| 摘要 |
PURPOSE:To easily detect cracks in a main insulating layer by arranging an optical fiber along the longitudinal direction of a coil in the main insulating layer of a coil, and connecting a light emitting device and a light receiving device at both ends of the optical fiber. CONSTITUTION:An optical fiber 5 which is an insulating material is arranged along the longitudinal direction of a raw-wire conductor 2 in a main insulating layer 3 of a stator coil 1. Both ends of said optical fiber 5 are exposed at both ends of longitudinal direction of the main insulating layer 3, and connected to a light emitting device 6 and a light receiving device 7 at the insulation test. In this constitution, since the amount of transmission of light is reduced if there is a crack A in the main insulating layer 3, the position and magnitude of the crack can be easily detected. Therefore, reliablity can be improved and the accident can be prevented beforehand. |
