University of Tasmania
whole_GreenMichaelJeffreyIvo1982_thesis.pdf (14.8 MB)

Development of direct current heteropolar machines with superconducting field windings

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posted on 2023-05-26, 22:53 authored by Green, MJI
A practical and theoretical study of direct current heteropolar machines with superconducting field windings was conducted with the aim of proving their technical feasibility and to indicate their advantages and disadvantages over machines of more conventional design. These studies were conducted in conjunction with extensive tests on small superconducting D.C. machines of various formats. Three stages of machine development occurred. In the first stage machine the superconducting field winding was shielded from armature reaction fluxes with the aid of iron and compensating windings. In the second stage machine the superconducting field winding was subjected to the full effects of the armature reaction fluxes. Tests conducted with these machines indicated that the operation of the superconducting field winding was not influenced by the flow of armature currents. A third, four pole superconducting D.C. machine which exhibits all the advantages gained by using superconductors in the field windings has been constructed. This machine has most of the construction features of a full size prototype machine for future industrial applications. As a result of difficulties encountered in inducing the superconducting state into the field windings operational tests on this machine could not be conducted. Possible reasons for the difficulties are discussed with the result that some of the reasons are rejected and measures that could overcome the difficulties are forwarded. The project began with no experience in cryogenics, cryostat design and construction nor superconductivity. Consequently details of practical techniques utilised during the project are included. Continued development of superconducting heteropolar D.C. machines should prove that the design and operation of a prototype machine with a rating in excess of 10 MW is possible. This is essential if this type of machine is to make any impact in the future. Providing the expectation that voltage per commutator bar limits can be substantially increased is realised, machine ratings that are limited only by armature cooling should be possible.


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Copyright 1982 the Author - The University is continuing to endeavour to trace the copyright owner(s) and in the meantime this item has been reproduced here in good faith. We would be pleased to hear from the copyright owner(s). Thesis (M.Eng.Sc.)--University of Tasmania, 1982

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