under-voltage open phase relay

例句：

1. 1. Thisrelay is designed to detect and protect against under-voltage conditions.
   这个继电器被设计用来检测和保护免受欠压条件的影响。
2. 2. The relay switches the power supply to the motor when the voltage drops below a certain level.
   当电压降至一定水平以下时，继电器会切换电源供应给电动机。
3. 3. The relay is crucial for maintaining safe operation in environments with frequent power fluctuations.
   在频繁出现电力波动的环境中，继电器对于保持安全操作至关重要。