Patent ID: 8288674

Claim:
A copper-based winding, of diameter greater than 90 mm, intended to generate a magnetic field in an electrical contact for a medium voltage vacuum circuit-breaker, the winding comprising a hollow cylinder including helical slots made methodically about its longitudinal axis and opening out both to the hollow and to the exterior of the cylinder, in which winding the space between two consecutive turns that constitutes a slot is empty of material and the width of each slot is less than 0.2 mm for an outside diameter Ã˜ ext of the hollow cylinder that is greater than 90 mm, the winding being made from a hollow cylinder of an initial height hl with helical slots about its longitudinal axis, the helical slots opening out both to the hollow and to the exterior of the hollow, the space between two consecutive turns being empty of material and the width of each initial slot being greater than 1 mm; the hollow cylinder being compressed until it reaches a calibrated intermediate height h 2 so that after release of compression of the hollow cylinder, the width of each final slot is less than 1 mm.