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Title: An investigation into the mechanical and electrical losses of permanent magnet disc machines
Author: Lamperth, Michael
ISNI:       0000 0001 3604 5065
Awarding Body: Imperial College London (University of London)
Current Institution: Imperial College London
Date of Award: 2000
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The subject of the thesis is the investigation of the loss-mechanisms in high-speed permanent magnet disc generators. Such electrical machines can be directly coupled to gas turbine engines and run at speeds of up to 60000 revolutions per minute. The work focuses particularly on the losses occurring in the stator of the machine, which are: 1. Ohmic resistance losses 2. Eddy current losses 3. Circulating current losses 4. Pumping losses of coolant fluid Numerical modelling was used to gain a theoretical understanding of the loss-mechanisms involved. Validation of these results was carried out by means of experiments conducted on several purposely built test rigs. The results of the experiments were then correlated to the numerical solutions so that the prediction of the losses for different geometries can be obtained with a high degree of certainty. For the numerical analysis, commercial software was used for thermal and flow problems, but for the electro-magnetic problems a new computer code using the object oriented language C++ was developed. Besides this, the magnitude and relation of eddy-currents and circulating currents in Litz cables was investigated in depth by modelling the Litz cables macroscopic properties in detail, which allowed the investigation of the effect of the cable bundling configuration. It was shown that the design of these machines is always bound onto the operating conditions as the magnitude of the different losses do not allow the ideal combination of properties to be found for a range of load points but only for given operating point.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available