Vacuum pressure impregnation: The key to void-free coil insulation

The trend toward treating complete stators with a solventless resin in a vacuum pressure cycle has gained considerable support in the electrical power apparatus industry. (Fig. 1), When the decision was made at E-M to develop such a system for form wound motors and generators, a number of original objectives were outlined as a guide for the project. Many of the characteristics desired by E-M were not available in existing systems.