These 1100W server power supplies are available pretty cheap on Ebay ($20-30), and I couldn't find any documentation so I had to work it all out myself and I will share my results. I run two S3's off each one and they run very well, >90% efficiency. They might be able to run three but I got the power supplies so cheap I can't justify pushing it and losing efficiency.
They don't come with fans installed so I guess they rely on cabinet ventilation for cooling, so the first thing I did was add some little 40 mm fans. Crazy glue them to the connector side of the frame blowing in, put terminals on them for power, and seal up the gaps on the connector side so the air blows through to the power cord side. It will look something like this:
Then you have to pin the thing so it starts up without being in the server. There are 4 pins on the 24-pin connector that have to be connected together. I did it by dyking open the backs of two Berg jumpers and soldering a wire between them, then attaching them to the proper pins. Here's a pic:
If that's not clear, the secret pins are the bottom two on the leftmost column, and the rightmost two on the second from bottom row.
Good luck, hope this info gets somebody on the air cheap!
