Browsing by Subject "Engineering - Electrical, Electronic and Electrotechnical Engineering"

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    A microcomputer controller for a nylon spinning machine
    (1985) Kirk, Terence Enfield; Braae, Martin
    This thesis will show how a new type of controller for a Nylon spinning machine was developed from an initial specification. The controller is a component in a loosely coupled feedback system which reads two tachometer pulse trains and various plant interlocks and produces two pulse trains which are used to control two solid state variable frequency variable voltage inverters and their AC motors. The specification calls for 24 controllers to be linked to a PDP 11/23 host computer which holds a library of operating parameters which can be downloaded into each control unit by ~n operator. After examining the requirements of the system, a microcomputer implementation was chosen as· best meeting the needs of the project. Elsewhere in the plant several earlier attempts at using micro-computers as dedicated controllers had been made, with rather poor results. Consideration of the future requirements of the company showed that there was a clear role for these controllers, and it was clear that there was a need to define standards for their development and implementation, and so a survey of the company's requirements was done, on the basis of which a standard was adopted. The thesis covers ali system related aspects of the project, from the initial selection of a microcomputer system and software development system to the design and implementation of the controller.
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    The influence of unbalanced magnetic pull on the reliability of induction motors
    (1978) Israel David Braude; Professor N.C Enslin
    This thesis is a study of the influence of unbalanced magnetic pull (~.m.p.) and associated phenomena on the reliability of induction motors. The work arose from investigations into the premature failure or malfunction of several large and important 6600 volt induction motors whilst in service. Insofar as the writer can determine much of the work reported iii in this thesis constitutes a new contribution to the experimental and theoretical knowledge of induction motors. This applies particularly to the experimental observations on large 4-pole induction motors, to the theoretical analysis and discussions and to the development of detailed enquiry documents and associated documents which include all the principal factors involved in the selection of 6600 volt induction motors. The success of the writer's approach has been shown by the outstanding performance and perfect reliability in service of all the motors selected on this basis. This supports the writer's thesis that the effects of the radial electromagnetic forces, including the unbalanced magnetic pull due to airgap eccentricity must be carefully taken into account in the design and construction of induction motors in order to achieve high reliability. The following preface provides an expanded abstract of this work.