Eaton 3C3-EX Series Manual

-43-3.2 Parallel machine installation1. Redundancy introductionN+X is currently the most reliable power supply structure, in which N indicates theminimum UPS number required for the total load and X is the redundant UPS number,namely, the malfunctioning UPS number that the system can simultaneously bear. Thelarger X is, the higher reliability of system will be. For instance, if the total loads of acustomer register 55kVA, we can use Castle 20KS for N+X design. With N taking up3, X can be selected in accordance with reliability degree or cost requirement.Supposing customer selects X=2 and equalized UPS power supply is 11kVA for eachunit, when one set of UPS breaks down with malfunction, the remaining four sets willprovide power with almost 14kVA equalized current; if two sets of UPS fail, theremaining three sets of UPS are supposed to provide power supply with almost 18kVAequalized current. The maximum allowance of this system is for two sets of UPSgoing down at the same time, the chances of which are much smaller than those ofone UPS malfunction. Therefore, the reliability degree can be largely enhanced,making it an optimal mode for application in locations where high degree of reliabilityis always a focus.2. Castle EX Series UPS is capable of direct parallel connection, which only requiresthe parallelconnection wires (optional) for 2 to 8 sets of UPS in parallel connection in order torealize power redundancy (N+X). Ventilation spacing between machine flanks shouldbe a minimum of 10cm，input wiring for each set of UPS should follow therequirements for that of single unit. Each UPS input/output should be connected to thesame input patch board, from which wires are distributed for load as illustrated infollowing figure:Remark: 1）Common battery pack is applicable in parallel machine mode; each battery packshould be of the same model from the same manufacturer.2) Requirement of output wiring length: