Which statement correctly describes core loss dependencies on frequency and flux density?

Which statement correctly describes core loss dependencies on frequency and flux density?

• A. Hysteresis loss ∝ f × B^n (n ≈ 2–2.5); eddy current loss ∝ f^2 × B^2.
• B. Hysteresis loss ∝ f^2 × B^2; eddy current loss ∝ f × B.
• C. Hysteresis loss ∝ f × B; eddy current loss ∝ f × B.
• D. Hysteresis loss and eddy current loss are independent of f and B.

Answer: (A)

Two main loss mechanisms in magnetic cores govern how losses depend on frequency and flux density: hysteresis loss and eddy current loss. Hysteresis loss comes from repeated magnetization reversals and scales roughly with frequency and with the flux density raised to about the second power, often written as proportional to f × B^n with n around 2 to 2.5 for common materials. Eddy current loss is due to circulating currents induced in the material and increases with the square of both frequency and flux density, so it’s proportional to f^2 × B^2. The statement that matches these relationships—hysteresis loss ∝ f × B^n (n ≈ 2–2.5) and eddy current loss ∝ f^2 × B^2—best describes how core losses depend on frequency and B. The other descriptions would imply incorrect scaling, such as hysteresis or eddy current losses growing with the wrong powers of f and B, or being independent of f and B.

Two main loss mechanisms in magnetic cores govern how losses depend on frequency and flux density: hysteresis loss and eddy current loss. Hysteresis loss comes from repeated magnetization reversals and scales roughly with frequency and with the flux density raised to about the second power, often written as proportional to f × B^n with n around 2 to 2.5 for common materials. Eddy current loss is due to circulating currents induced in the material and increases with the square of both frequency and flux density, so it’s proportional to f^2 × B^2. The statement that matches these relationships—hysteresis loss ∝ f × B^n (n ≈ 2–2.5) and eddy current loss ∝ f^2 × B^2—best describes how core losses depend on frequency and B. The other descriptions would imply incorrect scaling, such as hysteresis or eddy current losses growing with the wrong powers of f and B, or being independent of f and B.