> From: [email protected] [mailto:[email protected]] > On Behalf Of Tracy Reed > > they currently have to run me 4 20A per rack. Coudldn't they cut > that > approximately in half (power factor correction etc, as mentioned earlier) if I > ran 208v?
Depends what you call "cut it in half." If you have a single 20A 120V circuit, as compared to a single 20A 3-phase 208V circuit... Well, indeed you have three 120V lines bundled into the 3-phase circuit, so it's three times as many hot wires, but it's less than twice the effective voltage, but it's able to draw a smoother current, less spiky, which means you're less prone to blowing circuit breakers. All in all, I would say, yes you're approximately able to power twice as much equipment (a little more, say ~2.3x) with a 208V 3-phase power supply as compared with the 120V single-phase. And since they're billing you by the Volt-Amp-Hour, remember one thing: Supposing you have non-stupid power supplies in your equipment, you were already getting a power factor of around 0.95 in your 120V equipment. You might get a little better, say 0.99 with your 3-phase power supply, but the difference is marginal. Which means, for all intents and purposes, 1VAh ~= 1VAh. By changing the way you deliver your power, you have not changed how much power you consume. (Just marginally.) If you're trying to reduce energy costs, the only number you need to look at is the cost per VAh, and whatever few percent marginal PF gain you might get by changing how you deliver your power. _______________________________________________ Tech mailing list [email protected] https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
