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Help me pick a 1 to 3 phase 220v converter

aronht

Plastic
Joined
Sep 21, 2019
Hi everyone, I have recently paid for, but yet to pick up a new to me mill. Silly me forgot take pictures or even remember the mill brand, even when the owner took me through everything for 20+ minutes. It's a very nice for the price, and far beyond what I'll need for quite some time.

My question is what single to 3 phase converter / VFD should I get, when the mill ALREADY has factory dials and switches that run from 60 rpm to 3000 or so, and reverse?

Basically, what's the cheapest option for a reliable driver as I don't need the actual variable drive part? Posting a link to a specific product would be perfect!
 
Having no clue what you've bought either....

Can't go wrong with a rotary converter, size it with an idler motor about twice the mill's rated power and provide a couple of sockets so you can save money buying more machines, the hobbyists are scared of 3-phase so the prices are much more sensible!

Take a look through the RPC build thread, I put mine together following the advice there, started and worked first push of the button - I'm in the UK where our single-phase is 230v, used a transformer to get to 415v before the rotary, in the US you can use your 220 split-phase as a lot of 3-phase machinery is 208 3-phase, simple :)

Dave H. (the other one)
 
I went and got pictures. It is a supermax mill, with a skyey 2hp 4 pole 220v motor at 5.6 amps at 1720 rpm
 
Although a 3HP Rotary Phase Converter will drive your mill just fine, I wouldn't suggest to go this route as you're going to get more 3-phase machinery and will have to start all over again.

Personally, I think that a 10HP RPC would be a wiser buy (unless more powerful machinery is already in your plans). But 5HP would be the lowest I'd go in any case. And try to get one with a low RPM idler motor (1750rpm or, even better, 1200rpm) to make its noise tolerable.

If you're going to buy new, I can recommend WNY Supply ( WNY Supply & Phase Converter Store :: Rotary Phase converter panel ). They make modestly priced, well built and reliable RPC panels and whole converters. Buy a panel from them and add your own motor. That's how I did it. A good source of inexpensive motors is a local motor repair shop. See what they have in terms of low rpm motors. Check their offerings in 5-15HP range and decide (panel prices are not significantly different in 5-15HP range). Take into consideration your shop wiring/breakers.

Just make sure you, first, get the idler motor, and then order a panel: you need to tell WNY what motor you have (they may need to customize capacitors for certain motors. But they don't charge any extra for this).
 
The drill-down menu for a purchase like this starts with the options between:

1) static converter
2) rotary converter
3) variable speed drive (aka VFD)

Each path has further options and each path has plusses and minusses.
 
The drill-down menu for a purchase like this starts with the options between:

1) static converter
2) rotary converter
3) variable speed drive (aka VFD)

Each path has further options and each path has plusses and minusses.

Is static converter like a PhasePerfect?

Are the pluses and minuses like this?

Static Converter -
Pluses
1 Very quiet
2.Close to same quality of power as city supplied 3 phase
3.Nearly plug and play
Minuses
1. Very Expensive
2. Questionable service intervals for capacitors
3. Potential for units to become obsolete and no longer supported

Rotary Converter
Pluses
1. Robust and simple designs
2. Lots of options and suppliers
3. Nearly plug and play
Minuses
1. Noisiest of the three
2. Idler motor uses more power than static converter
3. Not cheap (to purchase) middle range of the 3 choices

VFD
Pluses
1. Can be programed or accessorized to add extra features that may be wanted (motor breaking, speed control, etc)
2. Cheapest of the three
3. Tons of support and choices of suppliers
4. smallest footprint of the three
Minuses
1. Not plug and play at all (if you follow the manuals you will need many more components that have to be sourced and program the thing)
2. Needs to be wired directly to the motor so there is a lot of planning and decisions to make (control switching, e stops, etc)
3. ?
 
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No. Far from it.

Ah shoot! I have these same questions so apparently my research is not complete! Feel free to fill in the correct pluses and minuses for a static converter if you have the time. It would be appreciated, by me anyway!
 
I wouldn't consider a static converter. You'll lose about 30% of mill motor power. That's the main drawback of them.

P.S. About all points you listed for static converters (except for being quiet) are incorrect.
 
I wouldn't consider a static converter. You'll lose about 30% of mill motor power. That's the main drawback of them.

P.S. About all points you listed for static converters (except for being quiet) are incorrect.

Yeah that was everything I had crammed regarding the phaseperfect product. I thought it was a static converter. People that have them sure seem to like them and all the negatives I mentioned were just what I found reading here over the last couple days. For me I am in a tropical environment that is hot, humid and we have bugs! Lots and lots of bugs, centipedes, cock roaches for days and thousands of lizards per house that eat them. When I saw the integrated fans on the phase perfect box I was a little concerned that my critters will make a home in there. Also if I am 17 or 1800 dollars in for "the best" solution I want to cry once and never need to think about the thing again. Not sure it's for me but still reading up and poking around. Thanks for advancing the knowledge in this thread it is very timely and I hope there are more questions and answers that help the OP.
 
In essence, static converter is a rotary converter without motor. The quality of power it supplies is a way worse than what's supplied by VFD or RPC.

Digital phase converters (like PhasePerfect) are quite complicated (and therefore very expensive to buy and repair) electronic devices. If you had a picky CNC equipment, such purchase might be justified. Otherwise, I don't see any need to spent thousands on something you don't really need and something that has a much higher chance to break than a simple, much less expensive bullet proof RPC.

And unlike VFDs, a single RPC of a sufficient power will serve the whole shop without any machine rewiring.
If you ever need a particular VFD feature (soft start, variable speed control, etc.) for any of your machines, you can always buy a VFD for it. So far, I don't remember ever really needing one.
 
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Apologies, I left out the Phase Perfect (tm) option as I suspected the expense for this
type of converter would probably rule it out for you. So yes there is an option

4) phase perfect unit

which is *not*, as mentioned, a static conveter. Static converters come with names like 'phase-a-matic'
and are basically start capacitors coupled with potential relays, and use one of the windings on a
three phase motor, as the start winding. And yes you do lose about 1/3 of the HP of the motor
being thus run.

Advantages for static phase-a-matics include inexpensive, nearly no moving parts. They do need
to be matched to the size of the motor they are running, more or less.
 
I used an American Rotary phase inverter or my southwestern industries Trak DPM 3 axis mill. It had a 5 hp motor and it worked fine for me. I went with a 7.5 HP phase inverter used it in my garage until we moved. went from 220v single phase to 220v 3 phase. It wasn't that noisy in my opinion. I think it was about $750 shipped.
 








 
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