This lead to placing redundant inverter modules in the bypass-maintenance circuits of the primary inverter modules that normally carry computer loads. All parties involved in the design discussion agreed that the isolated-redundant scheme of having user loads look through bypass circuits to another inverter module, and not to raw utility power, was a significant advantage. Two 400-kw modules perform redundant service to the primary modules. Distribution systems are arranged for two additional 400-kw primary modules. Each module has 18 minutes of battery support at full-load.
Batteries are lead-calcium with four cells per jar.
Output power from each UPS module goes through a wraparound bypass to allow inverter maintenance service, which then feeds to a distribution panelboard. A total of 24 PDUs, rated 75 to 225 kva, are housed in the transformers to isolate loads. The IACS facility under construction. The data center will be completed this summer. Calculations in support of design of IASC s power systems have been performed with advanced power-system analysis software.