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Title: The D.C. disc-armature electric motor
Author: Campbell, Peter
ISNI:       0000 0001 3517 4826
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 1974
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This thesis develops the theory relating to the d.c. Disc-Armature electric motor, and uses two particular machines as examples. Considerable importance is attached to the calculation of the field due to the permanent magnet poles, and both direct and iterative methods are employed. For the determination of e.m.f. and torque in the axial-field machine, the flux density at any point is inseparable from its radius, and a "moment of flux density" is defined to account for this. By considering the individual armature conductors, the fluctuations of e.m.f. and torque during rotation are found. These calculations are used to select the optimum dimensions for the machine and its components, for particular design criteria. The design of the machine is discussed, and certain problems receive particular attention. These include the realisation of the full magnetic field, and the materials for a rotating flux return ring. For the latter, iron powder compacts are found to be convenient, having the lowest power losses. The fan motor incorporates such a return ring, and its performance agrees well with the theoretical predictions. For the high coercivity magnets used, the field calculations are also quite accurate. The wheel motor's operation reveals a peculiarity of the commutation in this type of machine, and indicates an important area for further study.
Supervisor: Not available Sponsor: Science Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TK Electrical engineering. Electronics Nuclear engineering