Single Phase 240 Volts to 3 Phase 240 Volts

Not being the electronics electric guy, but what I woul do is to take a single phase motor driving a three phase generator.

Not cheap, not efficient but pretty straight forward.

Correct, that is also how rotary converters work anyway, NOT as the OP thinks.

VFDs can also be used nowadays I believe.....set to a single frequency of course.

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What the OP has forgotten to mention is "How much single phase has he got available?", the number of amps would be enough.

How much 3 phase does he want to have, again amps per phase would be enough.

He cannot get more out than he put in, minus the amount lost due to inefficiency of the conversion/heat losses etc..

15kW is north of 60A on a UK domestic single phase supply. Many houses have a supply fuse that opens at 80A, so that doesn't leave a lot of headroom for all the other things that get used around the home.

It might be worth getting the utility company to run-in a dedicated three-phase line. Another option would be to hire-in a generator for the time that the three-phase is needed and ditch it afterwards.

The power company's distribution system is true 3 phase. Get it thru a separate meter and service entrance. 15 kW is no problem.

All cases you listed are gimmicky, if you REALLY need clean power. To drive a three phase motor I would use one of them, as perfect phase or amplitude is no big concern.

lets try this.....why don't you state how you intend to use the power, what you're trying to drive, etc, some of us might be able to help. 3 phase is generated quite efficiently by power companies, all the gimmicks you cited wont get you there

When it really boils down to it an additional 15kW is quite high to be pulling out of a residential supply. A separate 3-phase supply may be your best option and may be the cheapest solution too.

It must be a foreign thing. Around here it's standard issue to have a 200 amp 120/240 single phase service in the average home. Larger houses and farms are running 400 amp services now.

A buddy of mine built a new shop a few years ago with all electric heat and they stepped up his main service to a 600 amp system. 200 for the house 400 for the shop.

I have a 200 amp service on my place and I am already thinking that in a few years I may need to have that redone into a 400 amp feed.

To me his 15 Kw load seems completely normal by my standards. Heck my plasma cutter draws more than that and so does my 15 Hp air compressor when it starts.

Ok, here we go.. The load center I have in the house is a 200 amp panel, which is pretty standard these days in the USA, though the power company said they upgraded the service, but to me it looks like the old #6 aluminum wire that was there before.. The equipment I intend to connect will a lathe, mill, plasma cutter and welder. The lathe and mill are going to be converted to CNC control as well as the plasma table. The servo's I plan on using are 240 volt A/C either 1 phase or 3 phase. I figure in the long run it would be more efficient and cheaper to run every thing using 3 phase power. I plan to be adding more equipment in the future as well..

Not really. You will be money ahead to just go ahead and pull the larger wire you need for the service.

To get 15 Kw off of a rotary unit it would need to be built out of a 20 HP electric motor plus the rest of the gear needed to make it into a phase converter would set you back close to $1000 or so if it was all done with new parts. I can't imagine that that cost plus the cost of the purchase and installation of the third line would ever pay for itself in power savings over just running the correct side of wire for the single phase supply.

At 15 KW on a 240 VAC service you are only drawing 63 amps peak which is safe to do on a 6 ga copper line or 4 ga aluminum line set unless you are more than 100 feet from the main service. At a short distance 6 ga aluminum will also handle 60 amps but does take short term peaks over that without issue.

Wire and Cable Ampacity ratings.

If you have issues with too much voltage drop before the main panel that is easily corrected by the utility company and their responsibility to keep up to meet the required service capacity codes and if it is after the main service $1000 - $1500 buys a lot of heavy 240 V 4 ga commercial power cord and few hassles over wiring codes being it's still technically just an extension cord.!

4 ga 3 conductor SOOW power cord. $7 a foot. Good for up to 70 amps cont and well over 100 peak.

4 ga 5 conductor SOOW power cord. $11 a foot. Double up on the two supply lines and you are good for 140 amps cont and well past your 200 amp service capacity peak.

3 phase residential in the US may be close to unobtainium. It does exist in some parts.

If your going to convert the mill and lathe to CNC and you need speed control, then why not use a 240 VAC single phase input to 3 phase VFD out per speed controlled motor.