Refurbishing wind turbine generator stator winding with winding conversions
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 star connection having three turns per coil, and reconfiguring the stator such that the plurality of stator windings are connected in a four-circuit delta connection having five turns per coil.
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 in a four-circuit star connection having three turns per coil, wherein the plurality of stator windings are supported by a plurality of slots,
adding a three-layer composite slot liner to the plurality of slots, wherein the three-layer composite slot liner is an aramid paper, polyimide film, and aramid paper composite insulation,
reconfiguring the stator such that the plurality of stator windings are connected in a four-circuit delta connection having five turns per coil, and
insulating the reconfigured plurality of stator windings with quad film insulation.
2 . The method of claim 1 , wherein the plurality of stator windings has a concentric wound configuration, and wherein the method further comprises:
replacing the plurality of stator windings with a second plurality of stator windings having a lap wound, single span configuration.
3 . The method of claim 1 , wherein the plurality of stator windings are fully annealed copper windings.
4 . The method of claim 1 , wherein the stator includes one selected from the group consisting of 36 slots, 48 slots, 60 slots, 72 slots, 84 slots, and 96 slots.
5 . The method of claim 1 , further comprising:
removing cooling blocks located at an overhang portion of the plurality of stator windings.