The bulb turbine is a variation of the propeller-type turbine (similar to the Kaplan turbine). In the bulb turbine arrangement, the generator is encapsulated and sealed within a streamlined watertight steel housing mounted in the center of the water passageway. The generator is driven by a variable-pitch propeller located on the downstream end of the bulb. Unlike the Kaplan turbine, water enters and exits this unit with very little change in direction. The compact nature of this design allows for more flexibility in powerhouse design. Bulb turbines can, however, be somewhat more difficult to access for service, and they require special air circulation and cooling within the bulb.
Our team has provided bulb turbines for a wide variety of applications world-wide, with sizes ranging from 450 kW to 400 MW.