[idtkid]

I have a small VMC that requires 20 amps of 3 phase 230v power.

Im assuming that buying a rotary phase converter is my cheapest option to get 3 phase power into my house?

Can anyone advise me as to a good converter to buy?

Do these converters also convert the voltage or will I have to plug it into my dryer outlet to get the ~200volts? Machine comes tomorrow so any help would be greatly appreciated! Thanks in advance!

[awerby]

I have a small VMC that requires 20 amps of 3 phase 230v power.

Im assuming that buying a rotary phase converter is my cheapest option to get 3 phase power into my house?

Can anyone advise me as to a good converter to buy?

Do these converters also convert the voltage or will I have to plug it into my dryer outlet to get the ~200volts? Machine comes tomorrow so any help would be greatly appreciated! Thanks in advance!

[You can't get 230v off a 110v outlet, but if you have a dryer outlet with 220V that might be sufficient (depending on the amperage you need). Rotary converters used to be the best (and only) bet, but now you can get electronic inverters that will produce 3-phase current more efficiently, without having to run a big motor the whole time. Make sure you get a variable frequency drive (VFD) that can accept single-phase current as an input, that has the right frequency range for the machine you want to run, and puts out the right amperage. I've found Dealer's Electric to be a good source for this sort of thing - www.dealerselectric.com - ask for Harold.]

Andrew Werby
www.computersculpture.com

[idtkid]

Thanks so much for the speedy help, few more quick questions.

If I find out that my machine strictly wants 230V is that as simple as having an electrician come out and install a 230V outlet? How do you get a voltage other than 110 into your house out of curiousity?

The machine isnt DIY, its an Emco PC Mill 125 so the spindle inside is ready to go once I get the correct power source.

I will be sure to look into electronic vs. rotary converters to find my best bet.

[awerby]

In the US, anyway, most household electric services are capable of supplying single-phase 220-240V. Basically, it's two hot 110v leads and a ground. Yes, any competent electrician should be able to install a circuit for you that will deliver that to wherever you're putting your mill. Make sure you spec it for the maximum amperage you expect to need. That determines the size of the wires that are required.

Emco is a European company, so they're expecting everybody to have 220V power (they don't use 110V at all there). Check with the company to see what the electrical requirements of the mill are. Remember to add in the load from the drives and any auxilliary functions like the knee motor (if any). You'll probably want to run 220V power to those things separately, if they're single-phase, and just power the spindle from the VFD. But if they want three-phase as well, make sure to get an inverter with sufficient power for the whole machine.

Andrew Werby
www.computersculpture.com

[Al_The_Man]

You should look closer at the nature of the machine first, often 3 phase is required for different reasons, if you just have a 3 phase spindle motor, you could look at fitting a VFD just for this, in the majority of cases, the controller and sometimes servo's run off 1 phase, even when 3 phase is supplied to the machine.
With that small a machine I suspect that you may be in the position I outlined.
Therefore the spindle could be fed from 240v VFD and the control be fed from 120 or 240v 1 phase direct from the service supply as required.
The majority of N.A. residences have 240vac supplied (2x120).
Your stove and drier will probably be hooked up to 240v.
If you are setting up a workshop, it may be worth looking at getting a 50amp or 100amp supply or socket installed.
For the size of machine you quote, a VFD can be used with 240v 1 phase and produce 3 phase for the spindle motor, this also gives you the option of variable speed if you choose.
Al.

[idtkid]

You guys are the best. Ill look more in depth as to why my machine requires 3 phase to see if the VFD option will work.

[idtkid]

Well there are a ton of options out there and I simply dont know what brands to look for, what is a good rotary and what is a good electronic phase converter. Here are the spec's on my machine, if anyone wanted to give me some recommendations that would be great!

It wants 1 input of 3Phase 230V power (+5%/-10% max V fluctuation)
Its "connected load" is 28kVA (what does this number and unit represent?)
Preliminary fuse for the machine is to be max. 20A-slow (this is the max it will draw? what does the word "slow" represent?)
Lastly, the spindle in the machine is 700W (= about .9HP)

Thanks!

[Al_The_Man]

I don't see a 28Kva load surviving on a 20 amp fuse.
That is 28,000 volt-amps.
Slow blow is a fuse rated with a time delay to avoid nuisance blowing due to inrush etc.
If the spindle is the only thing 3 phase then something like a 1.5hp Hitachi VFD should work for you.
They appear to be economically priced and are popular here.
Al.

[idtkid]

Thank your for the answers, forgive me for still having questions.

The machine is an all encompassing unit, 1 power input provides power for the axis drives and motors, the spindle, the Fanuc control and display etc. Would a VFD power all this? The only time I have seen an VFD was one that was used to change the spindle speed on a gantry router. I dont need any adjustment (the VFDs I see all have digital displays and buttons on the front), I simply need 2 more phases of power. Thanks again!

[Al_The_Man]

If you use a VFD you would intercept the motor feed so the VFD would solely feed the motor, and then divert the 1 phase 240 prior to the VFD to feed the rest of the machine.
If you want to feed the whole thing with a RPC, then you would still need to make sure that the two 1 phase conductors that form 2 of the phases would feed the control section of the machine.
I still think the simplest is to use a VFD.
More information is needed as to exactly the nature of the spindle.
Are you sure it does not Emulate the Fanuc controller?
Al.

[idtkid]

I think im sure :P that the machine has 1 input, 3Phase 230V and it breaks it off, splits it up, shares it etc with all the components on the inside. If this proves to be the case (i will know tomorrow when I pick the machine up), then I will go the simplest route, no "intercepting" of wires, providing multiple power sources etc and I will just get a rotary converter. Otherwise I will pursue the VFD, if this all makes sense? :P

Ya know, now I dont know about the control system. What would be the difference between simulating it and "actually having it"? As long as I can post Fanuc21 code out of my laptop, load that onto the Emco machine and run it all is good.

[Al_The_Man]

Ya know, now I dont know about the control system. What would be the difference between simulating it and "actually having it"? As long as I can post Fanuc21 code out of my laptop, load that onto the Emco machine and run it all is good.

As I understand them, these are hobbiest machines, so it would not make alot of sense to put a Fanuc 18i on which would cost over 10x the cost of the machine itself, it would probably price it right out of the market.
The site mentions replacing the overlay to what control you want, Fanuc, Heidenhain, Seimens etc. and reconfiguring the software.
Whether you go with a RPC or static, Remember to make sure the control side is fed from the two main 240v conductors.
Al.