Repair method for bar or coil of rotating electrical machine

1. A repair method for bar or coil of a rotating electrical machine, the bar or coil including a conductor arranged in the rotating electrical machine and an insulating aver having a predetermined insulation thickness disposed on a surface of the conductor, the repair method comprising:

a step of extracting the bar or coil as a repair target;

an insulating layer removing step of removing the insulating layer in a part of the bar or coil as the repair target;

a first insulating layer formation step of disposing a first insulating layer in the part where the insulating layer is removed at the insulating layer removing step, the first insulating layer having an insulation thickness thinner than the predetermined insulation thickness; and

a second insulating layer formation step of disposing a second insulating layer on a surface of the first insulating layer to form an insulating layer after a repair including the first insulating layer and the second insulating layer, the insulating layer after the repair having a thickness of the predetermined insulation thickness,

wherein the insulating layer after the repair has an end portion having a tapered shape when a cross-sectional surface in the longitudinal direction of the bar or coil is viewed,

wherein the tapered shape bar or coil having an inclined part, inclined with respect to the surface of the conductor,

wherein the inclined part having a length in the longitudinal direction of the bar or coil as L, and the insulating layer after the repair has an insulation thickness as T, L≥T×3 is satisfied.

2. The repair method for bar or coil of a rotating electrical machine according to claim 1 ,

wherein the part where the insulating layer is removed at the insulating layer removing step is divided into at least two regions, a first region and a second region in a longitudinal direction of the bar or coil, and after the first insulating layer formation step and the second insulating layer formation step are performed on one of the at least two regions, the first insulating layer formation step and the second insulating layer formation step are performed on other region of the at least two regions.

3. The repair method for bar or coil of a rotating electrical machine according to claim 2 , wherein a length of the at least two regions in the longitudinal direction of the bar or coil is 2000 mm or less.

4. The repair method for bar or coil of a rotating electrical machine according to claim 2 , wherein in the at least two regions, a spacer is disposed in a region adjacent to a region on which

the first insulating layer formation step and the second insulating layer formation step are attempted to be performed, the adjacent region being a region on which the first insulating layer is formed or the second insulating layer is formed.

5. The repair method for bar or coil of a rotating electrical machine according to claim 1 , wherein the first insulating layer has a thickness of ⅓ or more and ⅔ or less of the predetermined insulation thickness.

6. The repair method for bar or coil of a rotating electrical machine according to claim 2 , wherein the insulating layer after the repair has the end portion disposed in each of the at least two regions, and the end portion has a tapered shape when a cross-sectional surface in the longitudinal direction of the bar or coil is viewed.

7. The repair method for bar or coil of a rotating electrical machine according to claim 1 , wherein, the first insulating layer formation step and the second insulating layer formation step include taping insulation tape along a circumferential direction of the conductor and pressurizing a surface of the insulation tape with a pressing member to perform molding.

8. The repair method for bar or coil of a rotating electrical machine according to claim 7 , wherein the part as the

repair target is covered with a heat insulating material during the molding and is heated by supplying hot air between the bar or coil and the heat insulating material.