A method to construct an electric machine, which comprises: a stator comprising a magnetic core longitudinally crossed by a plurality of stator slots; and a stator winding having a number of phases and comprising a series of rigid bars, which are "U"-shaped and are inserted through the stator slots defining an entry side, in which the cusps of the "U"-shaped bars are placed, and an exit side, in which the legs of the "U"-shaped bars are placed; the construction method comprises the steps of: twisting the legs of the "U"-shaped bars coming out from the exit side of the magnetic core through relative double folds, each of which comprises an internal fold in one direction and an external fold in the opposite direction; electrically connecting to one another the ends of the legs of the "U"-shaped bars so as to form the electrical paths of the stator winding; and electrically connecting the ends of at least two non-adjacent legs by means of a connection bridge (18; 28; 30; 32; 34), which is made of a flat plate arranged perpendicular to the central axis of rotation and has, for each leg, a corresponding "U"-shaped seat, which is suited to receive the end of the leg itself; the construction method is characterized in that it comprises the further steps of: initially manufacturing the seats of the connection bridge (18; 28; 30; 32; 34) with a size that is larger, beyond the tolerance needed to simply insert the ends of the legs, than the ends of the corresponding legs; inserting into the seats of the connection bridge (18; 28; 30; 32; 34) the ends of the corresponding legs, so that the end of each leg is " loose " inside the corresponding seat; and locally and plastically deforming the connection bridge (18; 28; 30; 32; 34) so as to tighten the seats of the connection bridge (18; 28; 30; 32; 34) around the ends of the corresponding legs. a stator comprising a magnetic core longitudinally crossed by a plurality of stator slots; and a stator winding having a number of phases and comprising a series of rigid bars, which are "U"-shaped and are inserted through the stator slots defining an entry side, in which the cusps of the "U"-shaped bars are placed, and an exit side, in which the legs of the "U"-shaped bars are placed; the construction method comprises the steps of: twisting the legs of the "U"-shaped bars coming out from the exit side of the magnetic core through relative double folds, each of which comprises an internal fold in one direction and an external fold in the opposite direction; electrically connecting to one another the ends of the legs of the "U"-shaped bars so as to form the electrical paths of the stator winding; and electrically connecting the ends of at least two non-adjacent legs by means of a connection bridge (18; 28; 30; 32; 34), which is made of a flat plate arranged perpendicular to the central axis of rotation and has, for each leg, a corresponding "U"-shaped seat, which is suited to receive the end of the leg itself; the construction method is characterized in that it comprises the further steps of: initially manufacturing the seats of the connection bridge (18; 28; 30; 32; 34) with a size that is larger, beyond the tolerance needed to simply insert the ends of the legs, than the ends of the corresponding legs; inserting into the seats of the connection bridge (18; 28; 30; 32; 34) the ends of the corresponding legs, so that the end of each leg is " loose " inside the corresponding seat; and locally and plastically deforming the connection bridge (18; 28; 30; 32; 34) so as to tighten the seats of the connection bridge (18; 28; 30; 32; 34) around the ends of the corresponding legs. twisting the legs of the "U"-shaped bars coming out from the exit side of the magnetic core through relative double folds, each of which comprises an internal fold in one direction and an external fold in the opposite direction; electrically connecting to one another the ends of the legs of the "U"-shaped bars so as to form the electrical paths of the stator winding; and electrically connecting the ends of at least two non-adjacent legs by means of a connection bridge (18; 28; 30; 32; 34), which is made of a flat plate arranged perpendicular to the central axis of rotation and has, for each leg, a corresponding "U"-shaped seat, which is suited to receive the end of the leg itself; the construction method is characterized in that it comprises the further steps of: initially manufacturing the seats of the connection bridge (18; 28; 30; 32; 34) with a size that is larger, beyond the tolerance needed to simply insert the ends of the legs, than the ends of the corresponding legs; inserting into the seats of the connection bridge (18; 28; 30; 32; 34) the ends of the corresponding legs, so that the end of each leg is " loose " inside the corresponding seat; and locally and plastically deforming the connection bridge (18; 28; 30; 32; 34) so as to tighten the seats of the connection bridge (18; 28; 30; 32; 34) around the ends of the corresponding legs. initially manufacturing the seats of the connection bridge (18; 28; 30; 32; 34) with a size that is larger, beyond the tolerance needed to simply insert the ends of the legs, than the ends of the corresponding legs; inserting into the seats of the connection bridge (18; 28; 30; 32; 34) the ends of the corresponding legs, so that the end of each leg is " loose " inside the corresponding seat; and locally and plastically deforming the connection bridge (18; 28; 30; 32; 34) so as to tighten the seats of the connection bridge (18; 28; 30; 32; 34) around the ends of the corresponding legs.