Polyphase Motors - Voltage Imbalance vs. Derating Factor
Electrical motors are designed to operate with a high efficiency within some variation in the electric power supplied.
- voltage variation should not exceed +/- 10%
- frequency variation should not exceed +/- 5%
- combined arithmetic sum of voltage and frequency variation should not exceed 10%
- voltage imbalance between phases should not exceed 1%
Voltage Imbalance Derating Factor
Voltage Imbalance % | Derating factor |
---|---|
0 | 1.00 |
0.5 | 1.00 |
1.5 | 0.97 |
2.0 | 0.95 |
2.5 | 0.93 |
3.0 | 0.89 |
3.5 | 0.85 |
4.0 | 0.82 |
4.5 | 0.78 |
5.0 | 0.76 |
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