Wound rotor for wind turbine generators
A wound rotor for use in an electric machine. The wound rotor includes a winding overhang portion and a connection ring formed of a plurality of rectangular cross-section conductor sections connected in parallel, the connection ring disposed underneath the winding overhang portion. The wound rotor further includes a first plurality of conductor coils extending from the winding overhang portion and forming a star connection with the connection ring and a second plurality of conductor coils extending from the winding overhang portion to form a line connection.
1 . A wound rotor for use in an electric machine, the wound rotor comprising:
a winding overhang portion;
a connection ring formed of a plurality of rectangular cross-section conductor sections connected in parallel, the connection ring disposed underneath the winding overhang portion;
a first plurality of conductor coils extending from the winding overhang portion and directly forming a star connection with the connection ring; and
a second plurality of conductor coils extending from the winding overhang portion to form a line connection.
2 . The wound rotor of claim 1 , wherein each of the connection ring, the first plurality of conductor coils, and the second plurality of conductor coils are individually insulated.
3 . The wound rotor of claim 2 , wherein each of the connection ring, the first plurality of conductor coils, and the second plurality of conductor coils are positioned below the winding overhang portion.
4 . The wound rotor of claim 1 , wherein the connection ring is secured to the winding overhang portion using woven glass tape.
5 . The wound rotor of claim 1 , wherein a total area per turn of each of the first plurality of conductor coils is less than 13 mm 2 .
6 . The wound rotor of claim 1 , wherein the star connection is formed by one selected from the group consisting of brazing, tig welding, and soldering.
7 . The wound rotor of claim 1 , wherein ends of the conductor coils included in the second plurality are crimped and fitted with a lug; and
wherein the lug is used to form a line connection via a hole formed in a shaft of the wound rotor.
8 . The wound rotor of claim 1 , wherein the electric machine is an induction motor and/or generator.
9 . The wound rotor of claim 1 , wherein the electric machine is a synchronous motor and/or generator.
10 . A method for constructing a wound rotor for use in an electric machine, the method comprising:
extending a plurality of conductor coils out of a winding overhang portion;
forming a star connection directly between the plurality of conductor coils and a connection ring;
after forming the star connection, individually wrapping each one of the plurality of conductor coils with an insulating material;
after forming the star connection, wrapping the connection ring with the insulating material;
moving the wrapped connection ring to a position underneath the winding overhang portion; and
securing the position of the wrapped connection ring underneath the winding overhang portion by binding the connection ring to the winding overhang portion with woven glass cloth or tape.
11 . The method of claim 10 , further comprising securing the connection ring to a steel support ring using woven glass tape.
12 . The method of claim 10 , wherein forming the star connection includes one selected from the group consisting of brazing, tig welding, and soldering.
13 . The method of claim 10 , wherein the plurality of conductor coils is a first plurality of conductor coils, the method further comprising forming a line connection.
14 . The method of claim 13 , further comprising crimping ends of the second plurality of conductor coils and fitting each of the crimped ends with a lug, wherein the lug forms a line connection via a hole formed in a shaft of the wound rotor.
15 . The method of claim 10 , further comprising forming the connection ring via a plurality of rectangular cross-section conductor sections connected in parallel.
16 . The method of claim 10 , wherein the connection ring is bound to the winding overhang portion with the woven glass cloth or tape at a plurality of separate circumferential locations.
17 . A method for refurbishing an existing wound rotor for use in an electric machine, the method comprising:
at least partially disassembling the existing wound rotor to provide access to a winding overhang portion of the existing wound rotor;
extending a plurality of conductor coils out of the winding overhang portion;
forming a connection directly between the plurality of conductor coils and a connection ring;
after forming the connection, individually wrapping each one of the plurality of conductor coils with an insulating material;
after forming the connection, wrapping the connection ring with the insulating material;
repositioning the wrapped connection ring from a location outside of the winding overhang portion to a location underneath the winding overhang portion; and
securing the position of the wrapped connection ring underneath the winding overhang portion by binding the connection ring to the winding overhang portion with woven glass cloth or tape.
18 . The method of claim 17 , further comprising replacing an existing connection ring of the existing wound rotor with the connection ring formed via a plurality of rectangular cross-section conductor sections connected in parallel, wherein wrapping the connection ring with the insulating material includes wrapping the new connection ring with the insulating material.
19 . The method of claim 17 , wherein the connection ring is bound to the winding overhang portion with the woven glass cloth or tape at a plurality of separate circumferential locations.