What is eddy current loss in a transformer?

Eddy current loss in a transformer refers to energy losses that occur due to induced currents circulating within the conductive materials of the transformer, such as the core. When alternating current flows through the windings of a transformer, it creates a changing magnetic field. This changing magnetic field induces currents in the conductive core materials, leading to the generation of loops of electrical current that flow in a direction opposite to the main current. These induced currents, known as eddy currents, generate heat due to the resistance of the material, resulting in energy loss.

Minimizing eddy current loss is crucial for improving the efficiency of transformers, which is often achieved by using laminated cores, where the core is constructed from thin sheets of material that are insulated from each other to reduce the path through which eddy currents can flow.

The other choices do not accurately describe eddy current loss: insulation breakdown relates to failures in the insulating materials of a transformer, energy storage in magnetic fields does not inherently involve losses, and thermal expansion is related to physical changes in materials due to heat rather than energy dissipation through induced currents.