folievindning

Folievindning, or foil winding, is a method of creating electrical windings using flat metal foils instead of conventional round wires. The foils are typically copper or aluminum and are insulated from adjacent turns with dielectric layers. This approach is used in transformers, inductors, and some motors where high current handling, compactness, or efficient cooling are important.

Construction and materials commonly involve cutting thin foil strips, applying insulation between layers (such as polymer films or paper), and winding the foils around a nonconductive former. Foil windings can be arranged as stacked coils or formed into planar or cylindrical configurations. Ends are connected to busbars or terminals, and the finished winding is often impregnated with resin or oil to improve electrical insulation and thermal transfer. Proper tensioning and alignment are essential to minimize gaps and insulation stress.

Advantages of foil windings include low DC resistance for a given cross-sectional area, improved heat dissipation due to the large surface area, and reduced magnetic leakage in compact geometries. These attributes can enable high-current operation and compact, robust designs. However, foil windings require precise insulation, careful mechanical design to withstand thermal cycling and vibration, and typically involve more complex manufacturing and assembly than traditional wire windings.

Common applications are high-current transformers and power electronics where efficient cooling and space savings are important, as well as specialized industrial equipment and large-scale energy storage systems. Folievinding remains favored in niche applications where its thermal and electrical benefits justify the added fabrication complexity.