Η παρούσα διπλωματική πραγματεύεται τη μελέτη της συμπεριφοράς ενός σύγχρονου κινητήρα μόνιμου μαγνήτη (Brushless DC) στην υγιή του κατάσταση και σε διάφορα σφάλματα με σκοπό την εύρεση διαγνωστικών δεικτών για την αναγνώριση και τη διακριτοποίηση των σφαλμάτων. Η εργασία αυτή εκπονήθηκε στο Εργαστήριο Ηλεκτρομηχανικής Μετατροπής Ενέργειας του Τμήματος Ηλεκτρολόγων Μηχανικών και Τεχνολογίας Υπολογιστών της Πολυτεχνικής Σχολής του Πανεπιστημίου Πατρών. Για τους σκοπούς της διπλωματικής εργασίας προσομοιώθηκε ένας κινητήρας τύπου BLDC στην υγιή κατάσταση και στα σφάλματα με σταθερό αριθμό στροφών. Τα σφάλματα που μελετήθηκαν είναι πλήρης απομαγνήτιση ολόκληρου μαγνήτη, πλήρης τοπική απομαγνήτιση των άκρων ενός μαγνήτη, στατική και δυναμική εκκεντρότητα. Οι κινητήρες BLDC κερδίζουν συνεχώς έδαφος στη βιομηχανική παραγωγή και σε άλλες εφαρμογές, εκτοπίζοντας σιγά σιγά τους κινητήρες Συνεχούς Ρεύματος και τους Επαγωγικούς κινητήρες. Καθώς διαδραματίζουν σημαντικό ρόλο στην βιομηχανική παραγωγή, και όχι μόνο, είναι απαραίτητο να προλαμβάνονται όσο το δυνατόν νωρίτερα διάφορες βλάβες που μπορεί να συμβούν στους κινητήρες και δημιουργηθούν έτσι προβλήματα στις εφαρμογές που χρησιμοποιούνται. Συγκεκριμένα χρησιμοποιήθηκαν τα φασικά ρεύματα και η ηλεκτρομαγνητική ροπή του κινητήρα ως τα υπό διερεύνηση μεγέθη, και αφού έγινε FFT ανάλυση στα παραπάνω μεγέθη συγκρίθηκαν τα φάσματά τους για να βρεθούν τυχών διαφορές και να χρησιμοποιηθούν ως διαγνωστικοί δείκτες. Η παραπάνω μέθοδος, δηλαδή η ανάλυση FFT κάποιων μεγεθών της μηχανής, είναι και η πιο ευρέως διαδεδομένη για παρόμοια χρήση, χωρίς αυτό να αποκλείει και άλλες μεθόδους. Ο κινητήρας BLDC που μελετήθηκε είναι ισχύος 660 W, τροφοδοσίας 48 V μέσω ενός αντιστροφέα (inverter), έχει ονομαστική ταχύτητα περιστροφής 3000 rpm και διαθέτει 8 μαγνητικούς πόλους στο δρομέα του. Για την προσομοίωση όλων των καταστάσεων χρησιμοποιήθηκε το πρόγραμμα Opera-2d της εταιρίας Vector Fields, ένα λογισμικό πεπερασμένων στοιχείων. Για την ανάλυση FFT χρησιμοποιήθηκε το πρόγραμμα Matlab της εταιρίας Mathworks. Αναλυτικά, στο κεφάλαιο 1 γίνεται μία αναφορά στα μαγνητικά υλικά, χρήσιμη διότι έχουμε να κάνουμε με έναν κινητήρα που διαθέτει μόνιμους μαγνήτες στο δρομέα του αντί για τυλίγματα και επίσης, θα μελετηθούν σφάλματα απομαγνήτισης. Στο κεφάλαιο 2 αναλύεται θεωρητικά η δομή, η λειτουργία και η συμπεριφορά των κινητήρων BLDC, καθώς και παραθέτονται μαθηματικά μοντέλα και κυκλωματικά ισοδύναμα για τη δυναμική και για τη μόνιμη κατάσταση της μηχανής. Στο κεφάλαιο 3 γίνεται παρουσίαση των σφαλμάτων. Μελετούνται οι αιτίες που τα δημιουργούν και τα επιδεινώνουν, καθώς γίνεται και μία παρουσίαση των συμπερασμάτων από διάφορες εργασίες και άρθρα όπου μελετώνται παρόμοια σφάλματα σε σύγχρονες μηχανές μόνιμου μαγνήτη. Στο κεφάλαιο 4 παρουσιάζονται τα αποτελέσματα των προσομοιώσεων των διαφόρων καταστάσεων. Αρχικά γίνεται μία παρουσίαση της μεθόδου των πεπερασμένων στοιχείων. Έπειτα παρουσιάζονται τα αποτελέσματα των προσομοιώσεων, και συγκεκριμένα η συμπεριφορά διαφόρων μεγεθών του κινητήρα. Αυτά τα μεγέθη είναι οι μαγνητικές γραμμές, το μέτρο του μαγνητικού πεδίου στο μέσω του διακένου, τα φασικά ρεύματα και η ηλεκτρομαγνητική ροπή, από τη μελέτη των οποίων βγαίνουν τα πρώτα συμπεράσματα για τη λειτουργία και την κατάσταση του κινητήρα. Στο κεφάλαιο 5 παρουσιάζεται αρχικά η μέθοδος FFT και μετά παρουσιάζονται τα αποτελέσματα αυτής της ανάλυσης στα φασικά ρεύματα και στη ροπή. Από τη σύγκριση των φασμάτων της υγιούς κατάστασης και των σφαλμάτων βρίσκονται οι διαγνωστικοί δείκτες για την κατάσταση της μηχανής. Τέλος, καταγράφεται η βιβλιογραφία που χρησιμοποιήθηκε. / In this thesis for diploma a Brushless DC (BLDC) is studying at healthy condition and under different kinds of faults. The purpose of this thesis for diploma is the For the purposes of this thesis for diploma a BLDC motor was simulated for the healthy condition and the faults. The faults under study are the uniform and the partial demagnetization of one permanent magnet, static and dynamic eccentricity. The variables that are studying are the phase currents and the electromagnetic torque of the motor. First, the waveforms of those variables were studying for the finding of the first conclusions and for the study of the behavior of the motor for those conditions. Furthermore, those variables were analyzed with the use of Fast Fourier Transform (FFT). The amplitudes of the harmonics of the phase currents and of the electromagnetic torque for the different faults were compared with the healthy condition for the finding of diagnostic indicators for the different faults.

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This dissertation investigates the crustal structure of the eastern Basin and Range Province in the western United States and its relationship with the present-day extensional regime governing this region. The use of combined results from different geophysical methods provide a better understanding of the subsurface crustal structure and the processes involved in this extensional deformation. Teleseismic receiver functions were used to create a uniformly sampled map of the crustal thickness variations and stacked images of the crust beneath the majority of the state of Utah, which provide additional constraints on the seismic characteristics of the crust and upper mantle. These results reveal crustal variations characterized by a distinct change in crustal thickness that closely follows the surface trace of the Wasatch fault, with differences in depth of up to 10 km across a distance of less than 55 km. Analysis of seismic reflection profiles, horizontal and vertical crustal velocities from continuous GPS, and surface geology provide new constraints on the relationships between interseismic strain accumulation, subsurface fault geometry, and geologic slip rates on seismogenic faults. Seismic reflection data show recent activity along high-angle normal faults that become listric with depth, sole into preexisting décollements, reactivating them, and appear to be connected at depth with a regionally extensive detachment horizon. GPS data reveal present-day crustal extension of ~3 mm/yr and no net vertical motion between the Colorado Plateau and eastern Basin and Range. Inverse modeling results of the crustal deformation data include a low-angle dislocation (~8-20°) at a locking depth of ~7-10 km, consistent with the interpreted seismic data, and slipping at 3.2±0.2 mm/yr, suggesting an active regionally extensive sub-horizontal surface beneath the eastern Basin and Range. A test of this hypothesis using seismic data interpretation as the basis for a forward strain accumulation model shows that displacement across a deep low-angle detachment imaged seismically is also consistent with geodetic velocities. Seismic and geodetic data support a model for eastern Basin and Range mechanics wherein diffuse permanent strain of the upper crust by multiple discrete faults is facilitated by displacement along a single low-angle detachment at midcrustal depth.

This work is aimed towards the development of an artificially intelligent search algorithm used in conjunction with an Auto Associative Neural Network (AANN) to help locate and reconstruct faulty sensor inputs in control systems. The AANN can be trained to detect when sensors go faulty but the problem of locating the faulty sensor still remains. The search algorithm aids the AANN to help locate the faulty sensors and reconstruct their actual values. The algorithm uses domain specific heuristics based on the inherent behavior of the AANN to achieve its task. Common sensor errors such as drift, shift and random errors and the algorithms response to them have been studied. The issue of noise has also been investigated. These areas cover the first part of this work. The second part focuses on the development of a web interface that implements and displays the working of the algorithm. The interface allows any client on the World Wide Web to connect to the engineering software called MATLAB. The client can then simulate a drift, shift or random error using the graphical user interface and observe the response of the algorithm.

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The statistics from the US Department of Energy show that about one-third of the total consumption of electricity in the households and industries is due to the Air Conditioning and Refrigeration (AC & R) systems. This wide usage has prompted many researchers to develop models for each of the components of the vapor compression systems. However, there has been very little information on developing simulation models that have been validated for the conditions of start-up/shutdown operations as well as vapor compression system faults. This thesis addresses these concerns and enhances the existing modeling library to capture the transients related to the above mentioned conditions. In this thesis, the various faults occurring in a vapor compressor cycle (VCC) have been identified along with the parameters affecting them. The transients of the refrigerant have also been studied with respect to the start-up/shutdown of a vapor compression system. All the simulations related to the faults and start-up/shutdown have been performed using the vapor compression system models developed in MATLAB/Simulink environment and validated against the 3-ton air conditioning unit present in the Thermo-Fluids Control Laboratory at Texas A & M University. The simulation and validation results presented in this thesis can be used to lay out certain rules of thumb to identify a particular fault depending on the unusual behavior of the system thus helping in creating certain fault diagnostic algorithms and emphasize the importance of the study of start-up/shutdown transient characteristics from the point of actual energy efficiency of the systems. Also, these results prove the capability and validity of the finite control volume models to describe VCC system faults and start-up/shutdown transients.

Four folded maps in pocket on back cover. / Copy of author's previously published work inserted. / Includes bibliographical references (9 leaves). / 1 v. : ill. (chiefly col.), maps (some fold.), (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / An integrated biostratigraphic, wireline, seismic, lithological and 3D-Chronostrat sequence stratigraphic study has been conducted to investigate the evolution of the Albian to recent section of the Dampier Sub-basin on Australia's North West Shelf,. / Thesis (Ph.D.)--University of Adelaide, National Centre for Petroleum Geology and Geophysics, 2000

Condition monitoring involves taking measurements on an induction motor while it is operating in order to detect faults. For this purpose normally a single sensor type, for example current is used to detect broken rotor bar using fault frequency components only under the full-load condition or a limited number of load cases. The correlations among the different types of sensors and their ability to diagnose single and multiple faults over a wide range of loads have not been the focused in previous research. Furthermore, to detect different faults in machines using any fault frequency components, it is important to investigate the variability in its amplitude to other effects apart from fault severity and load. This area has also often been neglected in the literature on condition monitoring. The stator current and axial flux have been widely used as suitable sensors for detecting different faults i.e. broken rotor bar and eccentricity faults in motors. Apart from detecting the broken rotor bar faults in generalized form, the use of instantaneous power signal has often been neglected in the literature condition monitoring. This thesis aims to improve machine condition monitoring and includes accurate and reliable detection of single and multiple faults (faults in the presence of other faults) in induction machines over a wide range of loads of rated output by using current, flux and instantaneous power as the best diagnostic medium. The research presents the following specific tasks: A comprehensive real database from non–invasive sensor measurements, i.e. vibration measurements, axial flux, 3-phase voltage, 3-phase current and speed measurements of induction motor is obtained by using laboratory testing on a large set of identical motors with different single and multiple faults. Means for introducing these faults of varying severity have been developed for this study. The collected data from the studied machines has been analysed using a custom-written analysis programme to detect the severity of different faults in the machines. This helps to improve the accuracy and reliability in detecting of single and multiple faults in motors using fault frequency components from current, axial flux and instantaneous power spectra. This research emphasises the importance of instantaneous power as a medium of detecting different single and multiple faults in induction motor under varying load conditions. This enables the possibility of obtaining accurate and reliable diagnostic medium to detect different faults existing in machines, which is vital in providing a new direction for future studies into condition monitoring. Another feature of this report is to check the variability in healthy motors due to: test repeatability, difference between nominally identical motors, and differences between the phases of the same motor. This has been achieved by conducting extensive series of laboratory tests to examine fault frequency amplitudes versus fault severity, load, and other factors such as test repeatability and machine phases. The information about the variations in the amplitudes of the fault frequency components is used to check the accuracy and reliability of the experimental set-up, which is necessary for the practical application of the results to reliably detect the different faults in the machines reliably. Finally, this study also considers the detection of eccentricity faults using fault frequency amplitudes as a function of average eccentricity, instead of as a function of load under different levels of loading. This has not been reported in previous studies. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1298314 / Thesis (Ph.D.)-- University of Adelaide, School of Electrical and Electronic Engineering, 2008

The North Canterbury tectonic setting involves the southward propagating margin of easterly strike-slip activity intersecting earlier thrust activity propagating east from the Alpine Fault. The resulting tectonics contain a variety of structures caused by the way these patterns overlap, creating complexities on the regional and individual feature scale. An unpublished map by Jongens et al. (1999) shows the Ashley-Loburn Fault System crossing the plains from the east connected with the Springfield Thrust Fault in the western margins, possibly the southern limit of the east-west trending strikeslip activity. Of note are two hill structures inferred to be affected by this fault system. View Hill to the west, is on the south side of this fault junction, and Starvation Hill further east, was shown lying on the north side of a left stepover restraining bend. During thrust uplift and simple tilting of the View Hill structure, at least two uplift events post date last Pleistocene aggradation accounting for variations in scarp morphology. Broad constraints on fault dip and the age of the displacement surface suggest that slip-rates are in the order of 0.5 mm/year. East from View Hill, the strike-slip fault was originally thought to curve northeast, around the southeast of Starvation Hill. But there is neither evidence of a scarp, nor other clear evidence of surface faulting at Starvation Hill, which poses the question of the extent to which folding may reflect both fault geometry and fault activity. Starvation Hill is a triangular shape, with a series of distinctive smooth, semi-planar surfaces, lapping across both sides of the hill at a range of elevations and gradients. These surfaces are thought to be remnants of old river channels, and are indicative of tilting and upwarping of the hill structure. 3D computer modelling of these surfaces, combined with studies of the cover sequence on the hill, resulted in inferences being drawn as to the location of hinge lines of a dual-hinged anticline and an overview of the tectonic history of the hill. This illustrates the potential to apply topographical and geomorphic studies to the evolution of geometrically complex structures Starvation Hill is interpreted to be the result of two fault-generated folds, one fault trending north, the other, more recent fault, trending east. These two faults are thought to be sequentially developed segments of the original fault zone inferred by Jongens et al. (1999) but with reinterpreted location and mechanism detail. The presence of two faults has resulted in overprinted differential uplift of the structure, which has been significantly degraded, especially in the southwest corner of the hill. The majority of the formation of the northerly trending structure of Starvation Hill is inferred to be pre-Otiran, with uplift of the later east trending structure continuing into the late Pleistocene and Holocene.