Unlike stationary structures, rotating machinery has unique features due to the rotation so that the conventional modal testing methods often fail in clear explanation of the dynamic characteristics of such machines. To identify the modal parameters of rotating machinery, the complex modal testing has been developed. However, the complex modal testing methods are based on complex inputs and outputs, new excitation and measurement techniques are required.
The objective of this work is the development of an effective complex modal testing system for rotating machines using a newly developed magnetic exciter equipped with hall sensors. Hall sensor is used to measure the excitation force instead of force transducer. The on-line software for complex modal testing is also developed for fast processing of direction spectrum. Finally, the excitation and measurement techniques developed for asymmetric rotors are experimentally verified for practicality and realization. The experimental results suggest that the one exciter-two sensor method is most effective.