Resonant Vibrations Resulting from the Re-Engineering of a Constant-Speed 2-Bladed Turbine to a Variable-Speed 3-Bladed Turbine

controls research. The purpose of this conversion was to develop an advanced controls eld-testing platform which has the more typical 3-bladed conguration. A result of this conversion was the emergence of several resonant vibrations, some of which initially prevented operation of the turbine until they could be explained and resolved. In this paper, the investigations into these vibrations are presented as \lessons-learned". Additionally, a frequency-domain technique called waterfall plotting is discussed and its usefulness in this research is illustrated.