GE 400 User Manual

Also see for 400 Series: Maintenance manual User manual Instruction Instructions Instructions

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GE 400 User Manual Manual pdf 16 page image

Modifications reserved Page 16/79OPM_SGS_USM_M40_M50_2US_V010.doc User Manual SG Series 400 & 500 UL S24.3 PARALLEL SYSTEM OPERATION4.3.1 Introduction to the parallel systemTwo or more equal power units can be paralleled to increase the output power (paralleling for capacity)or to improve the overall reliability of an UPS system (paralleling for redundancy).The outputs of parallel units are connected to a common power bus, and in normal operation the unitsconnected on the parallel bus share the Load equally.The modular concept of SG Series 400 & 500 allows parallel operation of up to 6 units, without usingparalleling switchgear, external bypass circuits or common control circuitry (see Fig. 4.3.1-1).Parallel units for power capacitySeveral units can be paralleled in order to achieve output power greater than the maximum power of asingle unit.The maximum total power shared between the paralleled units is equal to the total installed nominalpower.In the event of a failure of one unit, the power supplied by the UPS system becomes insufficient and theLoad will be transferred to the Utility Bypass source.Parallel units for redundancyThe nominal power rating of the n+1 out of n redundant paralleled modules must be equal to or greaterthan the required Load power.The Load will be equally shared by the n units connected on the output bus.Should one of the n paralleled units trip Off-line, the remaining (n+1) modules will supply the load,maintaining conditioned power to the critical load.From this results higher reliability and security for the Load plus a higher MTBF (Mean Time BetweenFailures).Fig. 4.3.1-1 Block diagram parallel system operation