STATOR CONSTRUCTION FOR WIND TURBINE GENERATORS
Rotors and stators for use in electric machines and methods for refurbishing the same. One method for refurbishing a stator for use in an electric machine includes at least partially disassembling the stator to provide access to a plurality of stator windings connected in a four-circuit delta connection having three and four turns per coil, and reconfiguring the stator such that the plurality of stator windings are connected in an eight-circuit delta connection having seven turns per coil. One method for refurbishing a rotor for use in an electric machine includes at least partially disassembling the rotor to provide access to a rotor core, the rotor core including first rotor bars, and reconfiguring the rotor core to include second rotor bars that are longer than the first rotor bars.
1 . A method for refurbishing a stator for use in an electric machine, the method comprising:
at least partially disassembling the stator to provide access to a plurality of stator windings connected and reconfiguring the stator such that the plurality of stator windings are connected in a four-circuit delta connection having three and four turns per coil, wherein the plurality of stator windings consists of only conductors that are insulated with quad film.
2 . The method of claim 1 , wherein reconfiguring the stator includes adjusting the conductor size such that a slot fill factor includes a total conductor area of between 43% to 49% of the available slot size.
3 . The method of claim 1 , further comprising:
reconfiguring the stator such that the plurality of stator windings are connected in an eight-circuit delta connection having seven turns per coil.
4 . The method of claim 1 , wherein the plurality of stator windings are fully annealed copper windings.
5 . The method of claim 1 , wherein the plurality of stator windings are situated in stator slots lined with an aramid paper, polyimide film, aramid paper composite slot liner.
6 . The method of claim 1 , wherein each coil end of the plurality of stator windings on the overhang portion is taped with porous glass cloth or tape during refurbishing of the stator.
7 . The method of claim 1 , wherein the plurality of stator windings is wound with phase-to-phase separators, using an electrical insulation material.
8 . The method of claim 7 , wherein the electrical insulation material includes polyester coated closed weave fabric.
9 . The method of claim 7 , wherein the electrical insulation material includes aramid paper.
10 . The method of claim 7 , wherein the electrical insulation material includes composites of aramid and polyimide film.
11 . The method of claim 1 , wherein the stator includes 96 stator slots.
12 . A generator comprising:
a stator including a plurality of stator windings consisting of conductors that are insulated with quad film, wherein the conductors are situated in stator slots, and wherein the conductors fill between 43% to 49% of an available slot size of the stator slots.
13 . The generator of claim 12 , wherein the plurality of stator windings are connected in an eight-circuit delta connection having seven turns per coil.
14 . The generator of claim 12 , wherein each coil end of the plurality of stator windings on the overhang portion is taped with porous glass cloth or tape.