Abstract: A method and a device for determining the fault current which occurs in case of a fault through a short circuit between phases or from phase/phases to ground. A measure of the fault current can be obtained by a linear combination of the sum of measured current samples for each phase at two adjacent points in time and in which each of these sample values is multiplied by a coefficient which is chosen such that the fault current gets into phase with the positive- and negative-sequence current changes.

Abstract: A faulted circuit sensor is disposed in a releasable and reusable clamp mountable on an electrical conductor. The clamp includes a body for receiving the faulted circuit sensor indicating circuitry, and a pair of hinged fingers which actuate over the conductor to grip the clamp to the conductor and align the fault indicating circuitry with respect to the conductor. The fingers include a triggering arm which causes the arms to engage over the conductor when the conductor is properly aligned in the proximity of the clamp.

Abstract: A method for non-intrusively measuring the shielding effectiveness of coaxial wiring by employing an inductive current probe which causes current to flow on the shield of the wiring. A second inductive current probe senses the current on the shield circuit and outputs a voltage which is a function of the shield current. The method employs loop self-impedance in contrast to transfer impedance.

Abstract: An assembly for protecting a conduit having a core and an axial length, which length is susceptible to being pinched by a structure is disclosed. The conduit includes an insulating coating in surrounding relationship about the core, with the assembly including a semiconductive layer in surrounding relationship about the insulating coating, and a switching layer in surrounding relationship about the semiconductive layer. The semiconductive layer being formed from partially vulcanized ethylene propylene rubber including particles of a conductive element in the form of carbon black, silver, nickel, aluminum or the like. The switching layer is non-conductive in its unstressed state and conductive when pinched such that the switching layer completes a current flow path between the semiconductive layer and either a grounded structure or another conductive layer, which condition may then be detected.

Abstract: A self-diagnosing resistance welding cable and method for monitoring the relative increase in cable resistance while a cable is in use, without disconnecting the cable. The cable incorporates a reference resistor in one of the terminals in thermal communication with the cable, such that a comparison in resistance variation between the cable and reference resistor cancels the effects of temperature variation on resistance change. The reference resistor is connected in series with the cable in an electrical test circuit. The test data is sampled each time the welding machine is cycled, and the data is updated and processed by a computer on a continuous basis. The system also monitors the actual temperature of the cable and the flow of coolant through the cable. Multiplexer circuits are used to monitor multiple welding cables with the same computer.

Abstract: A system and method for detecting an improperly terminated network for networks using a collision detection access scheme. Embodiments of the present invention also contemplate a system and method for detecting a short circuit in a network. For detecting both an improperly terminated network and a short circuit in a network, the present invention relies on the detection of certain changes in the voltage of the network.

Abstract: An array processing system including a plurality of processing elements each including a processor and an associated memory module, the system further including a router network over each processing element can transfer messages to other random processing elements, a mechanism by which a processor can transmit data to one of four nearest-neighbor processors. In addition, the processing elements are divided into groups each with four processing elements, in which one of the processing elements can access data in the other processing elements' memory modules. The routing network switches messages in a plurality of switching stages, with each stage connecting to the next stage through communucations paths that are divided into groups, each group, in turn being associated with selected address signals. A communications path continuity test circuit associated with each path detects any discontinuity in the communications path and disables the path.

Abstract: A fault indicator for indicating the occurrence of a fault current in a monitored conductor includes an electrostatically-actuated indicator assembly. During normal operation a lightweight indicator flag rotatably mounted in and viewable from the exterior of the indicator housing is held in a reset-indicating position by electrostatic force resulting from an electric field existing between the flag and adjacent electrodes. Upon occurrence of a fault current in the monitored conductor the electric field is removed and the indicator flag, under the influence of a permanent magnet, is caused to rotate to a fault-indicating position. By avoiding the use of magnetic actuator windings and associated pole pieces the indicator assembly is easier and more economical to construct.

Abstract: A method and apparatus are provided for determining transmission line parameters of a length of single-wire transmission line that is deployed in seawater. The seawater is utilized as an electrically grounded return for the transmission line such that a two-port network is formed at either end of the transmission line. An alternating voltage of known amplitude and frequency is generated and applied to a first end of the length of transmission line. Open and short circuit parameters at the first end are then determined as a second end of the length of transmission line is alternately switched between a open and short circuit mode. The alternating voltage of known amplitude and frequency is then applied to the second end as the first end is alternately switched between an open and short circuit mode so that open and short circuit parameters may be similarly determined at the second end.

Abstract: Method and apparatus for identifying and determining the energization status of a cable having a conductive neutral member and an internal resistive screen layer involving probes radially movable relative to the cable to contact the neutral member and the internal resistive screen. Narrow-band AC signals and resistance measurements are utilized for self-testing and for cable testing. A microprocessor controls probe-heating in the advancing of probes through plastic sheath to reach the neutral wire and resistive screen layer. Resistance measurements made under control of the microprocessor are monitored with probe advance. Oscillators provide two signals of different frequencies, one of which is that of the power being transmitted through the cable, to provide distinctive signals indicative of cable energization status.

Abstract: An indicator for instantaneously indicating the presence of voltage on a monitored electrical conductor of an AC power distribution system utilizes a high impedance liquid crystal display component providing an "N" display in response to an applied signal. The "N" segment display electrode and associated backplane display electrode are capacitively coupled to the monitored conductor and system ground to provide an "N" display when voltage is present on the conductor.

Abstract: An apparatus and a method for detecting conductive irregularities in an overwrapped ignition wire core during the manufacturing process thereof which preferably includes two conductive sheaves spaced preferably 24 inches apart about which the wire core is traversed and preferably two non-conductive sheaves for bending the wire core between the two conductive sheaves. A current is induced in the overwrapped wire core between the two conductive sheaves and is monitored by preferably a Newport Model Q90010, indicator/controller module or equivalent which includes means for converting the monitored current into a resistance reading which is compared against predetermined resistance end point limits. A numerical reading indicating resistance is displaced on the face of the inductor/controller module.

Abstract: A method of detecting insulation defects in a wire using an extended ion source wherein ions are generated along the entire length of the extended ion source and flow toward an insulated cable located in close proximity thereto. If there are defects in the cable insulation, a real current will flow through the insulation defects and into the cable conductor. The presence of this real current can be measured by connecting one end of the cable conductor to an ammeter and changes in this current indicate the existence of a defect in the wire insulation. In another embodiment of the extended ion source, the ions are generated only in a small portion of the extended source at any one time. By exciting the source with the proper sequence of signals, the ion generation scans or propagates along the entire length of the extended ion source.

Abstract: The present invention incorporates a conductor contact apparatus, a conductor defect detector, and a relay or equivalent added to the emergency stop circuit of a conductor insulation extruder apparatus in order to detect conductor defects and shut-down the extrusion apparatus before the conductor defect can cause the extruder to become blocked, interrupting normal production operations. The defect detector is especially adapted to detect variations in the cross-sectional area (or apparent cross-sectional area) of a conductor being insulated.

Abstract: A pocket-size Time Domain Reflectometer is described. The pocket-size Time Domain Reflectometer consists of a pulse generator for producing a test pulse along with a delay line for delaying the test pulse before it is transmitted to a cable whose impedance characteristics are to be determined along its entire length. A test connector outputs the delayed test pulse to the cable that is being tested and the test connector receives reflections of the test pulse produced by the cable. The delay pulse generator produces a delay pulse having a pulse width identical to the test pulse at a time t after the production of a test pulse determined by the delay adjuster which is set in accordance with the specific point along the length of the cable which is being tested. A reflection sensing device is reponsive to the delay pulse and reflections received by the test connector and produces a reflection output signal which is monitored by a meter.

Abstract: In order to test conductors on substrates for current constricting defects, such as cracks, narrow conductors, line breaks and intermittent opens, a test signal combining two alternating current signals at different frequencies and direct current offset signal is applied to the conductor. Upon encountering a defect, intermodulation signals are generated and detected. The phase of the detected signal and the phase of a reference signal are compared. The difference between the phase of the two signals is indicative of the presence of a defect in the conductor. The invention has particular application for testing thin conductors.

Abstract: A device for testing continuity of coaxial cables and tracing coaxial cables through junction boxes and the like includes a cylindrical housing formed in penlight fashion with an LED at the distal end and a battery disposed therein. The proximal end of the housing is provided with a female coaxial fitting having the conductor receiving portion connected in the LED-battery circuit. A cable terminator is provided, including a male coaxial fitting in which the conductor portion is shorted directly to the shield-engaging portion. The cable terminator is secured to a distant end of a coaxial cable, e.g., far removed from a cable junction box. The female coaxial fitting is secured to one of many near cable ends within or exiting from a junction box; if the coaxial circuit is completed and the LED is illuminated, it is determined that the distant and near cable ends are opposite ends of the same coaxial cable.

Abstract: A method and apparatus for detecting breakage of a wire electrode in an electric discharge machining apparatus, and an apparatus for carrying out this method, whereby breakage of the wire electrode is detected by detecting a change in a current from a detection power source provided separately from the main power source. Current from the detection power source is applied through the wire electrode by a roller in contact therewith. When the wire electrode is unbroken, current passes from the detection power source, through the wire electrode, to an optical coupling circuit, the secondary of the latter driving and indicating circuit. When the wire electrode breaks, the power flow to the primary of the optical coupling circuit is interrupted, thereby indicating breakage of the wire electrode.

Abstract: An acoustic detection method and apparatus includes a source of high voltage pulses to be applied to an underground cable suspected of having a ground fault. As the pulses encounter the fault, acoustic energy is generated which may be sensed by a pair of transducers located along the path of the cable. The transducers are connected to signal processing circuitry which provides a display signal indicating which of the two transducers lies closer to the fault. The transducers are moved along the path of the cable in the direction indicated and the test is repeated until the fault is indicated as lying in the opposite direction. Thereafter the transducer are moved in the opposite direction in a shorter increment. This procedure is repeated until the direction to the fault changes each time the transducers are moved. The fault then lies midway between the midpoints of each of the two final transducer positions.

Abstract: A reset coordinated fault indicator for indicating the occurrence of a fault current in a monitored conductor includes an electrically actuated indicator flag. A trip circuit within the fault indicator impulses the indicator flag from a normal reset-indicating state to a fault-indicating state following the occurrence of a fault current in the conductor. A reset circuit periodically impulses the indicator flag to the reset-indicating state upon restoration of power to the conductor. To preclude simultaneous actuation of the trip and reset circuits and consequent failure of the indicator flag to register a fault, the trip circuit, upon the occurrence of a fault, first actuates the reset circuit to render the reset circuit inoperative, and then actuates the indicator flag to provide a fault indication.

Abstract: A system for testing conductor lines in a printed circuit board includes circuitry for the burning out of constricted regions of the printed circuit lines so as to insure that such defects are noticed. The system includes circuitry for measuring the resistance in a path through a printed circuit line under test and including connecting circuitry to a generator of an electrical pulse. A resistor network and switching circuitry is employed for adjusting the resistance of the path through a desired value. The electrical pulse is generated by the discharge of a capacitor previously charged to a predetermined value of voltage, the discharge occurring via a pulsing circuit switch which limits the duration of the pulse through a predetermined value of sufficiently short duration to prevent damage to the circuit board associated with excessive heating.

Abstract: A current sensing circuit senses current and signals if such current exceeds a predetermined level within an etched circuit board. The circuit comprises a conductive trace of a predetermined resistance within a metallization layer of the board and a reference voltage circuit and comparator coupled to the trace. The reference voltage circuit senses voltage at first sense point on the trace and offsets the voltage a predetermined amount to form a reference voltage. The comparator senses voltage at a second sense point on the trace and compares it to the reference voltage. So long as the second voltage exceeds the reference voltage, the comparator indicates that the current is below the predetermined level. If the second voltage drops below the reference voltage, the comparator generates an output signal indicating that the current has exceeded the predetermined level.