Aging of hermetic motor insulation

Reliable hermetic refrigeration systems require the use of trouble-free motors since there is no opportunity for motor replacement or repair during the operating life of the unit. The hermetic motor is sealed into the system and is exposed to lubricating oil and refrigerant and this environment places special demands on the insulation materials. The ground insulation, wire enamels and varnishes which are used must withstand the physical, electrical, chemical and thermal stresses in the operating environment. In addition to retaining their functional properties, the insulation materials must not be a source of contaminants to the other components in the system.