Same-load efficiency savings calculator

Applies when rated hp and actual shaft load remain the same.

Units

\Delta \mathrm{kW} = \mathrm{HP} \times 0.746 \times \mathrm{LF} \times \left(\frac{1}{\eta_{\text{old}}} - \frac{1}{\eta_{\text{new}}}\right)

Calculator

Enter the values you know and leave one box empty. Calculate finds the empty one, the result or any input.

Given

\Delta \mathrm{kW} = 50 \times 0.746 \times 0.75 \times \left(\frac{1}{0.89} - \frac{1}{0.945}\right) \approx 1.829

Symbol	Meaning	Unit
$\Delta \mathrm{kW}$	power reduction	kW
$\eta_{\text{old}}$	old motor efficiency	—
$\eta_{\text{new}}$	new motor efficiency	—
$\mathrm{HP}$	common rated horsepower	HP
$\mathrm{LF}$	common mechanical load factor	—

Symbol	Meaning	Unit
$\Delta \mathrm{kW}$	power reduction	kW
$\eta_{\text{old}}$	old motor efficiency	—
$\eta_{\text{new}}$	new motor efficiency	—
$P_{\text{rated}}$	common rated power	kW
$\mathrm{LF}$	common mechanical load factor	—

Results are estimates for study and screening. Check the inputs, units and assumptions before you use them for design, billing or contract decisions.