Foil windings in transformers are a special winding structure used to conduct current in the magnetic circuit of a transformer. Compared to conventional wire windings, foil windings offer higher electrical conductivity, better heat dissipation and a more compact construction. The following are details about foil windings in transformers:

Winding structure: Foil windings consist of several layers of thin copper foils which are separated by an insulating material. Each layer of foil is connected to form a continuous conductor path. The shape of the foil winding can be round, rectangular or other specific geometrical shapes to suit the design requirements of the transformer.

Foil material: Foil windings are usually made of high-purity electrolytic copper foil as conductor material. Electrolytic copper has good electrical conductivity and mechanical properties to withstand the current and magnetic field stresses in the transformer.

Insulating material: foil winding in the foil between the foil needs to use insulating material for isolation, in order to prevent the conductive foil between the short circuit. Commonly used insulating materials include insulating paper, insulating film and insulating varnish.


Advantages and features:

   - Low resistance: Foil winding consists of multiple layers of continuous foils with shorter conductive paths and lower resistance, which can reduce the energy loss when current passes through the winding.

   - Good heat dissipation: foil windings have a compact structure and a large contact area between the foils, which can dissipate heat more effectively and reduce the temperature rise of the windings.

   - Uniform voltage distribution: The structure of the foil winding can make the voltage distribution more uniform, reduce the influence of voltage gradient on the insulation, and improve the insulation performance.

   - High mechanical strength: the multi-layer foils of the foil winding are tightly fixed together and have high mechanical strength, which can withstand the vibration and impact when the transformer is running.

   - High production efficiency: Compared with the traditional wire winding, the manufacturing process of foil winding is more automatic and efficient, which can improve the production efficiency.

Manufacturing process: The manufacturing of foil windings usually includes the following steps:

   - Cutting of foils: Copper foils are cut into foils of appropriate sizes according to the design requirements.

   - Insulation treatment: The foils are insulated, e.g. by applying insulating varnish or by placing insulating paper or film between the foils.

   - Lamination: The foils are laminated together after insulation treatment to form a multilayer winding.

   - Press-fixing: The foils are fixed together using pressure to ensure the stability and compactness of the windings.

   - Welding connection: The ends of the foil windings are welded together to form an electrical connection.

Applications: Foil windings are widely used in various types of transformers, including high-voltage transformers, power transformers, frequency converters and transformer rectifiers. Due to its superior performance, foil windings are widely used in transformers.

It is important to note that the design and construction of foil windings in specific transformers may vary for different applications and transformer types. During the design and manufacture of transformers, suitable winding structures and materials should be selected according to specific requirements and standards, and the appropriate manufacturing processes and specifications should be followed.