Abstract: Electrical insulation materials containing a synergistic mixture of either a metal acetylacetonate and a dicyclopentadienyl metal compound, a chromium salt and a dicyclopentadienyl compound, or a chromium salt and a metal acetylacetonate have unexpectedly high levels of corona resistance. The insulation materials preferably are prepared by dissolving the synergistic mixture in an organic resin such as an epoxy resin and then curing the resin.

Abstract: The first capacitor of a capacitive divider adapted for measuring the voltage on a bus bar utilizes the bus bar as one plate, the normal insulation provided on the bus bar as the dielectric and a first conductive layer applied over the insulation as the second plate. While a separate capacitor can be used for the second capacitor of the capacitive divider, preferably the first conductive layer serves as a common plate for both capacitors, with a second insulation layer applied over the first conductive layer forming the dielectric of the second capacitor, and a second conductive layer applied over the second insulation layer serving as the second plate which is grounded. The voltage on the common plate formed by the first conductive layer is applied to a voltmeter to provide a voltage reading proportional to the voltage on the bus bar.

Abstract: Disclosed is an apparatus for determining the eccentricity of insulation on an elongated conductor comprising two flat parallel opposing electrodes positionable on opposite sides of an insulated conductor in physical contact with the insulation of the conductor, means for moving one of the two electrodes relative to the other in a direction parallel to the electrodes, whereby the insulated conductor is rotated therebetween, electrical contact means for making electrical contact to the conductor, means for translating the electrical contact means at the same rate that the insulating conductor is translated between the two flat opposing electrodes, and electrical means for determining the ratio of the capacitance of each of the two electrodes to the conductor as the insulating conductor is rotated between the two electrodes.

Abstract: Disclosed is a method of determining the eccentricity of the insulation on a round wire without making electrical contact with the wire. The insulated wire is passed between two pairs of opposing electrodes, pair A-C and pair B-D, positioned at a known distance from the insulated wire and spaced apart azimuthally at a known angle. Known, out of phase, alternating voltages are applied to each pair of electrodes. Signals are generated from the four electrodes that are proportional to (1) v.sub.A -v.sub.B +v.sub.C -v.sub.D and (2) -v.sub.A -v.sub.B +v.sub.C +v.sub.D, where v.sub.A, v.sub.B, v.sub.C, and v.sub.D are the voltages on electrodes A, B, C, and D, respectively. From those signals the eccentricity of the insulation on the wire can be determined by ##EQU1## where .vertline.q.vertline. is the magnitude of ##EQU2## The direction of the eccentricity can be determined from the difference in phase between the two signals.

Abstract: Disclosed is a method of measuring the depletion of basic additives in a lubricating oil. A sensor is immersed into the oil, an electric current is passed through the sensor, and the resistance of the sensor is measured. The sensor is made of copper, lead, mixtures of copper and lead, copper alloys, lead alloys, or mixtures thereof. Also disclosed is apparatus for indicating when the basic additives in a lubricating oil have been depleted. The apparatus consists of a sensor which is immersed in the oil, a first pair of electrodes for passing an electric current through the sensor, a second pair of electrodes for measuring the electrical resistance of the sensor, and an indicator for indicating when the electrical resistance has increased to a predetermined amount.

Abstract: Apparatus for detecting and locating corona discharges within the tank of an electrical apparatus. Acoustic waveguides are disposed within a tank of an electrical apparatus, with each having one end situated in proximity with a portion of the electrical apparatus to transmit acoustic emissions from the source of a corona or partial discharge to acoustic sensors located at remote locations.

Abstract: An electric fuse is disposed within a fluid tight submersible enclosure. The status of the fuse is indicated by an externally mounted neon lamp. The outside surface of the enclosure is coated with conductive paint for safety. Likewise, most of the inside surface of the enclosure is coated with conductive paint to reduce corona therein. A relatively thin annular band of semiconductive paint is disposed between terminals of the fuse apparatus on the inner surface of the enclosure. The enclosure is made primarily of insulating material. When the fuse blows, the voltage difference between the opposite ends of the fuse is capacitively coupled through the enclosure to the indicator. The indicator is sensitive to a change in voltage thereacross and periodically illuminates to indicate that the fuse within has blown.

Abstract: A low frequency oscillator including a pair of novel integrator circuits and a resistive inverter circuit electrically connected together in cascade and having ganged gain control following each integrator. The novel integrator circuit includes an operational amplifier having first and second input terminals, said first input terminal being adapted for connection to a voltage source and including a resistor between said source and terminal. A first negative feedback loop including a capacitor is electrically connected between the output of the amplifier and the first terminal. A second positive frequency independent feedback loop is electrically connected between the output of the amplifier and the second input terminal. The second feedback loop preferably includes a voltage divider having a temperature variable resistor and a pair of independent heaters for varying the resistance of said resistor.