The paper presents results of an experimental study on the vibration levels of a small Pelton
turbine operating both with balanced and unbalanced runner. To unbalance the runner, a
concentrated mass was added on a bucket, close to the runner periphery. Vibrations were
measured in axial, transverse and vertical directions at different nozzle openings, ie at
different discharges, and at different runner speeds and turbine loads. The results obtained
suggest that the vertical vibrations at large nozzle openings and runner speeds are mostly …