![cover image](https://wikiwandv2-19431.kxcdn.com/_next/image?url=https://upload.wikimedia.org/wikipedia/commons/thumb/c/cb/Francis_Turbine_inlet_scroll_Grand_Coulee_Dam.jpg/640px-Francis_Turbine_inlet_scroll_Grand_Coulee_Dam.jpg&w=640&q=50)
Francis turbine
Type of water turbine / From Wikipedia, the free encyclopedia
Dear Wikiwand AI, let's keep it short by simply answering these key questions:
Can you list the top facts and stats about Francis-type?
Summarize this article for a 10 year old
The Francis turbine is a type of water turbine. It is an inward-flow reaction turbine that combines radial and axial flow concepts. Francis turbines are the most common water turbine in use today, and can achieve over 95% efficiency.[1]
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/c/cb/Francis_Turbine_inlet_scroll_Grand_Coulee_Dam.jpg/640px-Francis_Turbine_inlet_scroll_Grand_Coulee_Dam.jpg)
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/5/5f/M_vs_francis_schnitt_1_zoom.jpg/320px-M_vs_francis_schnitt_1_zoom.jpg)
The process of arriving at the modern Francis runner design took from 1848 to approximately 1920.[1] It became known as the Francis turbine around 1920, being named after British-American engineer James B. Francis who in 1848 created a new turbine design.[1]
Francis turbines are primarily used for producing electricity. The power output of the electric generators generally ranges from just a few kilowatts up to 1000 MW, though mini-hydro installations may be lower. The best performance is seen when the head height is between 100–300 metres (330–980 ft).[2] Penstock diameters are between 1 and 10 m (3.3 and 32.8 ft). The speeds of different turbine units range from 70 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 usually mounted with a vertical shaft, to isolate water from the generator. This also facilitates installation and maintenance.[3]