Abstract: An adaptive sequential controller (480) for controlling a single-phase circuit breaker, multiple circuit breakers in a multi-phase configuration, or a multi-phase circuit breaker to substantially eliminate transients upon closing the circuit breaker and to minimize switching energy when the circuit breaker for any phase of the line is open. The device adaptively compensates for changes in the response time of the circuit breaker due to aging and environmental affects. To control the circuit breaker so that is closes at a zero crossing of the voltage waveform, the adaptive sequential controller includes a potential transformer (70) that is connected to the distribution line. The potential transformer provides a reference signal corresponding to the zero crossing or zero instance of the voltage waveform. If the power factor of the load coupled to the line is known and remains relatively constant, a current transformer is not required.

Abstract: The first zero crossing of the power signal, after the detection of an opening/closing signal, initiates a series of predetermined, timed, steps which reduces or eliminates the overvoltage after opening/closing a circuit breaker on a high power line.

Abstract: The present invention relates to an effector comprising power contacts for power supply of a receiver. The effector comprises an operating mechanism for the power contacts, this mechanism being actuated by an electromagnet. Between a power circuit for supplying power to the receiver and the return power circuit, there is connected a measuring and processing unit arranged to measure the impedance at the terminals of the power supply circuit of the receiver. This unit is coupled to a contact of the control circuit. The contact is arranged to cut the power supply of the control circuit in the event of a short-circuit of the power supply circuit of the receiver.

Abstract: The present invention relates to an apparatus and method for distributing electrical power from power substation circuits. The apparatus of the present invention is responsive to overcurrent conditions and selectively actuates a switching network so as to restore power to at least a portion of the users connected to the faulty circuit of the power distribution system.

Abstract: The specification discloses a solid state auto-reset circuit breaker intended for use in ac circuits, dc circuits and ac/dc circuits. A current sensing device is used to generate a voltage drop proportional to the current flowing through the device. When the voltage drop reaches a predetermined level, resulting from an over-current condition, it trips a control means that opens a solid state switch in the line. After a defined delay interval the circuit will automatically reset to close the solid state switch. If the over-current condition still exists, the control means will again open the solid state switch. This cycle is repeated at the delay interval until the over-current condition has subsided. Circuits are also disclosed which provide over-voltage protection, through detectors which trigger the control means when an over-voltage condition is detected. The application of the invention to lightning or surge protection is also disclosed, for single line and multiline environments.

Abstract: A control circuit synchronizes operation of a latching relay to extend contact life. The relay is switched using an H-bridge drive circuit. The synchronization is done using a two-step delay. The first delay is provided by a phase shifter, which delays the timing signals used by a logic controller relative to a zero crossing. The second delay is provided by an adjustable timer circuit including a potentiometer. The two delays are used so that the latching relay is tripped at a selectable time coinciding with the second zero crossing after a switching command is received.

Abstract: A device for detecting and isolating a downed conductor in a three-phase four-wire multi-grounded distribution system. The device cooperates with a power supply protective device if the device has a breaking capacity less than the maximum prospective short-circuit current of the distribution line, and the device is installed at a tap point of the distribution line. The device comprises a current detector, a low-pass filter, a high-pass filter, an arcing ground fault current-detecting circuit, a first overcurrent-detecting circuit that delivers an output when the output current from the low-pass filter exceeds a given value, a second overcurrent-detecting circuit that detects an overcurrent exceeding the breaking capacity of a device which has a breaking capacity less than the maximum prospective short-circuit current of the distribution line, a no-voltage detecting circuit for sensing that the distribution line is not electrically charged, a main contact and a trip mechanism.

Abstract: The operation of an electromechanical relay is synchronized with the power line waveform where an electrical power supply is supplied from a source to an electrical load. The current voltage supplied to the load is characterized by a power line waveform. An electromechanical relay is positioned between the power supply and the load where contacts of the relay are opened and closed to interrupt and supply power to the load. A microcontroller is positioned between a power source and the electromechanical relay and actuates the relay so that the contacts are closed or opened at a preselected point on the power line waveform. Closure of the contacts at the preselected point is accelerated by supplying an increased power signal to the relay coil and thereafter returning the signal to the rated power.

Abstract: A current-limiting load cutout includes at least one contact pair (1, 2) with one contact (3, 5) rigidly linked to electrodynamic current limiter (9, 10) that is electrically connected to controllable pulse current supply (17), and at least one emergency state sensor (12, 13, 14) kinematically linked to contact displacement and clamping assembly (11) which is kinematically linked to the other contact (4, 6) of contact pair (1, 2). The current-limiting load cutout is equipped with a pair of power terminals (20, 21, 22, 23) per each contact pair (1, 2) with one power terminal connected to the other contact (4, 6) of the contact pair (1, 2) and the other power terminal connected to contact (3, 5) which is rigidly linked to electrodynamic current limiter (9, 10) equipped with terminal (15, 16) to which a controllable pulse current supply (17) is connected via an emergency state sensor (12).

Abstract: In a hybrid relay circuit for supplying current to a load with a AC power supply, an electromagnetic relay is provided and the contact thereof is connected in series to the load and the AC power. The electromagnetic relay is driven by a driving circuit in accordance with an input control signal, thereby switching the supply of current to the load.

Abstract: In a circuit having an electro-mechanical relay, the contacts of which are subject to arcing, bridging across the electro-mechanical relay in a manner configured to begin conducting electrical current around the electro-mechanical relay prior to closing the electro-mechanical relay and to continue conducting electrical power around the electro-mechanical relay for a predetermined time after the onset of separation of contacts of the electro-mechanical relay pursuant to discontinuance of current flow through the electro-mechanical relay. An optical coupler is provided to ascertain a current flow through the relay coil effected to close the electro-mechanical relay contacts, and activates a shunt device in bridging electrical current flow around the electro-mechanical relay. The shunt device is provided to be substantially non-load carrying while the electro-mechanical relay is closed. Utility is found in protecting electro-mechanical relay contacts against damage due to arcing.

Abstract: The contacts of an isolation relay are positioned between a line interface circuit and the associated feed resistors, the relay being controlled to open the contacts in response to an excessive common mode alternating current through the feed resistors. The common mode a.c. is detected by a sensing amplifier, and is integrated and compared with a threshold level in a dectector unit. If the common mode a.c. is excessive, a zero crossing predictor enables the detector unit to control the isolation relay and open its contacts at a zero crossing of the a.c. A phase shifter in the zero crossing predictor compensates for the response delay of the isolation relay. As the excessive current is now interrupted, the sensing amplifier responds to the line voltage. When this falls below a predetermined peak level, a delayed resetting of the protection arrangement is automatically effected.

Abstract: A zero-current a.c. switching system is provided for controlling actuation of relay contacts between a power supply and a load. A primary switch selectively energizes the relay to maintain the relay contacts in the closed state. The load current flowing through the relay contacts to the load is sensed. A secondary switch responds to the sensed load current for normally conducting to energize the relay in parallel with the primary switch. The secondary switch ceases conducting each time the load current drops below a predetermined level to cease energizing the relay and open the relay contacts the next time the load current drops below the predetermined level following the opening of the primary switch.

Abstract: A method for interrupting an inductive load in a three-phase, high voltage network by means of a switch having a quick dielectric recovery, in particular a vacuum switch, in which two of the three vacuum switches, having a quick dielectric recovery, open at least 1/3 of a cycle of the network frequency later than the first vacuum switch, augmented with the minimum arcing time in the first vacuum switch, in order to prevent high over-voltages, caused by virtual chopping.

Abstract: There is disclosed a high-voltage DC circuit breaker apparatus with reverse current insertion system by line voltage charge, which comprises a commutation switch, a series circuit of a capacitor, a reactor and a switch connected in parallel with the commutation switch, a resistor connected so as to charge the capacitor by a line voltage. The charging time constant of the capacitor determined by the capacity of the capacitor and the resistor is used as a reference in a manner so that the rise time constant of the line voltage is smaller than the charging time constant of the capacitor, and the rise time constant of the line current is larger than the charging time constant of the capacitor, thereby interrupting the fault current without fail.

Abstract: A circuit for the arcless de-energization of a direct current load receiving direct current from a rectified alternating current source. The circuit includes a means for rectifying alternating current from an alternating current source to provide direct current to the direct current load. The means for rectifying has a current flow controller, such as a silicon controlled rectifier, connected with each phase of the alternating current source. The circuit also has means for de-energizing the then conducting current flow controller in said means for rectifying, the means for de-energizing having a current flow controller, such as a silicon controlled rectifier. The circuit further includes a voltage detection device for detecting a predetermined voltage drop in the circuit; and a time delay device for regulating the activation of the means for de-energizing.

Abstract: A D.C. power controller for interrupting a high voltage high current D.C. power line supplying a load (L) from a D.C.

Abstract: A secondary arc extinction device in an electric power system, including a bus bar; an electric power line connected to the bus bar; protective relaying means connected to the bus bar; first reactance means having two terminals, one terminal of which is connected to the electric power line; a transformer having a primary winding and a secondary winding connected between the other terminal of the first reactance means and ground; second reactance means connected to the secondary winding of the transformer; and means for controlling the second reactance means in response to the protective relaying means.

Abstract: A.C. switching circuit capable of opening and closing contacts without generating any arc. When D.C. source restores from its interruption, the contacts are maintained in or shifted to a predetermined state. A change-over switch is provided for selecting as required whether the contacts are to be forcibly opened or closed after the D.C. source interruption, or whether the previous state of the contacts is to be maintained.

Abstract: A hybrid D.C. power controller of the relay/circuit breaker type that uses a hybrid arrangement of hard contacts (4) and power FET's (18, 20) in cooperative functional combination as the arc quenching means for 270 volt D.C. power systems in low atmospheric pressure environments such as at 80,000 feet altitude in aircraft applications. Also, the relay is provided with arc horns (44c, 48b, 48c, 46c), magnetic field amplifiers (60, 62) looped stationary contacts (44, 46), arc splitters (64, 66), and gas ablating insulating members (60b, 62b, 72, 74, 64b, 66) to enable the relay to interrupt the power circuit if necessary without the help of the power FET's. The power FET's are controlled in both opening and closing the power circuit to afford arcless contact operation in normal load make-break situations. Current and voltage sensing (28, 32) and sampling (CS, VS) circuits determine when to turn the power FET's on after contact arcing has provided the required values.

Abstract: An arc suppression device (40) for protecting the load carrying contacts (30, 31, 32) of a power contactor (20) includes gate controlled semiconductor devices (TR1, TR2, TR3) connected in parallel with the contacts. A signal from a control circuit (45) causes gating current to be applied to the semiconductor devices nearly simultaneously with the application of current to and removal of current from the solenoid (25) of the power contactor. Circuit means (90) responds to the control signals to provide gating current for a limited period of time prior to, during and following the closing of the contacts. Gating current is not continued after the contacts have closed to protect the semiconductors from possible damage. Additional circuit means (110) responds to the removal of the control signal to provide gating current for a limited period of time prior to, during and following the opening of the contacts.

Abstract: A hybrid AC power switching arrangement in which two ganged switch banks in series are employed along with a pair of reverse parallel (back-to-back) SCRs across each contact pair of the second switch gang. SCR control means and interlock control means are provided so that the first switch gang (closest to the power source) closes first, energizing the SCR control and permitting the SCRs to conduct load current in a corresponding phase leg, beginning at or near a zero voltage cross-over point. After all phase legs are conducting through the SCRs, the second switch gang is closed bypassing the SCRs. On circuit break, the second switch gang (i.e., the one closest to the load) is opened first, the load current diverting immediately through the SCRs for another interim period until the SCRs in each individual phase leg are extinguished as the instantaneous current in the corresponding phase lead passes through or near zero.

Abstract: A switching control signal switches a pair of emitter coupled transistors via a drive circuit jointly connected to the base electrodes of the transistors so as to drive the base-to-emitter junctions between an "on" condition in which both base-to-emitter junctions are forward biased and an "off" condition in which both base-to-emitter junctions are reverse biased. In the "on" condition, the collectors of the transistors simulate closed relay contacts capable of conducting substantial current flow and in the "off" condition the collectors simulate open relay contacts capable of accomodating substantial standoff voltages. The drive circuit which controls the "on" and "off" conditions of the transistors includes separate turn "on" and turn "off" circuit paths for producing fast and uniform switching characteristics at the collectors.