在额定控制电源电压低于35%时，欠电压脱扣器应防止断路器合闸。

At rated control supply voltage less than 35% under-voltage should prevent breaker from closing.

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在额定控制电源电压的35%～70%时，欠电压脱扣器应可靠使断路器脱扣；

Under the voltage of 35% ~ 70% of the rated voltage, the under-voltage release should make the breaker trip correctly.

youdao

在额定控制电源电压低于35%时，欠电压脱扣器应防止断路器合闸。

In case of the operation voltage less than 35% of the rated voltage, the under-voltage should prevent the breaker from closing.

youdao