WINDING
In distribution transformers, low voltage and high voltage windings are winded by means of appropriate winding techniques for related current and voltage conditions, and using round and profile electrolytic copper, high quality insulating paper and transfer board materials. Low and high voltage windings are resistant against atmospheric shockwaves, and the cylinder layer is in winding form.
Mechanical compressions are applied against short-circuit dynamic forces. Sufficient axial and radial channels are ensured for cooling the windings.
CORE
The core of transformer is made of cold rolled and grain oriented silicon coil. The core consists of electrical silicon coils of ZDHK, MOH, M1, M2, M3, M4 and M5 quality levels depending on the no-load losses requested by customer.
These sheets are slit via zero burring and they are cut as requested by modern cut-to-length machines. It is possible to form the cores in every form such as step-lap, over lap, 90° cut, perforated and imperforated.
ACTIVE PART
Core coil and cover assembly is formed so as to resist envisaged short-circuit mechanical forces. The active part of standard transforms, including the cover, are fitted to the tank via bolts; there also active part applications where they are directly assembled to tank; depending on customer request, transformers with such implementations can also be manufactured.
All fasteners on the cover and HV bushing spark gaps are made of stainless and anti-corrosive material with special facing. Cover-top arrangement, insulators, hood and accessories are produced pursuant to customer demands and specifications.
TANK AND COVER
Transformer tanks and covers are made of medium steel. On tank surfaces of Distribution Transformers, wave wall panels also function as cooler. The lower part of the tank is integrated by means of connecting the walls and frames. Besides, it is possible to use several slices and radiator groups as cooling surface. Each tank, the welding works on which is completed, undergoes pressure test before painting. In case of any welding error, it is perceived and the contact error is corrected.
Each tank and cover, whose craftsmanship is over, is subject to grinding. The standard grinding procedure in use complies with DIN norm. If the customer has a special request or detail on grinding, it will be ensured. Upon request, it is possible to coat the tanks via hot-dip galvanized method. Depending on customer request, it is possible to implement a protection box made of plates compliant with ICE 144 STD, and the coating by mountable covers or cables on lateral surfaces of transformer pursuant to BS2562.
PAINTING
Once their production is over, the tanks are painted with spray. Standard painting consists of one undercoat, and two layers of topcoat. Total film thickness is not below 105 . Standard transformer colour is RAL7033, which is called as cement gray.
Upon customer request, it is possible to paint them in different structures (like zinc-plating), thicknesses
and colour codes.
DRYING AND OIL FILLING
The active parts of transformer (Core + Coil) are dried in drying kilns that operate under high vacuum. Drying process is carried out within the frame of a programme which is formed depending on voltage and power.
Oil filling for hermetic transformers is done under vacuum
