1. Three phase in and out system, compatible with ... 60Hz±3Hz, adjustableFrequency precision (free running)±0.02%Phase tolerance120°±0.5° (balance and unalance load)Voltage ... Ports )RS232,RS485,Dry contacts,SNMP card,EPO,Generator interfaceInstallation/ConnectionTop or bottom cable connectionOperation temperature0-40° ... : lindayunyun true on line double convertion three phase in three phase out 15KVA UPS