3 phase converters

[trimguy]

I'm looking in to getting one for some equipment I got a while back, 14" table saw and a 20" planer. A little history, when I got in my house I rewired it, I have wired my shop, I have been doing wiring like this most of my life. Not as a job. I have never been around three phase power, so this is all new to me. The information I have found out says the converter needs to be rated twice the horsepower as the equipment. If it is oversized that won't be a problem, right? I am looking at an American Rotary AR-15 and a North American Phase Converter PL-15. How do amp load figure in to the horsepower equation? Does anyone have any experience with either one of these converters? If so, good bad indifferent, I would like to know before I invest this kind of money. I am open to other suggestions.Any dues and don'ts will also be appreciated.

[trimguy]

Here's a picture of the motor plates.

 

 

[muggs]

You can probably get away with a 10 hp converter but a 15 would be better. It will give your motors more power. Sizing a converter has to do with the starting torque required of the machine. The table saw is easy starting, but the planer is hard starting.

[scsmith42]

If you have some basic electrical skills and access to a good, used 15hp or larger electric motor, you can buy a kit for around $400 and build your own.

Be sure that your donor motor is rated for the current that you want to operate it on (typically 240).

For converters, higher rpm motors will handle more current inrush as opposed to low rpm motors.

American rotary is a respected brand; I'm not familiar with the other.

[Larry]

Call the manufacture and ask for their recommended size for your use.  The generated leg or wild leg comes off the idler motor hotter than the utility legs and at the same time sags a lot more under load.  Different ways and ideas on how to balance the legs. 

If sometime later you add a machine that needs more than your converter can provide, its fairly easy to add a second idler motor.  Another question you can ask.

I've seen a lot of shops where the rotary phase converter is pretty low tech.  A big 3-phase motor only, that is started by a rope pull or a kick of the boot.

At present in my shop I built a balanced phase rpc with a small breaker panel for the big machines.  Also have 3 VFD's on small machines mostly for the variable speed option and one static converter on a small metalworking bandsaw.

[YellowHammer]

You can build your own or "call da man."  I have been using American Rotary for years, they are excellent, maybe the best, and are warrantied for life.  They have very simple installation instructions, with good photos, and excellent covered floor mount system, excellent wire terminal blocks, and you'd want probably an ADX15 or larger because once you switch to 3 phase you'll never go back to single phase.  You would run a wire from your single phase panel to the converter, then from the converter (where it produces the "manufactured leg" to a 3 phase distribution panel that you then wire your woodworking tools to. Very easy.

Oversized is desirable in phase converters because of their lower conversion efficiency.  

You can get a remote start button for your workshop and put the phase converter where it doesn't take up usable space.  

As far as the basic equations:
1 hp = 746 W,
P (Watts) = I (amp) * Volts

[Al_Smith]

Generally speaking a converter will start about as large of a motor as what the converter is made from .In other words a 10 HP will start another 10 HP .However it will run up to 3 times that amount providing none of the others are larger than a 10 HP .
In simple terms a rotary converter is just a 3 phase motor using a start /run circuit .Once in rotational speed  it becomes an induction generator for the generated phase .
On starting the larger capacitor acts just like a start cap on a single phase motor .In run the smaller caps add enough capacitance to the manufactured leg to bring it into balance for the correct voltage because without same it will be below line voltage .Too small it will be below line and too much it will run higher than line .Rule of thump is 7.5 microfarad per HP .
If a person feels a larger unit is better go for it .It won't hurt a thing .
If a person wanted you can find directions of building a rotary on the internet which would be lot less expensive than buying one .I've lost track of how many I've built over the years . BTW there is nothing magical or black magic about these things,they've been around for decades .
I might add my shop has a 5 HP that runs at the present 6.5 HP .It has a large enough starting cap it will start all three motors plus the converter at the same time .These are 480 volt motors .> more 

[Al_Smith]

A lot of this stuff is dependent on how resourceful a person is .A little background on myself .I was a navy submarine sonar tech starting in 1967 until 1971  then after until 2018 when I retired an industrial electrician .So a little over 50 years .In that time I've amassed a huge amount of what basically was salvage more commonly labeled as junk . From that junk providing I can find it I've been able to brain storm a lot of things less commonly done or even thought about by most .  To me this stuff is simple which I realize to many it is not .By the same token I get befuddled with a computer .Different strokes for different folks they say .

[trimguy]

Thank you for all the replies. Electrical and electronics are kind of separate things, to me. I don't have any electrical motors that large, so I will probably just buy one. Another question, videos of wiring the converter up, show stranded wire. If I wire this up to a three phase panel box can I use standard Romex wire ( solid wire ) to my outlets ?

[Al_Smith]

If you have the correct size .

[Don P]

Beat the bushes with the recyclers and junk guys, I think I came home with 4, one was hooked to a blower for the cost of the gas to go get them. I let the magic blue smoke out of one figuring it out. Its probably best not to experiment beside the panel in the kitchen. Its run the sawmill blower for probably 20 years.

[YellowHammer]

Typically, as allowed by NEC code, the local electrical wire drops to the actual equipment is usually best if done with multi strand SOOW cord.  It is flexible, abrasion resistant, and not prone to machine vibration fatigue such as is solid Romex.  SOOW wire (pronounced ES-SO) is designed for this sort of thing, as shown in the link below and any electrical house or Lowes/Home Depot stocks it:

https://www.reynoldsonline.com/ASSETS/DOCUMENTS/ITEMS/EN/SOOW104_Spec.pdf  

It's normal procedure to run solid stranded Romex from your individual branch fused central distribution panel (fed by the phase converter) to a manual disconnect/saftey switch within easy reach of the tool you are powering.  This allows you to cut power instantly in case of an emergency simply by throwing the lever.  It also allows you to be certain there is an electrical disconnect/lockout anytime you work on the machine and gives you an easy transition point to go from Romex to SOOW cable.

https://www.grainger.com/product/55CH39?gclid=EAIaIQobChMI6pK_mYDb6wIVk-DICh3M2w5AEAQYAyABEgLIzPD_BwE&cm_mmc=PPC:+Google+PLA&ef_id=EAIaIQobChMI6pK_mYDb6wIVk-DICh3M2w5AEAQYAyABEgLIzPD_BwE:G:s&s_kwcid=AL!2966!3!281698275264!!!g!470148536790!&gucid=N:N:PS:Paid:GGL:CSM-2295:EUGDJC:20500731

A generous run of SOOW wire goes from the safety disconnect switch to the machine.  Make sure you are using the correct plug to the machine, if you use one.  Most machines of this type are directly wired to the SOOW cable and don't use a plug.  

It's always a good idea to follow the NEC codes, or even hire an electrician if in doubt.  If you work with American Rotary, they will help you out all you want.      

[Al_Smith]

At the risk of sounding like a snob I don't use Romex for anything except residential homes and that's only my own stuff as I refuse to do residential work .Over the years people some how had the idea because I am an electrician I loved to do this stuff for free or for pennys .Since I retired on purpose I let my city license expire that way I don't have to lie to them .Besides that I am retired .
Having said that mouthful thin wall conduit is not that expensive .It's relatively easy to bend .Of course you need a bender to do it .You could do it with plastic too but it takes a different method to bend it with heat .If you wanted to use thin wall info is on the net of how to bend it .It's not that difficult . 

[muggs]

Yea, what Al said, Romex is better suited for inside walls. If you don't want to learn bending emt. There is always flex.  

[trimguy]

Sorry I wasn't clear. My intentions are to run romex to a wall outlet with a twist lock and then the cord for the saw. The saw and planer cord are stranded , I just need matching ends for them. I hadn't thought about the conduit yet ( probably an extra trip to the store when I get started) so thanks . I will run conduit up into the attic to protect it. I don't want the equipment hard wired so I can roll up the cords out of the floor when not in use. Also to be able to move the equipment out of the way. Thanks for the help, American Rotary it is.

[Al_Smith]

I just might add to the conversation .Except for my own home built I never knew how people wired them up to use . I do know one person used a three phase sub panel but most used rubber cords .They all work .

[mrfu]

You can build your own or "call da man."  I have been using American Rotary for years, they are excellent, maybe the best, and are warrantied for life.  They have very simple installation instructions, with good photos, and excellent covered floor mount system, excellent wire terminal blocks, and you'd want probably an ADX15 or larger because once you switch to 3 phase you'll never go back to single phase.  You would run a wire from your single phase panel to the converter, then from the converter (where it produces the "manufactured leg" to a 3 phase distribution panel that you then wire your woodworking tools to. Very easy.

Oversized is desirable in phase converters because of their lower conversion efficiency.  

You can get a remote start button for your workshop and put the phase converter where it doesn't take up usable space.  

As far as the basic equations:
1 hp = 746 W,
P (Watts) = I (amp) * Volts

I second american rotary, they were really helpful and installing the convertor was super simple and only took two trips to the hardware store.(which is good).
It's been in place for around 15 years and just does what it supposed to
Tom

[Al_Smith]

I'm kind of at cross roads myself .On a home built bandsaw mill weather to  use a gasoline engine or  a better  choice  10 HP electric motor .The later would most likely  be the better choice because I have no intentions of hauling a mill all over northern Ohio to cut up a bunch of yard trees for nothing .Try as you might regarding power and cost of operation you cannot beat an electric motor .Besides that they always start .