unattended switcher

例句：

1. 1. The unattended switch was a major cause of the power outage.
   这个无人值守的开关是停电的主要原因。
2. 2. The engineers had to replace the unattended switcher due to its failure.
   由于开关设备的故障，工程师们不得不更换它。
3. 3. The unattended switcher is crucial for maintaining the electrical system's integrity.
   无人值守的开关设备对于维护电气系统的稳定性至关重要。