Impregnation
Current trends in terms of energy efficiency and environmental requirements call for rigorous product development by electrical machinery manufacturers. The new EuP motor regulation (640/2009) prescribes minimum efficiency levels, which are likely to become stricter over the coming years.
These requirements call for the ongoing development of production technology and must be aligned with cost and material efficiency in order to ensure long-term entrepreneurial success.
Impregnation is an important part of the workflow in modern electrical engineering. Its primary function is to solidify windings and protect them from moisture, dust, contamination and chemically aggressive substances. The impregnating medium can ensure that the heat that is generated in the conductor can be transferred to the environment and the laminated core more effectively.
Two methods are being widely used at present:
- Bath impregnation
- Trickle impregnation
In bath dipping, the parts to be impregnated are usually immersed in the impregnation medium. In order to avoid the formation of air pockets, this is usually performed in a vacuum, or using a vacuum pressure method. This process is widely used for larger coils.
In trickle impregnation, the preheated winding has the bath medium “trickled” onto it from above via nozzle arrays as it rotates. Capillary action ensures that the bath medium penetrates the winding.
After completion of the impregnation, the bath medium is hardened in an oven.
