steinmetz's equation

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·fᵃ·Bᵇ 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 B-H hysteresis curve by curve fitting.