SIRMET ELETTRICA constructs, repairs and modifies MV and LV epoxy resin transformers  in the range from 160 KVA up to 10MVA and a maximum operating voltage of 36KV.

The magnetic circuit is made with silicon lamination with low loss oriented crystals with 45 ° weaving in order to minimize the noise level. The core tightening system is sized to withstand the electrodynamic stresses of the windings in the event of a short circuit. The low voltage windings are normally made of aluminum or copper sheet insulated with F or H class materials.

They are protected by H class, high cementation varnish, that once dried in the oven, forms a highly compact mass which is resistant to radial short-circuit stresses to obtain a reduced percentage of additional losses. The axial stresses are very low thanks to the single plate conductor.


The MV coils  are made of aluminum or copper wire or with a wire insulated with an interwoven polyester film. The coefficient of thermal expansion of aluminum, close to that of the resin, allows the structure to respond homogeneously to temperature variations due to frequent load changes, thus avoiding dangerous stresses that would damage the transformer over time. The different rolls of the medium-voltage winding are lined up and connected in series with each other so as to form a phase coil which is subsequently tested in order to check the insulation and the absence of partial discharges as per CEI 14- 8. The coil thus obtained is incorporated into an epoxy resin loaded and mixed with a computerized embedding system in an autoclave.

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Technical Construction Features
The core is manufactured with grain-oriented silicon sheet with low losses, with 45° cut and step-lap assembly in order to reduce noise.
Windings are made of aluminum or copper sheet insulated with material in class F or H. The insulation between turns is made with insulating coupled with a layer of B-stage resin on both sides. Finished winding, the coil is subjected to heat and polymerize the resin, cementing the insulator to the conductor and making the winding a mass highly compact and resistant to the stresses of a short circuit.
They are manufactured with band or wire of aluminum or copper insulated with a fim of intertwined polyester material. The various bands of the medium voltage are connected in series between each other so as to form the phase coil which is then incorporated in epoxy resin and mixed with a computerized under vacuum encapsulation system in an autoclave. The windings are so insensitive to moisture and dust. MV winding has insulation class F


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