Transformers are normally static electrical devices that transfers electrical energy between two or more circuits through electromagnetic induction. Low-voltage transformers can be found in industrial, commercial and residential applications. As with medium-voltage units, low-voltage transformers are fed (primary) with one voltage and produce (secondary) a different voltage. Most common are step-down transformers.

Rectifier transformers for indoor installation, oversized type, specially designed for thyristor converters. The transformer is normally dry type and is enclosed in a cubicle for indoor installation. The temperature of the core, metallic parts and adjacent materials will cooled enough to not reach a value that will cause damage to any part of the transformer; for this purpose, a cooling system will be considered to prevent temperature increasing of the transformer. To improve cooling efficiency and minimize difference between room ambient temperature and air temperature inside enclosure and moreover, to ensure that winding temperature of the three phases is nearly equal, one cooling fan with failure detection, not redundant, will be installed under each winding. Transformer will be sized for Air Forced cooling and will be included in enclosure with IP 42 protection degree.

The transformer normally conforms the IEC standards. The transformer cores are carefully assembled and clamped to ensure adequate mechanical strength to support the windings and to minimize movement during handling, transport and to reduce vibration to minimum under operation conditions. The design will also inhibit the movement of the core due to forces caused by short circuits and overloads.

The winding insulation would be adequate to withstand the effects which may be caused by harmonics and high thermal and mechanical stresses due to fluctuating and sustained overloads during emergency conditions or short circuits. The equipment is ergonomically designed to facilitate ease of inspection, cleaning, maintenance and operation.

All moving components would be adequately guarded to prevent personnel from coming into contact with moving components. Guards are easily removable and are designed to enable lubrication points to be serviced without removal of guards.

The transformer box would incorporate thermostically controlled electric heaters capable of maintaining a cabinet temperature approximately 5°C above ambient with a minimum panel temperature of 0°C. Also the nuts, bolts and washers are made by the best quality stainless steel and BS Standards and DIN Standards would be allowed.