MT-BT Mineral Oil Transformers

Technical characteristics

All transformers are made in conformity to the following norms :

Italian Order in Council ( DPR 547 of 27/04/1955 and succesive integrations )

CEI 28-3 N.796 Recommendations for the co-ordination of the isolations
CEI 14-4 N.609 Power transformers

The respect of the application of such norms is guaranteed by Company's Quality procedures
Magnetic circuit

Is constructed from high-grade , cold rolled grain silicon steel lamination insulated on both sides cutting at 45°

The material of LV winding is copper or aluminium.
Conductors are insulated by of pure cellulose or enamel.

Are provided at the high voltage winding to allow adjustment for voltage variations on the network voltage.
It is operational by the knob on the cover, only when transformer is disconnected
Passing insulators

High tension type 20/250 UNEL 38144-74 , low tension UNEL 38128-67 according to prescription of the CNR-CEI 21001-74

Generally realized in sheet metal to perfect oiltight to elevated temperature and provided of radiators in printed plate or of so that cooling fans with natural oil circulation.
All the parts are sand-blasted and paint with two hands of rust-preventer and enamel RAL 7031
Filling insulation liquid

Either mineral oil according to IEC CEI 10-1-232, on demand siliconic fluid , not inflammable and not polluting

The trasnsformer comes assembled with the cover and it is subordinated to rigorous thermal cycles of drying, in order to eliminate every humidity trace from the used materials.
Hermecatilly sealed transformers are also available on request.
Standard accessories

Conservator placed on the short side of the case that is the L.V. neutral side, provided witth:

Level indicator with level marks at temperature -20° , +20°C and +85°C ;

oil filling hole valve

provision for dehydrating breather
drain valve for conservator only
lifting lungs to either the complete transformer or
the live part only
thermometrer pocket
two door plates disposed according to UNEL 21003-74
to support everyone the plate of the characteristics
electrical workes and the plate of customer inventory
two characteristics plates according to UNEL 21005-74
two earthling terminals for case acoording to UNEL 06131-71
four consistent rollers according to UNEL 21002-71 to move the transformer in the two directions of traslation skids under-base for transformers up to 200 KVA according to UNEL 21002-74
drain valve for a fast discarghe of insulation oil
Optional accessories

dehydrating breather
dial type oil thermometer with two sets of concats ( alarm and trip )
remote dial type oil thermometer with two set of contacts
buchholtz protection relay
fastening gear for filter press
reversible truck from 25KVA up to 100 KVA
protection on air L.V. and H.V. sides
cables sealing boxes on L.V. and H.V. side according to 2562/2(boxes are designed to receive and to protect the end of metal-sheathed cables )
R.I.S. Integrated Safety Detector to control pressure
level and oil temperature for transformers hermetically sealed