A UPS (sometimes called a Battery Backup unit) is designed keep your equipment running when the Utility Power Fails. The essential required information is: the Power Rating Required in VA, Amps or Watts and the Runtime (how long the Unit is required to support the load after the power fails). Additionally, you will need to know whether the Power Source and Required power by the load is Single Phase or Three Phase. There are two primary technologies in UPS design, Line Interactive and On-Line (Double Conversion). The Line Interactive UPS switches to backup mode when the input falls outside of the permitted window. The Oneac UPS’ are Power Conditioned and are always cleaning up the power whether in backup mode or not. Lesser expensive devices do not have this feature additionally the cheaper UPS often have a long switch over time which may affect your equipment’s performance. Some Single Phase and all Three Phase UPS’ use the On-line Double Conversion Technology. The output voltage is always being generated by the internal Inverter.