Do homework, operate safely!
FYI,
Here's some information on phase converters from phase-a-matic, and notice the gauge required for 15HP...geez, 3 gauge, I've never seen that in any homes, I don't think. I guess you'd have to run from the breaker box to the motor, but the motor to machine could be the gauge required for the machine.
http://www.phase-a-matic.com/PDF/SIS-2007.pdf
Also note the amps, it requires 100 amps per this chart. (that's 100amps of 220!)
Also note the pricing difference between the static converters that PAM sells, from 5HP to 15HP...I've seen info on building your own static converter online, if you feel comfortable doing so, but just to compare apples to apples, these are prices for pre-built static converters.
http://www.phase-a-matic.com/StaticModels&Prices.htm
Size your converter wisely.
In some cases, like bandsaws that require a lot of power to turn on/off, you need a converter that is 50% larger, so a 5HP would need a 7 1/2 HP. Table saws and jointers are not as bad, but bandsaws will require more power, I think it's the inertia needed.
So you would be able to start a 10HP machine. I'd like to see a show of hands for folks that have a 10HP machine? OTOH, you could run 30HP of machines at the same time.
I personally don't like to leave power machinery on, when I'm not using it, so will only need to use dust collection when I build it<g>, and one machine. Also the advantage of phase converters is that I can now build a pentz style DC with a 5HP 3phase motor that I only had to pay $40 for.
Lastly I'd like to ask a question. You will get 3x the amount of HP of the converter, so if the converter has a 15HP motor, you could safely run 3x. Will you need 30HP of machines running at the same time?