Using its consolidated technology and the experience it has accumulated in the construction of oil-filled three-phase rectifier transformers, TES designs, builds, tests, commissions and maintains transformers for rectifiers with power ratings of up to 100 MVA and primary voltages of up to 52 kV. Today, there are numerous applications that require transformers to supply rectifiers with ever-increasing levels of power. The classic example is provided by those industries that use electrolysis processes for the production of aluminium, and the high secondary currents, together with the harmonic currents generated by the rectification systems, must be taken into account fully when designing transformers to power such loads.