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试述电弧熄灭有哪些条件?

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正确答案:

在直流电路中, 如果外加电压不足以维持电路中各元件的电阻压降和电弧上的电压时,电弧就熄灭。交流电弧的熄灭,关键在于电流过零后,要加强冷却,使热游离不能维持,防止发生击穿; 另一方面要使弧隙绝缘强度的恢复速度始终大于弧隙电压的恢复速度,使其不致发生电击穿

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