A stator for a rotary electric machine and comprising: a magnetic core axially crossed by a plurality of slots; a stator winding comprising a plurality of bars, which are arranged inside the slots; a plurality of cooling channels, which, in use, can be flown through by a cooling fluid and are obtained inside the slots between the bars of the stator winding; and a plurality of covering elements, each of which is made of an electrically insulating plastic material, engages a corresponding slot, without clearance, on all sides of the slot and has, at the centre, a cavity where a series of corresponding bars are arranged and the cooling channels are obtained; wherein each covering element has two major side walls that are opposed and radially oriented and two opposite minor head walls connect the two major side walls to each other and have an extension lower than an extension of the major side walls; and wherein each cooling channel is delimited by walls (13, 14) of a corresponding covering element and by at least one corresponding bar; the stator is characterized in that: each covering element has seats, each of which consists of two facing and opposite recesses cut into the two major side walls of the covering element and is configured to accommodate therein, without clearance, the ends of at least one corresponding bar; the cooling channels are arranged next to the seats where the bars are arranged; two annular cooling manifolds (19, 20) are provided which are arranged at opposite ends of the magnetic core and into which the cooling channels flow; two annular containing bodies are provided, each of which internally delimits a corresponding cooling manifold and is made of plastic material; and two annular connection bodies are provided, which are arranged at the two opposite ends of the magnetic core, are connected without interruptions to all the covering elements with which they form a single, indivisible assembly, and thus connect all the covering elements together, and form a support base for the containing bodies. a magnetic core axially crossed by a plurality of slots; a stator winding comprising a plurality of bars, which are arranged inside the slots; a plurality of cooling channels, which, in use, can be flown through by a cooling fluid and are obtained inside the slots between the bars of the stator winding; and a plurality of covering elements, each of which is made of an electrically insulating plastic material, engages a corresponding slot, without clearance, on all sides of the slot and has, at the centre, a cavity where a series of corresponding bars are arranged and the cooling channels are obtained; wherein each covering element has two major side walls that are opposed and radially oriented and two opposite minor head walls connect the two major side walls to each other and have an extension lower than an extension of the major side walls; and wherein each cooling channel is delimited by walls (13, 14) of a corresponding covering element and by at least one corresponding bar; the stator is characterized in that: each covering element has seats, each of which consists of two facing and opposite recesses cut into the two major side walls of the covering element and is configured to accommodate therein, without clearance, the ends of at least one corresponding bar; the cooling channels are arranged next to the seats where the bars are arranged; two annular cooling manifolds (19, 20) are provided which are arranged at opposite ends of the magnetic core and into which the cooling channels flow; two annular containing bodies are provided, each of which internally delimits a corresponding cooling manifold and is made of plastic material; and two annular connection bodies are provided, which are arranged at the two opposite ends of the magnetic core, are connected without interruptions to all the covering elements with which they form a single, indivisible assembly, and thus connect all the covering elements together, and form a support base for the containing bodies. each covering element has seats, each of which consists of two facing and opposite recesses cut into the two major side walls of the covering element and is configured to accommodate therein, without clearance, the ends of at least one corresponding bar; the cooling channels are arranged next to the seats where the bars are arranged; two annular cooling manifolds (19, 20) are provided which are arranged at opposite ends of the magnetic core and into which the cooling channels flow; two annular containing bodies are provided, each of which internally delimits a corresponding cooling manifold and is made of plastic material; and two annular connection bodies are provided, which are arranged at the two opposite ends of the magnetic core, are connected without interruptions to all the covering elements with which they form a single, indivisible assembly, and thus connect all the covering elements together, and form a support base for the containing bodies.