UPS的作用是当外来电源停电后能为后续用电设备提供电源，其能量来源是蓄电池里存储的能量，这个能量是有一定限度的。

为了保证最最重要的设备获得最长时间的供电，有必要将不太重要的设备卸载，这就是UPS输出配电柜中有部分不太重要的回路安装了时间继电器，在市电停电的一段时间后（可以编程设定这个时间），将这些负载断开，保证剩余的电力完全供给最最重要的设备。这就是进行计时控制的原因和作用。

动力配电箱，  是配电箱的一种。配电箱分动力配电箱和照明配电箱，是配电系统的末级设备。

配电箱是按电气接线要求将开关设备、测量仪表、保护电器和辅助设备组装在封闭或半封闭金属柜中或屏幅上，构成低压配电装置。

The function of UPS is to provide power for subsequent electrical equipment after external power supply is cut off. Its energy source is the energy stored in the battery, which has a certain limit.

In order to ensure that the most important equipment can get the longest power supply, it is necessary to unload the less important equipment. That is, some less important circuits in the ups output distribution cabinet are installed with time relays. After a period of mains power failure (this time can be programmed), disconnect these loads to ensure that the remaining power is fully supplied to the most important equipment. This is the reason and function of timing control.

Power distribution box is a kind of distribution box. The distribution box is divided into power distribution box and lighting distribution box, which is the last level equipment of the distribution system.

The distribution box is to assemble the switchgear, measuring instruments, protective appliances and auxiliary equipment in the closed or semi closed metal cabinet or panel according to the electrical wiring requirements to form a low-voltage distribution device.