| 摘要 |
PURPOSE:To eliminate external noise pulses, etc., by providing a couple of grounding resistors which have one terminal connected to respective low resistance corona shield layers, and also providing a partial discharge measurement terminal to the ungrounded sides of the grounding resistors. CONSTITUTION:A stator coil 2 consists of a corona conductor 4, a main insulating layer 5, low-resistance corona shield layers 6, and a high-resistance corona shield layer 7, which is insulated from a stator iron core 1 and the layer 6 of a stator coil of the other phase put in the same slot. Further, a couple of grounding resistors 11A and 11B are connected through a conductive connection piece 9 and a lead wire 13 which are coupled with the layer 6 in a conduction state, and a balance input type partial discharge measuring instrument 10 is provided on the ungrounded sides of the resistors 11A and 11B through partial discharge detection terminals 12A and 12B. Then, if an external noise pulse enters the coil 2 through a conductor 4, the terminals 12A and 12B become equal in ground potential and polarity and a potential difference due to the external noise pulse is not generated between the terminals 12A and 12B; and the measuring instrument 10 is prevented from detecting the external noise pulse and the S/N ratio is improved. |
