美国维缔艾默生UPS电源ITA BC10020K02L4通信设备不间断电源
After the main power supply fails and the mains power is cutoff, the power supply will be instantly switched to the inverter toprovide energy, as shown in Figure 3. [3] (3) When the load carriedis too large or the inverter in the power supply malfunctions, theUPS will turn on the bypass main power supply to directly supplypower, as shown in Figure 4. [3] Figure 7 (1) Uninterruptible powersupply connection method: A single UPS power supply can supply allloads. The connection diagram is shown in the system schematic, andthe connection method is relatively simple. [3] (2) The total loadpower requires two or more UPS power supplies, as shown in Figure5. This connection method is called parallel without backup.
被动后备式UPS具有结构简单、价格Zui廉等优点，运用于某些非重要的负载使用，如家用计算机等。但市电断电时，继电器将逆变器切换至负载，切换时间较长，一般需几个毫秒的间断，所以稍微重要的计算机设备不应选用被动后备式UPS电源。
指逆变器串联连接在交流输入与负载之间，电源通过逆变器连续地向负载供电。此种UPS电源其供电方式如下：市电正常时，市电经过整流器、逆变器向负载供电；市电不正常时，由蓄电器经逆变器向负载供电。