Runner during balancing test, New Martinsville, USA.
Bulb / Pit / S turbines
The hydraulic development, design and manufacture of bulb and pit turbines has been significantly influenced by Voith Siemens Hydro Power Generation for decades. The higher full-load efficiency and higher flow capacities of bulb and pit turbines can offer many advantages over vertical Kaplan turbines. In the overall assessment of the project, the application of bulb/pit turbines results in higher annual energy and lower relative construction costs. For heads lower than 10 m, pit-type turbines have been applied, with a speed increaser located between the runner and generator. Since 1955 in excess of 180 machines have been placed into operation all over the world with outputs between 50 kW and nearly 50,000 kW and diameters between 800 mm and 8400 mm.
Characteristics:
As the bulb turbine represents the type most commonly used for high outputs at lowest heads, the S turbine is frequently favoured for the economic utilisation of small hydropowers for outputs up to about 8 MW.
