Abstract: A bridging contact is arranged across two fixed contacts with a pair of parallel, closely spaced conductors serving as the bridging contact carrier. A high current pulse in opposite direction within the parallel conductors generates electrodynamic forces rapidly propelling the conductors further apart. The bridging contact carried by the parallel conductors is rapidly driven out of contact relation with the fixed contacts to interrupt the circuit.

Abstract: Steering logic (10) for interconnecting a transceiver (11) with a baseband bus is disclosed. The transceiver is connected to a broadband bus and transmits or receives modulated carrier wave signals. The transceiver has a data in terminal (16 or 19) and a data out terminal (18 or 35) for inputting or outputting digital signals at baseband. The transceiver also has at least one control terminal (20 or 32 and 38) and is responsive to a control signal or signals for enabling or disabling the transmitting and receiving functions of the transceiver. The steering logic (10) includes a baseband bus terminal (A) to which may be applied baseband digital transmit signals and to which the steering logic may apply digital receive signals. The logic circuitry is responsive to baseband digital transmit signals applied to the baseband bus terminal (A) for generating a control signal or signals to enable the transmitting function and disable the receiving function of the transceiver.

Abstract: A circuit is employed to determine the presence of an open ground connection between a power source and a movable machine connected with the power source by means of a flexible cable. The circuit comprises a pulse generator for transmission of a pulse along the cable between the power source and the movable machine in combination with comparison means for determining whether the reflected pulse back along the cable from the movable machine becomes inverted upon reflection. The presence of a non-inverted reflected pulse indicates an open ground connection. Means are provided for disconnection of power between the power source and the movable machine upon the absence of receipt of an inverted reflected pulse along the connecting cable.

Abstract: Arcless circuit interruption from metallic contacts is accomplished by the combination of a solid state current interrupter with a control circuit and an impedance circuit. The impedance circuit diverts the contact circuit current through the solid state current interrupter prior to initiating contact separation. The contacts then open without sufficient current transfer to establish an arc.

Abstract: A solid state circuit interrupter utilizes a power transistor connected across a pair of separable contacts to eliminate contact arcing between the contacts upon circuit interruption. Stored charge is provided to the power transistor prior to contact separation by a separate power supply and control transistor which are immediately turned off after contact separation to turn off the power transistor upon depletion of the stored charge.

Abstract: Differential current static trip circuits interconnected with upstream and downstream current sensing transformers in a protected system provide automatic coordination of the downstream static trip circuit breakers. The differential current transformer associated with the breakers vectorially sense the difference between the upstream breaker currents and the sum of the downstream breaker currents. The output is processed within the trip circuits for I.sup.2 t and fixed time band delays to insure that the downstream breakers clear the fault.

Abstract: A gate turn-off thyristor is connected across a pair of separable contacts for diverting the interrupted current first to the thyristor and then to a metal oxide varistor connected across the thyristor. A saturable core current transformer in combination with the capacitance provided by the metal oxide varistor turns on the thyristor when the contacts separate and turns off the thyristor after the contacts have further separated when the core becomes saturated.

Abstract: A bridging contact abuts one end of a piezoelectric bar and is held across a pair of current carrying fixed contacts by means of a compression spring to assure a good electrical conductive path across the fixed contacts. To separate the contacts, a voltage pulse is applied to the piezoelectric bar in a direction transverse to its linear extent. The rapid expansion of the piezoelectric bar drives the bridging contact rapidly away from the fixed contact pair to interrupt the current therethrough.

Abstract: A noise inverter circuit substantially reduces the effects of noise generated within power lines operating as a communication media. Input noise signals are clipped to reduce the noise wave amplitude and the peak amplitude is inverted to a value less than the signal amplitude. By limiting the positive rate of change of peak signal amplitude, the prevailing signal level is averaged over a longer time base than the duration of the noise wave.

Abstract: A change of state circuit breaker contact material provides a low contact resistance at a low closing force by reducing current density through a pair of circuit breaker contacts. The use of a meltable metal alloy within the contact structure forces the current through a wider area of conduction whenever the temperature increases to melt correspondingly larger quantities of the metal alloy. The reduced contact hardness results in a substantial decrease in the force required to hold the contacts together, thereby allowing the contacts to open more quickly.

Abstract: A current limiting circuit breaker utilizes a first pair of contacts for carrying continuous current and controlled by an operating mechanism. A second pair of contacts is arranged on a pair of movable contact arms ahead of an arc chute for rapid repulsion under high current fault conditions.

Abstract: A flux shifting circuit breaker trip device is disclosed which includes a permanent magnet for retaining a solenoid armature in opposition to a spring force. Energization of the solenoid winding produces a magnetic flux in opposition to the permanent magnet flux to extend the armature under the spring force. In order to provide ambient temperature response, the solenoid armature is formed from a stem part and a barrel part held together by a meltable material. Increase in ambient temperature above a predetermined value causes the material to melt allowing the stem part to extend under the spring force to trip the breaker.

Abstract: A fault current interrupter is provided by the parallel combination of a positive temperature coefficient resistor and a voltage dependent resistor connected across a pair of separable contacts to permit the interruption of current without the occurrence of arcing between the contacts when the contacts first become separated. The positive temperature coefficient resistor is selected to have a relatively low resistance at room temperature and a substantially higher resistance at higher temperatures. This allows the current to transfer away from the contacts through the positive temperature coefficient resistor until the voltage across the voltage dependent resistor causes the voltage dependent resistor to become conductive and thereby transfer the current away from the positive temperature coefficient resistor.

Abstract: An ASK carrier current digital data transceiver for transparent transfer of data between a broadband communication port and a baseband port consists mainly of an integrated circuit with transmit/receive logic for providing the required transparency and the ability to sense a contending signal. The transmit/receive logic places the transceiver in the transmit mode only when the baseband port is pulled low externally and not internally. This provides "listen-while-talk" contention sensing when the baseband port is high.

Abstract: A time domain filter having ideal high pass and low pass characteristics is provided by means of a one-shot monostable multivibrator and a flip-flop interconnected by means of an AND gate and an EXCLUSIVE-OR gate wherein the set time for the one-shot is equal to the half-period of the cut-off frequency. The time domain bandpass filter circuit having ideal bandpass filter characteristics comprises a pair of one-shot monostable multivibrators connected in cascade with each other and interconnected with a flip-flop by means of an AND gate. A further application of a modified time domain filter is that of time domain FM demodulator having an optional phase-locked loop.

Abstract: At a point on a residential branch circuit downstream from the service entry load center where the termination of the neutral conductor thereof is solidly clamped to ground and the ground conductor is terminated in electrical connection in common with the neutral conductor termination, a transformer is linked with one of the neutral and ground conductors. Downstream from the transformer, a capacitive coupler is connected across the branch circuit neutral and ground conductors. A transmitter of high frequency voltage signals is connected with either the transformer or capacitive coupler and a signal receiver is connected with the other thereof, such as to establish a communications lin between the transmitter and receiver using the branch circuit neutral and ground conductors.

Abstract: Separate bargraph displays controlled by the electronic trip unit of a static trip circuit breaker continuously indicate the magnitude of the highest phase current as a percentage of the log-time delay pickup current setting and the timing out of a long-time delay as a percentage of the applicable long-time trip delay interval for a given phase current in excess of the long-time delay pickup setting.

Abstract: An integrated circuit ground fault signal processor utilizes a power supply having a first, regulated, half-wave rectified supply voltage section and second DC supply voltage section. Operating current for a fault signal amplifier and charging current for a fault signal integrating capacitor are drawn from the second power supply section on a full-cycle basis. Operating current for a trip threshold detector or comparator and a high frequency oscillator circuit is drawn from the first power supply section for operation on an alternate half-cycle basis.

Abstract: Power line communication over plural residential branch circuits is accommodated by creating a signal coupling inductive impedance in a tie conductor electrically interconnecting the grounded neutral bus, to which the branch circuit neutral conductors are commonly terminated, and a ground bus commonly terminating the branch circuit ground conductors, such as to support voltage signals propagating on the ground conductors with respect to the neutral conductors of the branch circuits. This inductive impedance is created either by a signal coupling transformer linked with the tie conductor and driven by a signal transmitter, with signal receivers capacitively coupled across the branch circuit neutral and ground conductors, or is of a passive nature, with both transmitters and receivers capacitively coupled across the branch circuit ground and neutral conductors.

Abstract: In an integrated circuit for a ground fault circuit interrupting device, a power supply voltage regulator is utilized to turn on a double grounded neutral excitation oscillator and to inhibit trip initiating thyristor triggering while the half-wave rectified supply voltage is in regulation and, as the supply voltage goes into regulation near the beginning of each alternate half-cycle, condition a comparator to issue a thyristor triggering pulse if an integrated fault signal voltage has achieved an established trip threshold level.