Which term describes magnetic loss in a transformer core caused by changes in magnetization?

Which term describes magnetic loss in a transformer core caused by changes in magnetization?

• A. Copper loss
• B. Eddy current loss
• C. Hysteresis
• D. Dielectric loss

Answer: (C)

Hysteresis loss. When the transformer’s magnetic field changes with the AC supply, the magnetic domains in the core realign to follow the field. This reorientation lags behind the applied magnetization, so the magnetization vs. field trace forms a loop each cycle. The area of that loop represents energy dissipated as heat per cycle, and multiplying by the switching frequency gives the power loss. This is exactly the magnetic loss described by changes in magnetization. Other losses exist in the core as well—eddy currents come from currents induced in the conductor by changing flux, and copper loss comes from winding resistance—but the specific loss caused by the lag between magnetization and the applied field is hysteresis. Dielectric loss relates to insulating materials, not the magnetic core.

Hysteresis loss. When the transformer’s magnetic field changes with the AC supply, the magnetic domains in the core realign to follow the field. This reorientation lags behind the applied magnetization, so the magnetization vs. field trace forms a loop each cycle. The area of that loop represents energy dissipated as heat per cycle, and multiplying by the switching frequency gives the power loss. This is exactly the magnetic loss described by changes in magnetization. Other losses exist in the core as well—eddy currents come from currents induced in the conductor by changing flux, and copper loss comes from winding resistance—but the specific loss caused by the lag between magnetization and the applied field is hysteresis. Dielectric loss relates to insulating materials, not the magnetic core.