Stator winding, generator, and connection method of stator winding conductor

1. A stator winding axially penetrating a plurality of stator slots which are formed radially inside a stator core so as to be spaced peripherally from one another and to axially extend, comprising:

a plurality of stator bars each penetrating one of the plurality of stator slots and having at least one hollow element wire, wherein inside the at least one hollow element wire a flow hole for a cooling medium is formed;

a connection structure having a sleeve whose axial one end is fitted to a vicinity of an end of the stator bar, a closing plate disposed at another other end of the sleeve, and a hollow extension pipe disposed in a space defined by the sleeve and the closing plate at the end of the stator bar, and making the flow hole of the hollow element wire and an outside of the space communicate with each other; and

a brazing material filled in the space.

2. The stator winding according to claim 1 , wherein

the sleeve covers a vicinity of ends of three side surfaces of the stator bar, and

the space is open to one surface side of the stator bar.

3. The stator winding according to claim 1 , wherein

the sleeve covers a vicinity of ends of four side surfaces of the stator bar and has formed therein, at a part thereof that covers one of the four side surfaces, an inlet port making the space and an outside of the space communicate with each other.

4. The stator winding according to claim 1 , wherein

a female screw is formed in a vicinity of an end of the hollow element wire, and

the closing plate has formed therein an extension pipe through hole, through which the extension pipe penetrates.

5. A generator comprising:

a rotor extending in a direction of rotation axis and having formed therein a rotor core at an axial center thereof; and

a stator having a hollow cylindrical stator core disposed radially outside the rotor core and a stator winding axially penetrating a plurality of stator slots which are formed radially inside the stator core so as to be spaced peripherally from one another and to axially extend, wherein

the stator winding includes:

a plurality of stator bars each penetrating one of the plurality of stator slots and having at least one hollow element wire, wherein inside the at least one hollow element wire a flow hole for a cooling medium is formed;

a connection structure having a sleeve whose axial end is fitted to a vicinity of an end of the stator bar, a closing plate disposed at another end of the sleeve, and a hollow extension pipe disposed in a space defined, at the end of the stator bar, by the sleeve and the closing plate and making the flow hole of the hollow element wire and an outside of the space communicate with each other; and

a brazing material filled in the space.

6. A connection method for a stator winding conductor, comprising:

preparing a stator bar having at least one hollow element wire, wherein inside the at least one hollow element wire a flow hole for a cooling medium is formed;

mounting a sleeve to an end of the stator bar;

mounting a closing plate to an opening of the sleeve and installing an extension pipe for making the flow hole for the cooling medium of the at least one hollow element wire communicate with an outside of the sleeve to define a space by the sleeve and the closing plate;

filling a brazing material in the space; and

mounting an end fitting to the sleeve.

7. The connection method according to claim 6 , wherein

the stator bar preparation includes cutting an end of the stator bar connected to a connection structure to be replaced.

8. The connection method according to claim 6 , further comprising:

engaging a bolt with a female screw formed in a vicinity of the hollow element wire, the bolt penetrating the extension pipe; and

releasing the bolt from the female screw;

wherein the engaging is performed before the filling and the releasing is performed after the filling.