Electrical Motors - Insulation Classes
Electrical insulation systems are rated by standard NEMA (National Electrical Manufacturers Association) classifications according to maximum allowable operating temperature. Electrical motors will rapidly degrade if the internal temperatures exceeds the insulation temperature limits.
| Insulation Class | Temperature Limit (oC) |
|---|---|
| A1) | 105 |
| B1) | 130 |
| F2) | 155 |
| H2) | 180 |
1) Hygroscopic insulation - avoided for open and outdoor locations - shortened lifetime if condensation in the insulation occurs
2) Non-hygroscopic insulation - preferred for open and outdoor locations, higher ambient temperatures ..
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