The three main types of water turbine: (A) the Pelton turbine (or wheel); (B) the Francis turbine; (C) the Kaplan turbine.
A simple turbine of the 16th century used the power of running water to work a pump for irrigation. Rotation of the turbine (1) turned a wheel (2) with teeth on only half its circumference. The cog wheels (3) turned alternately in opposite directions making the pump wheel (4) oscillate. Self-acting valves allowed the pistons (5) to draw water into one cylinder while pushing it out of the other.
A water turbine, aso known as a hydro turbine, is a turbine that uses water pressure to rotate its blades; the primary types are the Pelton turbine, for high heads (pressure); the Francis turbine, for low to medium heads; and the Kaplan turbine for a wide range of heads. Water turbines, like steam turbines, are primarily used to power electric generators.