Question: Why is Double Conversion On-Line UPS topology is recommended with Automatic Transfer Switch (ATS) products?
Cause: Due to the difference in the UPS topologies, Line Interactive UPS models do not have as tight an output control as Double Conversion On-Line UPS models, so the Line Interactive UPS output voltage can be anywhere within 10-20% of the input voltage, depending on sensitivity and AVR, and can also vary depending on input voltage variation. This can cause the ATS to do frequent nuisance switching.
Resolution: It is not recommended to use Line-Interactive UPS models with Automatic Transfer Switch products - only Double Conversion On-Line UPS models should be used.
Further information is contained in White Paper 62. Refer to:
https://download.schneider-electric.com/files?p_enDocType=White+Paper&p_File_Name=SADE-5TNRLE_R1_EN.pdf&p_Doc_Ref=SPD_SADE-5TNRLE_EN