Structure of EAF Transformer

The function of the transformer is to reduce the input high voltage and output it to generate a large current to supply the arc furnace.

Structure:

The electric arc furnace transformer is mainly composed of iron core, coil, oil tank, insulating sleeve and oil pillow.

Most of the iron cores of electric arc furnace transformers adopt a three-phase core structure. 

The core structure consumes less material and the manufacturing process is simpler.

The iron core skeleton of the transformer consists of an iron column, an iron yoke and a clamping mechanism.

The magnetic conductor is a vertical frame, which consists of three iron cores, a lower iron yoke and an upper iron yoke, and the coils are placed on the iron cores. 

The iron yoke connects the iron cores and together with the iron core forms a three-iron core magnetic circuit.

The role of the iron core is to conduct magnetism, and it is formed by stacking silicon steel sheets. 

Silicon steel sheet has high magnetic permeability, and the larger resistivity can reduce the energy loss caused by eddy current. 

In order to reduce the eddy current loss in the silicon steel sheet, both sides of the silicon steel sheet are painted or covered with paper insulation.

In order to connect the iron core and the iron yoke firmly, the magnetic conductor adopts cross-stacked silicon steel sheets to ensure that half of the iron core chips enter the two iron yokes. 

At the same time, the silicon steel sheet of one layer can cover the gap of the adjacent layer of silicon steel sheet.

Before placing the coil, the upper iron yoke is first opened, that is, the silicon steel sheet of the upper yoke is removed from its original position. 

After the coil is installed, the silicon steel sheet is inserted into the original position.

The silicon steel sheet of the iron core is clamped by means of a clamp and is clamped by a screw mechanism, and the screw penetrates the entire iron core and is insulated from the clamp.

The coils of the transformer are divided into high-voltage coils (primary coils) and low-voltage coils (secondary coils). 

According to the installation position of the coil on the iron core, it is divided into concentric type and overlapping type.

Most electric arc furnace transformers are of the overlapping type. 

The characteristic of the overlapping coil is that the radius of the high-voltage coil and the low-voltage coil are the same, and the average diameter is the same.

The overlapping coil has the advantages of simple structure, convenient welding, high mechanical strength, and convenient wiring;

For the concentric coil, due to the large current in the low-voltage coil, it is installed outside, and the high-voltage coil is installed inside the low-voltage coil.

For more information on transformer operation and maintenance, please refer to our news "Transformer Operation & Maintenance"

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