ABB AZ20 112112221112E是一种双电源自动转换开关，用于在主电源故障时自动将负载切换到备用电源。AZ20系列双电源自动转换开关是一种电源管理设备，旨在确保不间断的电力供应。这种开关在主电源出现故障（如电压骤降或电源中断）时，能够自动将负载从主电源切换到备用电源。这种设备的特性使其特别适合于那些不允许电力中断的重要设施，例如医疗设施、数据中心、制造工厂等。

It is a dual power automatic transfer switch used to automatically switch the load to a backup power source in the event of a main power failure. The AZ20 series dual power automatic transfer switch is a power management device designed to ensure uninterrupted power supply. This switch can automatically switch the load from the main power supply to the backup power supply in the event of a fault in the main power supply (such as voltage drop or power interruption). The characteristics of this device make it particularly suitable for important facilities that do not allow power outages, such as medical facilities, data centers, manufacturing factories, etc.