UPS system

The utility model discloses a UPS system, including the two -way controllable switch that the input is connected with the bypass power, the output is connected through first load end switch and load,the input passes through dc -to -ac converter and rectifier and mains connection, output and passes through the relay that second load end switch and load are connected, the controlling means who is connected with the control end of the control end of two -way controllable switch and relay respectively for in load power supply by bypass switching of power during to the commercial power, the disconnection of two -way controllable switch is controlled again to the control relay actuation time of predetermineeing after the complete actuation of relay. In this application, controlling means can control the disconnection of two -way controllable switch in control relay actuation a period again after the complete actuation of relay, the problem of electricity can not appear falling, has improvedUPS system's service reli