Core losses in a transformer are composed of which two types of losses?

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

Answer: (A)

When a transformer operates, the iron core is subjected to changing magnetic flux, which leads to two main loss mechanisms in the core material: hysteresis loss and eddy current loss. Hysteresis loss comes from the repeated reversal of magnetic domains in the core as the magnetic field cycles, converting some magnetic energy into heat with each cycle. Eddy current loss arises from currents induced inside the conducting core by the changing flux; these loops circulate and dissipate energy as heat. The other losses listed—copper loss from winding resistance and dielectric loss in insulation—are not core losses; copper loss is I²R heating in the windings, and dielectric loss occurs in insulating materials, not in the magnetic core. Hence, the two types that constitute core losses are hysteresis loss and eddy current loss.