Steinmetz's equation

Etymology
Named after, who proposed a similar equation on which this was based.

Proper noun

 * 1) An empirical equation used to calculate the total power loss (core losses) per unit volume in magnetic materials when subjected to external sinusoidally varying magnetic flux: $$P_v = k \cdot f^a \cdot B^b$$ where $$P_v $$ is the time average power loss per unit volume in milliwatts per cubic centimeter, $$f$$ is frequency in kilohertz, and $$B$$ is the peak magnetic flux density; $$k$$, $$a$$, and $$b$$, called the Steinmetz coefficients, are material parameters generally found empirically from the material's  by curve fitting.