The following table summarizes the different insulation systems available.
Insulation Rating | Insulation Class | Average Winding Temperature Rise | Hot Spot Temperature Rise | Maximum Winding Temperature |
Class 105 | A | 55 degree C | 65 degree C | 105 degree C |
Class 150 or 130 | B | 80 degree C | 110 degree C | 150 degree C |
Class 180 | F | 115 degree C | 145 degree C | 180 degree C |
Class 200 | N | 130 degree C | 160 degree C | 200 degree C |
Class 220 | H | 150 degree C | 180 degree C | 220 degree C |
Note: the maximum acceptable temperature rise based on an average ambient of 30 degree C during any 24 hour period and a maximum ambient of 40 degree C at any time.