Obvious characteristics of inter-turn faults in motor windings

Electrical faults in motor windings mainly include insulation faults to ground, between phases and between turns;

Inter-phase faults are exclusive to three-phase motors, while insulation faults to ground and between turns are problems that may occur in any motor winding.

Specifically, when a motor winding has an inter-phase or inter-ground fault, especially a more serious fault, the winding will be partially burned instantly. In most cases, the electromagnetic wire of the winding will be broken, and the winding outside the fault point will be in good condition. For inter-turn faults, the winding will start with local heating, and the fault point will continue to expand to the same phase and the same circle. The specific manifestation is that both ends of the winding coil have signs of burning to varying degrees.

From the fault analysis, it can be found that ground and inter-phase insulation faults occur more locally, and the fault diffusion and spread are relatively limited. For inter-turn insulation faults, it is more inclined to the fault manifestation of the entire coil. The inter-turn fault of the coil is caused by the insulation failure of the inter-turn of the same-phase winding. Therefore, the occurrence and qualitative change of this fault is a relatively slow process. It will develop from the insulation fault of a few turns to the insulation fault of multiple turns, and finally spread to the entire coil. Therefore, from the specific appearance of the fault, both ends of the winding will have different degrees of ablation marks, which is also an important means to distinguish the inter-turn fault.

However, the electrical fault of the winding is also difficult to be limited to one fault, and other electrical faults are often derived from one fault. If the inter-turn fault is more serious, it will cause damage to the phase insulation and slot insulation, and then there will be ground or phase faults. Similarly, when the phase insulation and ground insulation faults occur, it will also cause problems with the inter-turn insulation.

In the electrical fault analysis of the motor winding, the main cause of the problem should be found from the specific fault appearance. Especially for regular fault problems, the operation and even design level problems should be analyzed from the fault characteristics, and improvements should be implemented and solved fundamentally.

NIDE Group can provide customers with optimized motor manufacturing solutions according to customer needs, reduce the failure rate of motors, and improve the market competitiveness of motor manufacturers.