[Veering off-topic; mods, I'll not continue this branch of the thread much longer....] On Friday 14 September 2007, John R Pierce wrote: > I've gotten away with running some 208V equipment on a 120V UPS using a > step-up transformer which had a 208V tap (and 220V, 240V). Of course, > 3000VA is going to require a 120V 30A outlet to power said transformer > (and a UPS with 30A output probably needs a 50A circuit to feed it). Input power not a problem; we have a 125KVA Leibert PDU for the server room (about 4,000 square feet raised floor with 30 tons of A/C (Leibert System 3 15 ton x2)). There are a few L21-30R's, L5-30R's, and L6-30R's under the floor. > (googles, oh. 12V 75AH > monsters, online looks like $125 each). > > I'd put said batteries in a > series of battery boxes, and install the whole mess some place like the > basement, with ventilation to prevent accumulation of hydrogen fumes. You've just described the way our 48VDC system is connected, with the exception of the type of battery...we have a bank of 24 C&D KCT-450's for 48VDC, with two Lorain RHM200D50's floating them (cells and rectifiers were donated to us). The cells are in an old munitions building that was on-site (please don't ask; look up our history on www.pari.edu....:-)) that we moved from the pistol range to the back of the main building, and ran four 2/0 'jumpers' to. But if someone wanted to support an educational institution and wanted to lease floor space and/or bandwidth (we currently have 100Mb/s to the Internet, and an OC3 to our co-lo in Asheville (also our ISP's PoP; see www.ercbroadband.org) (which is part of the reason my equipment budget is so lean!)), we would love to talk. Perhaps even for CentOS mirroring and/or building. Peter Arremann visited us a while back (by the way, Peter: good article in LJ, and thanks again for the UltraSPARC goodies!); he could fill you in on how it was when he visited. -- Lamar Owen Chief Information Officer Pisgah Astronomical Research Institute 1 PARI Drive Rosman, NC 28772 (828)862-5554 www.pari.edu