help me understand three phase electricity
January 17, 2010 11:35 PM Subscribe
So the place I work is about to grow and needs more power in the building for more people and a very large serverfarm upgrade. I am a bit unclear on a few topics, mainly related to three phase vs single phase power.
posted by anonymous to technology (7 answers total) 2 users marked this as a favorite
So, currently we have two power lines coming into the building, a three phase 200A line and a single phase 400A line that goes into four single phase 100A meters. We are looking to replace it all with a single three phase 800A line.
My main issue is understanding what sort of increase we would actually get from this. At one point we were looking at a 1200A line, and thinking that would double our effective power (600A to 1200A), but after briefly talking to a few electricians and electrical engineers, they think that 1200Amps is way too much and that we will be getting much more with 800Amps than we understood.
Question #1. What is the effective % increase from a 600A ( 200A three phase and 400A single phase), to a 800A three phase?
Question #2. So lets say we have a 200A three phase 120/208V line. And we have a server that takes 2A at 208V. How many servers can I power? 100 or 300? Or would it be somewhere in the middle? Obviously this is a simplistic example, not taking into account overhead or anything else, I'm just trying to understand. This is where I am mixed up, some people have said that you have 200A to work with, but then others say that since three phase has three legs, each leg carries 200A, so you effectively have 600A.
Thanks for the help!