ABSTRACT
Hydroelectric stations may be classified into high, medium and low head categories, so that it is possible to class the types of machines involved by referring to head and flow as shown in Figure 1.1. Figure 1.2 illustrates the types of runner used: from the impulse (Pelton) turbine for high head; the Francis turbine for medium/low head; and the axial-flow (Kaplan) turbine for low head installations.
