Talk:Three-phase electric power/Archive 1

First Post
(added header)--Canoe1967 (talk) 21:39, 18 December 2012 (UTC)

While this article talks about star arrangements for electrical machinery, it does not discuss Delta arrangements, which do not require a neutal connection, because there isn't one available. Also, the function of Earthing is not discussed. - kiwiinapanic 11:28 Feb 9, 2003 (UTC)
 * You do not need a neutral connection to run in a Star configuration (e.g. in a motor), all current in one phase will return via the two other. If in a 400V TN-configuration you will need the neutral to extact 230V between one phase and neutral for normal appliances. KjellG visitor from no.wiki.

I believe Europe now uses 230 VAC supply (the average of UK's 240 VAC and continent's 220 VAC). - anon 24-May-2003
 * sort of the official standard is now 230V BUT it has such a wide tollerance band that both 220 and 240 are well within spec

This page is still riddled with errors. UninvitedCompany 12:32, 6 Oct 2003 (UTC)

Rotating field illustration
The rotating motor looks fine, but what does it illustrate? Beeing an engineer in electronics with some credits in electric machinery: this is different from anything I have ever seen. Can anyone explain this illustration? KjellG visitor from no.wiki


 * Agreed. This diagram seems to illustrate the summation of the three phases, each represented as vectors, as their magnitude changes.  While this ultimately results in a point which moves on a circular locus, it is neither indicative of what is happening electrically within the motor, nor does it give a useful way of understanding how the magnetic field rotates.  Trouble is, as an electrical engineer myself (like KjellG), I can't say I have a better solution for a graphical representation.  MDM visitor.

Question: Does the illustration indicate CW or CCW rotation, and based on which end of the motor? I sold motors for years and years, (G.E.) and it was my understanding that three phase motors are factory wound for CW rotation looking at the shaft end of the motor, and wired L1 L2 L3. To reverse exchange any two leads. Scott P - Washington —Preceding unsigned comment added by 67.185.55.200 (talk) 02:20, 3 March 2010 (UTC)

"two-phase" power in U.S./Canada is not quite right
"Two-phase" power in U.S./Canada is not quite right. Electrical grounding/earthing is "center tap", meaning that each small group of homes has a 240V transformer, with ground/earth tied to the middle. This makes the two opposite 120V sides exactly 180&deg; apart, making them in-phase, and therefore considered single phase by most electrical engineers. Many appliances, including the central (forced-air) heating unit in my apartment, can operate anywhere from 208V to 240V, but the BTU/kW power and heating capacity ratings change correspondingly. Only resistive loads ignore phase like this though, whereas inductive loads like AC motors must have the phase[s] they were designed for. Larger commercial buildings almost always have three-phase, and sometimes do use true 208V two-phase for certain things, such as ballast for fluorescent lights. –radiojon 05:41, 2004 Feb 16 (UTC)
 * Connecting a ballast between A and C of a three-phase system does not make it a "two phase" load, it's a single-phase load connected line-to-line. And just to further confuse the issue, you can run a three-phase motor on single-phase power, though it will need help to get started and you usually don't plan to do this delibrately. --Wtshymanski 23:10, 16 Dec 2004 (UTC)
 * ERROR! You can run an asyncronus (Or syncronus motor) on singlephase, After it is started!and if it is provided with a single-phase winding. BUT if yoou try to connect a three-phase motor to single phase you will usually blow a fuse since the current will bi wery high. Disconnecting one pnase will in practice mean that you try to run a three-phase motor on one phase and results in far to high current and will burn the motor, that is teh reason for the normal special three-phase breaker with thermoelements that will disconnect all three phases if one is lost (And also if the motor is braked to much).
 * Small refrigerators and fan motors can be run on one-phase motors if equipped with a starting phase, usually generated with a electreic condensor in series with the second phase winding, usually connected with a high current relay when starting and disconnected when motor is started and current is dropping. Electric syncronous clocks use a permanent second phase obtained with a shortcircuit winding on part of the stator pole, they are somewat inefficient put cheep and durable.Seniorsag (talk) 13:58, 30 January 2012 (UTC)


 * You're right. While there was at one time a fair amount of two-phase power in the U.S. (four wire service; two pairs 90 degrees out of phase), this hasn't been the case for decades.  The two-phase systems had the advantage that the windings are the same for a capacitor-start single phase motor and a two-phase motor; that is, they are 90 degrees apart.  Three phase service can be derived from two phase and vice versa using transformers.


 * The article is a mess right now because, as with the other electrical topics, there is so much difference in practices around the world that it is hard to make an integrated article, particularly since there aren't any contributors who have more than passing familiarity with practices outside their own country. UninvitedCompany 20:00, 17 Feb 2004 (UTC)

Three phase systems have a very nice property, that if they are loaded by a linear load, the amount of power transferred is constant, it does not have a 50 or 60Hz ripple. This means that three-phase motors and generators do not have the vibrations associated with one or two phase motors.

I believe this is the reason for the popularity of the three phase system, as it allows enormous amounts of power to be generated using relatively light machines. If there were a ripple in the power, the machines would need to be very heavy to not be blown to bits by the it.

Would this be interesting information to put on this page?

Evert van de Waal
 * This is now worked out in some detail in the three phase article. --Wtshymanski 04:16, 31 Dec 2004 (UTC)

And, as as layman, someone explained 3-phase to me and commented that different houses in a street (or streets in a town) would be on different phases, whilst at the generating station 3-phase generation was most efficient. I found that very significant way to appreciating how I'd never known about it before - yet it was a ubiquitous feature. Would someone with a good understanding like to insert a short explanation of that feature. 134.244.154.182
 * Practices vary, and I'm speaking from a North American viewpoint, but often a branch feeder from a substation will be three phases but individual homes are only single-phase loads. I suppose you could dedicate a street per phase, but I'd expect to see that only in rural areas - in more densely populated places I've seen a three-phase feeder down the street and houses connected A,B,C...on either side. --Wtshymanski 23:10, 16 Dec 2004 (UTC)

High Leg
The voltage difference between the phases and neutral is different in the US, the article mentions a "high leg". Can someone who understands the subject explain this a little further? I know that in Europe the voltage between all three phases and neutral is the same. Is there also a "high leg" in countries other than the US? 24.77.134.211 (talk) 02:50, 25 February 2008 (UTC)

phase sequence
from one of the images on your page Triplex outlet. The top 3 are used to run a phase sequence indicator comprised of 3 neon night lights. The bottom three run the desired triplex load. May i ask how exactly can neon lights indicate phase seqence? Plugwash 21:44, 26 Sep 2004 (UTC)

Beats me. You can interconnect lamps, capacitors and inductors to build a phase secquence indicator but that's not what the photo shows. I've never heard of or seen anyone attempt to supply a three-phase load with three regular duplex plugs - three-phase gear always has ONE plug with all phases in it. The photo is misleading because it shows a practice that is at the very best dubious and is almost certainly against any electrical code!

The most important thing about three-phase power is not the colo(u)r of the wires - this needs reorganization. All the stuff about testing is a bit too much "how-to manual", I think, for an encyclopedia...the article on heart I'm sure doesn't tell you how to start cutting for a transplant.

An article on the differences between UK and North American terms for electrical terms might make a good short Wiki project.

And on another matter: Anyone feeling up to explaining phasors and symmetrical components? Or higher phase order systems? --Wtshymanski 23:10, 16 Dec 2004 (UTC)
 * The more I look at the "triplexing" part of the article, the less I like it. I've never heard of such a scheme being used (three separate receptacles being used to power a single three-phase load - too error-prone to ever exist outside, perhaps, a laboratory situation). I'd like to remove that illustration as soon as I can get some proper images of real three-phase outlets. --Wtshymanski 04:16, 31 Dec 2004 (UTC)


 * there's a couple of images over at Industrial & multiphase power plugs & sockets e.g. the one to the right of this comment. or I intend to upload a 3P+N+E image soon.--Ali@gwc.org.uk 08:27, 31 Dec 2004 (UTC)
 * I can see how such an outlet arrangement could be usefull for lighting and i can see uses in a laboratoty situation but not for general perpose equipment supplies.
 * It is gone now. There is copy of the same in the Industrial & multiphase power plugs & sockets article, don't need two. Meggar 2005 June 29 03:00 (UTC)

splitting
This article is rather large anyway and it has almost noting on the mathematics of 3 phase.

I suggest a 3 way split three-phase: about the basic mathematics behind 3 phase three-phase electric power: about how and where 3 phase is used (ie most of what is here now) three-phase testing: basically what is now the testing section. This may be better located in a wikibook than here though i have little idea of the structure of wikibooks myself. Plugwash

ok no objections im going ahead Plugwash 21:36, 18 Dec 2004 (UTC)

ok well i've done it there is probablly still some content here that belongs on three-phase and there is a fair bit of three-phase that still needs writing. I've moved the color code information into a table beside the TOC expanded the intro section and altered the image so it fits beside the intro section. Plugwash 10:05, 20 Dec 2004 (UTC)

A good start but the article still rambles. "What's a neutral?" the reader will ask, or "Why are domestic loads single phase?" We need some a couple of simple diagrams to show the three voltage waveforms, and what we mean by "wye" and "delta" and "split phase". Something to work on during the holidays, I expect. --Wtshymanski 17:48, 20 Dec 2004 (UTC)

more two phase
"Two phase Like three phase, gives constant power transfer to a linear load." From my calcs this is not the case - can anyone confirm? --Ali@gwc.org.uk 23:48, 9 Jan 2005 (UTC)
 * Quick and dirty - call the phases sin(theta) and cos(theta), sin^2(theta)+cos^2(theta) = 1 for all theta, and power flow is proportional to the square of the voltage. So, two phases, 90 degrees apart in time, will also have a constant power transfer. --Wtshymanski 02:54, 10 Jan 2005 (UTC)

Rotary converter
The Wiki article rotary converter describes a completely different machine than the rotary phase converter used to make a 3-phase supply from single-phase power. This link is a little misleading. --Wtshymanski 01:52, 2 Jun 2005 (UTC)


 * It is written principally from the point-of-view of a traction engineer trying to convert three-phase AC power to direct current. But the rotary converter concept is fully-general; if you reversed the machine, it would create three-phase AC from DC. A similarly-constructed machine can convert single-phase AC to three-phase or vide-versa.


 * But you know what to do: be bold!! Please feel free to expand the rotary converter article as you see fit.


 * Atlant 11:50, 2 Jun 2005 (UTC)3fff

Modern technology overloading neutrals
Plugwash asks:


 * I've heared that this kind of thing is more of a problem in the usa due to lack of power factor correction cuircuitry. is this true?

I'm no expert but there's no doubt that modern switching power supplies seriously undermine the existing assumptions about how much current neutrals end up carrying in three-phase systems. As you doubtless realize, in the past, with passive loads (incandescent lighting, motor loads, and the like), the neutral only carried imbalance current and never more than the load of a single phase. The situation gets a bit worse with funny loads like fluorescent lamps and high-intensity discharge lamps. But now, with crappy switch-mode power supplies drawing huge current pulses but only at the peak of the sine wave (when the other phases are near zero volts), it's possible for the neutral to carry almost 3X the RMS current load of any phase wire!

One change that has definitely been made is that I think it has now become far less common to see "half neutrals" and such. Another change is that you guys over in the EU are starting to mandate power-factor correction on a lot more power supplies (although I don't think we're seeing as much of this in the US yet, but I'm sure it'll come along eventually).

I'm sure others know much more about this than I do.

Atlant 23:38, 3 Jun 2005 (UTC)
 * afaict half neutrals aren't allowed here in the uk anymore (i think they used to be but i'm not sure when they were phased out). I also belive that modern switched mode power supplies over here have correction cuircuitry to deal with this peak issue. However before we can add this to the article we need more solid information/sources. Can anyone here provide them? Plugwash 01:36, 4 Jun 2005 (UTC)

Regional bias?
Where the stepdown is 3 phase, the output of this transformer is ususally star connected with the standard mains voltage (120 V (in north america) or 230 V (in Europe)) being the phase-neutral voltage.

Someone embedded the following question in an HTML comment:
 * this comment shows rather a lot of national bias mentioning only north america and europe how best to deal with it?

-- Beland 01:57, 19 Jun 2005 (UTC)


 * Link to a list of systems, or place the list somewhere in this article. Crowding functional explanations with complete lists of examples isn't helpful. --Ikar.us 20:04:52, 2005-07-22 (UTC)

Confusing phrases

 * the output of this transformer is ususally star connected with the standard mains voltage

Can someone explain "star connected" with a sentence or two or a link to an appropriate article?


 * Another system commonly seen in the USA is to have a delta connected secondry with a centre tap on one of the windings supplying the ground and neutral.

Ditto for "delta connected secondry with a centre tap".


 * This allows for 240V three phase as well as 3 different single phase voltages (120V between two of the phases and the neutral, 208V between the third phase (known as a wild leg) and neutral and 240V between any two phases to be made availible from the same supply.

It's not clear why the third phase is 208V off from the neutral, or where the second 240V figure comes from, exactly. -- Beland 02:04, 19 Jun 2005 (UTC)


 * lemme think about this i think some diagrams may be needed of what star and delta are. it may be better to put them on the 3 phase page though as this one is already rather big. Plugwash 02:35, 19 Jun 2005 (UTC)


 * Hm, right now, there are no articles like Delta connection, Star connection... I only found Y-delta transform. As delta and star connections are a crucial part in phase systems, I would say there should be seperate articles for both. --Abdull 09:34, 22 July 2005 (UTC)

Never heard of that one
'''Three phase systems may or may not have a neutral wire. A neutral wire allows the three phase system to use a higher voltage while still supporting lower voltage single phase appliances.''' (from the introduction).

How does a neutral wire allow to use higher voltages on the phases? Thanks, --Abdull 08:51, 22 July 2005 (UTC)


 * If it is necessary to provide a specific one-phase voltage, then it is necessary to have this as the delta voltage, if there is no neutral wire. If the neutral wire is present, the voltage level can be chosen higher, so that the required voltage appears between phase and neutral. For example, in Austria existed 220/127V systems together with 380/220V, the latter need a neutral to supply 220V.
 * However, allowing a higher voltage is not the basic purpose of the neutral and may be confusing. --Ikar.us 10:47:58, 2005-07-22 (UTC)


 * thank you very much for that piece of information. Actually, what do you mean with the slash in 220/127V, or 380/220V? Thanks, --Abdull 11:45, 22 July 2005 (UTC)


 * The first number ist the delta voltage, i.e. the voltage between two phases. The second number is the star voltage, i.e. the voltage between each phase and the neutral (the first devided by sqrt(3)). --Ikar.us 11:59:48, 2005-07-22 (UTC)


 * so what is the main reason for chosing a 4 wire system with neutral and loads connected star over a 3 wire system with no neutral and the loads connected delta? higher voltage is the main one i can think of Plugwash 13:18, 22 July 2005 (UTC)


 * In a 4 wire system, you can connect incandescent lamps single-phase to neutral, and motor loads as three phases - for example, 120 V lamps and 208V motors for A/C ( in North America) or 240 V lamps and 415 V motors ( 240 volt countries). The advantage is that you don't need two systems at different voltages for lighting and power loads.  I remember being troubled by the single-line diagrams for station service power of the Owen Falls Dam generating station extension till I realized...no lighting transformers!  Lighting loads and motor loads all came from the same motor control center. In Canada, if you have a 600 V 4 wire 3 phase system, you can buy HID ballasts rated 347 V and they have a warranty, whereas 600 V ballasts aren't warranted by the manufacturers. --Wtshymanski 15:57, 22 July 2005 (UTC)


 * [adding my already written answer before reading Wtshmyanski's one]
 * One simple advantage: A one-phase circuit needs just one fuse in the phase. If it is delta-connected, it needs two fuses. In the case of real fuses (instead of circuit breakers), it is problematic that they aen't coupled.
 * Concerning power capacity, a 3-phase device can consume three times the power of a one-phase device, with same voltage and ampere rated components and lines. In delta-always-settings, the factor is only sqrt(3). So the same voltage level can accomodate a wider range of application needs.
 * Note that the four wire system doesn't mean that really all four wires have to be present (which would somewhat countervail the capacity gain). If the device consumes equal currents in all 3 phases, the neutral wire doesn't have to be present at all. The phase components can be star connected with open star point. If the currents aren't equal and the neutral wire is present, the sum of the 4 currents never exceeds 3 times the maximum current in one. This allows thrifty dimensioning of the lines.
 * --Ikar.us 16:19:29, 2005-07-22 (UTC)

constant power
I thought about the following statement from the article: '''Three phase has properties that make it very desirable in distribution. Firstly all three wires carry the same current. Secondly power transfer into a linear balanced load is constant.'''

the power transfer statement was some sort of odd to me, until i came up with the following:

We have three phases

$$i_1(t)= \hat i \cos (\omega t)$$

$$i_2(t)= \hat i \cos (\omega t + 120^\circ)$$

$$i_3(t)= \hat i \cos (\omega t + 240^\circ)$$

Imagine a powerline system with star connection. We have a (nearly) evenly distributed resistance on all three phases, that is:

$$R_1 = R_2 = R_3 = R$$

Imagine a big city with thousands of households all having random electrical machines at random phases in use, so in general you can think of three resistances of nearly the same size with negligible aberration among them.

Now, if we want to take a look at the time behavior of electrical power within the three phase system, we would say:

$$p(t) = u(t) \cdot i(t) = R \cdot i^2(t) = R (i_1^2(t) + i_2^2(t) + i_3^2(t))$$

$$p(t) = R \cdot \hat i^2 (\cos ^2(\omega t) + \cos ^2(\omega t + 120^\circ) + \cos ^2(\omega t + 240^\circ) )$$

With the help from trigonometric identities (that is power-reduction formulas), we will have:

$$p(t) = R \cdot \hat i^2 ({1 + \cos(2 \omega t) \over 2} + {1 + \cos(2 \omega t + 240^\circ) \over 2} + {1 + \cos(2 \omega t + 480^\circ) \over 2})$$

480° equals 120°.

Next, we can use Angle sum and difference identities:

$$p(t) = R \cdot \hat i^2 \bigg({3 + \cos(2 \omega t) + \cos(2 \omega t) \cos(240^\circ) - \sin(2 \omega t) \sin(240^\circ) + \cos(2 \omega t) \cos(120^\circ) - \sin(2 \omega t) \sin(120^\circ) \over 2}\bigg)$$

Sorting it all, we will have: $$p(t) = R \cdot \hat i^2 \bigg({3 + \cos(2 \omega t)\Big(1 + \cos(240^\circ) + \cos(120^\circ)\Big) + \sin(2 \omega t) \Big(\sin(240^\circ) + \sin(120^\circ)\Big) \over 2}\bigg) $$

Actually, $$ \Big(1 + \cos(240^\circ) + \cos(120^\circ)\Big) = 0 $$ and $$\Big(\sin(240^\circ) + \sin(120^\circ)\Big) = 0 $$, so we end up with:

$$p(t) = R \cdot \hat i^2 \Big( {3 \over 2} \Big) = {3 R \hat i^2 \over 2}$$

Although we started to look at the behavior of the electrical power over the time, we finally ended up to find out that in a three phase system, power is time-invariant, constant - which is good for a power plant (isn't it?).

I hope I didn't make a mistake. In my eyes, the article is missing some formulas, and if someone wants to give the above calculation a final touch, go ahead, it'll be great to put it in the article. --Abdull 14:25, 23 July 2005 (UTC)


 * That means time-invariant within one period? Perhaps this should be stated more clearly, also in the already existing sentence. Readers could wonder how three-phase power can influence how loads are switched on and off. --Ikar.us 08:59:27, 2005-08-02 (UTC)


 * Hi Ikarus - once again, take a look at the last expression:


 * $$p(t) = R \cdot \hat i^2 \Big( {3 \over 2} \Big) = {3 R \hat i^2 \over 2}$$


 * the t in p(t) can be 5 seconds, 12 seconds... any point of time. It turns out there is no "t" in the expression on the right side, therefore p(t) is constant at any point of time. It is time-invariant within one period, so to speak. --Abdull 12:10, 2 August 2005 (UTC)


 * It is time invariant provided the load stays the same. obviously if devices are turned on and off that will affect the power flow but there is no constant oscillation like there is with single phase transmission. Plugwash 01:24, 1 April 2006 (UTC)

Phase converters
I started a Rotary phase converter article that discusses rotary phase converters in general. I changed te link in the phase convertser section of this article to opint to that new page. The previously referenced page discusses rotary converters in general and made little relation to phase conversion (making of third phase). I hope that this change is acceptable and would like to ask for contribution to the Rotary phase converter article.

Thanks! Ichudov 19:41, 12 January 2006 (UTC)

User:65.184.166.57 added something about energy storage being required for phase converter operation. I think the revision by User:Atlant improved what the previous editor was apparently trying to say, but I don't think the original addition is correct. I think that energy storage is needed to produce a phase shift and is unrelated to the discontinuous vs. continuous power flow. --C J Cowie 15:15, 18 January 2006 (UTC)


 * ''I think that energy storage is needed to produce a phase shift and is unrelated to the discontinuous vs. continuous power flow.


 * Well, both, actually, they're sort of two sides of the same coin. If you think about a hypothetical single- to three-phase converter without any energy storage (imagine just three voltage converters that could instantaneously convert X volts in to Y volts out), then during the zero-crossings of the single-phase input waveform, the voltage converters would have no input voltage to convert to the three phase outputs! So a converter must store energy to continue outputing voltage during the zero crossings of the input waveform.


 * Another way to look at this is to say that the input single-phase waveform is time-shifted (~phase-shifted) to form the three output phases. But the time shifting process is just another cloak for energy storage.


 * Atlant 17:40, 18 January 2006 (UTC)

Single Phase to Three Phase (offtopic)
I want to convert single phase to in 'three phase', any one have solution about this matter?


 * I think the article discusses this (otherwise, one of our articles does; Google with "three phase site:en.wikipedia.org". But the usual solution today is an electronic converter. In t he old days, a motor-generator set or rotary converter was used.


 * Just curious: what application are you supporting that needs three-phase power? Usually, the serious applications are too big to conveniently power from a single-phase supply.


 * Atlant 12:55, 11 February 2006 (UTC)


 * The rotary phase converter article describes a relatively inexpensive "do-it-yourself" method. This method is often used by metal working hobbyists and others who buy used machine tools with three-phase motors. To operate a single three-phase motor you might consider using a Variable Frequency Drive. Newer small models accept either single-phase or three-phase input power and produce three-phase output power with provisions to change the frequency to adjust the speed of a three-phase motor. Some models even have a voltage multiplier circuit to accept 120 volt single-phase input power and operate a 240 volt, three-phase motor. Some older models that might be found on eBay will accept single-phase input power and operate reliably with a load current that is about half the normal rating. If you download the instruction manual before buying, you can determine the capability in advance. --C J Cowie 15:12, 11 February 2006 (UTC)

Color Codes
Are the color codes for North America correct? I thought L1=Black, L2=Red, and L3=Blue The page is currently showing L1=Red, L2=Black, and L3=Blue.


 * That's how they were, but 70.65.132.11 changed them (see here). Any reference(s) for the correct colours? --Evan C (Talk) 01:03, 1 April 2006 (UTC)
 * Canadian code rules don't give different color codes for different voltage classes. Isolated 3-phase circuits use orange, brown, yellow for A/B/C phases ( rule 24-208 (c).  Non-isolated systems (referenced to ground) use red, black, blue (A/B/C) (rule 4-036(3)(c)). --Wtshymanski 16:40, 22 March 2007 (UTC)
 * Why did you remove the 208V from "Connecting phase-to-phase"? I think it's a helpful reminder to let people know what we're talking about, at least in the US (and it said "US"). More generally, I think it's helpful to include the voltages as a reminder and a convenience to the user... Also, it seems silly that US is listed as B/O/Y and Canada as O/B/Y. Presumably in neither case is the order significant, but it seems weird for them not to be consistent? jhawkinson 16:45, 22 March 2007 (UTC)
 * I can't find my office copy of the US NEC so I can't correct the US color codes (if they have in fact been vandalized) It's NEC article 517.160, if anyone as a US code handy. (Just checking at http://www.iaei.org/subscriber/magazine/02_f/johnston.htm amd that gives O/B/Y.) This illustrates the problem with Wikipedia - nobody gives references! I took out "208 V" because it was wrong - the single-phase voltage is NOT 208 V in the US and not 400 V in Europe. The sentence reads better without all the numbers, and the whole point is beaten to death earlier in the article. Besides, there's also 347/600, 277/480, 14400/24940, etc. - why stop enumerating at just two cases? --Wtshymanski 17:13, 22 March 2007 (UTC)
 * Sorry, I meant to come back to this last week and it slipped my mind. 517.160(5) indeed says, "The isolated circuit conductors shall be identified as follows: (1) Isolated Conductor No. 1 — Orange; (2) Isolated Conductor No. 2 — Brown; For 3-phase systems, the third conductor shall be identified as yellow." But article 517 is "Health Care Facilities" -- isn't this a bit too specialized? I don't think the NEC mandates the specific colors used in the US (this based on searching my PDF full-text of it). It does mandate that the high-leg conductor shall be orange in delta system (110.15, 230.56). But it doesn't specify Black/Red/Blue or Orange/Brown/White at all &mdash; I assume that is convention? Actually, I guess there's one more bit: 408.3(E) (bus-bar phase arrangement) requires the B phase (in the middle) to be the high-leg, and thus orange. So that permits B/O/Y or Y/O/B but not O/B/Y. Is there any reason to associate the isolated conductor numbers with position? 517.160 goes on to indicate that orange must be the grounded conductor.
 * In 240V delta systems I have typically seen Black, Orange, Red, with Orange on the high leg to meet NEC. I've never worked on grounded 480 delta systems so I have no idea what the colors are there.
 * Should there be a mention of the requirement to identify neutrals? Often the neutral on 480V is gray to distinguish it from the 208Y120 neutral.17:24, 29 July 2007 (UTC)
 * In re 208V, I guess the problem is ambiguity. The text was "Connecting between two phases provides √3 or 173% of the single-phase voltage (208 VAC in US; 400 VAC in Europe)"; it is not saying that the single-phase voltage is 208V, it's saying that 173% of single-phase is 208V. In my view, it's important to include the number 208V several times in there, because it doesn't tend to be ingrained-in-the-brain for non-practitioners, and it really helps in understanding and giving examples to aid in learning. Unless you object, I'll put back 208V and try to eliminate the confusion about whether it is talking about phase-to-phase (yes) or phase-to-ground (no). jhawkinson 16:15, 27 March 2007 (UTC)
 * Please don't list the phase-to-phase voltages in the affected section; as I said above, they are different depending on which system is used. The actual numbers don't matter so much as the idea that the phase-to-phase voltage gives another option for powering single-phase equipment. --Wtshymanski 17:45, 29 March 2007 (UTC)
 * As best I can tell, your argument is that because there are different 3-phase systems, it is not a good idea to give an example of a 120/208Y system, even though it is the common case? I don't buy that argument, I do think that provide solid examples really aids in understanding. Anyhow, I don't want to get into a revert war, so I won't make this change, but I think we can do better than what is here now. jhawkinson 22:10, 29 March 2007 (UTC)

This page is still incorrect for Canadian colour codes. The Canadian Electrical Code clearly states A phase = Red, B phase = Black, C phase = Blue, it is NOT black blue red! CEC rule 4-036 (3)   —Preceding unsigned comment added by 24.64.125.122 (talk) 20:03, 17 August 2008 (UTC)
 * I think I've wandered into an edit war. I corrected this colour code for Canadian three phase from (black, red, blue) which is wrong, to (red, black, blue) which is straight out of my copy of the code right in front of me, and it was undone (and made wrong again!) without comment or explanation by --Wtshymanski in edit: http://en.wikipedia.org/w/index.php?title=Three-phase_electric_power&diff=237414020&oldid=237355282 Can we argue about this here rather than swapping 'undo's? This is all the more mysterious because you said yourself: "Non-isolated systems (referenced to ground) use red, black, blue (A/B/C) (rule 4-036(3)(c))" in this very discussion. --TonyGraySchneiderElectric   —Preceding undated comment was added at 16:58, 15 September 2008 (UTC).
 * argh. When the Alzheimer's sets in I won't even notice. 4-036(3)(c) does say red, black, blue, even though single-phase cables are black/white. --Wtshymanski (talk) 00:08, 16 September 2008 (UTC)
 * Many thanks for your contributions - you're clearly very knowledgeable - it was just an accident. All the best, TonyGraySchneiderElectric (talk) 17:25, 16 September 2008 (UTC)

The colour codes shown for the U.K. could also do with some expansion, but not being familiar with editing Wikipedia tables I'll leave that for somebody else to do. Red/yellow/blue for phases was introduced in 1964; prior to that the second phase was white instead of yellow. The 13th & 14th editions of the IEE Wiring Regulations can be cited as a reference. I don't have the edition to hand at the moment to give the exact date, but at some point through to the 1940's the phase colours were commonly red/blue/green, prior to the adoption of red/white/blue. The comment in the table that earth was green up to circa 1970 could also be clarified; it was circa 1970 that flexible cords adopted the European green/yellow for earth, but for fixed wiring use of plain green continued for several years, until approx. 1977. 87.112.148.252 (talk) 11:25, 29 March 2013 (UTC)

A Laymen's Introduction Perhaps?
First I want to say that this article was obviously written and contributed to by people who really know what they’re talking about. The depth of the technical detail is impressive.

However, coming in as a layman rather than an electrical engineer, electrician or mathematician, I was lost almost from the beginning, looking for a simple explanation of what three-phase as compared to a ‘normal’ electrical supply was. I have seen this issue before in Wikipedia articles—experts provide great in-depth detail without realizing that the average user may be looking for a concise, high-level explanation of the subject that can be quickly read and understood to a limited degree (drive-by users I call them). I doubt most people have more than a minimal understanding of AC power generation and transmission to begin with, so by immediately jumping into pretty technical details, a majority of readers may be left behind without gleaning even a basic understanding of the subject. For this article, I think it would be great to have a short introduction that in simple language explains, for example, why a three-phase supply is better suited to motors for industrial duty, while most household appliance motors can get by with single-phase that's usually supplied. peterr 02:55, 15 October 2006 (UTC)


 * It's in there, but maybe it should be moved to the top. The whole point of having a 3-phase system is to run AC induction motors.  Or stated more clearly: the whole point of the Tesla Polyphase System installed by Westinghouse Corp is to operate Tesla's polyphase AC motors.  These are brushless motors which require two or more AC circuits with differing phase to create a rotating magnetic field that drags a copper/iron cylinder into rotation.  No other reasons for having multiple AC phases make much sense, since other types of loads don't require 3-phase, and smoother DC rectification is a historically later benefit (Rectifiers didn't even exist in 1896 when Westinghouse Corp first started installing the Tesla Polyphase System.)  --Wjbeaty 02:24, 21 October 2006 (UTC)


 * I realize it’s all in there and well-explained, and the introductory sentence does mention AC induction motors. But the very next sentence is “Three-phase systems have at least three conductors carrying voltage waveforms that are 2π/3 radians (120°,1/3 of a cycle) offset in time. In this article angles will be measured in radians except where otherwise stated”.  This reads like a textbook, and in my opinion could scare away a reader with no concept of waveforms that measure 2π/3 radians, or those not prepared to use units other that radians for angle measurements (when specifically told to do so).


 * The article titled “Three-phase” has as its introductory sentence the second sentence of this article. The other article too jumps straight into technical concepts and mathematics, rather than providing a quick overview of AC power, or at least a link to a layman’s article on the subject.  (BTW I think these two articles should be combined—there is redundancy, and I’m not convinced of the usefulness of the shorter one that provides strictly a definition without touching upon application.  For example if I wanted to find out what a bolt was, I would be pleased to have the same article that describes it as cylindrical and threaded go on to explain its primary use as a fastener.)


 * A waterfall that from the top down moves from high-level, easy to comprehend concepts for the layman, down to hard-core technical details for the initiated, is the structure I’m advocating. There may exist already guidelines on this, and certainly there are a multitude of other articles that would benefit from friendly introductions to their complex topics.  I’m not picking on this article in particular; rather, because of its quality and wealth of information, I think it makes a good example of what a great Wikipedia article could be.  Writers on technical topics should consider the possibility that much of their audience is being directed to their articles from mainstream searches, not from footnoted references in scholarly publications.  Wikipedia should be not only accurate and comprehensive, but accessible to users of all educational backgrounds and fields of expertise.  Introducing an article by supplying a useful, high-level definition in a non-intimidating manner may interest and encourage a user to read on to the nitty-gritty if he chooses.  If he is satisfied with only the high-level definition, then the article has still served its purpose.  Nothing is gained by anyone when a reader is scared away by immediate immersion into complex or esoteric discussion, and I don’t think it is in the spirit of Wikipedia to be, or appear to be, elitist.


 * From laymen looking for one-minute definitions to professionals seeking in-depth answers, people of all backgrounds should find Wikipedia the best all-around encyclopedic resource on the Web. Contributors of the highest caliber, however, must assume that many readers of their articles may be completely new to the topics.  Detailed, technical information drawn from accumulation of knowledge and wealth of experience is of course invaluable to other professionals and students, those readers of the ability to comprehend such.  However, there is should exist the responsibility to provide for the most casual of information seekers as well, those who enter having no knowledge of the topic whatsoever.  These users deserve the best the contributor can provide in the manner of a concise, easily-understood definition or overview of the topic, and the contributor may take as much pride in creating this as in the sharing the detailed information that follows.  It may well be that a great majority of readers require that high-level explanation, and the ability of an expert to distill the complexity of their topic into this concise, layman-friendly introduction speaks to his professionalism and generosity.


 * To conclude this overlong “comment”, although an introduction of sorts may be in there somewhere, it’s not what I envision for the layman who just wants to know if his toaster runs on three-phase current.


 * BTW from what else I’ve read regarding the adoption of three-phase AC generation and transmission, it was due to more than just its ability to start Tesla’s AC motor turning, but I get the feeling you don’t believe the other arguments for the system. I’d be interested in what makes your opinion on this so strong.  I’m a layman myself, but this fascinates me, so I’ll try to keep up with whatever you want to tell me.  And thanks in advance!


 * peterr 02:44, 23 October 2006 (UTC)

Phase Converters...comments needed on Solid State Digital Phase Converters
In doing some research on phase converters, it can all be rather confusing when trying to choose which are better than others, particularly looking at 10HP models, and intrigued of the new phase converter on the market by Phase Perfect which introduces a Solid State Digital True 3 phase converter. Intended to be a 3rd choice as opposed to rotary and static. Wondering if anyone has comments on this new device, seems to be revolutionary to Phase Converters? —The preceding unsigned comment was added by Mag43 (talk • contribs) 00:59, 5 December 2006 (UTC).

Some sections of intro should be deleted
The subsections in the intro titled "Star connected systems without neutral" and "Unbalanced systems" should be deleted because they were copied vebatim from the more in-depth three-phase article. These paragraphs are only comprehensible with a theoretical intro given first. However, this "how and why" article does not have one. Hanjabba 00:49, 20 March 2007 (UTC)

Way Too Technical and Obscure
I'm a pretty well educated guy. I know my way around a circuit board. But I couldn't make heads nor tails of this article. What does three-phase mean, for gosh sakes? That's what Wikipedia is all about. Save the math for the engineering classroom. Give us some basic "stuff".Scott Adler 11:04, 7 April 2007 (UTC)
 * Would you look at the paragraph I added just now? Is this in the right direction?  It's hard for fish to define water, you know; your persepective from the shore is very useful. We could build up to the math...slowly. --Wtshymanski 23:26, 7 April 2007 (UTC)


 * I'm not Scott Adler, but that looks pretty good to me.


 * Atlant 16:53, 9 April 2007 (UTC)

Why three-phase
I know this sounds simple but can anyone describe the reason for, and generation of the three-phase supply as compared to a single phase supply? —The preceding unsigned comment was added by 62.140.211.130 (talk) 08:35, 9 May 2007 (UTC).

Single phase systems only deliver power roughly 2/3 of the time. This is tolerated where only small or modest loads need to be supported, because the simplification in wiring compensates for the inefficiency. However, where larger loads are present, a multi-phase system which delivers power nearly all of the time is preferable.

Another factor is the issue of motors. Single-phase induction motors are not inherently self-starting and require some additional means (such as an auxiliary winding) to get going. Multi-phase motors, on the other hand, are not only self starting, but they are typically smaller and lighter than single-phase motors of the same horsepower rating because they do not have to overcome the "valleys" of a single phase supply.

While it is theoretically possible to build a system with any number of phases that divide evenly into 360 degrees, Nikola Tesla always believed, and Charles Steinmetz subsequently proved mathematically that the three-phase system offers the best balance of performance and cost.

--Melvan 77 Melvan77 12:50, 24 October 2007 (UTC)

"NEC does require color code"
Err, Wtshymanski, can you substantiate this a bit better? While the US NEC does require coloring, and does mandate specific colors for ground and neutral and high-leg delta systems, it does not mandate particular colors for other applications. When I looked at the table recently, I felt like it was too easy to assume that BLACK/RED/BLUE were universally standard phase colors for 120/208V. With your recent change this problems seems to've gotten worse. What was your thinking in removing this?:


 * However, the current National Electrical Code (2005) does not require any color identification of conductors other than that of the neutral (white or white with a color stripe), the ground (green or green with a yellow stripe), and, in the case of a High Leg Delta system, the High Leg ("shall be durably and permanently marked by an outer finish that is orange in color or by other effective means"). (NEC 110.15).

Thanks. jhawkinson 12:11, 26 May 2007 (UTC)
 * These aren't phase colors. The copy of NEC that I have access to is at the office right now. I'll have to find the rule. The Canadian rule is 4.036 at least in my 1983 code...have to check the current edition at the office. --Wtshymanski 02:53, 31 May 2007 (UTC)


 * I don't understand your response. The NEC does not require phase coloring. The prior wording did not specifically make a statement about phase coloring as opposed to other coloring. I'm going to restore the above cautionary wording because I think it was helpful. I'm confident you won't find a requirement for phase coloring in the NEC, but if you do, feel free to revert. jhawkinson 20:22, 31 May 2007 (UTC)

Bill, would you please respond here before making further edits and reverting mine? I'm happy to discuss or be shown to be wrong, but I don't think it is reasonable for you to revert edits without explanation when you have been asked explicitly. I think article 517 is so obscure as to hardly deserve the prominence of mention on this table. It only applies to health care, a very small portion of the wikipedia community. The other uses of B/O/Y coloring far exceed the 517 use.

Also, 517 is about "isolated power systems," not "isolated ground." The former means transformers (or equivalent isolation devices), the latter means "homeruns of green wires." I do think it is important to note the unreliability of color codes prominently above the table. Even though it is mentioned in a footnote, I think, for safety's sake, it deserves more. I am not an expert, but I do not think it is common for local regulations to amend the NEC on color coding. What is common is for "common practice" to vary from region to region, or even site to site. jhawkinson 19:03, 5 June 2007 (UTC)
 * 517 is the only place the US NEC dictates phase colors. From what I've read on the Web up to 1975 there were NEC schemes for coloring phases. The Wikipedia is the *home* for obscure facts. What colors would you find in a US 347Y/600 V installation?  For that matter, what about  230V, 2300V,  4160V, 13.47 kV, etc. etc. - there are many more voltages than 120/208 in use, and it's useless to imply that the listed colors have any voltage significance *at all*. I see on the Web that Juneau, Alaska has implemented their very own local color codes - it must make it hard to buy cables that comply, and by using the same code for a 480V system as the NEC mandates for an isolated power system, it completely screws up the intention of that part of Article 517. Disproportionate discussion fo the US NEC is not appropriate for a general article on three-phase power ( arguably the whole color code nonsense should be dropped anyway, since its not fundamental and not even useful).  Finally, Wikipedia is not a safety manual and must never pretend to offer safety advice lest the lawyers sue Wales & Co. into bankruptcy. Safety notices on stupid things you can do with electricity would easily double the current size of the English Wikipedia alone. --Wtshymanski 17:50, 6 June 2007 (UTC)


 * I agree 517 is the only place the NEC dictates phase colors (I'd think that would be clear from my comments in March). That Wikipedia is the home for obscure facts does not mean that the obscure facts should lead the common ones. Almost any use of B/O/Y is more common than the 517 usage. B/O/Y for 277/480, B/O/Y for a seperately derived 120/208Y system, etc., etc. Perhaps you could offer a more clear citation to your concerns about Juneau, AK. I think the color codes are actually an important part of this article, and, for instance, if one is trying to find out about color codes for electrical wiring, the Color codes article takes a reader here.
 * I suppose the question is "what is disproportionate?" This change was added in 37447436 in Nov 2006. I think it should stay. You think it should go. Who decides? I would say we favor precedent.
 * I don't find your argument about safety messages compelling, but here you have precedent on your side and I'm less inclined to spar over that point.
 * It is, however, simply incorrect to say that B/O/Y is "Mandatory for isolated power systems." It is "Mandatory for isolated power systems in health care facilities," and that is a very very different thing. Non-healthcare B/O/Y uses far exceed health care isolated power uses. jhawkinson 23:26, 7 June 2007 (UTC)
 * Well, then, let's mark B/O/Y as "Mandatory for isolated power systems in health care facilities and commonly used for 480/277", which it already says in the footnote. But the whole point of the 517 rule then escapes me...what's the point of a special color code for an isolated system, which is the same as the standard color code for a non-isolated power system at 480 V?  The harmonized British/European color codes are even worse - it takes a strong light and clean cables to distinguish brown from grey from black.
 * What are the color codes in the US for other voltages, e.g., 2300, 4160, 13.47, etc. etc? There's even some 600/347 in the US, and I understand the oil fields use 800 V. I think it is at best mislead and at worst just wrong for the Wikipedia to imply that there's any standard to the assignment of voltage levels to color codes when it plainly varies depending on local practice. I've even found some specs that call for purple and other colors in 3-phase wiring. The Canadian rule gets rid of all this nonsense (though we have the isolated system color code too, at least ours isn't the same as non-isolated systems.  Though the Canadian rules have the phase sequence different from the US. --Wtshymanski 01:28, 8 June 2007 (UTC)
 * I think we would be better off labelled B/O/Y as a "US Alternative" coding, and mentioning both the 517 and 477 uses in the note, esp since the 517 use is less common. You are asking what the purpose of a piece of the NEC is? Code evolution is complex, political, and not always sensical...
 * Why did you remove the text about the orange triangle marking for isolated ground? jhawkinson 13:38, 8 June 2007 (UTC)

Digital Phase Converters

 * See Dr. Larry Meiners "Phase Converter Technology Overview" http://www.phaseperfect.com/files/phasewhitepaper.pdf Soothsayer2 (talk) 16:04, 28 February 2008 (UTC)

can i connect 3phase 380 v 50 hz motor to 480 v 60 hz supply
can i connect 3phase 380 v 50 hz motor to 480 v 60 hz supply —Preceding unsigned comment added by 41.233.31.153 (talk) 12:58, 3 August 2008 (UTC)

2 and 4 phase power
I wish to see information mentioned on 2 and 4 phase power as referenced in http://www.nordichardware.com/news,8295.html

Thank you. Habanero-tan (talk) 22:21, 10 December 2008 (UTC)
 * Then add it? Ironholds (talk) 13:42, 23 January 2009 (UTC)

Power availability in each country
I think some one can summarise various power situations available in various countries across the globe with details like Voltage, single phase & three phase Frequency, Power plug type Thank you, Vijai Shankar Raja (talk) 00:15, 16 March 2010 (UTC)
 * Look at Mains power around the world. --Wtshymanski (talk) 13:02, 16 March 2010 (UTC)

Linear Balanced Load
Can someone explain "linear balanced load" in layman terms for the public? Thank you. Yeokaiwei (talk) 06:53, 14 October 2010 (UTC)
 * "Linear" -voltage and current vary in strict proportion and if eitehr is zero, the other is zero. "Balanced" means all three legs the same. I would have thought the article explained this. --Wtshymanski (talk) 13:03, 14 October 2010 (UTC)

"Interesting" example?
From Three-phase electric power: "An interesting example of a three-phase load is the electric arc furnace used in steelmaking and in refining of ores."

I question the use of "interesting" to describe this example. It is a form of non-neutral/editor's-opinion (see WP:EDITORIAL). My cn tagging for justification of this description was removed with the comment "interesting because it's not a motor". But this is one of many non-motor examples in this very section of prose. On that basis, it is not exceptional at all, so I removed the word as an objectively incorrect assessment of that situation (with edit-summary saying as much). It was re-added (by the same editor who disputed my CN) with "Really?". Yes, really. Need some others' opinions to resolve this dispute here. DMacks (talk) 18:21, 2 September 2011 (UTC)


 * Hi. I've come in response to the 3O request. Yes, the word "interesting" is not appropriate, just on a "says who?" basis. Since the section has no cites (a situation which it would be good to rectify, BTW), there's no justification for it including anything which might be a matter of opinion. --FormerIP (talk) 18:40, 2 September 2011 (UTC)
 * Oh for heaven's sake. Arc furnaces are fascinating gadgets. Suddenly a very mild variation from the usual plonkingly dull prose for which Wikipedia is so justly famous becomes a matter for the ArbCom. --Wtshymanski (talk) 19:09, 2 September 2011 (UTC)


 * The wikilink is there, so readers can click through and find out about how fascinating arc furnaces are if they want to. The dispute may be tedious, I can't possibly comment. But DMacks has it right. --FormerIP (talk) 19:16, 2 September 2011 (UTC)


 * "Write a page full of dither, no-one notices; but pick one word and get a curb stomping"--Wtshymanski (in edit-summary for 19:09 comment)
 * Very well: there is also lots of good neutrally written content in this article that seems factually correct based on my understanding (albeit often substantially uncited, as has been tagged for years). DMacks (talk) 19:19, 2 September 2011 (UTC)
 * You left out "Ergo, Wikipedia rewards and encourages bad writing." It does, you know. --Wtshymanski (talk) 19:35, 2 September 2011 (UTC)
 * No, I chose not to state why I don't believe, and I am getting offended that you keep thinking you know what I and others think. Stop it. DMacks (talk) 19:38, 2 September 2011 (UTC)
 * Wtshymanski, I think what makes for good or bad writing may be in the eye of the beholder. Being an encyclopaedia, WP normally encourages a neutral, factual tone. It's contents should reflect established facts or representative expert opinion. The opinions of editors are not included, and I think most editors would say that including them comes across as unprofessional.
 * I can't believe this is worth arguing over, but DMack's edit is in line with normal WP practice. --FormerIP (talk) 19:56, 2 September 2011 (UTC)
 * Yes, yes it is. There's no argument. --Wtshymanski (talk) 20:01, 2 September 2011 (UTC)


 * Now we're getting somewhere: : it's interesting to you because you say a specific way it's different from all the others. Why is 3-phase used in this situation, given that it doesn't need rotational-direction or fluctuation-reduction? That would allow the fact to be written tied to other themes in the article, in particular, that this type of power has certain specific advantages. DMacks (talk) 21:09, 2 September 2011 (UTC)

Wtshymanski: Just in case you haven't noticed, you've reverted three times now. Any more could land you with a block. The sentence currently reads: "One example of a three-phase load is the electric arc furnace used in steelmaking and in refining of ores". Can I suggest that nothing else is now added to that without discussion on the talk page first and, preferably, reference to sources? --FormerIP (talk) 21:20, 2 September 2011 (UTC)
 * I am too busy spitting out bloody teeth to carry on with this now. --Wtshymanski (talk) 01:08, 3 September 2011 (UTC)

'Colour' or 'Color'?
Several editors keep changing the spellings in the article from British English to US English and back again. One editor claimed that the spellings used in March should be used or, "that was how Tesla spelled (sic) it" (Invalid arguments in both cases). Another changes the spellings to British English citing the policies of WP:ENGVAR and WP:RETAIN. Correct and good argument, not no cigar. Both of those policies require that the variant of English used for an article must be the one in which the article was originally written (not how it was written in March or how Tesla would write it). The original article was relatively language neutral apart from one US English term, 'wye' (the British English term being 'star'). Thus the original article was written in US English and thus that is the variant that rules. Indeed the spelling 'color' was introduced a bit later (ironically when introducing the old British colour code). The cited policies require that the English variant is not changed, "... without a broad concensus" - and that just ain't gonna happen.

Though it pains me to say it: as the original article was written in US English, those are the spellings that must appear in the article. DieSwartzPunkt (talk)


 * I don't give a damn what it originally was or later became, but the constant IPs' changing of it is absolutely forbidden so I semi-protected the article. For at least the second time for this exact reason. The article goes with whatever WP:CONSENSUS might develop, so thank you for starting the discussion, and no mind will be paid to those who do not participate here. DMacks (talk) 19:17, 23 November 2012 (UTC)


 * US English - From WP:ENGVAR "If discussion cannot determine which style to use in an article, defer to the style used by the first major contributor." The article was initially written in US English and it should stay that way. I am a Canuck and spelling it color brings up many things I would not say here about the language style but the article was written in AmEng originally. 174.118.142.187 (talk) 03:04, 10 December 2012 (UTC)

I do not see why, the concensus here is for American English. There is no proposal otherwise. Any editor who changes it is most probably risking a block for unco-operative slow time edit warring. DieSwartzPunkt (talk) 15:58, 11 December 2012 (UTC)
 * You were notified of the vote the same as the rest of the editors on the history list as standard procedure. Sorry to confuse you as you had already expressed your desire here. 174.118.142.187 (talk) 06:10, 12 December 2012 (UTC)


 * To summarize it in short form, I believe article retains original English version the article was started with, unless a consensus is made to change it. I think one of the exceptions is for articles with strong cultural tie to one form, ie article about US history / British history. Can we end this for now? Cantaloupe2 (talk) 21:26, 12 December 2012 (UTC)
 * Does this make you in favour of Brit, American, Canadian, Aussie, S. African or another English dialect? Which dialect are you referring to, so we are clear? An admin wants this finalized so we have a bigger stick. I believe we are all in agreement on AMEng, anyway. Is there a reason for the impatience? 174.118.142.187 (talk) 22:27, 12 December 2012 (UTC)


 * To avoid confusion this discussion continued below. 174.118.142.187 (talk) 13:35, 18 December 2012 (UTC)

Symbols or numbers
I don't agree with this edit (especially as it is the second time it has been applied after being reverted). A numerical example is much clearer than algebra to my mind. It does not really matter whose numbers are used, but I think that Wtshymanski may be right that high-leg delta is unknown in 240/230 V countries. I have certainly never seen it in a European country.  Spinning Spark  23:03, 16 November 2012 (UTC)


 * Paraguay has 440-220 center tap delta. Japan has 200-100 delta. If we express it in terms of algebra, we don't infuse country specific bias. I substituted with 200/100, because they're cleaner number than 240/120. To substantiate whats used by what countries, what they use/what they don't use require citation, but expression in in algebraic terms eliminates that.  Cantaloupe2 (talk) 04:30, 17 November 2012 (UTC)
 * Use the US standards. After the concensus I am sure that US English language will be used and the base examples should follow that. European and/or other systems examples should be included but not fantasy system voltages or math symbols that confuse everybody. Some readers may be 12*n old (where n = the time for earth planet rotations) and are consulting WP to learn something. 174.118.142.187 (talk) 22:09, 10 December 2012 (UTC)

Three-wire versus four-wire / Delta versus Wye Systems
What are you trying to get at with your comment "I have 3 wires coming out of the wall -- is it delta, or is it wye?" Number of wires at the wall is not good way to tell what you've got. It's the type of source winding that determines what kind of system you have.

If you're seeing 220v between any of the terminals, it could be a 230v delta as sometimes used in US, or it could be the 127Y/220v as used in Mexico. Delta with one of the coils center tapped could be arranged as 4W. Cantaloupe2 (talk) 22:45, 15 November 2012 (UTC)
 * I might have three phases on three wires. I couldn't have less than three wires for a three phase system. On the ohter hand, if I have four wires, I probably have a neutral. I think its more useful to say "three wire" and "four wire" than to experiment with typography and Greek letters. --Wtshymanski (talk) 22:47, 15 November 2012 (UTC)
 * It is not an experiment. Referring by the way it is fed from the transformer is an industry accepted practice. The use of neutral is optional. A three phase receptacle may have four wires. It can be L1,L2,L3+G from 120Y/208 system or L1,L2,L3+G from 230v delta system. In the latter, you could still have a neutral and have high-delta system.  So, three phase systems are not classified by number of wires, but rather by the transformer source winding configuration.  Does this make sense? Refer to delta/wye reference in industry here    "For combination single-phase lighting and power, and three-phase power: 120/240 four-wire delta, 120/208, four wire wye, volts and 277/480 four wire wye." Cantaloupe2 (talk) 22:59, 15 November 2012 (UTC)


 * How it is fed from the transfomer is completely irrelevant. If you have only those three wires coming out of the wall in an otherwise completely insulated room and you can positively determine that it is a three phase supply, there is no method by which you can determine whether the transformer is star (wye) connected or delta connected.  For the purposes of connecting a three phase load it doesn't really matter anyway.  The only time that it does become relevant is if you require a neutal connection because it is not directly available from a delta connection.  In a practical installation, the transformer is almost certain to be star connected because any mismatch in the windings of a delta connected secondary can result in unwanted currents circulating in the windings.  There are, however, more esoteric connections that can avoid these. DieSwartzPunkt (talk) 16:07, 16 November 2012 (UTC)
 * This isn't about how it matters to the person hoking wires up. Actually, neutral can be available for delta, which is shown in one of the diagrams in the article where one of the coils is center tapped and grounded which is called "120/240 four-wire delta" in the article I linked above. In the USA, this is used in industrial setup where most loads are 230v motors with a few 120v stuff here and there.  208/120(Y) is used in offices where most loads are 120v, but may use 208v for elevator and HVAC. They both have 4 wires.  Measuring phase to phase is not reliable means of identifying it, b/c 208 on high end of margin and 240v on low end of margin can end being about the same.  Cantaloupe2 (talk) 20:34, 16 November 2012 (UTC)
 * This conversation needs to be on the talk page of the article for future referrence and edit arguments. Can somebody please move it there?
 * The article title appears to be about three phase systems and the system is determined by the transformer windings feeding the system. Wires are not an appropriate title to determine the "system" as already indicated by the number of variations present. We also have 3 wire wye supplies, already discussed. Some know this as "three phase four wire, one leg out". Some meters companies call it "Network". Every combination is available so the system feed terminology has to dominate. Distribution systems can be 3 wire or 4 wire and does not determine what the supply system is. BTW: Our utility  discontinued 4w delta systems a few decades back as non-metering engineering staff could not understand the equipment installed by field personnel. 174.118.142.187 (talk) 02:22, 17 November 2012 (UTC)


 * End of copied text. Please continue discussion below. 174.118.142.187 (talk) 03:52, 17 November 2012 (UTC)


 * That would not be a proper neutral in the way most people understand it. If you want to be pedantic, you could create an artificial neutral from a delta secondary using three equal value resistors (or capacitors or inductors). 86.159.159.194 (talk) 16:55, 17 November 2012 (UTC)


 * What is the "proper" neutral the way "most people" understands it? Please cite sources. Cantaloupe2 (talk) 08:23, 18 November 2012 (UTC)

You know very well that I am talking about the neutral derived from the centre point of a star (or wye) would transformer. High leg delta systems are seldom encountered (if ever) on this side of the great pond. 86.159.159.194 (talk) 12:39, 18 November 2012 (UTC)
 * What do you call a system with a wye transformer high-impedance grounded, using 3 wires to connect to a delta/wye switched motor? "Delta" and "wye" describe winding connections, but the cables (bus) have either 3 or 4 wires. The key is if a neutral is distributed or not - the common star point of a wye transformer is not a usuable neutral if the system is resistance grounded. --Wtshymanski (talk) 19:03, 18 November 2012 (UTC)


 * It would be a wye system as it comes from a wye source. How the load utilize the power is not relevant. It's like "is it three phase or single phase" based on the load's characteristics. Cantaloupe2 (talk) 07:24, 19 November 2012 (UTC)


 * Since when was this article specific to geographical location? Just because it ain't so in UK doesn't mean its not valid. El Salvador uses center tapped delta as does Japan where the system for domestic power is 100/200 as opposed to 100Y/173 or 115Y/200. Cantaloupe2 (talk) 07:24, 19 November 2012 (UTC)


 * Neutral is a conductor capable of current carrying and the return for current back to its source. The system you describe is a floating wye system used for 87/GFI protecion of delta loads and to stop a tree wire system from floating away from ground/earth. The wye/star is not distributed as connection to it would disturb the GFI detection system but it is still a wye system. Don't confuse neutral with ground. How the neutral is grounded is of no consequence. Some utilies ground one phase of delta distribution systems. 174.118.142.187 (talk) 22:35, 18 November 2012 (UTC)


 * Elaborate what you mean by "87/GFI" in global sense. The grounded phase or B corner ground delta is what you're referring to.

Cantaloupe2 (talk) 07:24, 19 November 2012 (UTC)
 * The system I describe has no neutral, but it's grounded. 87 is differential protection and has nothing to do with "GFI" protection. It's not a floating wye system, it's a three-wire high-impedance (resistance) grounded system. (You don't even need to use a wye (star) transformer to feed it, as it's possible to use a zig-zag transformer to provide the grounding.) It's more useful and accurate to count the number of wires in the distribution system and say if it has a neutral or not, instead of giving all the typography which really only describes windings of particular apparatus, not the distribution system. --Wtshymanski (talk) 04:25, 19 November 2012 (UTC)


 * This is going off at the usual tangent. Unless there is any specific proposal to change something in the article, this discussion does not belong here. 86.159.159.194 (talk) 12:08, 19 November 2012 (UTC)
 * I agree. It seems there is a distraction from the issue using semantics of tech terms  and another distraction to avoid  consensus on the issue clearly labelled in this section header. We need to stay on topic. Plain and simple I see the argument as talking about three phase system supplies and not loads. Who knows what is connected behind the wall to the four wires from a wye system source? If somebody hooks up a delta load does that change the description of the system to delta? If we connect a single phase load to the star source does that mean we should label the system single phase? No, It's the winding configuration that feeds it and I propose that the system is the source, and not the load configuration. I propose we label the section Wye versus Delta and lose the wire counts for system descriptions. Again there are three wire loads that are hooked to many Wye distribution systems and there are single phase loads hooked to Wye systems sources. We don't call them single phase. The label for the system is not load dependent. Wire counts are not descriptive of three phase system configurations. Three phase systems have phasor based descriptions.174.118.142.187 (talk) 21:53, 19 November 2012 (UTC)
 * I thought the point was obvious but this is the Wikipedia, after all. I think the article should distinguish building wiring systems and distribution systems as either "four wire" (with neutral) or "three wire" (no neutral), to agree with literature on the subject. A wye transformer may not supply a four-wire system if the star point is ungrounded or impedance grounded. "Wye" and "Delta" are only useful for descrbing the connections of coils on machines and transformers.  Both three-wire and four-wire distribution systems can serve single phase loads. Only a four-wire (three-phase) system has a neutral. "Wye" and "delta" are weak descriptors compared to "four wire" and "three wire" because you can make a three-wire distribution system fed by a wye transformer with delta loads, or a four-wire distribution system can be fed by a delta transformer (with a zig-zag for creating a neutral) (and which could easily have either wye- or delta-connected three phase loads). But let's make the Wikipedia ever more obscure, instead of making a common and perfectly ordinary system of organization clear. --Wtshymanski (talk) 22:38, 19 November 2012 (UTC)
 * I am not sure what point you were referring to but... you make some good points. Your opinion is important here as you are a very technical contributor. We can argue over your 64/87 definition over a beer later. :) I would like to point out an error in observations in my previous post about the definition of the word "system", and I think that is what the article needs to discuss. "System" is about the source, the conductors and the load. I argued only source and you argued load or only distribution conductors. Since "system" needs to include all of it and all configuration combinations of wires and source windings are out there we need to specify both in the title to cut the confusion between readers of different habits and understandings. Thinking back, most tech people I encountered stated wire *and* winding config. such as "three phase three wire delta", "three wire wye" or "four wire, open corner delta". I think we need to use both qualifiers in the section title and prose for confusion (as seen above and edit history). ie. "Three-wire (delta) versus four-wire (wye)". No sysmbols as per WP:MoS. Objections? 174.118.142.187 (talk) 00:40, 20 November 2012 (UTC)


 * Including wire count and configuration seems like the best idea. Four wire could mean wye with neutral from star pulled through, or it could mean high-leg delta in which one of the transformers are center tapped to provided V and 1/2V. As I posted sometime during the past, configuration expressed along with wire count is the description used in application, at least in the US. example, see page 2. Cantaloupe2 (talk) 06:01, 10 December 2012 (UTC)
 * I concur. It is going to take both to clarify a system as was used in my adventures in real world power dist. Look at the different concepts here and on the edit history. Let's attempt to observe WP:BRD in future. It was written for a reason. Somebody got hurt! LOL I can make the changes once this jail cell door (page protect) gets openned again. 174.118.142.187 (talk) 22:03, 10 December 2012 (UTC)


 * I really don't feel like working on this article at the moment, but I suggest you create an account and start making contributions, so you become auto-confirmed, enabling you to edit semi-protected pages. Cantaloupe2 (talk) 04:40, 11 December 2012 (UTC)


 * I have taken the protection off the article so you can edit. Please do not make any changes that are still under discussion here until consensus is clear.  Spinning  Spark  16:59, 11 December 2012 (UTC)


 * I have to concur with Wtshymanski here. A basic three phase system (let's ignore the exotic flavours such as high-leg-delta et al for this argument) is either a three wire system or a four wire system, the fourth wire being the conventional neutral.  As I have already stated, although the fourth (neutral) wire has to be obtained from a star wound transformer or generator, the three wire can be obtained from either a star or a delta wound transformer or generator (in the case of a star winding the neutral being left unconnected).  I see no advantage to the article of specifying that the three wire system has to be derived from a delta winding when it is not a requirement.  As far as I can tell, the requisite section of the article is adequate in this regard as it stands. DieSwartzPunkt (talk) 15:43, 11 December 2012 (UTC)


 * I agree with both your main points; three-wire systems can be supplied from either a delta-wound or star-wound transformer; high-leg-delta is a side issue and should not be allowed to confuse the main explication (although it could be mentioned afterwards).  Spinning Spark  16:59, 11 December 2012 (UTC)


 * Heck, you don't even need the windings connected together. three wires is the minimum number of wires needed to carry three phases. However, the windings need not be connected, so as shown in elementary three phase system diagram in article, it can be six wires too. Where are you getting that high delta is exotic?  Why don't you call grounded center wye exotic too as well as anything other than the bare minimum three wire system?  Your use of "exotic" seems arbitrary to me.  If three sources that are out of phase by 120deg and windings are electrically insulated from eachother and connected by six wires a three phase motor woudl still turn.  Cantaloupe2 (talk) 21:35, 12 December 2012 (UTC)
 * The point is that high-leg delta is not very widespread (and neither is six-wire isolated). The main cases should be dealt with first.  Earthed neutral wye systems are ubiquitous - found pretty much worldwide - so the discussion should centre on that.  Spinning  Spark  23:43, 12 December 2012 (UTC)


 * Do you have references to degree of spread like census data does for people? Where do you get your claim that its not common enough to deserve a mention within the article?  Schneider electric discusses briefly that it was installed in industrial application where motors run on 240v and lighting on 120v in 1950s, although this only accounts for US. Unless they were gutted and fitted over, they remain in place. We have no data to show if they were converted over or not. Electrical system is affected by historical precedent, but is not as well documented as anthropological culture. . A great example of this is 50/60Hz in Japan where distro equip were purchased from EU for 50Hz region and USA for 60Hz region and it remains that way even today. Even if 480/277 and 208/120 are common configurations today, motors today are rated 230v and 115v. Per NEMA, motor ratings are 230 and 115 rather than 240 and 120, so 230 is acutally intended for 240v. Today, "230v" tag motors are far more common than "208" or "200" tag motors.  This shows 240v delta is common enough.  As far as I'm aware, we have no such thing as 138v/240v wye system in the USA.  I think its known enough that v & 1/2v delta deserves to be addressed. Cantaloupe2 (talk) 00:08, 13 December 2012 (UTC)
 * I'm certainly not saying it should not be covered. I only think it is a matter of due emphasis.  All I am saying is that the basic systems should come first and not be cluttered with too many variations.  Spinning  Spark  11:50, 13 December 2012 (UTC)

In my area 125/216v 3-wire wye is commonly used to supply multi-unit buildings. It still satisfies both the 120v and 240v voltage tolerence limits +/-10% but doesn't need the centre tapped domestic tansformers required for domestic consumers. Still these are all just 3-ph 4-wire wye systems with different loads connected. The 3-ph 4-wire delta (V) was discontinued an a full 3-ph 4-wire wye forced on the small commercial customers that wanted those voltages. It took one more transformer but reduced the confusion by EE people and avoids the field hook-up confusion errors using the odd neutral. Mention should be made of these but these don't warrant a major section to keep the article small, concise and uncuttered. 174.118.142.187 (talk) 14:37, 14 December 2012 (UTC)


 * Anything other than a 'basic' three or four wire system should be covered in the next section "More three-phase topologies". What is important here is that a three wire system does not necessarily come from a delta wound transformer.  Indeed, in a basic system, a delta secondary has the disadvantage that any mismatch in the voltages and/or phase can result in a circulating current.  I can also show you a good example of a three wire three phase system where the supply transformer has a star (or wye) wound secondary.  There is no connection to the star point.  In fact one of the phases is earthed (grounded) and the two remaining phases are 'live' relative to earth.  It even has a Wikipedia article and can be found at Jungfrau railway. DieSwartzPunkt (talk) 17:14, 17 December 2012 (UTC)


 * Of course, having suggested this, our resident edit warrior goes straight ahead and deletes it and then starts cramming any minor variation in the "three wire/four wire" section. DieSwartzPunkt (talk) 18:41, 17 December 2012 (UTC)

174.118.142.187 keeps editing back into the article the claim that three wire systems are delta systems and also claiming a concensus for such a claim on this very talk page. Having reviewed the above, I can see no concensus as claimed. Even if there was a concensus, I have to point out that this is an encyclopedia, so a concensus for a claim that goes against the technology is not really valid. If 174.118.142.187 really insists on editing the claim back in that a three wire system can only be a delta system, then I am going to demand a verifiable reference to support this claim (which means that I can resolutely delete it when one is not provided). Of course, it won't help if by some chance he finds one (unlikely) because I can cite almost an entire bookshelf full that have three wire systems derived from wye wound generators and transformers. DieSwartzPunkt (talk) 18:41, 17 December 2012 (UTC)
 * I have not made any such claim. Your logic appears confused. I am NOTlater edit claiming all three-wire systems are delta or vice versa. The article needs to be clear about what system is being discussed and that takes explicit descriptions including phases, wires and vectorial topology. The discussion, here, gives common opinion that there are many different configurations, as discussed, and "the basic systems should come first and not be cluttered with too many variations", to not confuse the reader. There is no reference to supply because there I made no claim in the article. Adding more system configurations to the talk discussion only adds further confirmation of the need for full system descriptions for reader clarity in the article. Do you have reasons to eliminate some of the system parameters? Let's hear your reasons. Please review WP:BATTLEGROUND and WP:PA 174.118.142.187 (talk) 05:56, 18 December 2012 (UTC)

In an attempt to end this, I have provided a reference that categorically states that three wire systems can be delta or wye. There are no shortage of references available so if more are required, I can supply them. I picked the one that I did solely because it is aimed at teenage (and possibly younger) wannabe electricians and deals with the fundamentals of the subject without getting bogged down in unnecessary detail. I B Wright (talk) 13:56, 19 December 2012 (UTC)


 * By what logic was my change deleting delta in connection with 3 wire systems deleted? Especially given that I provided the ever required reference to support the claim.  To revert my edit requires a reference more authoritative than the one I provided. I B Wright (talk) 16:43, 22 December 2012 (UTC)

Unverifiable contents
When adding new contents, especially things that assert advantages and such, please provide references. Encyclopedic contents should be verifiable. original research should not be posted here. Cantaloupe2 (talk) 23:36, 16 December 2012 (UTC)
 * In your revert of all my edits you have added some more edits of your own into the article under the disguise of your valid complaint. Many of these appear to be previous edits that were removed (slow editwarring).  You have also reverted valid reference updates I have added to the article that do not fit into the nature of your complaint.  I am sure the edits and mistaken references destroyed was not intended in your hasty edit. Please correct these mistaken edits asap so that editors may continue to improve the article.  Thank you 174.118.142.187 (talk) 23:52, 16 December 2012 (UTC)


 * I've referenced to the restoration point, so you can easily reference where it was rolled back to. There were some addition of contents that were original research or first hand knowledge you have. As WP:V says, something you insert may be challenged if not sourced and when challenged, onus is on the person adding the information to cite it. In the mean while you can edit it in your sandbox and once sourced, you're encouraged to add them back. Cantaloupe2


 * What appears to be your contention towards me on the sentence: "The three-wire system is used when the loads on the three live wires will be balanced, for example in motors or heating elements with three identical coils. " wasn't added by me. I should have tagged that citation needed though. Your recent addition was challenged, because you added contents w/o reference. (talk) 00:14, 17 December 2012 (UTC)
 * Your mass revert involved several editor's edits and references that have now become invalid. A bit of work may be needed to restore some of these careless edits made in your apparent haste. Most of these edits are only rephrasing of existing material and do not require references unless we want to delete all unreferenced statements and start from scratch? I hopetha is not the intention here. I will begin to restore references and formatting, until I can replace some of the existing unreferenced nonsense prose with better referenced materials. 174.118.142.187 (talk) 00:34, 17 December 2012 (UTC)
 * I agree that rolling back so much was uncalled for. This was not the sort of POV-pushing or wildly inaccurate editing that would justify such action.  It would have been far more constructive if you had specifically identified what it is that you object to.  You titled this section "unverifiable content" - is there something in the article that you feel really cannot be verified, as opposed to merely currently unreferenced?  If so, then of course that should be removed.  Spinning  Spark  07:40, 17 December 2012 (UTC)


 * Any newly added contents should be cited by the adding editor, rather than expecting someone else to chase references. Such a major change should have been hashed out in talk page. If you disagree, then revert it, I'll tag everything that is not cited. Cantaloupe2 (talk) 08:22, 17 December 2012 (UTC)
 * Please review WP:Consensus. Not all edits have to be agreed upon. Older edits have consensus by lack of dispute. 174.118.142.187 (talk) 17:33, 17 December 2012 (UTC)


 * Not quite correct. Even long standing edits that have not been disputed can still be challenged and a reference demanded.  Long standing inaccurate edits can go undisputed for many reasons.  DieSwartzPunkt (talk) 18:45, 17 December 2012 (UTC)

improper synthesis
"This can accomodate single-phase phase and three-phase delta loads simultaneously. This can also be supplied by two single-phase transformers in a V formation (open delta) "

The statement was a reflection created by an editor. The reference does not support the claim and I disagree with the claim. There is no such thing as "delta load". As long as the ph-to-ph V is correct, the transformer source does not matter. A 240v motor will operate fine on 240 delta or 240/138 wye. Both delta & wye permits the use of single and 3 ph loads simultaneously. A good example of this is 480/277 system in N.A. where 480 powers 3ph motor loads while 277 supplies lighting. Lighting can also operate ph-ph across two lines. (for example, 480v stadium lighting). Factual accuracy of inference of such usage being attributed to center tapped delta is disputed. Cantaloupe2 (talk) 08:33, 17 December 2012 (UTC)
 * I agree that the statement could apply generally to most three phase systems. It was not worded definitively enough and perhaps you could have improved the wording. The rest of your comments sound confused. I am not sure what points you were attempting to make.
 * When three individual loads are connected in a delta configuration what would you call it? 174.118.142.187 (talk) 06:09, 18 December 2012 (UTC)


 * You made an unreferenced inference that providing single-phase load is something attributable to high-leg delta and "delta loads" as opposed to regular loads came out of thin air. I certainly didn't see anything in cited reference that differentiate delta load from other 3 ph loads. It is unreferenced, as well as dispute such differentiation.

Whether the load is connected in delta or star/wye, it has no relevance to compatibility with source winding type. Cantaloupe2 (talk) 08:40, 18 December 2012 (UTC)
 * I have to agree after reading your comments several times over (maybe my hearing accent? :) The reference was not a clear one or a good one for a newbie reader in three phase power distribution. As I tried to indicate above, the statement in question, and the reference, were not definitive enough to exemplify the real difference and benefits of this type of source. Some work is definitely needed on that one or maybe we just need to give reference to the article with more clarity and verbage. I have never heard the term High-leg delta used for this before. We don't want to clutter the article with wild details about every system. Nice catch. 174.118.142.187 (talk) 02:29, 21 December 2012 (UTC)

America-centric examples
In single phase, the examples of application pertains to US/Canada. I think specific examples that only pertains to USA should be dropped, but replaced with the concepts that are globally applicable. To state "in US, it is common to see..." in article prose is only writing about local customs. Cantaloupe2 (talk) 09:44, 17 December 2012 (UTC)
 * Well, we could remove all the examples and hope our reader is experienced enough to figure out what we're talking about from all our brilliant prose. (If our reader is that experienced, she doesn't need Wikipedia articles in the first place.) Or, we could add examples of our "local customs" from whatever part of the world we happen to be in. You don't think a specific example is good practice when discussing abstractions? --Wtshymanski (talk) 14:41, 17 December 2012 (UTC)
 * If you can produce examples from Europe feel free to add them with references as a welcome addition. Mass deletions of edits are not the way to build an article to avoid your fear of the article containing too much "America-centric" content. It's disruptive. 174.118.142.187 (talk) 17:19, 17 December 2012 (UTC)


 * Why just Europe. Europe and NA aren't the world. West centricism in general should be avoided. Many other countries use English too and en.wikipedia is relevant in those cuntries as well. Cantaloupe2 (talk) 21:35, 17 December 2012 (UTC)
 * You mean other countries have electricity too? LOL. Sure. Any knowledge is good for the article with the proper weight of bulk for public interest. Many articles do tend to become US centric with the majority of English speaking population in the world. Other country informationmay be hard to reference also. 174.118.142.187 (talk) 03:49, 18 December 2012 (UTC)


 * For starter, this can be done by avoiding specific examples that cause selective representation of select regions, or making an assertion of commonality without having a reference supporting so. It's not necessary to add up filler words like "the most common" to remain encyclopedic. There are plenty of theoretical discussion on three phase power that do not involve specific arrangements that are dictated by local customs or historical reasons. Expressing that L-L vs L-N as having a relationship of 1 vs √3  as opposed to Canadia centric 347 vs 600 or NA centric 120 vs 208 is a good example.
 * I can agree that the article should be kept fairly generic in this regard but not completely. For the reader some numeric examples go a long way toward ubderstanding. The article is written in AmEng and should be slightly AM-centric (does EngVar apply to tech details?) but other numerics should be also be included to accomodate the poor young reader from other geographies. I think most of us N.Americans are fairly ignorant of the rest of the world electrically. 174.118.142.187 (talk) 02:35, 21 December 2012 (UTC)
 * EngVar applies to technical terms certainly, but that does not mean we should favour American examples in an AmEng article, unless of course the subject of the article is specifically American. On the contrary, WP:BIAS positively encourages us to take a world perspective in our articles.  Spinning  Spark  08:02, 21 December 2012 (UTC)

Open Delta?
The trouble with the Delta system of 3 Phase power transmission is the logistical problem of maintaining a consistent existence of voltage to neutral/voltage to ground of the elements of the system. This overcomes any advantages it might have for specific applications as I have tried to point out in the following offtopic segment. A consistent voltage to ground relationship is a necessary element of any generalized system for electrical power distribution and management. This fact is getting lost in the general discussion about other less important details.WFPM (talk) 02:12, 4 January 2013 (UTC)
 * I believe you are confused with a floating delta system that has no ground connection. This could also occur with other system shapes but typically they would be grounded somewhere. Open delta means there is an incomplete delta system supply shape (only two windings) and the shape of the windings is not related with ungrounded winding sysytems or floating voltages on secondaries of transformers. In my experiencees with ungrounded delta systems it has not usually been a problem once kilometers of customer wiring inside factories, motor windings and coils have been connected to the supply. The resulting inductive capacitance to ground divides the voltages across ground fairly well. Having said that, I had an electrician check an unloaded transformer trio with a voltmeter to ground and the blew the VM out of his hand so this delta stuff wants to be designed out by EE people. Usually replaced by grounded wye systems, but they have their own set of problems for transmission. Make more sense? 174.118.142.187 (talk) 22:53, 4 January 2013 (UTC)


 * Yes! and in the case of a reasonably complex electrical primary transmission system, the tendency is to stick with the center grounded Y system throughout the system which then propagates the extended Neutral/ground system and allows varying primary phase to phase voltages to be changed throughout the system as demand power volumes decrease and other conditions merit.This usually involves a consistent periodic grounding of the neutral system at interval distances of maybe 4 per mile as a means of assuring the reliability of propagating of the ground voltage potential.WFPM (talk) 02:56, 5 January 2013 (UTC)

offtopic
We lost a 1500kva transformer once and ran it open delta at .537(?) rated capacity until we could replace the burnt out unit. Is it legal/illegal in most places and should it be mentioned in the article if it is allowed?--Canoe1967 (talk) 17:07, 17 December 2012 (UTC)
 * Oh, it's legal, but probably something more used by utility distribution than by industrial users. There's lots of ways of supplying a three-phase system. --Wtshymanski (talk) 17:16, 17 December 2012 (UTC)
 * I have witnessed Scott-Tee transformers with only two windings at 90 degrees phase angle supplying three phase systems. Two transformers saves on transformer materials and is encouraged in some applications. The biggest drawback is the reduced capacity and efficiency of the cores. 174.118.142.187 (talk) 17:23, 17 December 2012 (UTC)
 * Is it High-leg delta? Ours were 3 single phase in one 14.4kv/600v bank. The plant was fed with 14.4kv and we had four 14.4kv/600v banks. It was our main one and we kept production at almost 80% until we could replace it. Far better than 0%. I suppose if there are 100s of ways to deliver 3 phase each one doesn't need to be mentioned here.--Canoe1967 (talk) 17:32, 17 December 2012 (UTC)
 * No, High-leg delta is a completely new name for me, (3-phase, 4-wire, delta) though. High-leg delta contains a neutral centre tap on one leg whether three or two windings. When one winding disappears in a delta transformer we called it open delta. Some, here, are calling it "V" as it represents it's vector diagram picture. 174.118.142.187 (talk) 17:39, 17 December 2012 (UTC)

Three-phase_electric_power Found it. I guess I should have read the whole article. It even refers to the situation we had.--Canoe1967 (talk) 17:46, 17 December 2012 (UTC)

The problem with center tapping one leg of a delta system is that the other legs then don't have a defined grounding circuit and there can have a varying voltage to ground. This makes it difficult to provide a neutral connection for an appliance hooked into a single phase circuit from the ungrounded transformers. Any ideas?WFPM (talk) 11:08, 31 December 2012 (UTC)

At the time of origen of the rural electrical power transmission system in the US the effort was made to make the maximum accomplishment with the minimum equipment expense. This resulted in the minimizing of the number of distribution transformers needed to supply the small systems and resulted in the initial installation of a large number of open (2 transformer) delta systems which could subsequently be augmented in capacity by a 3rd transformer at a later date. This also originated the problem of providing a grounded neutral connection to all the users of the system and resulted in the multiplicity of designs for same. It is now pretty well established that the best 3 phase supply system is the center grounded Y or "Star" system, which has the capability of supplying all of the phases with the same voltage to neutral/ground connection.WFPM (talk) 02:53, 1 January 2013 (UTC)However in the article, the between phase and phase to ground voltage relationships of the various power line systems is not adequately explained.WFPM (talk) 02:53, 1 January 2013 (UTC)

Consensus of English dialect used in this article
I have boldly closed this discussion early. As noted, the issue has already been discussed and decided to use AMENG. Nothing new has been brought to the debate. We can debate and confirm consensus here until the end of the world but it will not prevent new or inexperienced users continuing to change color/colour. Each one needs to be educated about ENGVAR anew.  Spinning Spark  17:43, 18 December 2012 (UTC)

This section was recreated after a user expressed objections to the format rearranging his comments. This became necessary after an Administrator User:DMacks demanded a consensus on this item following some edit warring.

I don't give a damn what it originally was or later became, but the constant IPs' changing of it is absolutely forbidden so I semi-protected the article. For at least the second time for this exact reason. The article goes with whatever WP:CONSENSUS might develop, so thank you for starting the discussion, and no mind will be paid to those who do not participate here. DMacks (talk) 19:17, 23 November 2012 (UTC)

The results of this consensus will affect some of the spellings (color vs. colour) (wye vs star), some formats of mnemonics and more. The original article appears to be written using American English and that is the current dialect.

Please discuss English versions

 * Canadian English - colour, wye is understood by the majority of English speaking peoples. 174.118.142.187 (talk) 18:59, 17 December 2012 (UTC)
 * Declined as irrelevant Voting is evil. The dialect for spelling is irrelevant to the article anyway. This article has bigger problems than deciding which correct spelling to use. Any literate Web user knows there's more than one corect way to spell many words and shouldn't get too hung up if the "other" spelling shows in a Wikipedia article. --Wtshymanski (talk) 20:04, 17 December 2012 (UTC)
 * While I agree partially much time is being spent on these spellings. 174.118.142.187 (talk) 04:28, 18 December 2012 (UTC)
 * Er - not until you started changing them. DieSwartzPunkt (talk) 13:37, 18 December 2012 (UTC)
 * Your comments are not based on actual events. Unless you can produce diffs to support your accusations your comments are disruptive to this process and I am asking that you refrain from further disruptions here. 174.118.142.187 (talk) 13:46, 18 December 2012 (UTC)


 * Having just gone through the edit history, I can categorically state that 174.118.142.187 did not make the first (or indeed any change) to 'color'. I B Wright (talk) 17:11, 18 December 2012 (UTC)


 * This has already been dealt with. There is no need for any discussion unless someone is disputing something.  Spinning  Spark  23:19, 17 December 2012 (UTC)
 * We have observed a lot of editwarring on certain word spellings in the last few months. It was disruptive and will cause the article to be protected and editors to get holidays, next. If this was dealt with let's present the diffs to the complaining admin, post the result here and get this monkey off our backs. 174.118.142.187 (talk) 04:28, 18 December 2012 (UTC)


 * Where did Jan 23 come from? I don't believe that any single editor has the authority to unilaterally declare deadline. Cantaloupe2 (talk) 08:31, 18 December 2012 (UTC)
 * It was selected as 60 days from the admin complaint. This is a reasonable time for those who care to express opinions whether to change the assumed existing dialect used. This issue needs closure as some issues have dragged on and I chose a length of time. Was there a specific complaint you wanted to voice about the length of time or was it just about who chose it? 174.118.142.187 (talk) 13:29, 18 December 2012 (UTC)


 * Another admin Spinningspark already stated that it has already been dealt with and that was my impression as well. Cantaloupe2 (talk) 13:42, 18 December 2012 (UTC)


 * OPPOSED: This discussion is pointless. WP:ENGVAR makes it quite clear that American english is the ruling english variant for this article. This whole issue has been triggered by one editor repeatedly changing 'color' to 'colour'. Quite why 174.118.142.187 thinks Canadian english should be used instead is a mystery. Will he subsequently be proposing the whole of Wikipedia is translated into Canadian english?  A logistical nightmare at best. DieSwartzPunkt (talk) 13:35, 18 December 2012 (UTC)


 * Oppose: Wikipedia has clear policies on English variants and there is nothing to be gained by changing spellings in one article. I B Wright (talk) 14:26, 18 December 2012 (UTC)


 * Comment: I have just had a good look at the history behind all this. It appears that one editor, for some reason, changed the spellings from 'color' to 'colour'.  After that with repeated changes one way and the other, sight of which spelling was the original apparently got lost in the noise.  It is quite possible that most of the subsequent changes were made in good faith either way.  At present, the article has the spellings that appeared in the first significant version of the article that had any regional english (as per WP:ENGVAR).  I therefore suggest that his discussion should be closed as needless.  I would have done this myself, but it would be better if the lead editor did this, or possibly an Admin.  I B Wright (talk) 17:07, 18 December 2012 (UTC)


 * Thank you for that closure Spinningspark! I think everybody is happy with that one and the guessing game should be over. Can a note be put in the talk page or article edit page that clarifies this to drive-by editors? I have seen it in other articles but not sure how I would do it. Thanks again. 174.118.142.187 (talk) 18:03, 18 December 2012 (UTC)


 * There is series of tags that can be placed on the talk page to flag the English variant being used in any article. For this article it would be the  tag.  However, I note that this tag is already at the top of this talk page so no action is required. I B Wright (talk) 12:52, 19 December 2012 (UTC)

3/4, delta/wye/star, etc
I reworded, because a credible source confirms that high-leg delta is "another popular system" in medium and small buildings and provided ref. I also changed "occur" to "setup". 3ph power do not require the three windings to be linked together. So, its not like it "occurs" like that. I think McGraw-Hill published book saying so is enough to take it out of exotic category. I removed references to numeric voltage values, but used percentages which should be easily understood by audience group that would be reading this kind of pages. Cantaloupe2 (talk) 09:06, 21 December 2012 (UTC)
 * Popular maybe but not a basic configuration and I highlighted the phrase in the opening sentence to avoid some of this continuous injection of confusion in this section. As noted in previous discussions, we could insert five or six popular types of grounding systems and neutral in this basic configuration opening and it would just be a confused mess again. It seemed the agreement was to start with the basic configuartions (there are only two ways to connect three phase winding and loads delta and wye) and add limited mention of the exotic systems later. Without experience in the field it's a big confusing subject. Best of luck. 174.118.142.187 (talk) 14:54, 21 December 2012 (UTC)
 * You have stated that you've never heard of it until now. Just because YOU have not personally heard of it does not get classified as "exotic".  You not only removed what you contend, but reverted my whole edit, including stripping of high quality reference. "Without experience in the field it's a big confusing subject." WP:VWP:OR disallows editors from injecting first hand knowledge and making up something based on anecdotal evidence not supported by reliable second sources. Your assertion for "exotic" is strictly anecdotal. The cited reference I added is retrievable by web. So, if reader can't understand something, they can access the reference, not only to ensure that its not some tale from some "field experience" but to read on further to help them understand. Cantaloupe2 (talk) 21:07, 21 December 2012 (UTC)
 * Please refer to my actual comments and do not attempt to distort them. I stated that I had not heard that name used for this type of system. Perhaps it is a Euro-centric name the rest of the world isn't familiar with. I do not know what high-quality reference was "stripped" from your edits unless you are the same editor as IB Wright. He placed a reference in the text that was removed as it went against the established concensus above. Is that the "high-quality referrence" you implied was yours? Your semantics regarding the usage of "exotic" for these non-basic systems is becoming tiring and disruptive to this section. I see only full circle edits back to where it started. 174.118.142.187 (talk) 21:09, 23 December 2012 (UTC)


 * I would wager its something YOU are not familiar with, not the world. References I've used in this and other articles about high leg delta have been America based publications. In this edit, you stripped the Fowler reference. Also your accusations of other editors of Sockpuppeting over this page on a mere hunch is not WP:AGF and including my name out of carelessness and causing me to receive undue attention is disruptive and defamation. Let's agree to disagree over the application of the term "basic". Cantaloupe2 (talk) 21:26, 23 December 2012 (UTC)
 * If you posted a good reference it should have left it in the prose. I must have missed the ref in my shortening the verbose prose as it was so tiny. It is behind a paywall but verifyable. Thanks! As far as the other issues you mentioned this is not the place as it disrupts the article talk page. I have proposed a solution for us all, below, that I hope you will keep a cool head in order to collaborate for a better solution in this article section. 174.118.142.187 (talk) 21:55, 23 December 2012 (UTC)
 * I see somebody has already replaced accidental link deletion. 174.118.142.187 (talk) 14:51, 30 December 2012 (UTC)

Three-phase configurations (3-wire vs 4-wire) (delta vs wye) compromise proposal from from discussion's consensus section above
Since there seems to be so much confusion of the basic mechanics of this subject perhaps we should separate "basic systems" into source/winding shapes, delivery conductor counts, load shapes, and grounding discussions. This would incorporate most of our concerns, here, (wires vs shape vs popular vs rare) and be a great and very simple section for readers. The section could appear something like this. (detail text based on knowledge and references would be added after getting basic layout agreement) Three-phase configurations
 * 
 * Source configurations
 * 
 * Delivery conductors
 * <3-wire & 4-wire text info. cover with and without neutral advantages etc. Sources require which number of conductors>
 * Load types
 * Delta or L-L loads.
 * 
 * Wye or L-N loads.
 * 
 * 
 * 
 * Grounding
 * 

 Let's discuss this out and attempt to move forward with it. Comments Please! 174.118.142.187 (talk) 21:35, 23 December 2012 (UTC)


 * "delta" load, "wye load" are misnomer. What do you call dual voltage motors which can be configured in wye or delta? i.e. delta connected for 1n V and wye connected for 1.73n V?  A 1.73n V motor internally wired delta or wye motor wired for higher voltage configuration will work any three phase source providing the correct voltage. Is it a wrong guess that you're looking at this through the eyes of electrical wiring technician/electrician POV?. References should be added in your sandbox before text is introduced into article so you're not using the article as sandbox. Cantaloupe2 (talk) 21:50, 23 December 2012 (UTC)
 * I call the motors reconfigurable. I call them a delta connected or wye connected winding exactly as your text says.  The discussion is here and you seem to be capable of good input on this. If you have a suggestion what to to call delta or wye wired loads, let's hear it. 174.118.142.187 (talk) 22:08, 23 December 2012 (UTC)


 * On the supply end, the wye or delta configuration of the motor does not matter. The supply side does not care if three heating module uses three 100v elements connected together in wye, the hub concealed and three wires brought in.. or three 173v elements connected in delta. What reference says the need to be distinguished to classify load type? You can provide reference link here too. Cantaloupe2 (talk) 22:14, 23 December 2012 (UTC)
 * Thanks. I agree! This is idea behind itemizing any system into components. I am attempting to stop everybody insisting on different formats for the specification of a system. Some say it's the wire count, some say it's the source, some say it's load, even grounding methods. Perhaps breaking it down into components we could make everybody happy and not specify a whole system. Your response was this. to which most of us agreed but editwarring has multi-changed the style of specification. 174.118.142.187 (talk) 22:35, 23 December 2012 (UTC)

'Invention' of three phase electric power
There seems to be some dispute going on over the invention of three phase power.

The contentious sentence seems to be:

I see that an fellow IP editor is asking who invented it first. This question actually raises more important issues. The sentence as currently worded claims (or at least appears to claim) that three phase power's invention was a co-invention by all three men. What is missing is any form of reference to support that claim. The sentence cannot make or imply that unreferenced claim (WP:V and WP:RS).

Indeed, all the available evidence would point to Galileo Ferraris being in Italy when three phase was developed; Mikhail Dolivo-Dobrovolsky being in Russia and Nikola Tesla being in America. Given the lengthy communication delays of the late 1880's, it would seem highly unlikely that the three men could have co-operated (and even more unlikely that they would have wanted to). If it cannot be proven that they did co-operate then the sentence, at the very least, requires a rewrite to remove the claim and make it clear that it was independantly 'invented' by all three. I would have had a go, but the article is protected.

It would be nice to document who really inveted it (i.e. who patented it first), but something tells me that this may not be so easy to discover given that we are dealing with the patent systems of three different countries. 212.183.128.231 (talk) 15:19, 29 January 2013 (UTC)


 * Since there has been no further comment, I have gone ahead and amended the sentence to emphasise that it was not a collaborative invention. 212.183.128.155 (talk) 11:01, 3 February 2013 (UTC)

Images to consider
This image shows the power contribution % from each phase at any given time. The Peaks are marked. You may find the last image I uploaded if you look for it, I noticed a math error so i had to discard it. I have a third image that also shows the missing power (what makes sine wave power output inconsistant) which makes the whole graph look like its based on sinsuioid again. Charlieb000 (talk) 23:40, 27 March 2013 (UTC)