3 Phase Electric question

[Dan Oelke]

So last weekend I went on a little trip and a few hunred pounds of stuff followed me home. Sorry, no pictures yet. I got a UniDrill - a radial arm drill press, but in a little bit different style than some I have seen. I also got a Jet 12" cabinet saw. The drill seems to be in great shape, but the saw has seen some hard work.

These are the first things I have bought that are 3 phase, and now I need to figure out how to power them. I have to re-wire the drill to be 230 instead of 480, but that isn't too hard as the wiring diagram is on the motor and the wires all labled.

My question comes down to - is there some standard for 3 phase electric and which color wire is which phase? I assume (is this correct?) that it is important to get the phases wired to the device in the right order. That is phase 1 goes to input 1, phase 2 to input 2 and phase 3 to input 3. Of course going 2-3-1 or 3-1-2 for the phases shouldn't be a difference as you are just going around in a circle, but 1-3-2 would be wrong.

Any hints as to where to get a phase converter in the Twin Cities area for a reasonable price? Or even where to scrounge a cheaper 3-phase motor and then I can purchase just the panel from someplace like Anderson Converters? I plan on going with a rotary converter not just a static one. At least that is the plan for now.

Thanks for any/all help and hints.

[Fred Ray]

Dan:
Know nothing about cheap sources for phase converters in your part of the country.Here's one link I found quickly http://www.phase-a-matic.com/RotaryDescription.htm Probably not too cheap. Google for rotary phase converters turns up several "build you own sites".

As for color code: 480v, three phase is most often colored brown, orange, yellow. Other voltages vary all over the place. For connections at the motor: simply connect per the motor nameplate for the voltage you have. Then "bump" the motor for a rotation check. If the motor turns correctly, you're done. If rotation is backwards, simply swap any two (but not all three of the phase connections and it'll turn the other way.

[Dev Emch]

Yes, there is. The short answer is check out NEC 310-12(c) for neutral and ground colors and NEC 384-3(e) for the use of an orange leg. I just pulled this out my 1996 NEC so you should check it with the current one. Mine is on site and I dont have it available right now.

O.K. Here is the scoop. Most of us will be using a Delta configuration which is often called a FOUR WIRE setup. The phases are labeled A, B and C. In a normal setup, you will use a meter to find the ONE leg that has the highest voltage from itself to neutral. For example, A-neutral, B-neutral and C-neutral. This is your ORANGE leg.

Now with a phase converter, things get twisted. The incomming service to your shop has an L1 and L2 line. Between these two you should measure about 220 to 245 volts depending on your utility. These are actually pass thru lines to your three phase system. So you can look at L1 and L2 as your first two phases. So if I measure my voltage between L1 to neutral or L2 to neutral, I will get about 110 to 120 or so volts depending on the utility. This makes sense. BUT HERE IS WHERE PHASE CONVERTER SYSTEMS DIFFER FROM NORMAL THREE PHASE IN A BIG WAY! The last phase which is generated by your phase converter is coupled to the first two phases to establish a phase shift of 120 degrees in all three legs. No worries here. But if I measure the voltage from the wild leg or manufactured leg to neutral, I will get the square root of 3 times 110 to 120 volts. So for me, I get 245 volts between L1 and L2. Thus, my wild leg to neutral voltage is about 208 volts.

So that means the orange wire should be connected to your wild leg or converter output leg because its higher.

The other two colors should be red and black but I dont remember where in the NEC if at all this is listed. I just know this from experience. So with normal 220 circuits, its customary to use Red and Black for the 220 lines. This carries over to the three phase. Only the wild leg gets special treatment with the ORANGE wire.

NOW THIS IS IMPORTANT! So we now have RED, BLACK and ORANGE for our three phase wires. If you hook these up as L1, L2 and L3, your off to a pretty good start. But one thing to make sure of. HOW are your control transformers and pull in coils wired? Most woodworking machines only have a pull in coil. More complex ones may have a control transformer. Usually, these are wired differentially so you would see about 220 volts across the input terminals. If you get one that is wired Phase to neutral, you need to to make sure its wired to either L1 or L2 and NEVER to L3 as this configuration can fry the coil. If you have say L1 and L2 connecting to your coil, your O.K. If its L1 to neutral or L2 to neutral, that would be a 110 volt coil and your O.K. If its L3 to neutral, you will be buying a new pull in coil. If its L2 to L3 or L1 to L3, you should be O.K. Make sure you understand this.

A control transformer steps down line voltage for use in controlling the machine. For example, if you have a 24 volt magnetic starter, a control transformer can drop the voltage from say 440 volts to 24 volts for the purpose of isolating the user from this high line voltage.

Now, once you turn on your machine, you *WILL* need to check the direction of rotation. Its very possible that your machine works great but its going the wrong direction! Should this happen, then you need to swap any two of the leads in your collection of three. BUT, you want to keep that wild leg away from any control gear that may be in the way! So even though there are no fixed rules for doing this, I would suggest you isolate this modification to swaping out the RED and BLACK wires. DONT touch the ORANGE. Try to do this inside your machine where the wires attach to the wire lugs going to the outside world. They are often labeled L1, L2 and L3.

The NEC is clear about using green and white/gray. GREEN is the universal ground and is often connected to the chasis ground. It is not needed to run a three phase machine. In fact, no neutral is needed to run a three phase machine. Once you have Red, Black and Orange good to go, you could punch the start button and the machine would run. But hook up the green wire first for safety. Cast iron is a lousy conductor; however, its good enough to fry your tail feathers!

The white or gray wire is a universal neutral. This is a single phase return path for current. IT completes the circuit when using only one power lead. Many woodworking machines have no such wire. Many others do. This line is used in conjunction with either the RED or BLACK wire to power up stuff like work lights or DROs, etc. Make darn sure your not running any ORANGE/WHITE circuits! If you do, you will replace the item at the end of this mistake.

So hopefully this explains a few items of note. I know it took me quite a while to unearth this info so your lucky to get it for free. Good Luck and Have At it.

[Dev Emch]

If anyone has found a reference in the NEC for the use of colors other than orange on three phase system, please pipe up with an NEC reference. I personally write the NEC references on the front page that pertain to this stuff. Currently, that is

NEC 310-12(c) and NEC 384-3(e).

If there are others that are super important, its nice to know about them. I would like to know if there are any new rules to the use of brown and yellow in lieu of red and black.

Thanks

[Rick Christopherson]

Since virtually all 3-phase motors are wired delta, you can completely disregard the whole discussion about an "orange" conductor. They are not 4-wire motors! They are 3-wire, with a ground. The motor doesn't care what the voltage between phase and neutral is, because it doesn't use the neutral. (And you cannot make a rotary converter operate with a neutral.)

You really don't need to worry about color coding the wires, but if you wish, the standard colors for lower voltage 3-phase are Red, Black, Blue, but there is no distinction in the sequence. The 480-volt colors are typically Orange, Yellow, Brown, but you don't need to worry about this since you will be changing the voltage.

As was mentioned in the first reply, after you build a converter, simply check the motor rotation. If it is backward, reverse any two wires.

If you Google for "phase converters" my article will come up as the first hit (oops, I see I got bumped from the top. I am #2 or #3 depending on the text.).

The best source for supplies is Ax-Man surplus on either University avenue or Highway 7 in St. Louis Park. They won't have your idler motor, but they will have the caps and other electrical stuff.

[Dev Emch]

Rick, have you ever had to go through an inspection? Based on your posts, I dont think so. I have. I have had to tear out a bunch of wire because it was **NOT** orange. We are outside the city limits and are under only the NEC codes.

I suggest you re-read NEC 310-12(c) and NEC 384-3(e) as well as *ALL* of NEC 455.

For the record, a FOUR WIRE system is one with L1, L2, L3 and Ground. The five wire system is something totally different. For phase conversion, I would stick with a FOUR WIRE system. This becomes an issue if your buying twist lock plugs such as the hubbles because there are both four wire and five wire versions. Know what your buying!

The recommended approach for certain applications that need single phase power to operate is not to use a leg to neutral connection. Instead, you may be better off using a step down control transformer. For example, if your shaper has an onboard DRO and you need 120 volts for this, use a 240/120 step down transformer. This was all done for me by Hofmann when they built my shaper.

My concern is that machines have been reworked using back yard engineering. Has this ever happened? Yes, it has. And I have a burned out control transformer to prove this. So now I always check to see if there is a leg to neutral connection anywhere in the electrics before I turn the machine over for the first time.

I also doubt that you can compete with my collection of three phase "toys". Your comments about all machines being wired delta is false. Martins are wired both ways. They are delta to start and then star to run. My oliver jointer is 440 volt delta only. My hofmann is identical to the martin and my porter is a star or Y.

And I dont recommend this one either but its here for illustration. When I first ran my oliver 299, I ran it on only 3 wires. No ground! No neutral! This one is wired as a star or Y.

As I had mentioned, the neutral does show up once in a while but its not for the motor! Let me repeat myself. Motors need no neutrals.

Everytime I post on this topic, you come to disagree. This is beginning to irritate me. For the rest of you, you have a choice. Either follow the NEC which stands for National Electrical Code or follow Rick's advice. But dont belly ache when you fail inspection or worse yet, when your shop burns down.

Do you remember the photo that was just posted.... Hmmmm, food for thought!

[Steve Clardy]

Two different opinions are good most of the time.
I don't see a need for irritation Dev.

[Dev Emch]

Steve...

Since when are building codes open to general debate as are opinions? I wish you could have explained this to my inspector. I asked several (single phase electrical contractors) electrical guys about which color scheme to use and the reply was that three phase is open to intrepretation as long as your consistent. O.K., sounds good to me. So having a bunch of 10 gage white THHN available, I used that for my wild leg. WRONG!!!!! Let me introduce you to NEC 384-3(e) *AND* NEC 310-12(c). By the way, it is now a current recommendation of the OWWM to follow NEC 384-3(e) and NEC 310-12(c) so its not just me or my inspector! Oh ya, anyone need a bunch of 10 gage THHN in white? Hardly used!

You are welcome to do what ever you wish. Heck, if your consistent, why not utilize green for your wild leg? As long as your consistent and the inspectors dont visit, you will be O.K. Motors are color blind as we all have learned so far. Just dont connect the first green wire to the second green wire. Or was that the second green wire to the first green wire. Heck, I forget. One is a converter wild leg and the other is my receptacle ground.

[Bill Simmeth]

Ouch. You didn't really run white for a hot leg, did you? Bet that made Mr Inspector's day!

While on the surface Rick's comments may have seemd a bit cavalier, I really don't think he was advocating the use of either white or green for hot legs, 3-phase or not. Their use is clearly delineated by the NEC and I think Rick knows the code quite well.

[Steve Stube]

An option I would suggest, especially for the drill press where variable speed can be desirable, is a variable frequency drive (VFD) to provide the 3 phase power you need from single phase. If you shop the on-line auction near the Bay you can probably get what you need for < $100.00 (assuming one HP motor or less).

[Dev Emch]

Yes Bill, I ran 10 gage white for the wild leg. Heck, everyone said it does not matter and I did not read the bible close enough until Mr. Muno pointed this out 1 week prior to inspection. By the way, if you hire an electrician to do this work, make sure you snag one with three phase experience! That was the only real mistake I made and I was consistent! Truth is, I should have known better. But I was used to working with massively heavier wires which do not have this color code system. A 10 gage wire is a toy for my background. Oh well, now I know ehhhh? Now everyone knows about this. Learn from my fubar!!!

On the topic of VFDs. The newer VFDs use a new switching scheme which can generate dangerous reflected waves. Many newer motors are designed to deal with these as VFDs are now an accepted method. Older motors as those found in old iron are not. So if your going to use a newer VFD with an older motor, try to use a RWF device as well. An RWF or Reflected Wave Filter removes these waves and makes it safe to run older motors. They are not at all expenisive either. Note that these reflected waves will not harm humans but can shorten your motor's life.

[Timo Christ]

Hello,
yes, do use an appropriate filter on the output of your VFD if you use a motor which isn't speced for VFD (all old motors). The VFD manufacturers sell appropriate filters. The filters must be sized according to the motor load. Long cable runs should be avoided, or fitted with a filter as well. VFDs can be EMI nightmares! Wrongly selected filters can lead to severe overvoltages and destroy motor and VFD.
However, a VFD doesn't only give you the possibility to use three phase motors but also a full feature set for motion control (speed, up and down ramps (braking)). It's also possible to boost the speed of a motor. In my opinion a much better choice than a rotary converter.
The older VFDs with full block control (simple switching pattern) have lower dv/dt due to slower switching devices and a lower switching frequency. The dv/dt is much higher than in a sinewave anyway and could also lead to insulation breakdown in old motors.

Regards,
Timo

[Rick Christopherson]

Dev, You are dangerous because you don't know electrical systems, but pretend too. You are even more dangerous because you don't realize that you don't know! This isn't a matter of one person's opinion over another. This is a matter of ignorance of electrical systems.

What boggles my mind is that you will stand here and argue electrical systems with a well known Electrical Engineer, yet you admit that you used white for a phase conductor. (And since you admitted to hiring an electrician, I also assume you aren't even a licensed electrician!!!) It is quite clear that you are self-taught in electrical systems, but you don't have the wherewithal to contradict those with a true knowledge of electricity.

If you think you are irritated, think how I feel; I have to clean up after you. Every time you go off on one of your diatribes, I get email asking what's going on.

What are your credentials? What is your education? Do you carry any certifications?

Stop writing as though you were an authority on electrical systems if your knowledge is limited to basement engineering!
========================
As for your other comments:

A four wire system is one which includes the neutral. Your own NEC reference supports this. If you had carefully read your own reference, you would have seen that NEC 384-3 was referring to a "grounded" conductor, not the "grounding" conductor. This is referring to a 4-wire delta system, which is NOT the same as a 3-wire Delta motor. A four wire system has three phases, Neutral, and Ground. A three wire (3-phase) system has three phases and ground. The naming convention of a system does not include the ground because it is always present.

(New Edit for Clarification: I wasn't arguing about the use of Orange for the stinger phase. I was stating that it isn't applicable to this situation because the Neutral is not used, and did nothing but cause confusion.)

Yes, I have gone through inspections. I have had inspections on multi-megawatt systems. My understanding of electrical systems is detailed enough that I have corrected many state inspectors on their interpretation of the NEC.

You stated, "But I was used to working with massively heavier wires which do not have this color code system."

This is a crock of s...t, and you know it! The larger the conductor, the more important color coding is.

Pay no attention to the man behind the curtain!

I am irritated because you pretend to be something you are NOT! You are not an electrician. You are not an electrical engineer. You are not an electrical expert in any shape or form!

You rehash what others say, and you mix up the details in the process.

[Mike Elo]

I have been in the electrical trade for a long time. I cringe every time these kinds of questions get asked. All I can add here is.... be careful when asking electrical questions on these kinds of sites. Very careful!
If Rick is who I think he is I would recommend everyone to read an article her wrote called Electricity in the workshop. If it's a different Rick than I apologize. But it's still a good article. I also enjoy it when the talk turns to Reflective wave. I worked with A.C. Drives for years and studied the Reflective wave phenomenon as much as I could and I found that few people including myself fully understand it. But it does sound cool. If someone even mentions Reflective wave on a wood working site I recommend you stop reading that post and move on. I guess my point to this is this......... The code book is not the bible or the law necassarily. The local inspector is the law and in most cases if one realy has an electrical question call the inspector, they have phones and they are the ones you have to satisfy. (and no, I am not one of them.) Other than that just be careful asking electrical questions on these types of sites.

I just hope they guy gets his new tools up and running regardles of the voltage.

[Rick Christopherson]

If Rick is who I think he is I would recommend everyone ......
Yes Mike, I am that Rick. I wrote Electricity in the Woodshop (http://waterfront-woods.home.att.net/Articles/Electricity/electricity.htm) and also Building a Phase Converter (http://waterfront-woods.home.att.net/Articles/phaseconverter.htm), which is the topic that started this discussion.

[John Renzetti]

Wow, the sparks (excuse the pun) are flying here. For a minute I thought my friend Paul Cresti had to be involved. :) Sorry Paul I couldn't resist.

From what I understand at least from wiring up my European three phase machines to 3ph power produced by a phase converter, was that the "blue" on the power cord of the machine was for neutral and that was for European 3ph only. Basically I just snip that wire and connect the three hot wires (I've seen 2 blacks and a brown), and of course the ground. I've measured the voltage output, and if I can remember this correctly L1-L2 was about 240, L3 to ground was about 272v. This would be the "high", "wild" "manufactued" or whatever you want to call it. All I know is I was told not to hook this leg up to the control circuits, so it goes on the brown wire on my machines.
It gets a little tricky with a VFD on a machine. I have one on my shaper and the VFD will sense this overvoltage and won't start. In this case I have a voltage regulator module on my Kay Phasemaster that brings this third leg down just temporarily to below 254v so the vfd won't sense an overvoltage.

In a nutshell it was pretty simple to hook the machines up to the phase converter output.
take care,
John

[Fred Ray]

I have been in the electrical trade for a long time. I cringe every time these kinds of questions get asked. All I can add here is.... be careful when asking electrical questions on these kinds of sites. Very careful!

...

I just hope they guy gets his new tools up and running regardles of the voltage.

Amen! Amen! and Amen!

This is exactly why I don't offer much electrical advice online, even with 30 plus years of industrial electrical engineering experience.

Dan: Find a local professional who can work directly with you and the specific equipment you have to provide a proper installation that meets the NEC and any additional local code requirements. I assure you this is the very best advice you'll ever get online about an electrical question.

BTW Article 384 in the 1996 NEC is now Article 408 in the 2005 NEC.

[Dan Oelke]

Wow - I posted this last night and didn't have a chance to get back until now. I knew that posting such a question might draw some "sparks" - but wasn't sure how much.

I am not a EE, but a Computer-Engineer - so I had enough classes and real life experience that I feel comfortable with the topic area, but lack experience with 3-phase in specific. I am comfortable that I won't be killing myself or burning the shop down so that is what matters.

Thanks much for everyone's help! Reading the discussion I seem some of the phrases that have led to disagreements - especially what a "four" wire system is. Different definitions of terms is almost always at the root of mis-understandings. People say the same words, but attach different meanings to them.

I am torn between building and buying a 3 phase converter. I have figured out that I want a rotary converter over a static. I have talked to one local place that can build me a 7.5HP for $600-700. That seems awfully steep as I can buy a panel from Anderson converters for $200 and then find a 3-phase motor. I have seen that size 3-phase recently on auction for <$50.

I could of course build the whole thing using instructions like Rick's - but I don't know how much time I want to sink into this. And I would need to find a 7.5HP 3-phase motor - not sure if I'll see another auction like that in the next couple of months. (and at the time that was I was telling myself I was not going to buy any 3-phase equipment for a long long time..... yeah right......)

Any hints for finding cheap 3-phase motors? (gee - it is a lot of time, but deep down I really am a tightwad)

[Steve Clardy]

http://www.surpluscenter.com/electric.asp?UID=2005110915394836&catname=electric

[Steve Stube]

John Renzetti
It gets a little tricky with a VFD on a machine. I have one on my shaper and the VFD will sense this overvoltage and won't start.

Do I understand correctly that you are feeding a VFD (variable frequency drive) with rotary phase converter three phase power? Why?

[John Renzetti]

John Renzetti
Do I understand correctly that you are feeding a VFD (variable frequency drive) with rotary phase converter three phase power? Why?

hi Steve, This is for speed control on the shaper spindle. Depending on the placement of the belt on the motor pulley and spindle I can get from about 1000 to 10k rpm with the shaper spindle and up to 20k using the separate router spindle. The motor itself is 7.5hp 3hp. I did the same thing with my horizontal boring machine. The motor is three phase with 3k rpm. I added a vfd and now can control the speed from about 500 to 4500.
A lot of vfd's can have either 1ph or 3ph input to power the 3ph motor.
take care,
John

[Steve Stube]

John I'm familiar with the merits of VFD's (I have 9 of them in my shop) I just never heard of running one off the generated (dirty) 3 phase from a rotary converter when there is a clean single phase source available. A 15 HP, derated for single phase input, would be the way I would do it. I'll chaulk it up to still another example of the forgiving nature of these if you confirm again that the VFD is running (powered by) the rotary phase converter. TIA.

[John Renzetti]

John I'm familiar with the merits of VFD's (I have 9 of them in my shop) I just never heard of running one off the generated (dirty) 3 phase from a rotary converter when there is a clean single phase source available. A 15 HP, derated for single phase input, would be the way I would do it. I'll chaulk it up to still another example of the forgiving nature of these if you confirm again that the VFD is running (powered by) the rotary phase converter. TIA.

Hi Steve, Yes the power going to power the vfd is from phase converter generated 3ph power. I use Kay Phasemasters. I don't consider this "dirty" power. Works pretty clean to me.
take care
John

[Steve Stube]

Dirty - maybe noisy signal would be a more appropriate term but I've picked up "dirty" (slang) to be all inclusive for fluctuating amplitude, sound, vibration and phase shifting. I mean even Kay says, "it is not possible to eliminate all sound and vibration but the Phasemaster is as good as it gets." and appearantly it works for you. Thank you, Steve

[Jim Becker]

John, wouldn't that be a "normal" setup for the Felder gear?

[Dev Emch]

Rick...

You are clearly a fake. Folks, if you use any of his information, please please double check it with a real engineer. I am not selling a some cheap advice on making converters.

First of all, I am a professionaly trained and certified electrical engineer. How about University of Colorado, Boulder for starts. I am also an Aerospace Engineer and its my work in this field that got me into elelctrical engineering. My two areas power and computer engineering. And I dont mean web software for windows... real time embeded hardware and software design.

Yes, I used white because I had/have 1/2 pallet of 10 gage spools of this stuff! An auction find. Not one or two rolls, a HALF PALLET of 500 foot spools!

And for what its worth, its guys like you that I have to clean up after. This is esp. true when it comes to getting martins, hofmanns and olivers running on these hokey home made converters you guys keep selling. Do us all a favor and copy the Kay designs.

And for whats its worth, I have had to debug no less than 6 application installations in the year of 2005. Most of these had to do with planers and jointers of substance and one was a martin T-26 which is a different issue. Most of the problems were the same old story. And your name came up more than once by the way.

I have studied your website and there is quite a bit of good info but unless the reader is ALSO an engineer, it is doubtful that he/she can filter out the chaff from the meat and pototoes. Then come the blown fuses and fried stator windings and then the emails to me. I am tired of helping folks here. On one end of the fence, I am glad to help folks get over the barrier of entry to using wonderful machines like olivers but at the same time, I am sick and tired of having to unravel the errors that you and many of the converter folks are pushing in the field.

SO YES, I AM AN ELECTRICAL ENGINEER IN POWER AND A NUMBER OF THINGS YOU HAVE WRITTEN ARE EITHER CAVILIER OR SIMPLY NEGLIGENT. I SINCERELY HOPE NONE OF YOUR WORK MAKES THE HISTORY CHANNEL ON "ENGINEERING DISASTERS".

[John Renzetti]

John, wouldn't that be a "normal" setup for the Felder gear?

hi Jim, They have a single phase input vfd that drives the .5.5hp 3ph motor or motors. They derate the motor to 5hp because the input is 1ph. On my shaper the motor is 7.5hp 3ph and they offer a bigger vfd to handle this and also not require the motor to be derated with the 3ph input.
As Steve mentions to get the motor to run on 1ph input you'd need a much larger vfd something that could handle say 15hp and derate it because of the 1ph input. As somebody explained it to me in very non techinical terms, with 1ph input you have two wires feeding three wires so the juice gets diluted. Not a very elegant explanation but it works for me.
take care,
John