Heating and losses of induction motor (IM) grow with the supply voltage unbalance and harmonic distortion. To avoid thermal overload, the IEEE 141-1993, the IEEE 3004.8, NEMA MG1-2014, and the IEC 60034-26 standards establish derating factors for IMs operating under those conditions. In this article, we show that while the derating factors proposed by these standards adequately protect standard-efficiency IMs, they are only marginally adequate to protect modern higher-efficiency IMs. To this end, we compare the derating factors provided by the standards with the derating factors required to maintain the losses at rated values in a standard-efficiency IM, in a premium-efficiency IM, and in a super-premium-efficiency IM. To extrapolate the results from these IM, we compared the nameplate data of 548 IMs of different efficiency classes and found that higher efficiency classes correlate to higher IM starting currents and lower impedances to the negative sequence and harmonic voltages. These lower impedances in turn may lead to higher losses for unbalanced and harmonic voltages conditions.

中文翻译：

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考虑到电机效率等级，因电能质量问题而降低感应电机的额定值

感应电机 (IM) 的发热和损耗随着电源电压不平衡和谐波失真而增加。为避免热过载，IEEE 141-1993、IEEE 3004.8、NEMA MG1-2014 和 IEC 60034-26 标准为在这些条件下运行的 IM 建立了降额系数。在本文中，我们表明，虽然这些标准提出的降额因子足以保护标准效率的 IM，但它们仅勉强足以保护现代的高效率 IM。为此，我们将标准提供的降额系数与在标准效率 IM、溢价效率 IM 和超溢价效率 IM 中将损失维持在额定值所需的降额系数进行比较。为了推断这些 IM 的结果，我们比较了 548 个不同效率等级的 IM 的铭牌数据，发现更高的效率等级与更高的 IM 启动电流和更低的负序和谐波电压阻抗相关。对于不平衡和谐波电压条件，这些较低的阻抗又可能导致较高的损耗。