Efficiency and performance largely depend on the core, windings, and cooling system. Low-loss core steel and optimized flux density minimize no-load losses. Properly sized conductors and winding configurations reduce copper losses and control leakage reactance. Cooling capacity (radiators, fans, pumps) sets allowable temperature rise and overload capability. Insulation systems influence lifetime and limit operating temperatures. Tap changer design affects voltage regulation and additional losses. Together, these components define the transformer’s loss curve, regulation, reliability, and loading capability.