We have a residential client who is building a 7,000 sq ft vacation home in Cape May, NJ (right across the street from mine ) that we are going to air condition with fan coil units. That means an 18 ton chiller, and 18 ton chillers don't come in single phase. There are smaller chillers that are single phase that we could gang together, but we'd reaaaaaaally prefer not to. I spoke to the electric company and the street they are on is all 120/240 single phase, and to get three phase from 900 feet away would cost on the order of $70,000. My boss is of the opinion that if you can afford a 7,000 sq foot house on the beach at Cape May, you can afford to run a thousand feet of electric cable down the street. Sure, maybe, but I'm not sure the client will see it that way. Anyway, the electrical engineer that we use knows a tiny little bit about phase converters, but not enough to explain to me how they work, much less make educated decisions on them. I've done some research and found a few.... http://www.maxiphase.com/maxiphase_tech_info.htm http://www.phaseperfect.com/ ...and it appears to me that there are two basic types: rotary and rectfier/inverter converter. Let me explain how they work and you EEs can tell me if I understand it: The rotary ones are essentially just 3 phase motors that when run by one phase induce current in the other phases, outputting not-well-balanced 3 phase power of the same voltage that you put in. The rectifier/inverter ones (do they have a concise name?) rectify the power to regular DC, then invert it back to A/C, three phase, similar to how a VFD works. According to the marketteers, that yields high quality, balanced 3 phase power. So first, am I understanding these devices correctly(if oversimply...)? Second, how much of that marketteer bs is really bs - how good are these devices? How efficient? I realize it can't really be as good as real 3ph power from the power company, but is it a viable option or is it something that makes electrical engineers cringe?