Turbine Coil Failure
1. Corrosion damage to the main insulation of the coil
(1) The close of the stator winding of the engine along with the coil within the stator center vibrate to hurt the principal insulating material of the coil. This really is the most common and serious phenomenon in external corrosion damage accidents. The most important cause of such corrosion damage is the engine is vibrating under the action of the electromagnetic force during the performance of the engine, so the coil is not securely fixed in the inner end of the stator core slot.
(2) Wear and corrosion of magnetic substances inside the stator core. This situation is mainly due to the fact that during the overhaul process, that the stator windings were not carefully cleaned and purged, resulting in some small magnetic debris left in the winding coil gaps and other lifeless corners.
(3) Oil contamination of the stator coil. At present, oil spills are common in massive generators and high-voltage motor bushings. Therefore, accidents in which engine coils are burnt due to petroleum corrosion are also common. The location of these faults is concentrated in the motor stator slots, twisting ends and twisting nose leads.
(4) Wear corrosion of the stator core metal steel sheet into insulation. In the procedure for press-fitting the stator core, if the silicon steel sheet lamination is not neat, or the stator core venting channel steel and the end pressure finger are not correctly mended, or the stator core is damaged during upkeep, the engine will operate. The main insulation is broken down.
2. Corrosion within the coil
The results of multiple injury statistics and fault spiral anatomy demonstrate that the internal corrosion of this coil is also serious. The anatomical analysis of a large number of inner corrosion coils demonstrates that the inner corrosion normally starts from the atmosphere pit bubble between the insulation and the cable, the R angle of the coil line and the conclusion, and the false wire welding of this coil lead wire. The inner corrosion occurrence firstly turns the internal insulating material of the coil to white and gradually expands, then burns the insulation to form a pit and accumulates a great deal of green powder, thereby accelerating the corrosion damage between the strands and the main insulation before the main insulation breaks down. Additionally, heat aging caused by excessive temperature is also an important factor causing internal corrosion.