Electrical Motors Efficiency Ratings
NEMA - electrical motor efficiency ratings.
The efficiency of an electrical motor is the ratio mechanical power output to the electric power input.
NEMA has established the efficiency index:
| NEMA Letter Index | Nominal Efficiency | Minimum Efficiency |
|---|---|---|
| A | 95.0 | |
| B | 95.0 | 94.1 |
| C | 94.1 | 93.0 |
| D | 93.0 | 91.7 |
| E | 91.7 | 90.2 |
| F | 90.2 | 88.5 |
| G | 88.5 | 86.5 |
| H | 86.5 | 84.0 |
| K | 84.0 | 81.5 |
| L | 81.5 | 78.5 |
| M | 78.5 | 75.5 |
| N | 75.5 | 72.0 |
| P | 72.0 | 68.0 |
| R | 68.0 | 64.0 |
| S | 64.0 | 59.5 |
| T | 59.5 | 55.0 |
| U | 55.0 | 50.5 |
| V | 50.5 | 46.0 |
| W | 46.0 |
