Patent ID: 6956454

Claim:
Magnetic subassembly for electrical breaker apparatus, comprising a magnetic circuit consisting of a yoke ( 10 ), of a fixed core ( 39 ) and of a moveable core ( 30 ) sliding along a longitudinal axis (X) inside an insulating sheath ( 20 ) between a tripped position and a rest position under the action of an induction coil ( 25 ) arranged around the sheath ( 20 ), the moveable core ( 30 ) possessing a radial annulus ( 33 ) separating a first part ( 31 ) and a second part ( 32 ) of different radial section, the yoke ( 10 ) comprising a radial face ( 11 ) substantially perpendicular to the axis (X) with an opening ( 19 ) centered on the axis (X) and traversed by the first part ( 31 ) of the moveable core ( 30 ), characterized in that the said opening ( 19 ) comprises a fluted perimeter composed of a plurality (N) of teeth ( 17 ) directed towards the axis (X), hollow zones ( 15 ) situated between each tooth ( 17 ) accommodating an end of the insulating sheath ( 20 ).