The magnetic circuit is of column type with mitred joints. It is manufactured with first rate, grain oriented magnetic cold-rolled silicon steel lamination or amorphous steel. The mounted core is clamped down to reduce vibrations and minimize noise level. Further noise level and noload losses decreasing are achieved by step lap core construction
The mineral oil both inhibited and uninhibited types with its electrical and chemical characteristics is in compliance with IEC standards and PCB and PCT free. On special requests other insulation fluids, such as silicon, synthetic ester or natural ester are available
The tappings of MV windings are connected to the off-circuit tap changer. The handle is located on the cover and should only be operated when the transformer is de-energized. The mechanism can also be pad-locked during normal operation.
The windings are made of two components, conductor and the insulation materials. The conductors used are a high grade electrolytic copper or aluminum and are insulated with pure cellulose or double enamel. The MV windings are wound either with round, double enamel insulated or rectangular, paper insulated wire. The LV windings are wound with rectangular, paper insulated wire, enameled wire or foil.
Tank walls are made of corrugated cooling surfaces. The welds are tested for oil tightness. The complete tank is tested and approved acc. to Cenelec HD 428.6 S1 standard.
All metal parts are carefully sand-blasted and painted. Alternatively hot deep galvanized transformers can be supplied for use in heavy corrosion areas. Detailed painting procedures for different environmental conditions are available