Motor Efficiency

Written by Jerry Ratzlaff on . Posted in Rotating Equipment

Motor efficiency, abbreviated as \(\eta_m\) (Greek symbol eta), a dimensionless number, is the ratio of shaft power power out and electric power input of a motor.

 

 Motor Efficiency formula

\(\large{ \eta_m = \frac{ 0.7457 \; HP \; Load  }{ P_{in} } }\)   

Where:

\(\large{ \eta_m }\)  (Greek symbol eta) = motor efficiency

\(\large{ P_{in} }\) = input power

\(\large{ HP }\) = horsepower

\(\large{ Load }\) = output power as a % of rated power

 

Tags: Equations for Efficiency Equations for Motors