Energy Losses in a Transformer

Because a transformer has no moving parts, its efficiency is significantly higher than that of rotating machines like generators and motors, but three distinct mechanisms still cause an unavoidable energy loss. Core (iron) loss occurs in the transformer's core itself, and has two parts: hysteresis loss (energy dissipated as heat each time the core is repeatedly magnetised and demagnetised by the alternating primary voltage; minimised by using core steel with a high silicon content), and eddy current loss (the alternating flux induces eddy currents directly within the core, exactly as covered in section 4.2; minimised by using very thin, mutually insulated laminations for the core, rather than one solid block). Copper loss occurs because the primary and secondary windings both have some electrical resistance, so current flowing through them dissipates energy through ordinary Joule heating; this loss is minimised by using thicker wires (larger cross-sectional diameter) for the windings. Flux leakage occurs when not all of the magnetic flux produced by the primary coil is actually linked with the secondary coil (some field lines 'le …