1. Pelton Wheel is an example of such turbine.
Turbines classification based on how they operate Impulse Turbines and Reaction Turbines. Most hydro stations use either of these two turbines to produce electricity.
In an Impulse turbine, the whole of the available energy of the fluid is converted to Kinetic Energy before the water acts on the moving parts of the turbine.
Pelton Wheel is an example of such turbine.
Pelton Wheel (Impulse Turbine)

2. This type of turbine is highly efficient.
Pelton Wheels in a hydroplant
Components in a Pelton Wheel
Water is blasted at these cups by one or more jets mounted in the surrounding casing. Momentum is transferred from water to cups, and a torque is created, causing the wheel to rotate.
This type of turbine is highly efficient.

3. A Simple Reaction Turbine
In Reaction Turbines, the rotation is mainly achieved by the reaction forces created by the acceleration of the fluid in the runner (rotating blade). The basic principle is the same as a rotating lawn sprinkler in which water enters the arms of the sprinkler at low velocity and leaves through the jets at high velocity.
Newton's third law describes the transfer of energy for reaction turbines.
A Simple Reaction Turbine

4. Reaction turbines consist of fixed guide vanes called stay vanes, adjustable guide vanes called wicket gates and rotating blades called runner blades.
It also generally consists of a spiral casing or volute, as in hydraulic turbines. It surrounds the runner completely. The casing should be strong to withstand high pressure.

5. Top and Side View of a typical Reaction Turbine

6. Flow enters tangentially at high pressure, is turned toward the runner by the stay vanes as it moves along the volute, and then passes through the wicket gates with a large tangential velocity component.
Momentum is exchanged between the fluid and the runner, and the runner rotates.
Unlike impulse turbine, the water completely fills the casing of a reaction turbine.
Reaction turbine generally produces more power than an impulse turbine.
Wicket gates control volume flow rate.

7. Sectional and Top View of a Francis Reaction Turbine
There are two main types of Reaction Turbine – Francis and Kaplan Turbines.
Sectional and Top View of a Francis Reaction Turbine

8. Francis Turbine

9. Sectional View of a Kaplan Reaction Turbine

10. Both types of turbines are inward-flow reaction turbines.
Francis turbines utilize axial and/or radial flow concepts.
Kaplan turbines utilize axial flow of water.
Kaplan turbine is a propeller-type water turbine which has adjustable blades.
Kaplan Turbines

11. Various types of water turbine runners
Various types of water turbine runners. From left to right: Pelton Wheel, two types of Francis Turbine and Kaplan Turbine

12. A Francis turbine runner, rated at nearly one million hp (750 MW), being installed at the Grand Coulee Dam, United States.