In a transformer with no moving parts, the losses arise from field excitation and the resistance of what component?

In a transformer with no moving parts, the losses arise from field excitation and the resistance of what component?

• A. Windings insulation
• B. Core material
• C. Cooling system
• D. External load

Answer: (B)

When a transformer has no moving parts, the main losses come from the magnetic core as it is excited by the primary field. The changing magnetic flux in the core leads to energy loss through hysteresis in the core material and through eddy currents inside the conductive core. These core losses are intrinsic to the core material and scale with the level of field excitation and flux density, which is why the resistance associated with the core material is the source of these losses. Copper losses in the windings are a separate effect due to winding resistance, while the cooling system and insulation don't themselves dissipate significant energy; they merely carry away heat produced by those losses. External load affects the power delivered to the load, not the intrinsic loss mechanisms inside the transformer core.

When a transformer has no moving parts, the main losses come from the magnetic core as it is excited by the primary field. The changing magnetic flux in the core leads to energy loss through hysteresis in the core material and through eddy currents inside the conductive core. These core losses are intrinsic to the core material and scale with the level of field excitation and flux density, which is why the resistance associated with the core material is the source of these losses.

Copper losses in the windings are a separate effect due to winding resistance, while the cooling system and insulation don't themselves dissipate significant energy; they merely carry away heat produced by those losses. External load affects the power delivered to the load, not the intrinsic loss mechanisms inside the transformer core.