Stator Encapsulation Service Using Thermal Conductive Potting Materials
The magnet wire insulation and the VIP varnish used for many years in motor manufacturing has a very low thermal conductivity which make these layer between the conductors and the motor frame act like heat insulators. Any air gaps between the turns, the slot liners and the lamination core act also as insulators. The stator end turn space is also a very poor heat conductor and usually results as the hottest spot in the machine.
Significant improvements in machine continuous ratings can be achieved by eliminating the VIP treatment and replacing with complete vacuum encapsulation of the stator using thermal conductive epoxies or thermal plastics.