EXPERIMENTAL IDENTIFICATION OF POSSIBLE FAILURES OF A BÁNKI TURBINE
The aim of the present paper is to investigate the vibrations that occur during the operation of a low power Bánki turbine. The turbine was tested at different operating regimes in a laboratory installation, where it can operate with or without a variable load provided by a hydrodynamic brake coupled to the turbine shaft. Vibrations were measured on the turbine casing, on one of the turbine bearings, and on the brake. Dominant frequencies pertaining to each subassembly were identified. Measurements were also carried out with an added mass that simulates a piece of debris stuck inside the runner, causing an unbalance. The results obtained suggest that the bearings are a source of high frequency vibrations while relatively low frequency vibrations are caused by the turbine load. Very low frequency vibrations were also identified, which might be transmitted from the installation through the upstream pipe. The results underline the importance of vibration diagnostics to identify possible failures of a Bánki turbine, as a predictive maintenance method specific to rotating machines.
Key words: small hydraulic turbine, vibration diagnostics, added mass, unbalance, bearing, dominant frequencies, predictive maintenance.
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