Electrical Motors - Insulation Classes
Electrical motors NEMA temperature and insulation classes. Electrical insulation systems are rated by standard NEMA (National Electrical Manufacturers Association) classifications according to maximum allowable operating temperature.
Notes
Hygroscopic Insulation (Classes A, B): Avoided for open and outdoor locations due to shortened lifetime if condensation in the insulation occurs.
Non-hygroscopic Insulation (Classes F, H): Preferred for open and outdoor locations and higher ambient temperatures.