1 to 3 phase conversion

Dave H (MI) · Oct 24, 2019

I am looking at metal lathes again. A buddy of mine was a machinist and is going to work with me on using it. The unit in question is 3 phase so I have been looking at converters. I have looked at static phase converters, rotary phase converters and VFD's. Really only interested in the rotary or VFD options. Rotary are more expensive. VFD have a functions I won't use but seem to be a good option. I would be interested in opinions but also, my shop is on generator as it is super expensive to have a line dropped to it right now. When I build a house, they will run the line to it for free, but that will be a year or more. Will a phase converter run off a generator safely without harming either unit or me? I hear people talk about gennys and "dirty power". Just doing my research so I don't step in something.

Janicholson · Oct 24, 2019

I would go with the rotary unit because it is not electronic in nature. It will be a little more ttarting effort, but not under spike or brownout jeopardy. It will be easier to sell after it is no longer needed because the electronics found in VFDs are suspect in the eyes of a buyer, and a rotary is seen as it appears. Jim's opinion

Oliver 500 Wa · Oct 24, 2019

IMO the VFD is the least costly and handiest way to run a 3 phase lathe on single phase. I've converted my lathe, mill, and saw with them.

A friend runs his sawmill off a 3 phase genset. The blade motor is 40HP and on an VFD for blade speed adjustment. Been running like that for 7 years now with no trouble.

Stephen Newell · Oct 24, 2019

I have a rotary converter in my shop. On one hand it's nice to have one converter hooked up to all four machines. The down side is it's an electric motor itself and you have to either let it run all day or turn it on and off every time you go to run a machine. The VFD would be easier but you have to have one for every machine you have. I don't have experience with a static converter. From what I understand machinery is pretty starved for power with them.

I don't know about converting single phase to three phase off of a generator. Unless it was a very large generator you may lack the power. On a rotary converter you are getting 220v from L1 and L2 but L3 is bumped up using capacitors. Running two motors at the same time may be too much.

Steve@Advance · Oct 24, 2019

I agree with Jim, a VFD might not like the instability of the generator.

Have you discussed running 3 phase with the power company?

They usually won't without extra charge, but if it's in the area it might be a possibility if they see you as a viable customer.

BarnyardEngineering · Oct 24, 2019

Option D: Three-phase generator, maybe? I know of a couple of guys whose solution to not having three phase, is to fire up the old Detroit when they need to do lathe work.

Mike M · Oct 24, 2019

The VFD is really nice on a lathe so you can get infinite speeds. I have a phase converter on my mill. Just the little square box type.
I ran it for years with an extra 3 phase motor I would start with the breaker and a pull rope. That may be a good option for you now ? or on a lathe it might be real easy to just replace the motor.

buickanddeere · Oct 24, 2019

VFD doesn t notice input noise . The AC is all rectumfied to DC , the DV is filtered and then the DC is converted to AC via triacs or the like .

timcasbolt · Oct 24, 2019

(quoted from post at 16:15:24 10/24/19) I am looking at metal lathes again. A buddy of mine was a machinist and is going to work with me on using it. The unit in question is 3 phase so I have been looking at converters. I have looked at static phase converters, rotary phase converters and VFD's. Really only interested in the rotary or VFD options. Rotary are more expensive. VFD have a functions I won't use but seem to be a good option. I would be interested in opinions but also, my shop is on generator as it is super expensive to have a line dropped to it right now. When I build a house, they will run the line to it for free, but that will be a year or more. Will a phase converter run off a generator safely without harming either unit or me? I hear people talk about gennys and "dirty power". Just doing my research so I don't step in something.

I started with a medium duty phase a matic for my Bridgeport. Then used the instructions that came in the box to make it a rotary type. Then switched to a heavy duty version. By this time it was running my Bridgeport, a band saw and a surface grinder. When that expired, I bought a Cedarburg, which turned out to be a much, much better choice.

Philip d · Oct 24, 2019

We had a digital PerfectPhase and it worked good, wasnt cheap but worked good.

caterpillar guy · Oct 24, 2019

Might be about as cheap to just get a 3 phase generator to solve the problem. If you go to bins and dryers if you can't get 3 phase in. You will need to talk to your power supplier about a 400 amp service to begin with on your single phase to run the fans and dryer.
I realize this is a bit off the topic but makes for planning ahead for the appropriate service in the beginning with the house.

Dave H (MI) · Oct 24, 2019

I'm glad I asked here...so many great responses! I learned more in this one thread than I did in an hour on websites and youtube.

dr sportster · Oct 24, 2019

If you have any old 3 phase motors around you can make a converter .If not VFD is the way to go.

Bob · Oct 24, 2019

(quoted from post at 10:15:24 10/24/19).

Here's a site to check out, if you haven't already.

https://www.practicalmachinist.com/...s-and-vfd/?s=cf569600d2bee1a8c107d1a0bbd859c8

Dave H (MI) · Oct 24, 2019

.

Dick L · Oct 24, 2019

I have worked with an old 3 ph motor at a higher HP than the one I want use. The 3 ph motor will produce the third phase to and for your lathe. The older 3 ph motor will run on two hot wires. It just will not start. I always used an old washing machine motor loose belted to the old 3 ph motor and pulled the belt tight to start the old motor. No fuss or complicated wiring and parts. An extra two switch to throw and a belt to tighten that takes a few extra seconds.

Dick L · Oct 24, 2019

To be clear I stated to backwards! You start the small motor and get the old motor spinning before you throw the single phase power on. At least that was the way I did it to keep from over heating the winding.

the tractor vet · Oct 25, 2019

Arond here the W Va. phase converter like Dick L. is talking about is what everyone uses , the game plan is to get and old three phase of 10 or bigger Hp. as ya need one larger then what your piece of equipment is and a old signal phase motor as a Pony motor . I have a friend that has a automotive machine shop out in the sticks off the beaten path and only signal phaser at the pole and runs his whole shop that is all three phase with and old 50 Hp three phase that he gave 25 bucks for and a like Dick a whashing machine motor and a vee belt to get it turning . Every morning he fires up the W/Va. phase converter and goes at he can have the boring bar boring a block his bridge port running and his lathe all going at the same time , yes he looks like a chicken with his head cut off running back and forth to machines . when we still had the shop going we also had one for our old lathe and head surfacer , For a long time three phase stuff was sold at scrap prices.

Paul in MN · Oct 25, 2019

Check out this website:

https://www.americanrotary.com/products/view/ad-digital-smart-series

I have had one of their 7 Hp units for 5+ years. I run my Bridgeport and 2 big drill presses. Now I have a 14" HD Japan lathe which has a 7.5 Hp motor which is known to be a hard start motor as it is also powering lube pumps. I have just talked with American Rotary about which converter I need to power the lathe. Very knowledgeable phone help. They recommend the 15 Hp model converter. So probably my only error was to buy too small a converter in the first place. A single converter can run the entire shop.

If you are considering this brand (and I think it is a good choice), look at Keith Rucker's U-Tube videos for a 10% discount code. American Rotary is one of his sponsors.

Paul in MN

tmg50 · Oct 25, 2019

I have built several from .5 hp to 20 hp. Mine use a contactor, a relay, some capacitors and a 3 phase motor. They start easy and have low idle current. We even ran a CNC mill on one by making sure the controls were tied to the natural phase.
steve.

1 to 3 phase conversion

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