The name turbine was originally given in France to any water motor which revolved in a horizontal plane, the axis being vertical.
The principle of the undershot wheel, however, is extensively used in the water motor and the Pelton wheel (Fig. 114).
One type of water motor is made up of a piston and valves in a cylinder (Fig. 150).
Another type of water motor consists of cups or fans on the rim of a wheel.
In designing or selecting a water motor it is not sufficient to consider only its efficiency in normal conditions of working.
Before purchasing any device to be operated by a water motor, ascertain how much water pressure you have available.