Nameplate Power Formula

The nameplate method estimates operating power without direct measurement by using the rated motor power from the nameplate, adjusted for the actual load factor, the ratio of operational to line frequency (raised to the 2.5 power, representing the affinity law relationship for variable-speed drives), and the combined motor-and-drive efficiency.

\begin{equation}\label{eq:electricity-reduction-nameplate} P = P_{rated} \cdot f_L \cdot \left(\frac{f_{op}}{f_{line}}\right)^{2.5} \cdot \frac{1}{\eta}\end{equation}

Symbols

\(P\)	Estimated operating power \([\unit{ \kilo\watt}]\)
\(P_{rated}\)	Rated motor power from the nameplate \([\unit{ \kilo\watt}]\)
\(f_L\)	Motor load factor (dimensionless, 0–1) \([\unit{ \unitless}]\)
\(f_{op}\)	Actual operating frequency \([\unit{ \hertz}]\)
\(f_{line}\)	Nominal line frequency \([\unit{ \hertz}]\)
\(\eta\)	Combined motor and drive efficiency (decimal) \([\unit{ \unitless}]\)