MT-BT Resin Distribution Three Phase Transformers


Power fro 10 KVA to 12 MVA
All trasnsformers are made in conformity to the folllowing norms :
Italian Order in Council (DPR 547 of 27/04/1955 and succesive integrations )
CEI 28-3 N.796
CEI 14-4 N.609
IEC 726- CEI 14-8 N.1162

The respect of the application of souch norms is guaranteed by Company's Quality procedures

Magnetic core

Composed by oriented crystals ferrosilicon laminiations insulated by canlyte and assembled with 45° joints.
Cut and assembly core are executed with special equipment to reduce works losses
The column are locked with shring strips ;the yokes are toghtened with metallic armatures wich are insulated from the lamination and suitable for a correct tightening of both LV and HV windinings.
After the core assembly, an double surface painting is carried out so as guarantee protection even from chemically aggresive substances present in the atmospheres and to obtain , in exercise , a considerable noise reduction
L.V. windings

They are made of a alluminium conductor ( UNI 4507 STANDARD ) with rounded edges, insulated with a special resin-enalulled film.
The coils are made by winding simultaneosly the conductor tape , the turn and the end insulator with semiautomatic winding machines in order to obtain a high quality compact assembly of resisting short circuit radial compression forces without any risk
A subsequent vacuum resin treatment followed by an over hardening treatment guarantees a permanent protection of the winding from moisture infration.
The terminals for the connections to cables or bus-bars are oppurtnely moulded and welded during the winding operation ; they consist of a conductor plate with electrolyte copper surface.
H.V. windings

They are made of single coils of alluminium strip or wire.
The coils are wrapped together with an insulated film , stacked up in a special mould where filled epoxy resin is cast after vacuum heat treatment.
After a polymerisation and stress i relieving process with controlled time and temperature

a compact column is obtained with windings protected by a suitable resin thickness so as to guarantee the insulation
of the turns
of the column coils
between the columns
between the primary and secondary winding
between the primary winding and earth without striking any partial discharges
This technology allows to manufacture columns whose conductors are procected from moisture and other agressive environmetal agents.
The resin used has excellent self-extinguishing and inflammable characteristics
Regulator of the transformation ratio

Special terminal board on each HV column can be adjusted when the transformer is disconnected from the HV and LV. This allows the regulation of the transformer ratio for variations of 2x2,5% and ,if mounted , the facilty to adjust the supplied voltage to units with two primary voltages.

Columns bearing

The HV and LV windings are supported and locked by means of elastic insulating bearing anchored to the core reinforcement.
These bearings allows an axial compensation of thermal expansion and an attenuation of the vibration due to load variations

Standard accessories

The transformers will be equipped with three temperature sensors, one for each
LV columns, which terminals are brought into the terminal box
As optional accessories we supply :

temperarure indicator with alarm and trip contacts
vibration-damping mounts for tuck rollers
HV line connections with detachable connectors
core temperature sensor
protective container with removable front pannels
forced ventilation units