A spark gap with mercury jets as electrodes has been developed. Investigations show that the gap can be triggered reliably by photons from a trigger spark with a jitter in the formative time lags less than 0.2 µsec. To overcome uncertainties in the breakdown conditions produced by surface waves on the jet, it has been found necessary to trigger the spark no later than 0.5 sec. after starting the jets„ By suitably designing the geometry of the jets undesirable surface instabilities excited by electric fields have been eliminated. Since the spark gap is isolated electrically from the triggering source very little noise is produced in neighbouring measuring circuits when the main spark is fired. The continual regeneration of the electrode surfaces also eliminates the erratic features observed in normal spark gaps which are fitted with solid metal electrodes. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Thesis ( Ph.D.) -- University of Texas at Arlington, 2008.

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed September 10, 2009). Thesis advisor: William Nunnally. Includes bibliographical references.

Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

This research investigates the distortion on the electrical distribution system for a high voltage DC Integrated Power System (IPS). The analysis was concentrated on the power supplied to a propulsion motor driven by an inverter with simulated silicon carbide switches. Theoretically, silicon carbide switches have the advantage of being able to withstand a very large blocking voltage and carry very large forward currents. Silicon carbide switches are also very efficient due to their quick rise and fall times. Since silicon carbide switches can withstand high voltage differentials and switch faster than silicon switches, the switching effects on the electrical distribution system were investigated. The current state of silicon carbide power electronics was also investigated. This research quantifies the current and voltage distortion over various operating conditions. A system model was developed using Matlab, Simulink, and SimPowerSystems. The model consisted of a synchronous generator supplying a rectifier and inverter set driving an induction motor. This induction motor simulates the propulsion motor for a Navy ship. This model had a DC link voltage of 10 kV in order to simulate future Navy IPS systems. The current and voltage distortion were compared to MIL STD 1399 and IEEE STD 519 and 45. / Contract Number: N62271-97-G-0026

A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering, 2015 / Electrical utilities are tasked with managing large numbers of assets that have long useful lives and are fairly expensive to replace. With emphasis on medium voltage vacuum circuit breakers, a key challenge is determining when circuit breakers are close to their end-of-life and what the appropriate action at that point in time should be. Condition-based maintenance, intended to “do only what is required, when it is required,” has been reported as the most effective maintenance strategy for circuit breakers. This dissertation provides an overview, together with laboratory measurements, on non-intrusive technologies and analytics that could reduce maintenance costs, unplanned outages, catastrophic failures and even enhance the reliability and lifetime of circuit breakers by means of a real-time condition monitoring and effective failure prevention maintenance approach. The key areas of research are the condition assessment of the mechanical mechanism based on coil current signature diagnosis, degradation detection of the main interrupting contacts through thermal monitoring and interrupter vacuum integrity assessment based on magnetron atmospheric condition (MAC) testing. The information from test results allows both immediate onsite analysis and trending of key parameters which enables informed asset management decisions to be taken. / GS2016

Thesis (Ph. D.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed April 15, 2008) Includes bibliographical references.

Switching regulators are modeled as an unterminated two-port circuit to provide flexibility in system model building. Each functional block of switching regulators is modeled as an independent module so that an arbitrary regulator can be configured. Unified models for large-signal and small-signal analysis are developed in user-friendly manner. Analysis capabilities of switching regulator model are demonstrated using EASYS software program. / M.S.

Thesis (M.S.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 22, 2009) Includes bibliographical references.