This is my experimental Bitcoin mining farm. It is comprised of 12 AntMiner S1's.
They are all running from three phases of my 240v three phase power. Each phase runs four AntMiners.
They are powered by Dell Poweredge 2950 750w Redundant Power Supply 7001072-Y000. I wired each power supply according to this instruction. They cost me only $12 each delivered, on ebay. They are very high quality power supplies, with internal cooling, but they are noisy. It is OK in my warehouse, but would not be OK in a bedroom, for example.
Each power supply runs two antminers. As it gets hot in my warehouse, I decided not to overclock them. I have an additional fan in front of the rack, to direct warm air flow away from the rack.
The combined power of this setup is 2,160 Gigahashes per second. They consume approximately 4 kilowatt of power.