Abstract: The integrity and connection of cable wires (10-13) extending between two banks of terminals (20-1 to 20-4 and 16-19) are checked for shorts of the wires to ground, to battery wiring between each other and for opens and misconnections or cross-connections of the wires. Unique recognition circuits are provided for controlling, analyzing (circuits 43, 53, 68, 92, 112, 181) and displaying (displays 23, 24, 31 and 32) the test results to accordingly apprise an operator(s) stationed at either or both ends of the cable.

Abstract: An apparatus for identifying defective substation capacitors includes a variable power supply section for supplying an alternating electric current to a de-energized substation capacitor bank without disconnecting the individually fused capacitor from the capacitor bus and a second power measurement section for measuring the magnitude of the electric current entering the capacitor being tested.

Abstract: Apparatus for determining rotational speed includes a sensor for generating electrical pulse signals representative of rpm in a conventional manner. The electrical pulses are converted to light pulses at the sensor and transmitted to an evaluation circuit, where they are reconverted into electrical pulses that are processed by the evaluation circuit. Interference signals that a rise during the transmission of electrical pulses to the evaluation circuit are thereby eliminated.

Abstract: In determining shaft rpm (revolutions per minute), a transducer generates a succession of output signals, corresponding to the successive passages of a shaft indicium through the transducer field of view. Processing circuitry is provided for selecting a sequentially successive pair of transducer output signals and for computing rpm therefrom. Updated rpm is computed from a further pair of sequentially successive transducer output signals, both non-sequentially successive to the earlier selected signal pair.

Abstract: A circuit arrangement detects and stores power line faults. The occurrence of sporadic faults as represented, for example, by inadmissibly long network collapses, which could lead to shut-down of a current supply and, therefore, to downtime of a computer are generally difficult to detect because the faults disappear given a return of the network, as does, therefore, the prerequisite for detecting the cause of such faults. For the purpose of detecting the cause of the fault, the rectified power line voltage is supplied to a comparison circuit followed by a signal circuit. The signal circuit is connected to a memory which influences a display. As a result, power line faults remain stored despite the return of the power line input voltage. The circuit arrangement is particularly suitable for use in power supply systems for data processing devices.

Abstract: An easily portable test instrument designed to be plugged into a wall socket such as a socket forming part of a telephone modular jack assembly has a barrel part containing test and alarm circuitry the barrel part connected to a rigid jack by a flexible neck through which leads pass to electrically connect the jack to the test and alarm circuitry.

Abstract: An apparatus for capacitance or dampness measurement is provided. The apparatus is particularly suitable for continuous determination of dampness over substantially flat surfaces such as roofs, floors, pavements and walls. The apparatus essentially includes a pair of substantially elongate electrodes attached to a casing which has a pair of removable surface engaging wheels a handle for pushing and steering, a pair of grip handles for carrying and maneuvering, and two recesses, one for a power supply and the other for an electronic monitoring apparatus combined with a read-out display means. The electrodes are separated by a gap of approximately 5 cm and are retained on the casing so as not to be taut but to be slightly floppy so as to permit good contact between the electrodes and the surface to be tested. The value of capacitance/unit area of the electrodes in air is preferably in the range 50 pFm.sup.-2 -150 pFm.sup.-2.

Abstract: An improved electrical conductance soil moisture sensor for landscape and agriculture comprising electrodes imbedded in a granular medium that is separated from the soil to be measured by a layer of filter cloth supported by a plastic or metal screen.

Abstract: Apparatus for detecting at least one predetermined angular position on rotating devices, having a tachogenerator with a stator part and a rotor part for producing a tacho signal with speed-dependent frequency. The stator and rotor parts of the tachogenerator form at least four circumferentially directed, substantially equidistantly spaced pole areas. For the purpose of an angular position-dependent amplitude modulation, a pole clearance is provided in at least one of the pole areas in both the stator part and the rotor part of the tachogenerator. An envelope amplifier with a threshold value stage is preferably connected in series with the tachogenerator and essentially only permits the passage of the angular position signals resulting from the coincidence of pole clearances in the rotor and stator parts of the tachogenerator.

Abstract: A method and a device for detecting ground faults in a network for distribution of electric power from a power station from which a number of lines, included in the network, emanate and where the ground fault current I.sub.J of each line is measured. According to this method, that line is selected (10) which shows the greatest active ground fault current I.sub.JR (8), alternatively the greatest ground fault current I.sub.J, or the greatest change in the ground fault current .DELTA.I.sub.J. Thereafter, the measured ground fault current, or the change thereof, in the selected line is compared (12) with at least one predetermined reference value (11). A fault indication is obtained (13) at a level exceeding the reference value.

Abstract: A speed sensing apparatus (10) counts a predetermined number of gear teeth (18) on a gear (16) driven by a motor (8). The duration of time required to count the predetermined number of gear teeth (18) is compared to a timing signal of preselected duration. The comparison is used to make a determination as to whether the velocity of the gear is above or below a preselected velocity.

Abstract: A device for monitoring ungrounded power distribution systems that indicates the total hazard current from the isolated power conductors to ground. A measurement signal having at least two frequency components different from the power system line frequency is applied across the combined fault impedances that occur between the power conductors and ground. Voltage responses to the measurement signal components are separated from the power system line voltage and from each other by frequency selective means. These distinct voltage responses are proportional to the fault admittance magnitude at the different measurement frequencies. The voltage responses are applied to the computational circuit whose output is proportional to the maximum fault admittance magnitude at the line frequency. A gain signal related to the imbalance of the fault impedances of the different power conductor is used to scale the previously described voltage responses.

Abstract: In a four element modified bridge circuit for measurement purposes at least one impedance element is variable according to a magnitude to be measured. Via a first operational amplifier a DC supply voltage is connected across two bridge nodes facing each other, and at the other two nodes facing each other an output signal is delivered corresponding to the magnitude to be measured. By means of a second operational amplifier one of the output nodes is virtually drawn to ground so that the signal at the second output bridge node is referenced to ground. Thus, the signal at the second output node corresponds to the desired measured magnitude without a superimposed power supply voltage and may be amplified by a third standard operational amplifier without the need of a differential amplifier circuit.

Abstract: A method and apparatus for rendering a high-voltage current-comparator capacitance bridge insensitive to frequency fluctuations when used for measuring inductance. A compensating current, proportional to twice the change in the current through the reference capacitor due to frequency fluctuations, is driven into the first comparator winding through which the current from the reference capacitor passes, resulting in a current in that winding having frequency characteristics similar to those of the current passing through the second winding which is connected to the inductance. This compensating current is derived from a reduced replica of the applied high-voltage by deriving a voltage signal which is a function of the frequency fluctuation, producing an amplitude controlled reduced replica voltage using the frequency fluctuation voltage and converting the amplitude controlled voltage to the compensating current for the first comparator winding.

Abstract: A system for converting mechanical movement of a body under detection to a digital signal comprises a synchro generator having a primary and a secondary windings movable relative to each other, one of the windings capable of being coupled to said body, an exciting circuit for providing multiple-phase exciting currents to the primary winding at a frequency higher than the frequency corresponding to the maximum speed of the body, and a phase-locked-loop control circuit responsive to the output of the secondary winding for generating a frequency-multiplied digital signal at a frequency equal to the product of the frequency of an AC signal induced in the secondary winding and a predetermined factor.

Abstract: Testing device for indicating electric voltage, polarity, and for continuity testing, including:two handles connected by a cable and having test prods;high-resistance series resistors connected to the prods;indicating stages having optical indicating elements with staggered voltage ranges in one handle;an oscillator connected to the indicating stages and to an acoustical signal generator;an isolation amplifier connected between the indicating stages and resistors;a battery connected to the amplifier and activatible by the amplifier;a switching power supply connected to the oscillator;an energy storage device connected to the amplifier;a first switch connected to the battery;a second switch connected between the power supply and the storage device for feeding voltage in a rest position, when the storage device is charged and being switchable into contact for feeding a charge to the amplifier and for checking operability in sequence;transistors having bases connected to the oscillator for intermittently switchi

Abstract: The invention relates to a method for measuring impulse periods, faults locations and attenuations in cables and light wave conductors. The object is to provide a particularly simple method which can be realized with little expense. The solution basically consists in the fact that each measuring impulse releases a saw-tooth generator, that the time value of the voltage delivered from the saw-tooth generator is compared with an adjustable direct current voltage and serves to open a gate circuit at specific times, that the reflected impulse is compared by a second comparator with a second direct current voltage and that the thus separated signals are led to the gate circuit and displayed by an indicator. The invention will primarily be used in locating faults in light wave conductors under difficult conditions on the construction site.

Abstract: An electronic hand held fuse tester includes an elongated handle member to facilitate grasping of the device during use, a housing member integrally formed at one end of the handle, the housing member enclosing an electronic test circuit with light emitting diodes mounted to a PC board, the PC board mounted within the housing to a pair of pivotally mounted contact members, the contact members adapted to contact the ends of the fuse to be tested, and fixtures at the other end of the handle member to facilitate removal and insertion of replacement fuses.

Abstract: The specification discloses a computerized monitor for a coreless induction furnace. The monitor includes a first potential transformer connected across the coil and a second potential transformer connected between one end of the coil and an electric ground. The relative location of a ground fault along the length of the coil is determined by computing the ratio of the transformer outputs. The monitor further includes a first current transformer in the coil power line and a second current transformer in the melt bath ground. Internal ground faults are detected by computing the phase difference between the coil and ground currents. A graphic representation of the furnace is also generated to illustrate the location of the ground fault with respect to turns and yokes of the coil. The monitor also calculates liner wear by determining melt bath volume, which is inversely proportional to melt bath resistance, which in turn is proportional to coil resistance.

Abstract: A probe-type electrical identifying device for identifying individual conductors in a multiple conductor group such as in a cable or extending through a conduit pipe, including a conductor indicator probe and voltage supply unit, wherein the probe has a pair of light emitting diodes (LEDs) of different color and is capable of distinctively identifying as many as five individual conductors in the group. Connector leads having alligator clamps are provided to connect to the individual conductors at one end. The voltage supply unit has switches assigned to five of the connector leads and electrical circuitry is provided to enable distinctive identification of the five different conductors by different activation of the two LEDs in the probe.