Transformer Production Activities

Magnetic Core Production

In magnetic core production, BEST utilizes silicone steel core material which has high conductivity and low losses. Core material is slitted and cut into dimensions which are planned as per the needs of the specification prepared by the Engineering Department in microprocessor controlled modern machines. Slitting and cutting operations in BEST are done with GEORG machines. GEORG maintenance operations which are crucial in product quality is conducted periodically in BEST.

All the laminations sheets, which are sometimes of the length up to 4 to 4.5 meters, are stacked manually. In our facilities, high level of accuracy in stacking of the core and reliability of tension forces applied to hold to core laminations in place are taken with special care since loss and noise levels of the core are crucial parameters and fully dependent on these applications.

Last procedure of the core building workshop is the lifting operation which is done with special equipment and techniques in order to avoid the core to receive unwanted mechanical forces

BEST Transformer - Magnetic Core Production

Winding Production

The cleanness of the winding workshop are one of the most important factor in transformer production. The winding workshops of BEST are operating with a closed pressurized building technology. This technology allows BEST to have high level reliability in winding production. The windings are built on CNC controlled horizontal and vertical machines at high accuracy. In order to achieve maximum reliability, these machines are equipped with braking and pressing mechanisms. All blue color employees of BEST are either graduated from Industrial High Schools or Industrial Institutes who are experienced in the field of electromechanical production.

In power transformers, type of conductors used are mainly flat and transposed copper conductors. Depending on the power rating, voltage levels and on the customer specification, several different winding techniques are applied. Insulation material used in the windings are selected from top quality and high level insulation materials.

Following the winding operation, in order to avoid changes in the winding lengths, the winding are exposed to drying operation under pressesing. In this regard, all winding are dried with modern vapour phase technology under dynamic pressing, which brings high level of reliability in a most timely manner.

BEST Transformer - Winding Production 1

Active Part Assembly

Another critical factor in transformer production is to have a synchronized operation between core production and winding operation since once the core is ready in vertical position, the windings should be ready to start assembly on the core. The importance of this operation is to minimize the level of moisture to be absorbed by the windings from the environment before assembly. This criteria is fully respected in our operations which eliminates negative outcomes during upper yoke stacking. Following upper yoke stacking, tap changer is assembled and other connections are done between tap changer and tapping winding and between windings.

The transformers produced in our factories are periodically checked by Quality Department with pre-defined procedures at check points given in our standards also approved by the customers on project basis. Similarly, once the active part is fully assembled, a team consists of Production, Quality, Design and Test engineers are inspecting the active part before oven process.

Drying Active Part

During the manufacturing process, insulation paper on copper conductors, insulation material between windings and insulation parts in supporting structures are exposed to humidity. This moisture, further to its affects on dielectric withstand of the transformer, also impacts the forces active part can withstand. In this regard, drying of the complete active part is a must in transformer production. Therefore, all active parts in our facilities are dried in vapour phase ovens equipped with state of art technology. The period of drying is based and defined on the voltage levels and insulation quantities.

Final Assembly

Following drying process, active part is prepared for pressing operation in order to increase short circuit withstand capability of the transformer. This operation, which is a critical factor for a high quality product, enables us to increase stability of the windings and the active part. The active part is once more controlled by the specialized team in order to ensure the quality before tanking. Following this inspection, active part is inserted into tank and fixed. Consequently, the cover is closed, the tank is taken into vacuuming operation and the oil is filled. Following oil filling, the transformer is left for resting before factory tests and the period of resting depends on the capacity of the transformer.