Shaft torsional oscillations of hydrogenerators

The efforts to analyze, model, and instrument the shaft torsional oscillations of electric generators are described. The mechanics of the shaft torsional modes are presented through the defining analytical equations from which block diagram and analog computer representation of shaft torsional systems were developed. Results of an analog study of the torsional mode of a hydrogenerator as well as calculated data are presented. An instrumenation system which employs shaft-mounted strain gages to provide a torsional signal was developed for direct field measurement of the torsional behavior of hydrogenerator shafts. The design and circuit configuration of that instrumentation system are presented.