Supercomputers, fishing for information

On Nov 8, 2016, at 9:22 AM, Paul Koning <paulkoning at comcast.net> wrote: A VFD is a good option and may be quite economical if you get one of the low cost simple ones. I have one (3 hp model for my lathe) that cost only a bit over $100, though the price has gone up since. (Westinghouse TECO brand.) VFDs specified for single phase input tend to stop around 3 hp, as far as I have seen. Rumor has it that higher power units will also work (possibly with some derating) even though they claim to be 3 phase input, when you feed them just one phase on 2 of the 3 wires. I haven't tried that (but it matches how my VFD is connected). The other option is a "rotary converter". Basically that's a 3 phase motor connected to one phase power (with a start and run capacitor); it generates the missing phase roughtly in dynamotor fashion. Those can be built (articles on the web) or bought from machinery supply companies such as Enco; they show models up to 20 hp, i.e., about 15 kW. When I was looking into converters, I found VFDs to be the less expensive option. The instant reverse and variable frequency features were also attractive for lathe use; for powering computers that would not apply. Well, not unless you need 400 Hz for your Cyber 6600 -- in which case you'd need to check the VFD will go that high, not all do. Given that you have a number of smaller devices and that not all might need to run, several smaller converters sounds like a good option, especially if that gets you into the "economy VFD" range.