Quote:
"Originally Posted by Frank S.
To run a RPC (rotary phase converter in Australia, if you are in rule areas you could have what some call 2 ph 480 which would be to hots and neutral. but most areas without 3 ph or the rule areas with 2 ph there is only 1 240v line with a nuetral. to make a RPC run in those places a transformer would be required to make the 415v split phase L1 +N for input then tap at 175-0 240 +415 nominal for output. then connect the 2 output line to the PRC and the cap bank for starting and a module of thyristers for full balanced true sine wave 3p output.
Here is a commercial site selling their product but the information there will give you an idea of how to go about it
3 Three Phase Power Converter Australia converts single phase to three phase.
I think if it were me needing to do this I would buy MR nhengineer's plans then go from there adding what might be needed and contacting him for assistance."
Quote:
"Originally Posted by old kodger
Rhengieer,
I thank you for your effort, but now you see what I mean when I say, in Australia most of the options to date are totally uneconomic, for instance, I need to power a 3 phase mig welder which is name-plated at 10 amps per phase which is about 7.1kw at 230 volts. If a 3hp transformer is likely to cost $450 US that's around $600 AU, and I might need two...$1200 plus freight, and as I mentioned before freight from the US to AU needs the surrender of ones first born, I would not be surprised to find that the freight exceeded the initial cost of the transformers. Also 3hp would woefully inadequate, I need at least 10 amps per phase, for a overload margin, maybe more.
So at a potential cost in excess of $2400, a second hand 3 phase generator is starting to look a lot more realistic.
I thank you for all your effort, and indeed to all the other contributors to this thread, but unless I can find a way to control a synchronous motor acting as a generator, I have two options:- buy a generator or attempt to rewire the welder to run on single phase. Incidentally, I'm informed by the manufacturers of the welder, that the configuration internally is actually three separate transformers feeding a bank of full wave bridges, so it could be possible.
If anyone is interested I'll keep you informed.
Rob."
What empiracal evidence are you referring to Rob? Your power calculations make no sense what so ever to me. Is it 10 amps three phase at 415 volts or 10 amps 3 phase at 240 volts and what is the power factor?