rod.

Abstract: The present invention incudes a searching circuit which sequentially accesses a plurality of peripheral computers to receive requests for access by these computers to a principal memory normally occupied by a principal computer. The searching circuit determines the identity of the requesting computer and passes the request on to a decision circuit which receives information from the principal computer and the peripheral computers as to the state of occupancy of the access bus to the principal memory. If the bus is not occupied and the principal computer does not require use of the principal memory, the request is granted by the decision circuit.

Abstract: A total security time-delay circuit useful in railway communications, for example, provides a series of output pulses after a specific minimum interval in response to a direct voltage applied to an input of the circuit, the minimum interval being maintained even in the event of circuit component malfunctions. A pulse generator connected to the circuit input provides a series of pulses to control a first contact breaker which switches the primary winding of a transformer to partially discharge a capacitor which is series-connected to the primary winding. The capacitor charges through a resistive network of a transformer secondary winding circuit which includes a second contact breaker having a control terminal connected to the transformer secondary winding and operable to provide output pulses when the capacitor discharge reaches a sufficient intensity.

Abstract: The state of an all-or-none modulated useful signal subjected to a perturbed environment is determined, on reception, through the use of non-modulated reference signals subjected to the same environment. The reference signals have respective frequencies neighboring that of the useful signal and the same initial amplitude so that all of the signals are attenuated in the same manner by environmental perturbations. By comparing against a threshold reference value the differences between the respective amplitudes of the received reference signals and the amplitude of the received useful signal, the "all" and "none" states of the useful signal are accurately determined irrespective of the effect of perturbed environment on the amplitude of the useful signal.

Abstract: A control circuit which permits a direct current motor to operate during traction or during braking in such a manner that energy can be either dissipated or recovered; and, in particular, the invention embodies gradual, continuous, and reversible shifting from one form of braking action to another.

Abstract: This invention provides in centrifugal motor pumps and the like a safety structure embodying a bearing bushing coaxially mounted with respect to the pump shaft in a space between the shaft and the body of the pump, with the bushing designed to act as a hydrodynamic bearing in the case of decentering of the pump shaft or similar disfunction only.