Francis Turbine

Francis turbines are the most common Water Turbine in use today. They operate in a water head from 40 to 600 m (130 to 2,000 ft) and are used primarily for electrical power production. The electric generators that most often use this type of turbine have a power output that generally ranges from just a few kilowatts up to 800 MW, though mini-hydro installations may be lower. Penstock (input pipes) diameters are between 3 and 33 ft (0.91 and 10 m). The speed range of the turbine is from 75 to 1000 rpm. A wicket gate around the outside of the turbine's rotating runner controls the rate of water flow through the turbine for different power production rates. Francis turbines are almost always mounted with the shaft vertical so as to isolate water from the generator. This also facilitates installation and maintenance.