The ETM has its own development software for the modal analysis of rotating equipment without the need for external excitation, using appropriate techniques to separate the vibration signal from the stochastic excitation, due to the internal flow of the machine and to extract information regarding the rotodynamic stability, natural frequencies and modes of vibration, constituting an important rotating equipment troubleshooting tool.
The rotodynamic stability of turbomachinery should be guaranteed to avoid high vibration levels that could cause equipment failure.
Although the computational modal analysis is widely used to verify the logarithmic decrement of rotating equipment, there are still difficulties and uncertainties in the modeling of rotodynamic coefficients of components such as honeycomb, holepattern, labyrinth seals, oil seals, bearings and wear rings. For the minimization of these uncertainties in equipment such as centrifugal compressors operating in critical plant services, costly stability tests are specified and performed during acquisition, with the use of magnetic bearing excitation.
The use of the ETM Modal tools eliminates the need for these tests, allowing not only the level of stability of the equipment in the factory but also the monitoring of the logarithmic decrement, natural frequencies and modal forms of the equipment in the field. The monitoring and analysis of the alteration of these parameters allows the detection and early diagnosis of possible failures.