Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 98-102).

Thesis (Naval Engineer and M.S. in Electrical Engineering and Computer Science)--Massachusetts Institute of Technology, 2001. / Includes bibliographical references (p. 100-106). Also available online.

M. Tech. Electrical Engineering. / Investigates the mathematical modelling, analysis and simulation of a six-phase squirrel cage induction machine. This dissertation is the report of the analysis and simulation of this machine through three methods, namely: The direct-quadrature axis (dqxy0102) based on generalised theory of electric machines, which enabled the machine to be mathematically modelled in the arbitrary reference frame; the classical magnetic field distribution analysis; and the finite element method (fem). The resulting models of the analysis of the six-phase squirrel cage induction machine are implemented by simulation using appropriate software. The simulations generate unique results of the steady-state and the dynamic performance characterising the performance of the six-phase squirrel cage induction machine. Tests are conducted on a 1.5 kW experimental machine whereby the performance characteristics of the theoretical analysis and simulations are validated with the experimental results. The results of the three are compared among themselves, and also with the experimental results to appraise the suitability of each method for the modelling and analysis of the hpo machine.Even though six-phase machine is considered in this study it is believed that the methods as applied in this work are generally applicable to hpo squirrel cage induction machine of any number of phases.

Molecular motors are responsible for all long range transport and organization of organelles within cells. However, little is known about the interaction of multiple similar and dissimilar motors. In this thesis I describe experiments to probe the coordination of the motors kinesin and dynein which move towards the opposite ends of microtubules. Cargos they haul show bidirectional movement at short scales yet there is net transport in one direction or the other. Two distinct models for the bidirectional transport exist: regulation and a tug-of-war. In order to differentiate between them, kinesin-specific antibodies are injected into Drosophila embryos and the effect on transport of lipid droplets is quantified and compared to unperturbed motion. The function-blocking antibodies resulted in an increased run length of dynein-mediated transport and a decrease in that of kinesin. Furthermore, reduced velocities in both directions and a trend towards shorter pauses were observed. Comparison of these results to predictions the models provide for this scenario supports a tug-of-war model rather than regulation. / text

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The modern industry today is highly dependent on electric motors of differenttypes and sizes. Synchronous motors are used in applications where a fixedspeed is desired. These machines are often found in high power applicationswhere they are preferred over induction motors due to their higher efficiency.Synchronous motors represent large investments and typically drive processeswhere downtime results in significant capital losses. Thus, detecting faults atan early stage can help avoid catastrophic failures and be useful in thescheduling of maintenance. In order to detect faulty conditions before theyterminate in a failure, machine operators must perform some kind ofmonitoring on the machines. Typically, the more critical the machine is for aprocess, the more effort is put on monitoring it. Before building a monitoringsystem for a machine, one must first decide what parameters that should bemonitored. The obvious desire is to find a parameter that is easy and cheap tomeasure and at the same time can give detailed information about the workingstate of the machine.The aim of this thesis is to evaluate whether the exciter stator current is anadequate parameter to use within a monitoring system for synchronous motors.The evaluation has been made through simulations of two different setups;One using a synchronous motor in the 20 MW range fed by a synchronousmachine type exciter. And the other using the same motor but instead fed byan induction machine type exciter. It has been found that the exciter statorcurrent can be used for detection of faults associated to the rectifier and statorshort circuit of the main machine stator winding. It has not been possible todetect turn-to-turn faults in the main machine rotor.The work has been performed at ABB Corporate Research in Västerås fromJune until December 2013.