Analysis of application of high voltage motor end banding

Whether it is stator winding or rotor winding, whether it is soft winding or hard winding, the end of it will be bound in the manufacturing process. Theoretically, the purpose of binding is to ensure that the relative positions between windings, windings and insulation, windings and related parts remain unchanged, and it is helpful to the curing effect of windings after dipping and drying.

In order to achieve this goal, heat-shrinkable insulating straps or binding ropes will be used for winding binding, so as to ensure that the winding ends are relatively solid after being dipped in paint and dried. However, the thermal shrinkage of the binding tape has a certain range, so a certain tension should be ensured during the binding process.

It should also be emphasized here that for the binding and fixing of the lead, on the one hand, it is necessary to ensure that the lead cannot move at will after binding, on the other hand, it is also necessary to ensure that the connecting part between the lead and this line will not be pulled by post-processing. In view of the above reasons, the binding of winding ends must be standardized, not just in the form of winding.

Because the motor windings are in-phase and out-of-phase, there will be mutual attraction and repulsion forces between the two bars of adjacent coils at the end. In order to avoid the displacement caused by the forces, the ends should be fixed. In the side gaps between adjacent winding bars, polyester rope with a thickness similar to the gap size should be selected to tie them tightly.

At present, the stator of high-voltage motor mostly adopts the VPI integral immersion process, and its insulation structure is that the mica powder belt wraps the coil, the end of the coil is bound with polyester glass rope, and the coil and the end hoop are bound with rope, but it should not be too tight, so as to prevent the contact part of the two from being damaged to varying degrees, which will reduce the insulation performance. When the coil is heated according to the process requirements, the insulation at the end of the coil near the nose is softened. This damages the insulation and affects the service life.