Solenoid a DC

An electrical direct current comprising a magnetic circuit with a yoke and a magnetic core fixed to its pallet ends with the possibility of axial displacement. The magnetic core 21 is smooth and the paddles 22, 23 are fitted and fixed to the ends of the smooth ring. One of the vanes 22 is seated on the ring in a reference position, and then applied on the cheek 25 of the associated bolt 14, and the other vane 23 is pressed and pushed into an adjustable position determined by applying to the other plays 26 of the cylinder head 14.