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The addition of fillers, such as talc, mica and carbon black, are used commonly in industry to improve physical properties of polymers, such as stiffness, hardness, wear, heat distortion temperature or electrical conductivity, or to reduce the overall raw material cost of a part. Not withstanding these opportunities, the addition of micron-sized fillers to a polymer may have detrimental effects on...
Partial-discharge (PD) characteristics in three gases (air, argon and helium) at pressures between 101 kPa (760 Torr) and about 0.27 kPa (2 Torr) under 60-Hz ac energization were studied. Measurements for two representative electrode configurations showed that the electrical characteristics of PD (specifically, electric pulse waveforms) at low pressures differ significantly from those at sea-level...
This paper presents work on breakdown studies conducted in nitrogen at partial vacuum conditions for a point-to-plane electrode setup. The experiments are conducted under two different applied fields of 20 kHz unipolar pulsed square wave and 20 kHz unipolar sinusoid (DC shifted sinusoid). The applied square pulsed signal consists of a train of pulses at 20 kHz with 50% duty cycle and rise/fall times...
Partial discharge (PD) characteristics in air, argon and helium at pressures between 101 kPa (760 Torr) to about 0.27 kPa (2 Torr) under 60 Hz AC energization were studied with various electrode arrangements. Measurements are presented for two representative electrode configurations, (1) needle-plane, with 20 mm spacing and a dielectric barrier, and (2) a twisted pair of insulated conductors. Typical...
Partial discharge (PD) phenomena have been studied under low pressure environment at pressures in the range of 101.3 kPa (760 Torr) to 0.27 kPa (2 Torr). This paper discusses two main representations of PD measurement results (time-resolved data representation and phase-resolved data representation), and their relevant analysis techniques used for low pressure PD applications.
This work presents the breakdown characteristics of nitrogen in partial vacuum conditions under pulsed electric fields at 50 kHz to 200 kHz. Results of breakdown events are discussed and compared with the results of helium breakdown under similar conditions.
Summary form only given. A detailed knowledge of electrical insulation and high voltage design techniques is essential if reliable high voltage systems are to be designed and manufactured for use in sub-atmospheric environments. The trend is towards more advanced systems operating at higher voltages in compact, economical packages that have been submitted to a battery of diagnostic techniques to ensure...
Partial discharge (PD) experiments in argon and helium have been performed for 60 Hz AC energization, under pressures from 101.3 kPa (760 Torr) down to 0.27 kPa (2 Torr). The electrode arrangement was a twisted pair of insulated conductors taken from a standard aircraft wiring harness. The paper describes the physical PD test setup and electrical connections for AC energization. The results are presented...
In this paper we present our work on breakdown studies conducted in helium at partial vacuum conditions for a point-to-point electrode setup. A high frequency pulsed voltage signal is applied across the electrodes and the voltage-current characteristics are observed. The applied signal consists of a train of square pulses in the frequency range of 50 to 200 kHz with 50% duty cycle and rise/fall times...
Nanometer-sized inorganic fillers are increasingly used as reinforcing materials for mechanical or thermal property improvement of polymers. Improvements in mechanical modulus or heat deflection temperature are often realized. These fillers may also improve some electrical properties such as corona endurance or dielectric breakdown voltage in polymers. In compact high voltage power supplies, epoxy...
The paper describes the importance of partial discharge (PD) detection for aerospace electric power system wiring and components in low pressure environment. The relationships between recorded discharge pulse current waveforms and PD electrical characteristics are explained and discussed. Features of a new PD analyzer for low pressure applications are reviewed
There are three general classes of codes that can be used in the analysis of electrical systems and their interactive effects: circuit codes, Maxwell's-equations- solving codes (also referred to as field codes), and system codes. Circuit codes employ coupled equations to describe the currents and voltages associated with individual electronic components such as individual transistors, resistors, and...
In general, power devices and systems operating in vacuum or space environment are more susceptible to partial discharges, corona, or volume discharge due to the partial vacuum conditions. Partial discharge and breakdown measurements have been performed on electrical equipment operating in such environments for over decades. In spite of all the studies, fundamental understanding of partial discharge...
Arc fault circuit interrupters (AFCI) are a relatively new development in the area of circuit protection. Typical circuit breakers are designed to detect an overload current in the protected circuit and trip open within a specified period of time. The AFCI is a device that detects and interrupts an arcing fault when it occurs. An arc fault is a dangerous situation with very high temperatures in the...
The next generation of space vehicles is likely to utilize higher voltages than the traditional 28 Vdc for onboard power distribution. Such is already the case for the International Space Station (ISS), which utilizes 120 Vdc. The availability of switching power supplies operating at high switching frequencies makes it important to consider the effects of these higher operating frequencies in the...
As mission scenarios expand and flight profiles change, both military and commercial aerospace vehicles will be required to operate in a broader range of environments than current flight vehicles. This implies the need for increased reliability across a wide range of environmental conditions, i.e., environmental parameter space. A critical element to the overall operational capability of the vehicle...
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