# Single phase or three phase?



## Mans Racing

I’m thinking about purchasing a new Lathe and it is available in both single and three phase.In my shop I have single phase power only.Is it better to use a three phase unit with a phase converter or just order single phase unit and be done with it? 
Thanks


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## dlane

If I were in the market ied go three phase and a vfd.
Welcome aboard


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## 682bear

3 phase is supposed to be a lot more efficient... you get more power with less energy used. Or so I hear... I'm no electrical genius, so I just go by what I'm told.

-Bear


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## pstemari

Three phase allows for simpler motors—no starter caps, etc. Any efficiency gain, however, is going to be wiped out by the VFD. However, unless you're running a full time machine shop, I doubt that matters. The real advantage is being able to fine-tune the lathe speed without stopping and changing gears.

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## Bob Korves

Get three phase.  The motors are more robust and have less to go bad.  They run smoother.  You can hook up a rotary phase converter to make it run, or a VFD to make it run and do a lot of other good stuff.  I say go for the VFD unless you plan to be running other 3 phase equipment as well and don't care about the bells and whistles.


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## Bob Korves

pstemari said:


> Any efficiency gain, however, is going to be wiped out by the VFD.


The amount of heat coming out of a VFD is pretty small, which tells me they are efficient.


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## dlane

I was told a phase converter is less efficient than a vfd


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## Z2V

Another vote for three phase and VFD.


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## JimDawson

Yup, 3 phase and a VFD


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## Ulma Doctor

with high relative quality and low relative price, the VFD and a 3 phase motor is the way to go
surface finish greatly improves when 3 phase motors are used
you'll be omitting the lathes OEM motor control system, but it is pretty easy to add features you may wish


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## cvairwerks

If you have over a 100 amp service AND the lathe is under 5 hp on the main drive, go for 3p and a vfd. Otherwise single phase.


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## Ray C

This is over-kill now but, what the heck...  Go with 3Ph and a VFD.  Be apprised, there are pros and cons.   With a VFD and depending on the lathe you get, some tweaking of the wiring might be necessary.  With modern lathes that have a control board with relays for safety switches etc, some tweaking will be needed.   Also, the FVD's commonly available on eBay have terrible user instructions.  You may need to do a little homework to get it configured properly.

I think there's plenty of people here who have been thru this so if you get stuck, help is usually not that far away.



Ray


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## Eddyde

It also depends on what lathe and what you want to do with it? IMOH, if the lathe has a good range of easy to change speeds and you aren't planning to turn exotic materials you may be fine with the single phase motor. VFD's are great (I am run-in 5 in my shop), they give you, phase conversion, speed control, braking, soft start and other features, but as Ray said, there are some cons as well. For one thing, they aren't "plug-n-play" you'll need to wire it into your machine if you want to use the machines controls for stop-start, forward-reverse, etc. You cannot have any switches between the VFD and the motor, all machine controls must go to the VFD which then controls the motor. So hooking it up requires some electrical skills. Another is the cost, and the "it's another thing to possibly break down" factor. To be clear, I'm not trying to steer you away from the VFD, just want give you a clearer picture of what's involved.


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## 3strucking

I have VFD's running lathe and mill but If I were buying a new lathe I would want a 3 phase and a control system from MKSJ.


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## projectnut

Keep in mind that if you do go the VFD route it's quite likely that all the machine controls will have to be done through the VFD.  That means the start/stop, reverse, and speed change functions will now be controlled through the VFD.

I went the phase converter  route on my Sheldon mainly because I wanted to retain all those functions on the original control panel.  One difference between this Sheldon and most other machines is that the speed control is done with a couple push buttons on the control station, rather than mechanically selecting gear ratios.  The push buttons control a 120 volt gear motor at the rear of the machine.  The gear motor controls sheaves much like a Reeves drive.

Here's a picture of the machine with the control panel just below the tachometer on the left side.  The buttons are, top row left to right, reverse, forward, stop.

The lower row left to right are, speed reduce, speed increase.  If your machine has similar controls you'll have to determine how to transfer these functions to a VFD or go a different route.


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## MrWhoopee

3 Phase.

Because I have both a lathe and a mill, and for reasons of cost, I went with a static phase converter. Under $100 
http://phaseconverterusa.com/Static-Phase-Converter_c_11.html
Once the motor is running, the converter kicks out. This leaves the motor running on 2 legs of power. Some have stated that this can cause finish issues with a lathe. For this reason, I start the mill and leave it running (serving as a rotary converter) while using the lathe.

I will be receiving a rotary phase converter once its current owner is done with it, but I really have no complaints with the static.


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## projectnut

MrWhoopee said:


> 3 Phase.
> 
> Because I have both a lathe and a mill, and for reasons of cost, I went with a static phase converter. Under $100
> http://phaseconverterusa.com/Static-Phase-Converter_c_11.html
> Once the motor is running, the converter kicks out. This leaves the motor running on 2 legs of power. Some have stated that this can cause finish issues with a lathe. For this reason, I start the mill and leave it running (serving as a rotary converter) while using the lathe.
> 
> I will be receiving a rotary phase converter once its current owner is done with it, but I really have no complaints with the static.



At the current time I have a Lathe, a saw, and a mill all running on static phase converters.  There has never been a problem with finish on any of the machines.  The mill has been on the converter nearly 20 years with no issues.  The saw has been on a static converter about 4 years, and the lathe has been on one for about a year, again with no issues.

Having said this I have had a 15 hp rotary converter waiting to be installed for over a year.  I need to add another sub panel to power it.  Hopefully that panel will be installed within the next couple months as part of a remodeling project.  Once that's done I'll install the converter and connect all the 3 phase machines.


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## MikeInOr

Check with the manufacture to see if the lathe is available with a 3ph motor and a vfd pre-installed?  If so it will save you a bit of wiring and configuration.  If not you will need to do a bit of wiring and configuration to get the vfd working with the lathe... nothing too technical.

I would go for 3ph with a vfd myself... I have installed several vfd's on 3ph machines... a lathe is very small bit more tricky because you have to bypass the reversing switch if there is one and wire the vfd directly to the motor.


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## MattM

I have an American Rotary 7.5hp rotary converter powering: VFD controlled full size mill, VFD controlled 10EE Monarch ,and non VFD controlled surface grinder and Clausing lathe.

I really like the fine tuning speed control the VFD affords on the mill and the 10EE.  A little pricey but worth it.

The converter lives with my compressor in a separate structure to attenuate the noise.


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## blue_luke

Me too I suggest 3Ph and VFD but there is a caveat!
Get a VFD rated motor. The difference between a standard 3ph and a VFD rated is in the insulation rating of the copper wire used to do the windings. VFD produces high voltage peaks that are often over the insulation rating of the standard motor.
Also the better quality VFD motors have a fan that runs all the time independent of the motor in the case where you may want full torque at 0 RPM or while braking a system. 
Having said this... don't worry too much about that! In the case of a lathe you will never stall a motor and if it happens the extent will bee a blown fuse or a tripped breaker! 
If I was in an industrial environment I would replace the motor for a VFD rated one, but for a hobbyist you will probably never have this problem.
It is just something you have to know and if the motor burn eventually, don't blame the motor, just replace it with a VFD rated one... in 10-20 years maybe!??


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## derf

If you are just a beginner/hobbyist, go with single phase and plug and play. If you are going to use this more than once a week, go the other way.


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## f350ca

I'd personally get the lathe with a single phase motor and avoid the hassles and expense of a phase converter.
I bought my first lathe with a single phase motor, then a bridgeport clone mill single phase with variable speed belt drive. No need for 3 phase. My whole cabinet shop runs on single phase as well. 
That being said there are times 3 phase is a necessity. I bought a large lathe with a 10 HP motor, single phase wasn't an option so I installed a Phase Perfect converter to run it. 
When I replaced the first lathe with a Colchester Student I converted it to single phase rather than run power to it and have to start the phase converter every time I used it.
That was latter replaced with a Hardinge HVL, single phase wasn't an option as it uses a precision balanced two speed motor that couldn't be replaced. At that point I had to install a 3 phase panel to power the Hardinge with lower current breakers.
I latter added a surface grinder. It was 3 phase but the panel was already there so powering it was easy.
Latter acquired a radial drill that was gear drive so not easy to convert to a single phase motor. I used a VFD on it rather than run 3 phase lines to it and have to walk across the shop to start the phase converter. But I only use it as a phase converter, the drill has 8 speeds on its own so no need for the variable function.
The Phase Perfect acts like a solid state rotary phase converter not caring about switching loads or motor sizes up to its limit, so machines are easy to run with it not having to alter any of the electrical controls.
Sometimes you can't avoid 3 phase but if you can why bother with it.

Greg


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## projectnut

I guess the main reason I look for 3 phase machines is that in our are they are more plentiful, and less expensive than single phase machines.  Most hobbyists either aren't familiar with, or don't want to deal with heavy industrial machines that use 3 phase power.  That situation is not lost on those selling primarily to hobbyists.  Similar capacity single phase machines are almost always more expensive.  Not to mention industrial grade machines are built to higher standards.

I'm a bit spoiled having used industrial grade machines for the better part of my life.  I like the accuracy, speed, and power of industrial grade machines.  There is another thread running about a finish on an aluminum tube.  One member was questioning whether his machine was capable of making a .010 deep cut.  On any industrial machine that would be close to if not a finish cut.  A heavy cut could be somewhere north of .250.

To me the willingness to deal with 3 phase power makes the pool of available machinery far larger than those only willing to consider single phase machines.


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## lcrepairs

Mans Racing said:


> I’m thinking about purchasing a new Lathe and it is available in both single and three phase.In my shop I have single phase power only.Is it better to use a three phase unit with a phase converter or just order single phase unit and be done with it?
> Thanks


I would never go 3 phase unless you have to. I have a mill and lathe both single phase, smooth and powerful.

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## kd4gij

Well we have 2 BP mills at work both 2hp one single phase and the other 3ph. side by side. No comparison 3phz hands down


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## lcrepairs

kd4gij said:


> Well we have 2 BP mills at work both 2hp one single phase and the other 3ph. side by side. No comparison 3phz hands down


Would be great if you have the service. Not worth the extra expense to me to make FAKE 3 phase power.

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## 100LL

I’m happy with my 3phase lathe and roto-phase converter.  I’ve never used a static converter but have been told they’re inferior to rotary phase converters which create that third phase.

My mill is single phase, and since I have the roto phase I’ve thought about putting in a 3phase motor but, well, there are more important things on the list.  

Worst thing would be having no motor at all.  It’s a good decision to get to make.


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## Chipper5783

Are you thinking there will be any more machines in your future?  If you are intending to get more machines, are you thinking of purchasing new?

Industrial machines from about the 1950's forward are very nice and widely available (at least in some places) - they are nearly always 3 phase and will often have multiple motors.

If you are purchasing new you will often get to choose single phase or three phase (same as what you are doing now).  Of course what ever you finally choose, no reason you can't go down the other path at a later date.

I have about 9 (?) three phase machines connected and running (probably 15 different 3 phase motors) - I don't think it would be practical to run them on some sort of a VFD system.  I have one drill press (3 phase) running on a single phase supplied VFD (it worked out easier in my shop arrangement and how the power was set up originally).

I am running all the machines off a 5HP rotary phase converter (my largest motor is 5 HP).  It works awesome - I can just keep on plugging in more machines.  It is true that the rotary units make a "fake" 3 phase power, but it works great and I have never had a problem.

There is a more deluxe option which has not been mentioned - using a Phase Perfect to get 3 phase power from a single phase source.  Again, you can just keep on plugging in more machines to the capability of the unit.  With a PP, the power quality is excellent - generally better than grid 3 phase as the voltage control is managed on site and not subject to the vagaries of the distribution system.

The VFD option is a good solution, but it is not "plug and play".

It really comes down to what you want to do with your machining.  If you only plan to get the one machine (and with just a lathe and the usual small machines and work space + tools, you can have a very nice & capable shop).  Lots and lots of iron really is not necessary to do much good work.

Single phase or 3 phase are both good options.  If you are just doing an opinion poll - I'll put in my vote for 3 phase.

David


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## MattM

I'd be in the three phase camp.  I paid $500.00 for my 7.5hp American Rotary converter.  Had it for over three years and am very pleased.  No problems.  Of course I only run one machine at a time since there is only one of me in the shop at any time.


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## 682bear

Please explain the meaning of 'fake 3 phase' in regards to an RPC...

-Bear


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## pstemari

Dunno what he meant, but the static phase converter mentioned that only powered two phases after startup is pretty lame.

The voltage you get from an RPC is skewed relative to ground. That can occasionally cause problems, especially if auxillary circuitry picks off a single phase to derive a 120VAC to neutral. With an RPC, that works for two of the three phases, but the phase created by the RPC (the "wild leg") runs at 208VAC relative to ground.

VFDs don't have that problem, but because they use pulse-width modulation to simulate a sine wave, they do generate a lot of RF noise.

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## 682bear

My understanding of it is that an RPC creates 2 phases... you have one phase already, which is the L1-L2 phase (where L3 is the 'wild leg') and L2-L3 and L1-L3 are the 2 phases generated by the RPC...

The installation manual states that you can get reliable 120v current by either connecting to L1 and ground or L2 and ground (again, where L3 is the wild leg). 

That may be what was meant, IDK, but IMO, saying it is 'fake' 3 phase is sort of like saying my gasoline generator creates 'fake' electricity...

Not trying to be argumentative... I'm no expert and I'm trying to learn what I can about the subject... 

-Bear


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## projectnut

682bear said:


> Please explain the meaning of 'fake 3 phase' in regards to an RPC...
> 
> -Bear


I believe he was referring to a static converter, not a rotary converter.  A static converter generates a temporary 3rd phase using a series of capacitors.  The third phase is only generated during the start up.  Once the motor is spinning the third phase drops out and the motor continues to run on single phase.  A motor running with a static converter only generates approximately 2/3 of it's rated horsepower.


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## JPMacG

If you are purchasing a small hobbyist type lathe and you think that some day you might want to sell it, then I think you should get single phase.


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## MrWhoopee

"Fake 3 phase". A basic rotary phase converter (no additional electronics) generates the third leg, but it doesn't generate full voltage on that leg.


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## markba633csi

The source impedance characteristics are different on the generated leg vs the two utility power legs- fixed motor loads usually don't care when
the 3rd leg is "tuned" to give the proper voltage
Mark
I guess you could call the 3rd leg "fake" for that reason


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## wrmiller

Mans Racing said:


> I’m thinking about purchasing a new Lathe and it is available in both single and three phase.In my shop I have single phase power only.Is it better to use a three phase unit with a phase converter or just order single phase unit and be done with it?
> Thanks



If you are not interested in variable spindle speed, go with the single phase and plug it into the wall. 

The only reason I went with 3-phase machines (lathe and mill) was because I wanted variable speed and a VFD gives me that without having to buy a much more expensive DVS-type machine.


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## Silverbullet

I vote three phase if you can afford it. The electric bill will also show a savings over single phase. You should weigh the differences and go with what you can do. My first garage shop had one outlet in it ,ad thirty ft from the house. I bought 10-3 uf feeder wire and hand dug the trench from the basement to the shop . Wired 220 and ran an RPC to my lathe and Bridgeport. Worked everyday for a month and it only raised the bill $15.00 .
I was happy with that just starting out doing work and lowering cost .


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## pstemari

682bear said:


> My understanding of it is that an RPC creates 2 phases... you have one phase already, which is the L1-L2 phase (where L3 is the 'wild leg') and L2-L3 and L1-L3 are the 2 phases generated by the RPC...
> 
> The installation manual states that you can get reliable 120v current by either connecting to L1 and ground or L2 and ground (again, where L3 is the wild leg).



Right. L1 and L2 are the original two phases, and L3 is generated. Any pair of phases gives you 240 VAC, L1 or L2 to neutral gives you 120VAC, and L3 to neutral gives you 208VAC.

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## 682bear

pstemari said:


> Right. L1 and L2 are the original two phases, and L3 is generated. Any pair of phases gives you 240 VAC, L1 or L2 to neutral gives you 120VAC, and L3 to neutral gives you 208VAC.
> 
> Sent from my Pixel XL using Tapatalk



Umm... L1, L2, and L3 are just 'legs'... the 'phases' are dependant on the relationship between 2 of the legs, thus L1-L2, L2-L3, and L1-L3 are the 3 phases. Am I correct on this?

Otherwise, what we call a single phase motor would actually be 2 phase, with an L1 and L2 power wire...

Or am I completely backwards?

-Bear


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## lcrepairs

682bear said:


> Please explain the meaning of 'fake 3 phase' in regards to an RPC...
> 
> -Bear


Not supplied by the Utility Company. I know I will eventually have to get a RPC but they are very expensive and noisy.

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## Chipper5783

682bear said:


> Umm... L1, L2, and L3 are just 'legs'... the 'phases' are dependant on the relationship between 2 of the legs, thus L1-L2, L2-L3, and L1-L3 are the 3 phases. Am I correct on this?
> 
> Otherwise, what we call a single phase motor would actually be 2 phase, with an L1 and L2 power wire...
> 
> Or am I completely backwards?
> 
> -Bear



I suppose as long as everything is safely plugged in and a person can make it go - the details of how the energy supply system is described really does not matter.  I understand that certain 3 phase supplied machines are more sensitive to the source than other 3 phase machines.  Certain CNC machines may not perform well on the typical RPC phase converter, but a "better" RPC is suitable for that same machine.

A single phase motor, whether 120V (L1-N) or 208V or 240V (L1-L2) is still single phase.  Strictly speaking there is no such thing as 2 phase - since the sum of 2 sine waves of equal frequency is still a single sine wave - regardless of how far the shift is (the degree of shift simply impacts the amplitude in how the two waves sum).


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## markba633csi

Bear: It is confusing. It's sorta like you're "dropping in" a third leg in between the two existing legs kinda sorta
I'm not that great at explaining stuff otherwise I would have been a teacher
Mark


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## Dabbler

Bear: Most rotary phase converters run at a compromise with respect to the generated phases.  There's notheing wrong with that, but the voltages may be a little off, resulting in a little more motor heating.  My friend was running a 7.5HP lathe on a 10HP rotary phase converter for 39 years without a problem.  You get some problems if you are running near the stall torque of your motor.

Mans Racing:  If you can afford it, go for VFD/3phase every time.  If you hate wiring electrical stuff and can't afford a pro job, go 1 phase for the convenience.  Why?  3 PH gives you infinite speed control from 10% rated speed to more than 120% rated speed.  (on some motors, 220% rated speed)  It should be  a little smoother (but not enough to quibble). The range is always wider on VFD rated motors.


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## f350ca

Don't know the exact details David but apparently Niagara Falls at one time generated 2 phase power. Think there may still be remnants in New York state. Read about it a while ago. Given long enough we can come up with strange scenario's.

Greg


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## Mans Racing

Well I decided to go with a 3 phase unit so I ordered a PM1440GT Lathe.Im just going to start out with a static phase converter then at a later date when I have the time I will install a VFD.Even at 2/3 power to start with it should be just fine.I was just concerned about how smooth it would run with single phase vs three phase. Thanks for all the response and help on this matter.Being very inexperienced in being a machinist I’m sure glad I found this site.
Thanks


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## Eddyde

682bear said:


> Umm... L1, L2, and L3 are just 'legs'... the 'phases' are dependant on the relationship between 2 of the legs, thus L1-L2, L2-L3, and L1-L3 are the 3 phases. Am I correct on this?
> 
> Otherwise, what we call a single phase motor would actually be 2 phase, with an L1 and L2 power wire...
> -Bear


I believe that is essentially correct, however for practical wiring purposes it doesn't really matter, the "leg" can be considered a "phase".
I think the confusion over 2 "leg" power being called "single phase" Is because a single "phase" is split at the pole transformer into two "legs" (Split phase AC) and a neutral is taped from the center, either of the legs to neutral gives 120v and the to combined yield 240v.


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## lcrepairs

Eddyde said:


> I believe that is essentially correct, however for practical wiring purposes it doesn't really matter, the "leg" can be considered a "phase".
> I think the confusion over 2 "leg" power being called "single phase" Is because a single "phase" is split at the pole transformer into two "legs" (Split phase AC) and a neutral is taped from the center, either of the legs to neutral gives 120v and the to combined yield 240v.


Yep, that's why it seems dumb to call it 110v & 220v, I've measured mine many times while working on wiring and It's always been 249v


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## MrWhoopee

lcrepairs said:


> Yep, that's why it seems dumb to call it 110v & 220v, I've measured mine many times while working on wiring and It's always been 249v



Bonus, 249v for the price of 220!


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## Dabbler

The problem:  RMS vs Peak to Peak voltage abbrev. PP.  Gets you every time.  A true RMS meter will measure 220V at most panels, but a non RMS meter will measure anywhere from 236V to 247V. BTW RMS means Root Mean Square.  In a perfect world it will be .707 of the PP voltage.  a good explanation (a  bit over technical) is at https://en.wikipedia.org/wiki/Root_mean_square


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## pstemari

No, I've got several true RMS meters (Fluke 87V, Agilient U1252B) and they all read 120v/240v with a volt or two.  If you're reading 220V, that's at the low end of what the utility should be delivering.

Away from the panel, you can get some voltage sag if there's heavy loading on the line.

What everyone said above about phases and legs.  Nominally the US 240VAC lines have two phases, but since they are 180 degrees apart, you can't use them to start a motor directly.  There's a dead spot and no preferred direction.

It's not really a summing issue.  If you sum all three phases together from the power company you'd get 0V, too.  That's not true with RPC power, since two phases come directly from the mains. The generated third phase (wild leg) is 90 degree apart (relative to ground) and the vector sum of the three winds up at 120V * tan 30 ~= 70VAC.


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## Vladymere

If you plant o have multiple three phase machines then a rotary phase converter feeding a three phase breaker box with a three phase circuit breaker and circuit running to each machine is what I would suggest.

Below is a photo of my RPC/three phase set up with only one machine installed (Icurrently have four three phase devices).  Left side is my single phase breaker box.  On the right is my three phase RPC idler on the floor running up to the phase converter I built which feeds the three phase breaker box.  In between the single phase breaker box and the three phase system is a cut off switch/isolation switch to the three phase setup.

This set up will allow me to add to more than the four existing three phase devices.

Vlad


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## rock_breaker

Times may have changed but I wonder about the economics of grid 3 phase power. Here in the farming community I am given to understand grid three phase is more expensive than single phase. It seems that "power factor" has to do with the electricity cost and availability to the grid source and I believe single phase is billed by electrical power used. I stand ready to be corrected on this subject.     
Have a good day
Ray


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## projectnut

As far as initial installation cost 3 phase is more expensive.  As far as power usage (at least in this area) everyone is charged by the kilowatt hour used, plus a "demand charge".  The demand charge is larger or smaller depending on the size of the service installed.  The larger the potential current draw the larger the demand charge.  Then comes the "volume discount rate".  Once you reach a certain usage level the price per kilowatt hour is reduced substantially.

I have seen instances where a homeowner with a 300 amp, 220 volt single phase service is paying more than a commercial shop with a 300 amp 3 phase service.  They both pay a similar demand charge, but the commercial shop is actually using fewer kilowatt hours because the 3 phase machines draw less amperage than similar sized single phase machines.

I doubt you'll ever see 3 phase power go away.  The largest 220 volt single phase motor I am aware of is 50 hp.  More realistically 10 to 15 hp is the maximum that could be used in a residential setting.  There are 220 volt 3 phase motors that put out as much as 250 hp.  The most extreme hp units I've seen are made by Baldor.  They have some up to 15,000 hp, but don't try to run one unless you have a 13.2 KV power supply available. 

When we built our current house I tried to get a 3 phase service for running shop equipment.  The power company was happy to do it if I was willing to pay to have it extended from the nearest available connection.  Unfortunately the nearest connection was a little more than a mile away.  The cost was prohibitive in that had I run every machine I had at the time 24/7/365 I would never been able to recover the installation cost.


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## Eddyde

Here in New York City, it is now common for residential homes to get 3 phase power, mainly to run central air-conditioning and sometimes elevators as well.


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## Doubleeboy

Having seen a surface grinder , yes the same machine run on true 3 phase and a phase perfect generated 3 phase coming from single phase source, the machine gave better surface finish and ran quieter and smoother on the phase perfect.  I don''t know how or why that is, but having seen it with my own 2 eyes, they are the real deal.  If surface finish is not a big deal, I would go with static or VFD.  I ran a Clausing 5 hp machine on a 4-8 hp rated Heavy Duty static for years and it worked fine with very nice surface finish.


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## Low tech

I bought a used 5hp rotary phase converter in 1998 . This converter runs a 13” LeBlond servo shift,a step pulley Bridgeport,a 6x18 Reid Brothers surface grinder , a 10” pedestal grinder ,and a 20” heavy duty Cincinnati shaper . I needed 3 phase because all these machines came equipped for it .
The rotary phase converter cost $450 plus wiring and disconnect panel . The surface grinder has a small motor so I balanced the high leg with a transformer . 
The converter is a little noisy so I mounted it above the insulated ceiling . Not bothersome after that .....Steve


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## jdedmon91

Mans Racing said:


> Well I decided to go with a 3 phase unit so I ordered a PM1440GT Lathe.Im just going to start out with a static phase converter then at a later date when I have the time I will install a VFD.Even at 2/3 power to start with it should be just fine.I was just concerned about how smooth it would run with single phase vs three phase. Thanks for all the response and help on this matter.Being very inexperienced in being a machinist I’m sure glad I found this site.
> Thanks



I used a static phase on my mill that I purchased because it was the simplest solution 


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## Larry$

Another vote for 3 phase. My first 3 phase machine was before I had line 3 phase. I made a rotary converter from a 3 phase motor, some big electrolytic caps and a couple of switches. Ran for years that way. A minor catch is your machine won't quite have the same amount of power. 3 phase motors are way more durable/reliable than singles. I now have 800A 3 phase service but my electrician says I'll need to add more if I want to run additional equipment. You can run 50 cycle motors on 60 but not recommended to go the other way.


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## P. Waller

5 Phase is vastly superior, it has 2 more phases.


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## Dabbler

??


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## Larry$

I'll match your 5 and bid 5 more!


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## P. Waller

If 3 phase is better then 1 phase then 5 phase is better yet.


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## higgite

Anything beyond 3 legs would be just another pretty phase.

Tom


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## P. Waller

No pun intended I suspect (-:
Use a Phaseolator to determine how many phases work best for your individual application, not inexpensive yet very accurate at determining the quantity of phases needed.


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