Running a 3ph on 1ph Power- Which method?

[hoz53]

Topher-- Static converters just generate a third phase for starting and they dont work to good when your motor is under heavy load.

Rotary phase converters are basically a static converter with a 3 phase idler motor hooked to them. They create a third phase and if your machine comes under heavy load they can take up some of the slack and still supply it three phase power to operate your machine. They do not provide perfect three phase power so you are using a little more electricity than with true three phase power. The idler motor makes noise but many of them arent to noisy. The idler motor is under no load and so draws very little current. My 5hp idler draws 1 amp. So the idler isnt what uses alot more power. Besides for a part timer you are not gonna notice a big spike in your electric bill anyway from running your lathe once in awhile.

VFD You can buy these that convert single phase to three phase. They also allow you to very the speed of the motor. They also usually allow you to hook up a brake for when you need to stop that motor quick. The newer lathes dont run that slow in the slowest speed as they dont have a back gear. Alot of guys like to thread and do other operations at slower speeds than their lathe will run so that is where the variable speed capability of the vfd is nice. They are small - make no noise and so are a nice option for the same or less money than a rotary phase converter.

I made my rotary phase converter If you have much electric know how at all they are easy to make. Do an internet search. Used 3 pahse motors are generally pretty cheap because there is not much demand for them compared to single phase.

OK Go get em Tiger

PS only downside of vfd is you have to learn to program them which can be a challenge.

 

[smoooth]

As stated above, Rotary phase converters do not use much power. For your application a 5hp would be fine. I have one sitting now since I put in a 10hp upgrade. I probably have a 5hp motor and most parts to build a converter. If you are in NJ, find some online auctions or look on craigslist or ebay for 5hp 3ph motors, they are way less money than single phase motors and much more efficient, energy wise.

Rotary converters can be balanced very well with capacitors on each leg, if you, or the builder knows what they are doing. Any master electrician should be able to build one and often they advertise them for sale on Craigslist, too.

And, in case you didn't know, once your converter is running each motor you start (that is wired into the converter) adds to the horsepower, so you should be able to start a 7hp motor with your 5hp converter and 3hp lathe running equaling roughly 8hp.

Good luck!!

 

[TRA]

I'm running a rotary to power a 5 hp lathe and 3 hp mill. No issues other than the extra noise as others have mentioned. If going with a rotary you can get by fairly cheap by buying the control pannel then buying a used motor for the idler. Small used 3 phase motors can be found fairly cheap. A general rule of thumb is you want your motor/idler to be twice the size of you biggest driven load. If it will be mounted near your equipment find a TEFC rated motor. Mine is close to the mill and I've had no issues with the total enclosed motor. I originally planned to use a VFD but the options get limited for 5 hp and up. For a 3 hp motor VFDs are as cost affective as a rotary. The VFDs provide some additional options also. A more true phase angle than the rotary, variable speed and no additional noise are probably tops. You could also set up soft starts, dynamic braking, ect.... If you go the rotary direction, I can provide where I bought the control pannel. An individual sells them on Ebay at a reasonable cost, provides good directions and phone support.

All you need to build a rotary is a 3ph motor, 2-3 times as large as your load. Try to find one 3400 rpm, no less than 1700 rpm. More is better. A 3 fuse knife switch about 40-60 amp. You can either start the rotary with a pull rope like a lawn mower, with capacitors, or with a pony motor. With mine it was too big to rope start, the capacitors were more trouble than thew were worth. Find a 1-3hp motor and mount them shaft to shaft with something like a lovejoy coupling. wire it all up. and use a "motor rated" household style switch to energise the pony motor. When it spools up flip the knife switch and turn off the pony and you got your 3ph. Some will say you will need a bank of capacitors to tame the wild leg which can rum 275 volts depending on what motors you used. That's really nothing to worry about. According to the rotary guru from Texas that raced fuel Harleys, it's only there as the manufactured phase goes through 2 poles, and it will tame down with load. The more equipment you have running the better the system works. It's a piece of cake to build one and as alex has said he got buy under 150.00.

!0 hp 3ph motor 1700-3400 rpm
2hp single phase motor
40-50amp 3 fuse knife switch
20-30 amp wall toggle switch
lovejoy shaft coupling
wire.

The only complicated item building your own is the current flow directions determined in the knife switch.

 

[TRA]

What can you with a VFD.

Here is a picture of my 1024 with VFD, my 1236 has a VFD as well. The 1024 also has a proximity sensor, that shuts the spindle when tripped. Convenient when threading to a thread relief like on the AR barrels.

The control box on the top L has the toggle, speed, braking switch to select the shutdown, whether coast along or right now,View attachment 1006691 , and eStop The control box under the pan contains the forward, reverse, stop, and bypass for the proximity sensor.

Here is a short video on how the threading with the proximity sensor works. I have run it at 400 RPMs to the thread relief during testing, and it works.

That's a good idea that NEZ came up with to solve any issues with threading.
For anyone squeamish about threading,,,,this is as good a reason as any to go with a VFD.

 

[GNERGY]

I use Westinghouse Teco FM 50 VFD's for both my Bridgeport mill and Rockwell lathe. They are wired after the recommended fuses and then directly to the machines junction box. I use the normal controls on the lathe and the mill for operating them, for both forward and reverse directions. The VFD's just convert the 220V single phase to 220V 3 phase. The VFD's are turned on and set at 60 cycles and not adjusted after that. I control my speeds with the lathe and mill controls. Both VFD's were just under $150.00 each and came with a 2 year warranty.
Hope this helps.
Tarey

 

[Bully]

I use Westinghouse Teco FM 50 VFD's for both my Bridgeport mill and Rockwell lathe. They are wired after the recommended fuses and then directly to the machines junction box. I use the normal controls on the lathe and the mill for operating them, for both forward and reverse directions. The VFD's just convert the 220V single phase to 220V 3 phase. The VFD's are turned on and set at 60 cycles and not adjusted after that. I control my speeds with the lathe and mill controls. Both VFD's were just under $150.00 each and came with a 2 year warranty.
Hope this helps.
Tarey

This sounds like what I'm after. I would like to use the controls on the lathe.

 

[carlsbad]

My bridgeport ran for 20+ years on a static. Seemed to run fine. However, you lose 1/3 to 1/2 of horsepower. I got a rotary when I got the 3ph lathe and both machines run off of it great. The bridgeport has full power and both start and run strong.

Doe a VFD have the same HP loss issue that a static phase converter has?

--Jerry

 

[Bamban]

That's a good idea that NEZ came up with to solve any issues with threading.
For anyone squeamish about threading,,,,this is as good a reason as any to go with a VFD.

Terry,

To give credit where credit is due a retired Oncologist from Tucson, came up with the idea using the proximity sensor and he also cranked out the controls.

This is the one I came out with as an extended use of the VFD and DRO. Use the "Zero" on the DRO to control the VFD where to stop. Basically zero the DRO where you want to stop, once zero is attained in the operation, system stops. This was installed on the other 1024 I sold. The demo tapes are just to see how the DRO and VFD can work together. One of them is rather long when I was doing a boring operation with the controls still testing. For most work the system worked very well.

 

[TRA]

My bridgeport ran for 20+ years on a static. Seemed to run fine. However, you lose 1/3 to 1/2 of horsepower. I got a rotary when I got the 3ph lathe and both machines run off of it great. The bridgeport has full power and both start and run strong.

Doe a VFD have the same HP loss issue that a static phase converter has?

--Jerry

No, it can even overpower it.

A static loses hp and you lose any braking and direct reversing capability.

 

[Rustystud]

1. My advice is get a VFD. It makes true 3 phase. You can buy a good Surplus (new) or refurbished (used) VFD from www.DealersDirect.com
2. Have a qualified electrician or electrical engineer oversee the correct wires to be banked with yor new 3 phase motor.
3. In my case I had a single phase lathe that I converted to 3 phase. So I had to buy a new motor also. If your lathe is metric buy a NEMA Metric Motor. If your Lathe is not Metric buy a Standard NEMA motor.
Again My lathe came with a single phase 3hp motor. When I replaced it with a 3 phrase motor with the correct footprint The new 3 phase motor was 5 1/2 hp. This has been a plus.
With a 3 phase motor you will not have tool kick marks with high speed turning.

 

[hoz53]

1. My advice is get a VFD. It makes true 3 phase. You can buy a good Surplus (new) or refurbished (used) VFD from www.DealersDirect.com
2. Have a qualified electrician or electrical engineer oversee the correct wires to be banked with yor new 3 phase motor.
3. In my case I had a single phase lathe that I converted to 3 phase. So I had to buy a new motor also. If your lathe is metric buy a NEMA Metric Motor. If your Lathe is not Metric buy a Standard NEMA motor.
Again My lathe came with a single phase 3hp motor. When I replaced it with a 3 phrase motor with the correct footprint The new 3 phase motor was 5 1/2 hp. This has been a plus.
With a 3 phase motor you will not have tool kick marks with high speed turning.

And to the OP--If you buy a new motor you can get what is called an inverter rated motor. It is specially built to work with a vfd without being damaged. You can crank up the speed quite a bit on one of these to give you more speed at your lathe spindle. Poor Topher--He is probably thoroughly confused by now. I really dont see any reason to buy a phase converter any more. You spend less money on a vfd and you get speed control and other options if you ever do want it.

 

[GenePoole]

I thought I was pretty clever and I've done some neat things with my VFD, but that proximity stop is pure genius! Thanks for sharing.

 

[B Nettesheim]

A good quality vfd will have you set parameters in it at time of initial start up. You will enter horsepower or max current draw into it, this is your new motor starter/overloads.
You can also do your reversing with the vfd but it is usually more simple to use a drum switch between the vfd and the motor.
If you have your controls downstream of the vfd (low voltage) and run the vfd at 60+ hz your control transformer, and motor starter coil may not survive too long.
Once set up they are efficient and easy to use. BN

 

[Bully]

And to the OP--If you buy a new motor you can get what is called an inverter rated motor. It is specially built to work with a vfd without being damaged. You can crank up the speed quite a bit on one of these to give you more speed at your lathe spindle. Poor Topher--He is probably thoroughly confused by now. I really dont see any reason to buy a phase converter any more. You spend less money on a vfd and you get speed control and other options if you ever do want it.

If you've ever met me you would realize that confused is kinda my mantra.

I'm just learning. And I thank all that have contributed to the post.

 

[GenePoole]

A good quality vfd will have you set parameters in it at time of initial start up. You will enter horsepower or max current draw into it, this is your new motor starter/overloads.
You can also do your reversing with the vfd but it is usually more simple to use a drum switch between the vfd and the motor.
If you have your controls downstream of the vfd (low voltage) and run the vfd at 60+ hz your control transformer, and motor starter coil may not survive too long.
Once set up they are efficient and easy to use. BN

I agree with the control transformer bit, but why would a three-phase motor have a start winding?

 

[B Nettesheim]

Im referring to the coil that would pull in the motor contactor. They usually are rated at 60hz.

 

[GenePoole]

Im referring to the coil that would pull in the motor contactor. They usually are rated at 60hz.

Oh, OK. Probably missed that since my ancient South Bend doesn't have a contactor--just straight through from the VFD to the motor. All my add-ons like a coolant system, light, etc. all feed from a regular 120V household plug/socket.

 

[hoz53]

If you've ever met me you would realize that confused is kinda my mantra.

I'm just learning. And I thank all that have contributed to the post.

LOL. I think im the confused one.

 

[hoz53]

A good quality vfd will have you set parameters in it at time of initial start up. You will enter horsepower or max current draw into it, this is your new motor starter/overloads.
You can also do your reversing with the vfd but it is usually more simple to use a drum switch between the vfd and the motor.
If you have your controls downstream of the vfd (low voltage) and run the vfd at 60+ hz your control transformer, and motor starter coil may not survive too long.
Once set up they are efficient and easy to use. BN

It seems you know enough about it to know its generally a no no to switch power wiring between vfd and motor it controls. That can result in smoking your vfd.

 

[hoz53]

Terry,

To give credit where credit is due a retired Oncologist from Tucson, came up with the idea using the proximity sensor and he also cranked out the controls.

This is the one I came out with as an extended use of the VFD and DRO. Use the "Zero" on the DRO to control the VFD where to stop. Basically zero the DRO where you want to stop, once zero is attained in the operation, system stops. This was installed on the other 1024 I sold. The demo tapes are just to see how the DRO and VFD can work together. One of them is rather long when I was doing a boring operation with the controls still testing. For most work the system worked very well.

i havent watched these but using the dro to control the vfd seems like a really cool idea to me. Thanks