I live in Canada were most industrial machinery is run on 575V. I have five or six such machines in my residential garage. Some of them have motors that are not easily replaceable such as the Bridgeport and the Swedish gearhead drill press. I used to use a rotary phase convertor in conjunction with a three phase transformer but I got sick of the noise.
I have bought a used 1.5 KVA single phase 220 to 600v transformer which allows me to use small 575V VFDs that I can buy ebay every once in a while. They seem to work fine when fead with single phase instead of three phase.
My problem is my lathe, it is 60 year old 2-1/2 ton monster. It has a
7.5 hp motor tucked under the headstock gearbox. To replace the motor I would have to jack the headstock end of up a couple of feet off the floor and drop the motor. I should probably replace the 575V motor with a 5hp 208V motor that I could buy quite cheaply, but I dont relish the job.I have been toying with the idea of using a 30 KVA 3 phase transformer that I have to step up 220V single phase to 600V single phase and running the lathe with a 7.5 HP 600V VFD. The problem is that I have not been able to get the output voltage I need. The transformer's primary is 600V and wired in a Y and the secondary is 220V and is wired in a Delta. I beleive the transformer original use was as a step down distribution transformer. When I apply 230V single phase to two of the secondary connections, I measure 500V (phase to phase,no load) on the primary side.
I am thinking of buying a 480V VFD and driving the motor with that, the loss of power (according to my calculations) would be about 2.5 hp which is fine by me. Anyone have any comment on this scheme, if not I'm just going to try it and let you know how it all works out.
stan