الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
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Abstract
This thesis is concerned with the speed control of direct current motors driven by three phase thyristor converters with and without circulating current
The thesis presents the design , the analysis and testing for their regulating techniques and their firing control circuits to control the speed of SCR driven motors.Three industrial applications have been considered in this study . The first application concerns with a thyristorized reversible regenerative DCM driven by field current reversal .To reverse motor speed , the field current is reveresed whereas the armature current direction is unchanged . The control scheme is based on double regulation loop . The outer loop is for speed regulation and the inner loop is for current regulation . The speed regulator receives at its input the error signal between the reference voltage and the feedback voltage supplied by tachogenerator . The output of this loop is the reference for the current regulator and the feedback voltage of a current loop proportional to the armature current . The output of this amplifier drives the pulse generator and phase shifter . The motor field winding is supplied by a double controlled rectifier which can vary the field current from zero up to nominal value and also reverese the direction of the current . Field regulator amplifier receives at its input the error signal between the reference voltage which comes from the output of speed regulator and feedback signal proportional to the field current . The polarity of field current determines the direction of rotation . A reduction of the reference signal causes the inversion of the error polarity and also the field current is reveresed .