What is NEMA Motor Insulation classes?

NEMA - National Electrical Manufactures Association

Four types of motor insulation classes are there - A,B,F,H

Class A - 60 deg C rise,5 deg C hotspot

Class B - 80 deg C rise,10 deg C hotspot

Class F - 105 deg C rise,10 deg C hotspot

Class H - 125 deg C rise,15 deg C hotspot