primary power supply的用法和样例：
例句
- The integrated battery guarantees an operation independent from mains supply.
内置电池保证显示不依赖主电源操作。 - Three-phase UPS systems are used in most large data centers for power conditioning and battery back-up in the event of mains power failure.
当数据中心一旦发生主电源掉电的时候，三相不间断电源系统是应用最广泛的后备电池和供电条件。
