Abstract: A corona resistant thermoplastic composition comprises about 15 to about 85 wt % of a thermoplastic resin comprising polyarylene ether and polyarylene sulfide; about 10 to about 30 wt % glass fibers; and about 5 to about 51 wt % of a mineral filler having an average radius of gyration effective to produce a corona resistance of greater than 200 hours when continuously subjected to a voltage of 5000 volts and wherein the weight percents are based on total composition. The compositions find particular utility in automotive applications, for example in under-the-hood applications such as ignition coil cases, as copier components, circuit breaker components, electrical switches, insulators, electronic encapsulants, and other applications requiring enhanced corona resistance.

Abstract: A diagnostic method for determining a characteristic of electrode contacts and/or contacted surfaces comprising the steps of: sensing, during a movement that causes an electrode to have a break contact event with a first contacted surface and to have a make contact event with a second contacted surface, an RF signal from at least one electrical discharge event during that movement; and using a parameter of the RF signal to diagnose the characteristic of the electrode contacts and/or contacted surfaces. In a preferred embodiment of the present invention, a step may be included of sensing, simultaneously with the RF signal sensing step, a vibration signal generated by at least one of the break contact event and the make contact event; and using a parameter of the vibration signal to assist in diagnosing the characteristic of the electrode contacts.

Abstract: A signal obtained from the drive input of a motor or an insulated winding is applied to a sensor that strongly rejects high frequency drive signal components yet passes discharge signal components. This allows discharge signal components to be detected in the presence of harmonics of the drive signal. The voltage of the drive signal may be varied so that the lowest drive signal voltage producing a discharge event may be determined. That voltage is the motor or winding's corona inception voltage.

Abstract: A partial discharge analysis (PDA) coupling device contains a shell, a potting material in the shell encapsulating at least two capacitors and a conductive, flexible joint connecting the capacitors. The joint may be a hose clamp or a spring which expands during the thermal expansion of the potting material while providing an electrical connection between the capacitors.

Abstract: A hydrophobicity imparting particulate is a hydrophobicity imparting particulate. A silicone composition comprises (A) a silicone polymer and (B) a hydrophobicity imparting particulate filler that imparts a hydrophobicity property to the composition. An insulator comprises a housing portion that includes a cured product of (A) a silicone polymer and (B) an hydrophobicity imparting particulate filler. A hydrophobicity recovery property of a silicone polymer composition can be improved by determining a target hydrophobicity recovery property for the cured silicone composition, selecting an hydrophobicity imparting particulate (HIP) to impart the hydrophobicity recovery property to the silicone polymer composition and compounding a blend of (A) a silicone polymer and (B) the selected inorganic filler and heating to cure the blend.

Abstract: A stray field electrode (1) includes a base material (2) and a conductive filler material (3). The base material is preferably an insulating material, such as a silicone elastomer film. The conductive filler material is preferably a metal, such as silver particles dispersed in the silicone elastomer film. A set of stray field electrodes (16, 17, 18) may be used to determine the presence of water in a material (8), such as electrical generator insulation (14), by comparing a phase angle for the electric field (19, 20) between the electrodes with a predetermined phase angle for a dry material (8).

Abstract: A radio frequency (RF) or other form of detector detects discharges of an insulated system which can occur when electrical insulation becomes wet, for subsequent analysis and decision processes. Additionally, for RF detection, a frequency selector can be used to select a “quiet” region of the discharge spectrum before demodulation and further analysis and decision. Finally, redundant sets of such filters avoid the need to continuously reconfigure the detection system.

Abstract: A partial discharge (PD) coupler for coupling electrical machinery to partial discharge analysis testing equipment includes at least one capacitor capable of withstanding high voltages; a current sensor for sensing current passed by the at least one capacitor; and potting material surrounding the at least one capacitor and the current sensor for providing flashover protection.

Abstract: A hydrophobicity imparting particulate is a hydrophobicity imparting particulate. A silicone composition comprises (A) a silicone polymer and (B) a hydrophobicity imparting particulate filler that imparts a hydrophobicity property to the composition. An insulator comprises a housing portion that includes a cured product of (A) a silicone polymer and (B) an hydrophobicity imparting particulate filler. A hydrophobicity recovery property of a silicone polymer composition can be improved by determining a target hydrophobicity recovery property for the cured silicone composition, selecting an hydrophobicity imparting particulate (HIP) to impart the hydrophobicity recovery property to the silicone polymer composition and compounding a blend of (A) a silicone polymer and (B) the selected inorganic filler and heating to cure the blend.

Abstract: Statistical methods of partial discharge analysis utilizing histogram similarity measures are provided by quality assessment and condition monitoring methods of evaluating high voltage electrical insulation. The quality assessment method is utilized to evaluate the quality of insulation within the electrical equipment. The condition monitoring method is utilized during normal operation of the equipment to identify degradation in the insulation and to predict catastrophic insulation failures.

Abstract: An improved process for determining the presence of water in a material is disclosed. A set of electrodes is placed on the surface of a layer of the material being monitored, and an electric field is established therebetween. The phase angle for the electric field at a pre-selected frequency is measured, and compared with a predetermined phase angle for a dry portion of the material. A significant difference between the phase angle for the material being monitored and the predetermined phase angle is indicative of the presence of water in the material. The material being monitored may be an electrical insulating material, e.g., for conductive components in water-cooled electrical generators. Electrical generators monitored in this manner are also within the scope of this disclosure.

Abstract: Statistical methods of partial discharge analysis utilizing histogram similarity measures are provided by quality assessment and condition monitoring methods of evaluating high voltage electrical insulation. The quality assessment method is utilized to evaluate the quality of insulation within the electrical equipment. The condition monitoring method is utilized during normal operation of the equipment to identify degradation in the insulation and to predict catastrophic insulation failures.

Abstract: A partial discharge (PD) coupler includes at least one high voltage capacitor; potting material surrounding the capacitor; and a fuse physically and electrically connected in series to the capacitor. The capacitor and the fuse are capable of passing high frequency partial discharge with minimal attenuation. The PD coupler can have potting material surrounding both the capacitor and the fuse. The PD coupler can include a housing surrounding the capacitor, the potting material, and the fuse.