Electric Arc Furnace Transformer

Electric Furnace Transformer

A special transformer that supplies power to various electric furnaces. Resistance furnace transformers are applied to resistance furnaces and salt bath furnaces for mechanical part heating, heat treatment, powder metallurgy sintering, non-ferrous metal smelting and other processes. Due to the excessively low resistance of the heating element, or the significant variation in the resistance of the heating element during the temperature rise process, a resistance furnace transformer must be installed between the furnace and the power grid to reduce and adjust the input voltage of the electric furnace.

Small-capacity, low-voltage resistance furnace transformers and salt bath furnace transformers are mostly dry-type transformers with enclosures and natural cooling; medium-capacity resistance furnace transformers (several hundred to several thousand kVA) are mostly oil-immersed self-cooled transformers; and large-capacity ones are forced oil circulation water-cooled transformers.

Structural Features

The iron core of the electric furnace transformer is made of high-quality grain-oriented silicon steel sheets, processed by a fully automatic shearing line, and manufactured with 45° fully mitered seams, no punching, and glass fiber tape binding without weft. The coils adopt an international main and longitudinal insulation structure, and the winding structure and insulation are rationally selected to ensure sufficient mechanical strength of the windings. The transformer features strong short-circuit withstand capacity, high overload capacity, high efficiency, low loss, safety and reliability.

The capacity of the electric furnace transformer is configured according to the size of the electric arc furnace and the smelting process, and it meets the requirements of the smelting process through voltage regulation. There are two types of voltage regulation methods: on-load tap-changing and off-circuit tap-changing.

Large on-load tap-changing electric furnace transformers are not equipped with series reactors. The structural forms of medium and small off-circuit tap-changing electric furnace transformers can be divided into two types: those with series reactors and those without reactors. Both structures can change the impedance at two voltage levels. The former changes the impedance by switching the series reactor on and off, while the latter changes the winding impedance by altering the connection mode of the high-voltage winding of the electric furnace transformer itself.

Operating Conditions of Electric Furnace Transformer

Altitude: <1000m

Ambient temperature: +40°C ~ -25°C

Relative air humidity: 90% (+25°C)

Device type: Outdoor type

Installation site: Areas free of corrosive gas and obvious dirt

Application: Steelmaking, non-ferrous metal smelting, production of various ferroalloys, silicon compounds and high-purity silicon, etc.