As one of the manufacture in transformer and stabilizer, we are not only offering our product but also wanting customer to understand our product quality. Therefore, in this global description we provide valuable information about construction of Transformer CENTRADO and hopefully this information can help customers to know our product wisely.
First of all, we can begin with the Transfomer working principle itself :
The primary coil connected to a voltage source back and forth, changing the electric current in the coil primary cause of changing magnetic field. Changing magnetic field is strengthened by the existence of an iron core and iron core is delivered to the secondary coil, so that the ends of the secondary coil will arise through induction.
Construction Of Transformer :
1. Core
The core has to be constructed in such a way to limit the energy losses caused by eddy currents and hysteresis to a minimum. This is achieved by the use of silicon steel, which is characterized by low hysteresis losses and high resistivity. The core is constructed using thin sheets of cold-rolled grain oriented magnetic silicon steel insulated lamination sheet on both sides. Minimum magnetic flux distortion in the transition area between yokes and core legs is achieved by cut all the core sheet at an angle of 45˚. This allowing maximum flow of magnetic flux in the rolling direction. Then the sheets are stacked in an overlap pattern of either single or multiple overlap. By using simple profiled-steel yoke clamping systems and a number of metal tensioning band, we also eliminated the need for either clamping bolts in the yokes (which would distort the magnetic flux) or tie rods between the upper and lower yokes.
2. Windings
Both of the primary and secondary windings are made of copper or aluminum conductors with use of high quality insulating materials. Windings are placed around the magnetic circuit legs. Low voltage windings are usually made of copper or aluminum sheet conductor (foil). The benefit of this is that any high voltage ampere-turn asymmetry which might occur is compensated automatically by an appropriate internal current distribution in the low voltage foil. High voltage winding are almost exclusively of layered construction. The copper or aluminum conductors are made of one or more round or square wires, either with an insulating enamel coating or wrapped insulating paper. There are 4 main benefits of layered windings , first they form a simple winding, which allows continuous or semi autommatic winding. Second, the impulse voltage distribution throughout the winding is predictable and controlled. Third, axial cooling ducts are simple to build and fit. Last benefit is any taps required can be brought out anywhere in the winding through the layers.
3. Transformer oil
Transformer is filled with mineral insulating oil. Oil must be done after vacuuming if the transformer active part characteristics of the transformer oil are in compliance with the requirements of standard IEC 296 and value of the oil breakdown voltage is above 50 KV/2.5mm. This type of transformer’s construction guarantees that the oil cannot come into contact with air, this use ensuring preservation of its electricity integrity, reduced maintenance ex: no checking required of silica gel breather.
4. Conservator
Conservator is located horizontally over the tank and mounted on conservator’s supports connected with the cover. Conservator is designed in such a way to accept all oil volume variation during temperature change between -25°C to 100°C. The contact is realized through silica-gel placed inside dehydrating breather (placed on the conservator) which absorbs all moisture from air and prevents it for entering the transformer tank.
As a default, the conservator is equipped with oil level indicator. In the event that oil level falls below minimum mark on the scale of oil level indicator, the transformer must be immediately switch off, any leaks found, sealed and poured with the oil up to necessary level. Only when these actions are done it is allowed to start-up the transformer.
5. Tank
The tank is made of high quality steel. Hermetically sealed and completely filled transformers have tank with corrugated walls. Transformers with conservator may have tank either with corrugated walls or with cooling radiators. High quality of the tank welding provides high mechanical strength and impermeability so tank withstands, without permanent deformation, all strains during transport and exploitation. In accordance with type of the transformer and its installation place the following facilities can be found on the tank:
• Oil drain valve or oil draining device, • Oil sampling device, • Hooks for pole mounting, • Transformer support (with or without bidirectional wheels), with holes for pulling of the transformer, • Reinforcements for lifting and pushing the rating plate (at LV side as a default), • Earthing terminal
