I have a three phase generator that I run my stuff off of. I've also got a large solid state converter that I haven't had time to install yet.
I asked the power company about getting an open delta to feed my shop, and figured I would get a price break since I buy so many poles from them. Cost would be $20 per foot of over head + transformer + meter + high electric rates and meter charges. Total came up to about $20,000.
Two best ways to do it are buy/build a rotary phase converter or buy a used three phase generator. The generator has the added bonus of being to able to run your house when the lights go out. Needs to be at least 10kva for sirens though.
Link that shows how to build a rotary phase converter out of a used three phase motor. Sirens will need at least 20 horsepower of idler motor. 30 is better. BTW you don't need to add a buck-boost transformer like that guy did.
http://www.laserfx.com/Backstage.LaserF ... nvert.html
BTW where are you located at? I know some people in different places around the country who have used motors that would make good idlers.
Stay away from static phase converters unless they are the transformer type. The Ronk Add-A-Phase and Gentec T-3 are good transformer converters. Occasionally a used Add-A-Phase will pop up on ebay or craigslist.