How are eddy current losses in a transformer's core reduced?

Eddy current losses in a transformer's core are primarily reduced by using a laminated core. This design involves slicing the core into thin sheets, or laminations, which are then electrically insulated from one another. The reason this approach effectively decreases eddy currents is that the thin layers restrict the flow of the circulating currents that are induced within the core material due to changing magnetic fields.

When a magnetic field varies, it induces electrical currents in conductive materials, such as the core of a transformer. If the core were made of a solid piece of metal, these currents could flow freely, leading to significant power losses in the form of heat, known as eddy current losses. By utilizing laminated materials that limit the path that these currents can take, the overall resistance to their flow is increased, thereby reducing these losses. The laminations are generally oriented to be perpendicular to the direction of the magnetic flux to further enhance effectiveness.

The other methods mentioned do not address the core's magnetic properties or conductivity in a manner that effectively mitigates eddy current losses.