The electric furnace transformer is a transformer designed to provide power for various electric furnaces. It can convert a higher voltage into a lower voltage suitable for the electric furnace. The electric furnace transformer is the power transformer of the steel-making electric arc furnace. The capacity of the electric furnace transformer is configured according to the size of the electric arc furnace and the smelting process. It meets the requirements of the smelting process by adjusting the pressure.
The large-scale electric furnace transformer with load voltage regulation does not have a series reactor, and the structure of small and medium-sized electric furnace transformer without excitation voltage regulation can be divided into two kinds with series reactor and without reactor.
On-load voltage regulation relies on the input and removal of series reactors to change the impedance. Non-excitation voltage regulation relies on changing the connection mode of the high-voltage winding of the electric furnace transformer to change the winding impedance.
Industrial furnace transformers can be roughly divided into three categories: resistance furnace transformers, electric arc furnace transformers, and induction furnace transformers(industrial servo motor voltage regulator).
Because the resistance of the heating element is too small, or the resistance of the heating element changes too much during the healing process, it is necessary to equip a resistance furnace transformer between the furnace and the power grid to reduce and adjust the input voltage of the electric furnace.
The electric arc furnace transformer is mainly composed of an 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, which consumes fewer materials and the manufacturing process is simpler. The iron core skeleton of the transformer is composed of an iron column, an iron yoke, and a clamping mechanism.
The permeable magnet is a vertical frame, which consists of three iron cores, a lower iron yoke, and an upper iron yoke. The coil is placed on the iron core. The iron yoke connects the iron cores and forms a three-core magnetic circuit with the iron core. The function of the iron core is to conduct magnetism and is made of laminated silicon steel sheets. The 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.
The coil of the transformer is divided into a high voltage coil (primary coil) and low voltage coil (secondary coil). According to the installation position of the coil on the iron core, it is divided into the concentric type and overlapping type. Arc furnace transformers are mostly overlapped.
The characteristic of the overlapping coil is that the radius of the high-voltage coil and the low-voltage coil is the same, and the average diameter is also the same. The high-voltage coil and the low-voltage coil are arranged alternately along with the height of the core. Overlapping coils have the advantages of simple structure, convenient welding, high mechanical strength, convenient wiring, etc.; concentric coils, due to the large current in the low-voltage coil, install it outside and install the high-voltage coil inside the low-voltage coil.
Electric furnace transformers are mostly used in resistance furnaces, electric arc furnaces, and salt bath furnaces for heating mechanical parts, heat treatment, powder metallurgy sintering, and non-ferrous metal smelting.