In today’s competitive world the electrical insulation materials and the processes are viewed with tremendous cost and quality consciousness. Varnishing of electrical machine winding forms a major part of the total cost of the electrical insulating materials. With the increasing costs of energy and solvents for use in varnishing, it has become a need of the hour to look into the change in the conventional impregnation methods such as Dip and bake varnishing or the Vacuum impregnation.
On this background Trickle impregnation technique was evolved to improve the varnishing quality coupled with reduced cost. This technique is now well accepted and used for impregnating stators/fields and armatures/rotors in all the advanced countries.
Trickle impregnation process is especially characterized by its low energy cost due to a very short cycle time compared to Dip varnishing or the Vacuum impregnation. Compared to the Dip and bake varnishing method, which uses varnishes containing 50 to 55% solvents and the impregnation cycle of 8 hrs to 24 hrs. Trickle impregnation cycle times are substantially low to the tune of 20 min. to 40 min. Hence it is quite evident that trickle impregnation process offers the most cost economical answer to the impregnation process.