If you buy it and you don't have 3 phase power in your shop you will be faced with buying a new motor and these run $400-500, or you can buy a phase converter module for about $300 to make the existing motor work on single phase home power, or you could buy a rotary phase converter for about $500 to make 3 phase power for it, or you could try to get your power company to install 3 phase power into your home shop so you can run it. This last choice will likely be very expensive, if you can even get the power company to do it. Most power companies won't provide 3 phase power in residential areas.
This is why 3 phase machines sell for so little. Most homeowners can't use them without significant additional expense. If the selling price is low enough to justify the additional work and cost, then it may be worth getting.
Now you have to decide if this saw is a good enough deal to be worth doing one of these modifications after you get it. In my opinion, there are many used single phase Unisaws in the world and you will find a good one if you are willing to wait. I bought a 1983 Unisaw for $700 that had a 50" Unifence and a single phase 3 hp motor and it was in near perfect condition. I cleaned it up, installed new belts, and it has been running fine for 4 years now. I couldn't want a better saw.
A contractors saw is a bit lighter and has a smaller motor than a Unisaw. I found on of these for my son. The motor that they come with is designed to be a 1 1/2 hp when connected to 120 volt power (to run on a 15 amp circuit), but it becomes a 2 hp motor if you switch it over and run it from 240 volt power. While they aren't a Unisaw in design, have the motor hanging out the back, and have no base cabinet, they can do precision work and are great for home shops. However, dust collection on them tends to be difficult due to the open bottom and back of the cabinet. The bottom can be closed but the back is difficult because of the belt connection to the motor and the need for it to move as you tilt the blade. The trunions are mounted to the table, so they can be tough to get right, but this is usually a one time adjustment. The original fence isn't bad, but one of the available upgrades can be better. I prefer a fence that is T-Square in design where it only attaches in the front. Unifence and Biesmeyer are a few of these and these are available from Delta. There are others too, but I'm not familiar with them.
I've owned a Ryobi BT3000 and while they are one of the best products that Ryobi has produced, I don't feel that they are anywhere near as rugged or have the quality and precision that you get from a Delta Contractors saw or a Unisaw. Stay away from brush type motor driven saws. They don't live for very long and have poor resale value. Look for a saw that is belt driven from an induction type motor.
Good luck in your search.
Last edited by CharleyL; 02-17-2012 at 10:18 AM.