Motor Insulation Class
Technical Information for Motor-Gearbox Combinations, ⑥, Understanding Motor Insulation Class
Insulation class of motor refers to the heating resistance class of insulation material including A, E, B, F, H, C, N, R. Insulation class of motor is using E, B, F, H mostly) The insulation classes herein are defined in accordance with NEMA standards.
| Temperature class | Class A | Class E | Class B | Class F | Class H | Class C | Class N | Class R |
| Max allowable temperature) | 105℃ | 120℃ | 130℃ | 155℃ | 180℃ | 200℃ | 220℃ | 240℃ |
| Winding temperature rise limit | 60K | 75K | 80K | 105K | 125K | 135K | 150K |
170K |
| Performance reference temperature | 80℃ | 95℃ | 100℃ | 120℃ | 145℃ | 155℃ | 170℃ |
190℃ |
*All winding temperature rise limits are based on a 40°C ambient temperature.