The thesis Is concerned with the development of a separately
excited DC machine In which gate turn-off thyristor devices with
their associated firing and protective circuits are used to provide
the static commutation of armature coil current. The developed
machine has Its armature winding with 24 tapping points located on
the stator and Interconnected In "Lop" configuration. The
Initiation of the conduction periods of armature switching devices
Is defined by a digital control logic circuit. In conjunction with
an Incremental rotary encoder which provides the necessary feedback
Information relating to shaft speed and shaft angular position.
This Is arranged such that, under normal running conditions of the
machine, the axis of the radial field of the armature winding
maintains the normal space-quadrature relationship with that of the
main field winding, giving the optimal torque angle of 000.
Provision Is made, however, within the digital control circuit for
controlled departure of the armature switch tapping points from the
quadrature axis positions, and the effect of this, In Improving
commutation Is Investigated. The effect of Interpoles Is also
explored. On the basis of the analysis carried out, a proposal Is
made for the future development of the machine employing a reduced
number of armature switching devices without the need for Interpole
windings. / Electricity Directorate, Ministry of Works, Power and Water, Manama, Bahrain.
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/3371 |
| Date | January 1986 |
| Creators | Karim, A.H.M. |
| Contributors | Gray, Clifford B. |
| Publisher | University of Bradford, Postgraduate School of Studies in Electrical and Electronic Engineering. |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Thesis, doctoral, PhD |
| Rights | <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>. |
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