Some effects of variable excitation on synchronous motor oscillation

In this paper are presented the results of a study of synchronous motor oscillations resulting from sudden application of mechanical load. By means of the Differential Analyzer at the Moore School of Electrical Engineering of the University of Pennsylvania, theoretical synchronous machine equations were solved for conditions of suddenly applied load, and the effect on the resulting oscillations of variations in field excitation was determined for the most practical cases. The analyzer results were checked by a number of experimental observations, and it was found that the magnitude and duration of the oscillations could be greatly decreased by using the proper type of excitation variation.     

Steady forced vibrations of single mass systems with symmetrical as well as iinsymmetrical non-linear restoring elements

Part of the theory and all the experiments reported on in this paper were condensed into a four-page discussion or addendum to Professor Den Hartog's original paper on “Amplitudes of Non-Harmonic Vibrations” at the time of its presentation at the June Meeting of the A.S.M.E. in Chicago, 1933. Upon the instigation of Professor Den Hartog and the Editor of the Journal of the Franklin Institute, the original discussion has been brought into the present form.