Fill factor (grooves)
In coil winding technology, the fill factor is the ratio of the effective cross-sectional area of the copper conductor to the theoretical maximum cross-sectional area of the available winding window (e.g. in an electric motor , transformer , or relay ).
For a given geometry, a fill factor of 100% is aimed for in order to minimize copper losses as much as possible. With round wire, the cross-section is not fully utilized and is therefore limited to a theoretical maximum of approx. 78% (≈ π / 4). Winding and wire insulation as well as wire entry further deteriorate the fill factor. For large machines and thick solid wires, rectangular profile wires are used, which means that fill factors of over 90% can be achieved. With very thin wires, a completely regular layer structure can no longer be guaranteed (wire crossings, etc.), which can reduce the fill factor to below 50%. In the case of HF strands with many thin individual wires, the fill factor within the strand is already very poor, which means that the total fill factor is also drastically reduced.
Individual evidence
- ↑ Franz Spüntrup: The subject examination in electrical occupations. Verlag W. Girardet, Essen 1967, p. 79.