Whether it is stator winding or rotor winding, whether it is soft winding or hard winding, the end of the winding will be tied in the manufacturing process; Theoretically, the purpose of bundling is to ensure that the relative positions of winding and winding, winding and insulation, winding and associated parts remain unchanged, and contribute to the curing effect of the winding after dipping and drying.
In order to achieve this purpose, the winding will use heat shrinkable insulation binding or binding rope to ensure that the end of the winding is a relatively strong whole after drying. However, the heat shrinkage of the binding tape has a certain range, so a certain tension force should be ensured during the binding process.
It should be emphasized here that for the bundling and fixing of the lead, on the one hand, it is necessary to ensure that the lead can not move randomly after bundling, and on the other hand, it is necessary to ensure that the lead and the connection part of the line will not be pulled by post-processing. For the above reasons, the binding of the winding end must be standardized, and can not just stay in the form of winding.
The motor windings are in phase and out of phase, and there will be mutual attraction and repulsion forces between the two wire rods near the end of the coil. In order to avoid the displacement caused by the force, the end should be fixed as necessary. In the side gap between the wire rods of the adjacent winding, polyester rope with a thickness similar to the gap size is selected to tie up.
At present, the stator of high voltage motor mostly uses VPI whole immersion process, its insulation structure is powder mica tape bandaged coil, coil end with polyester glass rope binding, coil and end hoop with rope force binding, but can not be too tight, to prevent the two parts in contact with different degrees of insulation damage, so that insulation performance is reduced. When the coil is heated and wired according to the process requirements, the end insulation of the coil near the nose is softened. This damages the insulation and affects the service life.
Because of the large pitch and the large distance between electrodes, the stator winding generally has the characteristics of long end size and large horn. Some also use large and small coils, the end of the inner circle coil is wavy, and the gap between the lower and upper layers is very small. To this end, a layer of 4-5mm thick polyester felt can be flat-wrapped on the coil end collar insulation to play the role of padding between the coil and the coil. Because the polyester felt is soft and has a certain amount of compression, it can make the coil insulation of the wire binding no longer be compressed by the end hoop, and also increase the contact area at the binding place to ensure that the coil and the end hoop are in close contact. After the winding is cured with paint, it will be conducive to the fixation of the end in radial and tangential direction.
Post time: Sep-11-2023