# Phase Converter Good Or Bad



## roadie33 (Mar 20, 2015)

I found this on Ebay and was needing to know if it was any good for converting 220 1 phase to 3 phase?

http://www.ebay.com/itm/HD-1-3-Hp-S...856?pt=LH_DefaultDomain_0&hash=item2c8a31c260


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## Doubleeboy (Mar 20, 2015)

Do not know anything about that static converter, but I did run a static on my 5hp lathe years ago.  It worked fine, I had no troubles but everyone warned me of impending doom.  I now use either rotary phase converter or VFD.   The motor did survive 5 years of use with the static but I noticed the motor did run pretty warm even with light loads on it.   I would spend the money and either build a rotary or buy a small VFD for not a whole lot more and have full hp with no worries.

michael


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## Kevinb71 (Mar 20, 2015)

As it says right on the label static convertors only allow about 2/3 of the motors rated capacity to be produced. If you have a cheap motor it may not last. Then again if it's a cheap motor if it fails then replace it. For my money I would get a rotary unless that's not doable for you.


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## John Hasler (Mar 20, 2015)

roadie33 said:


> I found this on Ebay and was needing to know if it was any good for converting 220 1 phase to 3 phase?
> 
> http://www.ebay.com/itm/HD-1-3-Hp-S...856?pt=LH_DefaultDomain_0&hash=item2c8a31c260


"Static converters" do not convert single phase to three phase.  They convert three phase motors to single phase.  I use one on my mill and I'm happy with it but I was able to build it from parts on hand.  I wouldn't buy one.


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## roadie33 (Mar 20, 2015)

That answers that question.
Thanks.
I guess I'll be looking to do a Rotary.
I have a 7.5HP 3 phase I took off a industrial Compressor I got at an Auction just laying around collecting dust.
I could use it to build a rotary converter, but I know nothing about how to wire a rotary box or what all is needed for it.
I can wire regular 110 or 220 with no problem.
Read all kinds of info on them but still can't quite grasp the how to of them.
I would need very detailed instructions on parts and connections.
I know I could buy it already assembled, but $$ is the deciding factor.


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## Ulma Doctor (Mar 20, 2015)

roadie33 said:


> That answers that question.
> Thanks.
> I guess I'll be looking to do a Rotary.
> I have a 7.5HP 3 phase I took off a industrial Compressor I got at an Auction just laying around collecting dust.
> ...




Hi Roadie33,
i made easy to follow plans for a pushbutton start/stop RPC unit...
http://www.hobby-machinist.com/threads/rpc-simple-design-unbalanced.12712/

heres a video of the box made from the plans







and how to hook it up:






i hope the info is helpful!
mike


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## Doubleeboy (Mar 20, 2015)

Ulma Doctor has a pretty slick set up in post above.  If you want it done for you with minimal thinking or work involved I can attest to the excellence and affordable prices of Phase-Craft.  They are on ebay, have good prices, very well built, instructions anyone can follow.  They use good parts and stand behind their stuff.  You can contact them direct at phasecraft@gmail.com or call 714 710 9094.  Jim Gorman is the guy.   I ordered one on a Monday and had it 2 days later.  Several year guarantee.

michael


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## roadie33 (Mar 22, 2015)

Thanks Mike. 
What size Cap for a 7.5HP 3 phase Pony?
You mentioned Contactor from a heater 220V, what exactly is that and where or what kind do I need?
What type of start and stop switches are those, and where to get them?
I have purchased other supplies from Surplus Center before and know they carry a lot of this stuff but don't know exactly the type or what size it would take.

Any help would be appreciated and am sorry if I ask too many questions.
I am not wanting to waste money on something I can't use because I got the wrong item.
A lot of electrical parts are non returnable once you buy it.

Thanks also Michael.
If I find I can't build it myself I might go that route.
I am willing to try to build it myself first. With some guided support, of course.


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## Ulma Doctor (Mar 22, 2015)

a 400 microfarad 377 volt rated start capacitor would be just fine.
Furnas is the company that manufactured the contactor (it didn't come out of a heater).
any 3 pole 40 or 50 amp rated 220 volt coil contactor would work for your situation- Ebay has tons of them
i have a few in stock if you have trouble, although you shouldn't have much trouble finding one.
the start/stop switches are manufactured by square d .
they are momentary contact- the start switch(es) are 2 normally open switches controlled by the same pushbutton
the stop switch is a normally closed single pole switch. both start/stops are rated for 3amps at 240 volts (not much current goes through the start/stop circuit)
you don't necessarily have to use furnas and square d any products that are NEMA certified or UL listed are more than sufficient for what were doing here.
Surplus vendors are excellent sources for inexpensive goodies, i shop surplus vendors all the time.

i'd be happy to assist you in building a unit. as long as you get minimum 220v 3a rated switches, a 40 or 50 amp 3 pole 220v coil, 2 40 amp fuses and holder or a 40 amp 2 pole overload relay, a 400 microfarad start cap, some wire, disconnect device(plugs or 2 pole knife type switch or drum switch)
from my video you'll see the system is quite simple.
heres a video of the 7.5 hp starter box i made for another member a while back


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## rgray (Mar 22, 2015)

I'm running 2 of these units a 3 hp and 15 hp .  They have worked well and are easy to wire and come with good instructions.
http://www.ebay.com/itm/7-5-Hp-phas...-/191515793882?pt=LH_DefaultDomain_0&hash=ite


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## randyc (Mar 22, 2015)

No dispute with any of the rotary converter comments - rotary converters are highly efficient and far simpler than most people assume.  Of course Ulma Doctor is all over that topic, as he usually is about most stuff 

But I have to put in a small plug for static converters.  They are dirt cheap and do a good job if one doesn't need every last foot-pound/minute of horsepower, LOL.

I've been using one on my horizontal/universal mill for some years now, powered from the 220 volt single phase welder outlet.  No problemo (and 2 horsepower from the 3 horsepower motor still removes a LOT of chips).

I mention this mainly for those who are slightly frightened by high voltage electricity - as they SHOULD be.  Some may feel more comfortable hooking up a relatively simple static converter if they are intimidated by the challenge of constructing a rotary converter.

To each his own, right ?

I'll have to disagree with a statement made previously:

_"Static converters" do not convert single phase to three phase. They convert three phase motors to single phase..._

Static converters DO convert single phase AC to three phase AC with all of the consequent advantages like instant reversing.


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## Brain Coral (Mar 23, 2015)

roadie33 said:


> That answers that question.
> Thanks.
> I guess I'll be looking to do a Rotary.
> I have a 7.5HP 3 phase I took off a industrial Compressor I got at an Auction just laying around collecting dust.
> ...


 
Hello Mike,

Here is another option for you.

http://www.wnysupply.com/index.cfm/fa/items.main/parentcat/25258/subcatid/0/id/328115

I bought their 10hp  RPC panel last fall and hooked it up to a 10 hp 3 phase motor that I had lying around. I ran a 50 amp 220v single phase circuit to the panel and then wired in the motor. It was easy and relatively cheap and it runs like a champ.

Brian


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## GK1918 (Mar 23, 2015)

Phase O Matic   three years and counting (so far) no problems 'yet'.  and I can still smoke a belt


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## roadie33 (Mar 23, 2015)

Thanks Brian.
That looks to actually be affordable.
Do they send good instructions with those kits?

I just can't see why all of the other places want so much for the same thing. They don't even include the motor for the high prices they are charging.


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## uncle harry (Mar 23, 2015)

Ulma Doctor said:


> a 400 microfarad 377 volt rated start capacitor would be just fine.
> Furnas is the company that manufactured the contactor (it didn't come out of a heater).
> any 3 pole 40 or 50 amp rated 220 volt coil contactor would work for your situation- Ebay has tons of them
> i have a few in stock if you have trouble, although you shouldn't have much trouble finding one.
> ...



I like the double pole pushbutton approach. I have a small sub-fractional 3 ph centrifugal pump that I might just use this approach on as a coolant pump.  I would be a little concerned about the contact rating for the pushbutton for large horsepower starting this way though.


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## gi_984 (Mar 23, 2015)

I debated the same thing when building up my shop.  How to run 4 different 3 phase machines.  Looked at static and home made rotary converters as well as VFD.  Based on a lot of favorable reviews I went with these guys.  Excellent quality and I just push one button and get clean reliable 3 phase power.  Had it for over 2 years without a single hiccup.   Comes with a purpose built Baldor idler motor.  I've got the 7.5 HP version.  I can run all four machines (almost 5 HP) at the same time with ease. 

https://www.americanrotary.com/products/view/ar-pro-series


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## randyc (Mar 23, 2015)

randyc said:


> I'll have to disagree with a statement made previously:
> 
> _"Static converters" do not convert single phase to three phase. They convert three phase motors to single phase..._
> 
> Static converters DO convert single phase AC to three phase AC with all of the consequent advantages like instant reversing.



John, my humble apology for disputing your post.  Ulma Doctor has corrected my misconception although I'm still troubled by how a motor running on single phase can instantly reverse.  No other single phase motor in my shop is capable of doing that - only the 3-phase motor connected to the phase converter.  (I'm also at a loss as to why the device is called a "phase converter" if it's not converting phases ...)


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## Ulma Doctor (Mar 23, 2015)

uncle harry said:


> I like the double pole pushbutton approach. I have a small sub-fractional 3 ph centrifugal pump that I might just use this approach on as a coolant pump.  I would be a little concerned about the contact rating for the pushbutton for large horsepower starting this way though.



Hi Harry,
the control switches see less than one amp- the contactor is taking all the load (amps)
the switches operate the contactor coil, and on half of the start switch it allows the start caps charge to be dumped into the generated leg for starting purposes.


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## John Hasler (Mar 23, 2015)

randyc said:


> John, my humble apology for disputing your post.  Ulma Doctor has corrected my misconception although I'm still troubled by how a motor running on single phase can instantly reverse.



It's internally two phase.



> (I'm also at a loss as to why the device is called a "phase converter" if it's not converting phases ...)



Marketing.


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## Alan Douglas (Mar 23, 2015)

It creates unbalanced three-phase: the third leg is not necessarily at the same voltage, and it will have different degrees of phasing to the other two legs (hard to explain without vector diagrams).  The phase and voltage of this third leg will also vary with load.


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## randyc (Mar 23, 2015)

Alan Douglas said:


> It creates unbalanced three-phase: the third leg is not necessarily at the same voltage, and it will have different degrees of phasing to the other two legs (hard to explain without vector diagrams).  The phase and voltage of this third leg will also vary with load.



Now this I can understand rather than the concept of a 3-phase motor running on single phase.

This would allow the motor to instantly reverse (and brake, if you reverse, then quickly switch to neutral). despite the phase/voltage imbalance.  The imbalance in the artificially created third phase also explains the inefficiency of the conversion process.  I'm guessing that phase error is on the order of thirty degrees nominal and that the phase error is mostly responsible for the voltage difference, is that correct ?

Thanks Alan.


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## Brain Coral (Mar 23, 2015)

roadie33 said:


> Thanks Brian.
> That looks to actually be affordable.
> Do they send good instructions with those kits?
> 
> I just can't see why all of the other places want so much for the same thing. They don't even include the motor for the high prices they are charging.


 

The wiring is really simple and they do send a sheet describing what to do. It's a simple matter of running a new circuit from your panel to the converter...  single phase 220v and ground, sizing the wire and breaker according to the instructions. Then, the motor gets wired to the panel with a 3 wire and ground. If you go that route, there's plenty of guys here to help.

Brian


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## Andre (Mar 23, 2015)

Have a kit from WNY supply and a 3ph 5hp motor from C-list. Just waiting to put it together to fire up my surface grinder 

Picked up a air compressor form the side of the road, needs a TOTAL rebuild, but I will set it up with a disconnect so when not using the grinder I can use it as a small (and much quieter) air compressor. Then disconnect it when using it as a phase converter, or at least that's the plan anyway.


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## randyc (Mar 23, 2015)

Here is a circuit simulation of what Alan explained.  A single phase generator is driving a three-phase load through a phase shift network consisting of two capacitors (the starting capacitor is not shown).






As is apparent from the waveforms, the output IS three-phase, not single phase.  As Alan noted, there is a phase and amplitude imbalance.  I have no idea if the amount of imbalance shown is typical.  The circuit values selected for the simulation were fairly arbitrary and I saw no point in trying to optimize them.


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## Cactus Farmer (Mar 23, 2015)

Please excuse the wordiness (if that's a word at all) , that said, I have an 8-12HP Add-a-phase that is wired to a 10HP very heavy motor(picture two guys lifting it with a tommy bar to the taigate of a 4X4 Dodge PU). This powers all my 3 phase motors in the shop. I was always curious about the wave forms of this "made" third phase. I understand some about how the third phase is generated in the extra windings of the idler motor by the changing magnetic fields of the two other windings. As I looked at this wave diagram they are not in perfect phase but the idler sure allows more work to be done by the 3 phase motor being operated this way. Idid expect them the b chopped up saw tooth wave forms.
My intro to Add-a phase operation was at a shared shop where there was a 3 phase motor on a mill, 1HP as I remember, and the other fellow bought a "phase converter". The mill was weak and spun up to speed slowly. Now ,this fellow was sometimes secetrative and "hid" the instructions to the Add-a-phase. I found them one day and as I read the small pamphlet is implied adding an idler might help the mill run better with an increase in power/work done. There was a 3600rpm 2 HP 3 phase motor laying around so I took it upon myself to wire it in the works. Old whistle britches  came in as this was being done and started to complain. I sugested he be quite and help me try something. We put an old wafer switch to work controling  the 220 to the Add-a-phase and then rewired the 2HP motor between the mill and AAF. As I turned the switch on the 3600 motor screamed like a banshee as it should running that fast. I then turned the milll on. It ran backwards! Confused I shut it down and began calling electrical pros. Voilla! Two wires were swapped and all was normal again. Now as for increasing power, I was sharpening end mills with a new to me grinder and thought this was the perfect time to test the newly sharpened mills and the power of the old Bridgeport. A 3/4" mill plunged down 3/4" into some mystery metal, probably A-36 plate , and it cut like a cheese. Happy camper,even old fuddy duddy was thrilled. I was building my shop at that time and asked about these Add-a-phase contraptions. Well, an old friend sold his to a fellow I knew and he was moving him operation to a new three phase wired building and no longer needed the 8-12 and the 10HP monster motor. I aquired it and as I was wiring my shop with the help of an experienced elec. helper (he could bend pipe pretty) we wired the lights and 220 around the shop. I then had him do one more run of EMT around the first girt on the building and every 15 feet or so added a "T" with a blank box. We then ran 3 green wires through the EMT and looped it throught the blank boxes. I then wired it to the BIG motor and the Add-a-phase. He is telling me the whole time that this is not going to work, I just kept stripping wire. As the moment came to test, he stood well clear of the building. I flipped the breaker for the 220 and the 10HP started to hum............I then shut it down and wired in my old camelback with the old style open frame motor to the 3 green wires and restarted the 10HP rotary converter. The DP ran like a Swiss watch and I put a sharpened 1 1/2' drill in it and drilled a hole in a trailer hitch that I had built. The old DP has a back gear and power downfeed too, so I just let it work and stood back. The pipe bender was shaking his head saying that this shouldn't work......
sometimes you just have to show 'em that book learning is good but sometimes there are other ways...........life is good on days like this.


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## randyc (Mar 23, 2015)

We want MORE, I love anecdotes like this one !


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## Alan Douglas (Mar 24, 2015)

Yes indeed, an idler motor will help balance the phases.

To get three-phase from single-phase, something has to store energy during the AC cycle and release it out of phase.  This can be a capacitor, or the magnetic field of an idler motor.



> I'm guessing that phase error is on the order of thirty degrees nominal and that the phase error is mostly responsible for the voltage difference, is that correct ?


Sounds reasonable.  Some of the voltage difference is also because the neutral point isn't the same.


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## Alittlerusty (May 17, 2015)

First post phase amatic rotary phase converter on my bridgeport purrs nicely , bought mine used on Craigslist for $250 and took about 10 mins to hookup just make sure to not hookup any electronics to the wild leg (generated leg)


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