Efficiency of electrical polyphase motors decreases with increased voltage imbalance
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