Abstract: A fault distance locator for underground cable circuits for calculating more accurately the location of a cable fault includes a pulse generator unit for injecting a series of chirped pulse streams into the faulted cable shortly after the cable fault has been established. The delay times between the reflected pulse signals and the sending pulse signals are obtained by a correlation process which is specially designed to eliminate the effect of noise caused by arcing voltage and thus provide an accurate calculation of the distance to the cable fault. The accuracy is further enhanced by injecting pre-fault pulse signals periodically into the cable prior to the occurrence of the cable fault in order to obtain a reference pulse signal. This pulse signal provides information concerning the speed of propagation of the cable and thus affects the distance calculation to the fault.

Abstract: The reliability of thin film insulators is determined with noise measurements which find the barrier height mean and standard deviation. A constant voltage source is applied across the thin film insulator. A low noise amplifier is connected across a resistor which is in series with the insulator. A spectrum analyzer is connected to the low noise amplifier. The power density is obtained by observing the output of a spectrum analyzer. The current spectral density is compared to a predetermined reference to detect the presence of defects in the insulator.

Abstract: The apparatus for testing electrical switch matrices includes a potential selector (30) for receiving and applying a voltage (28) to a predetermined input (101-106) of each of the plurality of electrical switches (12), a controller (15) for receiving and applying signals to the plurality of electrical switches (12), and a combiner (36) responsive to an output (22) of each of the plurality of electrical switches (12). The controller (15) selects electrical paths (16) associated with each of the switches (12) which are in communication with the predetermined inputs (101-106) of each of the switches. The output (38) of the combiner (36) indicates whether at least one of the selected electrical paths (16) failed.

Abstract: A metal particle detecting sensor (10), having a simple structure, can perform in-line analysis for metal particles in fluid and also can precisely estimate or detect the number of metal particles for each particle size. Metal films (1) and insulating films (2) are alternately laminated one upon another, and every other metal film (1) in the laminate is connected in parallel with one another to one of two lead wires (3a, 3b) so as to form comb electrodes in the laminate of the sensor, and one end face of the laminate is immersed in a fluid (4) containing metal particles so as to detect the metal particles.

Abstract: Fluid transmission pipelines and similar structures which are cathodically protected from electrolytic corrosion and are disposed in urban areas under pavements and other structures which prevent access to the soil for verifying pipe-to-soil potentials are subjected to pipe-to-soil potential measurements using a reference electrode disposed in a container which has a permeable bottom and which is capable of saturating a pavement layer with a brine electrolyte to provide electrical conductivity between the reference electrode and the soil. Validation of electrical conductivity is made by a second reference electrode of a dissimilar metal which is also disposed in a container having a permeable bottom and an electrolyte which permeates the pavement layer and establishes electrical conductivity between the soil and the second reference electrode. Potential measurements between the first and second electrodes validate ion transport between the soil and the first reference electrode.

Abstract: An electric fence energizing apparatus is described in which a chargeable capacitor is connected to the primary winding of a transformer. The secondary winding of the fence is connected to receive pulses at the discharge of the capacitor, the discharge time serving as a measure of the voltage of the corresponding output pulse on the fence. The primary winding of the transformer is divided into two oppositely connected windings. The capacitor is arranged to be discharged through a first one of the primary windings. A voltage determined by the discharge of the capacitor is produced over the second of the primary windings during the discharge process. A measuring unit measure the time of the duration of this voltage over the second winding determined by the discharge of the capacitor.

Abstract: A condition indicator assembly (tester) for determining the condition of a main cell, e.g. a battery, is disclosed. The condition indicator assembly may comprise an electrochemical indicator cell connected in series to a auxiliary cell. The indicator cell and auxiliary cell each have an anode, cathode and electromotive force (e.m.f.) of its own. The condition indicator assembly may be permanently connected in parallel to the terminals of a main cell being tested. The condition indicator assembly is thin enough that it may be interated into a label for the main cell. As the main cell discharges, the indicator cell anode clears proportionally to the discharge of one of the electrodes of the main cell to provide a continuous visually discernible indication of the state of charge of the main cell.

Abstract: A method for indicating electrical breakdown in a nonconductive water coog system for high power electrical equipment at an early stage so as to avoid the danger of accidental faults. The method utilizing a small resistor to generate a detectable voltage when the resistance of the water breaks down, thus degrading from a nonconductive to a conductive state. Once a voltage is detected, the electrical equipment is shut down until the cooling water is made nonconductive again. An apparatus for indicating electrical breakdown in a water cooling system for high power electrical equipment is also provided.

Abstract: A mobile x-ray unit operates from a rechargeable battery in a number of different modes which draw current from the battery. Remaining battery capacity is calculated by integrating the current drawn from the battery in each of its operating modes, and periodically subtracting this value from a value indicative of remaining capacity. The result is displayed to provide an accurate indication of remaining battery capacity.

Abstract: A non-invasive testing system for video signals includes a jack having a monitor conductor connected across an amplification circuit to a central conductor. The amplification circuit amplifies the power of a signal drawn off of the central conductor such that the power level at the monitor conductor is substantially equal to the power level on the central conductor. When it is desired to test a power level of a signal being produced by a video source, test equipment is connected to the monitor conductor to permit non-invasive testing of the signal.

Abstract: A battery pack (10) has a charge measurement circuit (12) for estimating the state of charge during use. The charge measurement circuit (12) includes a sense resistor (24), amplifier (26), at least one oscillator (28), counter (30), and a communications circuit (32). The battery pack powers a host device (16), which has a limited number of modes of operation, each mode requiring a different current level. The number of oscillators (28) equals the number of modes of operation of the host device (16). As current is drawn from the battery cells (18), the sense resistor (24) and amplifier (26) act to convert the current to a voltage level. The voltage level is fed to each oscillator (28) present. Each oscillator (28) provides a clock signal at a frequency corresponding to one mode of operation of the host device, and is activated when the voltage level is within a preselected range. The clock signal is fed to a counter (30), which counts at a rate determined by the frequency of the active oscillator (28).

Abstract: A circuit is provided for generating a voltage signal corresponding to a wiper position in a linear or circular potentiometer having an open wiper position or an open wiper angle, respectively. The voltage signal circuit includes provisions for determining when a wiper is in an open wiper position or angle region. When the circuit is used with a freely rotating circular potentiometer, the voltage signal may be used to determine wind direction. The circuit includes a voltage source coupled to a conducting element and a wiper. A pulling resistor driven by an operational amplifier is coupled to the wiper and voltage source to provide an identifiable voltage signal corresponding to the open wiper state during rotation through the open wiper angle region.

Abstract: Impedance of an energized electrical line which carries electrical current at a predetermined line frequency is nondistruptively measured at frequencies which are above and below the predetermined line frequency. A measurement current is generated at a measurement frequency between, for example, 10 Hz and 30 kHz for a 60 Hz line. The current generator is coupled to the energized electrical line by an isolating circuit which blocks only the predetermined line frequency and frequencies which differ from the predetermined line frequency by substantially less than the predetermined line frequency. For example, a notch filter may be used. A current sensor measures the line current in the energized line at the measurement frequency. A voltage sensor measures the line voltage in the energized electrical line at the measurement frequency. An analyzer determines impedance of the energized line at the measurement frequency. The measurement is repeated over a wide range of frequencies above and below the line frequency.

Abstract: An apparatus and method for measuring the variation in the capacitance of a capacitive sensor. The apparatus and method include means for constantly applying a constant electrically current to an electrode of the capacitor and means for generating a first series of timing pulses. The voltage on the capacitor is compared to a reference voltage and an electrical signal is generated when the voltage on the capacitor reaches a first voltage which exceeds the reference voltage. The first series of timing pulses emitted by the generating means from the time that the charging of the capacitor beings until the electrical signal is generated is counted and an output signal is generated corresponding to the number of timing pulses counted. An application of the sensor to the measurement of the change in length of a telescoping device such as a shock absorber is also disclosed.

Abstract: An apparatus is disclosed for determining the concentration of a fluid. In one aspect of the invention an apparatus for detecting the ionic concentration of a fluid is provided. The ionic concentration detecting apparatus may include a resonance coil or other suitable receiver that arranged to be influence by the fluid being monitored. The resonance coil is driven by a high frequency signal having a frequency in the range of 10-100 MHz. A detector is provided to measure the losses experienced by the resonance coil. In another aspect of the invention, an ultrasonic based density detecting apparatus for detecting the density of the fluid is provided. The ionic concentration detecting device may be used in conjunction with the density determining device to provide concentration detecting capabilities for solutions having multiple constituents.

Abstract: A load test system for testing an engine/generator (12) and battery set (14) of a backup power system by simulating a load with desired linear, non-linear and/or reactive load characteristics. The load test system also recharges the battery set (14) after testing. Battery imbalance circuit (40) is connected to battery set (14) to determine whether bad cells are present therein. Controller (110) uses signals from current monitors (24, 125) to monitor the current, and isolation transformer (47) to monitor the AC line voltage. The controller (110) simulates a desired load by causing a rectifier (200) comprising thyristors to turn on at a selected point on the AC waveform and/or by causing a load bank (300) to draw a predetermined load current when a predetermined load voltage is present. Capacitive load circuit (28) selectively places a large capacitance across the DC bus (203). When the capacitance is present, surge current at thyristor turn-on simulates a non-linear or reactive load.

Abstract: A tomographic technique for determining the power distribution of an electron beam using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams. A refractory metal disk with a number of radially extending slits is placed above a Faraday cup. The beam is swept in a circular pattern so that its path crosses each slit in a perpendicular manner, thus acquiring all the data needed for a reconstruction in one circular sweep. Also, a single computer is used to generate the signals actuating the sweep, to acquire that data, and to do the reconstruction, thus reducing the time and equipment necessary to complete the process.

Abstract: A water purity testing system includes a sensor housing having an internal chamber within which pair of electrodes are supported. Fittings are provided for coupling the housing to a water supply and introducing water into the chamber. A temperature sensor is supported within the housing. A system processor and control unit is operatively coupled to the electrodes and the temperature sensor and includes a source of voltage DC current measurement which is applied to the electrodes to facilitate the measurement of water conductivity within the housing chamber, followed by a grounding period to provide as settling time to prevent the build-up of debris on the electrodes. The microprocessor also utilizes the temperature measurement during the testing cycle to derive a temperature factored measurement of total dissolved solids within the water under test. A display system is coupled to the microprocessor and is operated under microprocessor control to provide a test result display output.

Abstract: A misfire detecting device for an ignition system, comprises high voltage applying device for applying a pulsed high voltage to each spark plug of an engine after completion of firing of the spark plug, voltage restricting device for restricting a peak of the pulsed high voltage to a highest possible value that does not cause firing of the spark plug, voltage detecting component for detecting a plug voltage across a center electrode-to-outer electrode of the spark plug after reducing the same, and misfire detecting device for detecting a misfire at each cylinder on the basis of a decay characteristic of a detection voltage which is caused by application of the pulsed high voltage.

Abstract: A microwave densitometer comprises a phase difference detecting section for detecting a phase difference between a microwave generated from a microwave generator and a microwave received by a microwave receiver, a rotation number updating section for varying a value of number of rotations "n", a correcting section for obtaining a difference value .DELTA..THETA. indicating a difference between a true phase difference .THETA..sub.2 and a reference phase difference .THETA..sub.1 ' a signal converter for converting the difference value .DELTA..THETA. to a concentration signal an operation mode setter for setting a operation mode, and a holding circuit for holding the number of rotations "n" and the apparent phase difference .THETA..sub.2 ' when a concentration measuring operation of the fluid to be measured is switched to a non-measuring operation in response to a change of the operation mode set to the operation mode setter.