Sounds like a similar problem, we are about 2 miles away from 3 phase, and when we asked 5 years ago it was $24,000 to get it here.

I have two converters, one commercially built 10 HP rotary that works fine.
When I got my 15 HP lathe I needed more, so I built a rotary 15 HP converter at very little expense, and will do it again if I ever need another converter.

We have a total of about 40 HP worth of three phase tools, and occasionally will run over 30 HP at a time.
We started with the converter, and as the shop grew and tools got bigger we wanted to upgrade to real power, but for the cost it's not worth it.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-