Pelton Turbine Efficiency Curve

http://www.bing.com/search?q=pelton+turbine+efficiency+curve&src=IE-SearchBox&Form=IE8SRC

Pelton runners are low specific speed so they maintain efficiency over a large operating range. Have no time to look for an example, but if you plot load from 0 to 100 % on the Y axis and Efficiency 0 to 100% on the X axis you can draw an almost straight line at around 85% efficiency from say 30 to 90% of load.

Hey I would love to try it that way. I did infact but I really could not get the curve. How do I get % efficiency corresponding to % load??? I computed in the formula,

P= eff*rho*g*h*Q.

Say, if my rated power is 60 MW. And 10% of load is 6 MW. So I input 6 MW in above eqn. and find corresponding Efficifency??? Can I asumme 0.9 efficiency for transf and gen. in above eqn throughout my calculation???

Please do enlighten me. I asked this q in other forum but got no answer.

You can not calculate the efficiency that way, you would have to measure it. Just draw the curve.

What I am saying is that the efficiency of a Pelton wheel remains almost at a constant 85% from around 30% of full load up to around 90% of full load.