Rectifier-loaded synchronous generators with damper windings

The performance of a cylindrical-rotor synchronous generator connected to a bridge-rectifier load is derived from fundamental machine equations. The generator is fitted with both direct- and quadrature-axis damper windings, and the bridge-rectifier load is fully controlled. Expressions are obtained for the commutation and displacement angles, field and damper currents and d.c. -bridge voltage. From these equations, the performance of generators with and without damper windings, connected to controlled or uncontrolled bridge-rectifier loads, can be predicted from given loading data, field current, load current, generator speed and bridge delay angle. Equations for the generator-voltage waveforms are given, and the theoretical waveforms of three generator modes illustrate the effect of transient saliency on waveform distortion. Two laboratory generators were used to obtain a comparison between the theoretical and practical performance. The measurement of commutation and displacement angles is discussed.