# Overall Efficiency

Written by Jerry Ratzlaff on . Posted in Classical Mechanics

Overall efficiency, abbreviated as $$\eta_o$$  (Greek symbol eta), a dimensionless number, measures the ratio of the output of actual power to the input of actual power.  It determines the amount of energy lost overall.

## Overall Efficiency Formulas

 $$\large{ \eta_o = \frac{ output\; HP \; 100 }{ input\; HP } }$$ (motor) (pump) $$\large{ \eta_o = ME \; VE }$$ (motor) (pump)

### Where:

$$\large{ \eta_o }$$  (Greek symbol eta) = overall efficiency

$$\large{ ME }$$ = mechanical efficiency

$$\large{ VE }$$ = volumetric efficiency