Using amorphous steel in transformer cores primarily reduces which losses?

• A. Core losses
• B. Copper losses
• C. Dielectric losses
• D. Radiation losses

Answer: (A)

Core losses in transformer materials come from two processes as the magnetic field cycles: hysteresis losses from the lag between magnetization and the applied field, and eddy-current losses from currents induced inside the core. Amorphous steel has a disordered structure and higher electrical resistivity, which suppresses the loops that eddy currents can take and reduces the energy lost in magnetization reversals. Together, these effects significantly lower the core losses compared with crystalline steels. Copper losses come from winding resistance, dielectric losses from insulation, and radiation losses are negligible in the core, so using amorphous steel mainly targets reducing core losses.