Energy efficiency requirements for motors
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5. The minimum efficiency of 60 Hz motors at a rated power not provided in Tables 24 to 26 must be determined as follows—
(a)the efficiency of a rated power at, or above, the midpoint between two consecutive values in the tables is the highest of the two efficiencies;
(b)the efficiency of a rated power below the midpoint between two consecutive values in the tables is the lowest of the two efficiencies.
Table 27
Interpolation coefficients for motors with rated power output P from 0.12 kW up to 0.55 kW
| IE code | Coefficients | 2 poles | 4 poles | 6 poles | 8 poles |
|---|---|---|---|---|---|
| IE2 | A | 22.4864 | 17.2751 | -15.9218 | 6.4855 |
| B | 27.7603 | 23.978 | -30.258 | 9.4748 | |
| C | 37.8091 | 35.5822 | 16.6861 | 36.852 | |
| D | 82.458 | 84.9935 | 79.1838 | 70.762 | |
| IE3 | A | 6.8532 | 7.6356 | -17.361 | -0.5896 |
| B | 6.2006 | 4.8236 | -44.538 | -25.526 | |
| C | 25.1317 | 21.0903 | -3,0554 | 4.2884 | |
| D | 84.0392 | 86.0998 | 79.1318 | 75.831 | |
| IE4 | A | -8.8538 | 8.432 | -13.0355 | -4.9735 |
| B | -20.3352 | 2.6888 | -36.9497 | -21.453 | |
| C | 8.9002 | 14.6236 | -4.3621 | 2.6653 | |
| D | 85.0641 | 87.6153 | 82.0009 | 79.055 |
Table 28
Interpolation coefficients for motors with rated power output P from 0.75 kW up to 200 kW
| IE code | Coefficients | 2 poles | 4 poles | 6 poles | 8 poles |
|---|---|---|---|---|---|
| IE2 | A | 0.2972 | 0.0278 | 0.0148 | 2.1311 |
| B | -3.3454 | -1.9247 | -2.4978 | -12.029 | |
| C | 13.0651 | 10.4395 | 13.247 | 26.719 | |
| D | 79.077 | 80.9761 | 77.5603 | 69.735 | |
| IE3 | A | 0.3569 | 0.0773 | 0.1252 | 0.7189 |
| B | -3.3076 | -1.8951 | -2.613 | -5.1678 | |
| C | 11.6108 | 9.2984 | 11.9963 | 15.705 | |
| D | 82.2503 | 83.7025 | 80.4769 | 77.074 | |
| IE4 | A | 0.34 | 0.2412 | 0.3598 | 0.6556 |
| B | -3.0479 | -2.3608 | -3.2107 | -4.7229 | |
| C | 10.293 | 8.446 | 10.7933 | 13.977 | |
| D | 84.8208 | 86,8321 | 84.107 | 80.247 |