The Specific Speed Formula for turbine is the above formula implies that for the top head the specific speed is lowered. Thus the Pelton turbine with the top head has a specific speed lower than Francis and Kaplan turbines which are intended to operate at the lower head than the Pelton turbine.

The practical thermal efficiency of the steam turbine varies depending on the size of the turbine, the loading conditions, the loss and the loss of friction.

Explanation Global efficiency is defined as the energy ratio available for the turbine shaft the energy fed for the turbine input, which is also a product of mechanical and hydraulic efficiency.

The specific speed formula for the turbine is how the above formula indicates that for the head the specific speed becomes lower. Thus, the higher Pelton turbine has a specific speed lower than that of the Francis and Kaplan turbines which are intended to work on the lower head of the Pelton turbine.

The specific speed formula for the turbine is like the previous formula implies that for the head above the specific speed is lower. Thus, the Pelton turbine with the top head has a specific speed lower than the Francis and Kaplan turbine which are intended to operate on the lower head than the Pelton turbine.