Talk:Transformer

Old discussions

Old discussions have been moved to archives - use the navigation box to switch between them. I used the much nicer {{archives}} and {{archivesnav}} templates as found on the Personal computer talk pages to spruce up navigation a little. Rememember when creating new archive pages that they must have a space in the title - talk:transformer/Archive 7 would be the next page, for example. --Wtshymanski (talk) 21:55, 4 September 2009 (UTC)

Plugwash - please look at the transformer equation

From the transformer article:

${v_{P}}={N_{P}}{\frac {d\Phi _{P}}{dt}}$     and     ${v_{S}}={N_{S}}{\frac {d\Phi _{S}}{dt}}$

That is, the rate of change of flux at any instant is proportional to the instantaneous voltage. A non-zero voltage produces a non-zero rate of change of flux. A changing flux does not require a changing voltage. That's precisely what that equation says. Do you disagree? Alfred Centauri 02:59, 5 April 2007 (UTC)

This is a case where the equations have been simplified so much from reality that they imply a behaviour that can't happen in any real transformer. Since any transformer has both nonzero series resistance and noninfinite paralell inductance any DC voltage applied to the transformer will be dropped entirely over the resistance and will therefore not contribute to the magnetic flux. Therefore all changes in flux are a (possiblly delayed) result of a change in applied voltage.

Afaict in electronics a common approximation is to consider a transformer as if it were an ideal transformer apart from the fact it blocks DC. Plugwash (talk)

But if I take a little control transformer and put some DC on the secondary, if I try to take it apart *something* is holding the core in with great effort. There's got to be flux even with DC applied to a practical transformer! --Wtshymanski (talk) 03:09, 4 September 2009 (UTC)

This thread confuses me. Is it in reference to some particular part of the article? I could try to help explain but I'm not sure what question we are trying to answer. Ccrrccrr (talk) 21:47, 4 September 2009 (UTC)

"But if I take a little control transformer and put some DC on the secondary, if I try to take it apart *something* is holding the core in with great effort. There's got to be flux even with DC applied to a practical transformer!".

In the steady state with a DC input on a real transformer there is flux but not change in flux. As there is no change in flux there is nothing to induce voltage in the secondry.

When a step change is applied the initial step will be passed but will then gradually decay away since the real transformer is essentially a bandpass filter (as can be seen from the "equivilent circuit" in the article)

"This thread confuses me. Is it in reference to some particular part of the article?"

It was started by alfred when he reverted my edit ( http://en.wikipedia.org/w/index.php?title=Transformer&diff=120396448&oldid=120392870 ). I didn't notice it for some time but when I did I dug up the edit and then tried to explain the situation which is that DC blocking is both useful and a basic physical characterstic of a transformer even though the most simplified equations would seem to indicate an ability to pass DC. Plugwash (talk) 23:04, 6 September 2009 (UTC)

Thanks! I think the problem is that the issue is a subtle one, and not likely to be fully accurately addressed in the lead. I can't say that either wording is "correct" in the sense that it's fully accurate. I think the solution would be to explain more fully elsewhere in the article, and perhaps add an extra sentence to the lead, saying something along the lines that transformers don't work with dc. Ccrrccrr (talk) 22:58, 9 September 2009 (UTC)

Use of Single phase versus three phase

What is the advantage of using 3-single phase transformer VS 1-three pahse transformer, aside from physical side, I am talking about big power transformers, e.g. 30MVA —Preceding unsigned comment added by 216.135.182.146 (talk) 20:18, 18 September 2008 (UTC)

Transport weight is lower. Very large 3-phase transformers may exceed transport ratings and height limits. 30MVA is not exceptionally large, by the way. 600MVA 3-phase units are commonly transported. The 800MVA transformers I once worked on were however constructed as three single units. — BillC ^talk 22:05, 18 September 2008 (UTC)

Question about wheels

what is the reason almost all the power transformation installed along with the wheel.why not without wheel. —Preceding unsigned comment added by 196.44.248.134 (talk) 12:31, 30 September 2008 (UTC)

Order of article

This article recently had history moved up and applications moved down. I don't think that's appropriate for a technology article. The most important thing about technology is its application; it's history is often omitted from, for example, a textbook. Other topics are different. For example, in science, the phenomenon would be primary; applications secondary. I'm not aware of WP policy in this regard--I'm just stating my opinion. But I think that a change like that needs discussion. Ccrrccrr (talk) 22:20, 22 November 2008 (UTC)

Disagree. Engineering textbooks, in particular, shamefully neglect the history of just about everything...everything is handed down as if on a stone tablet, with no indication of the origins except a random name or date. (There's a reason for this...engineering students have limited time and interest, and textbooks can't afford to take the space to go into the history...look at Friedel's and Hughes' books for just how much space it takes to talk about history.) I don't think you can understand the applications of anything until you have some notion of where it came from and why it was created in the first place. --Wtshymanski (talk) 16:32, 23 November 2008 (UTC)

I agree that someone who wants an in-depth understanding should read the history, and I enthusiastically support having it in here, but I don't think that's the first thing most readers will want to know. Thus, if we follow news style or summary style guidelines it wouldn't come first. But that's just one recommendation, not a firm policy, and there doesn't seem to be much other guidance or policy on order in articles, so let's continue to discuss.Ccrrccrr (talk) 22:24, 23 November 2008 (UTC)

Net flux in transformer core

I notice someone has reverted my correct statement about there being no net flux (apart from magnetising flux) in the core. I would refer the person to any proper textbook on electrical engineering and in particular ,transformers, to establish that I am in fact correct. Also what is LC? Inductor capacitor resonant circuit or something?--GreenSpigot (talk) 01:48, 16 December 2008 (UTC) ~Featured article?

Why isnt this an FA yet (or have I missed it) its certainly inertesting enough and quite stable (apart from the net flux issue)--GreenSpigot (talk) —Preceding undated comment was added at 02:13, 16 December 2008 (UTC).

You know we all know you, Light current. A lot of work is required to get this article to FA. — BillC ^talk 02:50, 16 December 2008 (UTC)

Treaths

perhaps a threaths section can be added. Mention the possibility of a Geomagnetic storm —Preceding unsigned comment added by 91.176.221.91 (talk) 09:36, 8 July 2009 (UTC)

History references

For future reference, here's another good article with a lot of detail on how much of an advance the ZBD transformer was:

"Transformer Invented 75 Years Ago" by Halacsy, A. A. and Von Fuchs, G. H., in Power Apparatus and Systems, Part III. Transactions of the American Institute of Electrical Engineers, April 1961, Volume: 80, Issue: 3 pp. 121-125, ISSN: 0018-9510, Digital Object Identifier: 10.1109/AIEEPAS.1961.4500994

and a book with great detail on the many little advances made in various patents c. 1850 to 1885

Title The alternate current transformer in theory and practice

Author John Ambrose Fleming

Publisher "The Electrician" printing and publishing company, limited, 1892

Google books link: [1]

-Ccrrccrr (talk) 21:35, 22 July 2009 (UTC)

As all sources state, the most important newness in ZBD was its high efficiency: 98-99 percent(!). The efficiency of Gaulard & Gibbs' former "champion"-system was less than 38 percent. --Zolika76 (talk) 16:56, 4 September 2009 (UTC)

This was at least one of Edison's arguments against AC distribution - he knew that a system that was carefully calculated to turn a profit at the efficiencies he could get from DC generators and distribution would be intolerably expensive to run if he had to generatore 2 or 3 times as much power to give the same amount of light. --Wtshymanski (talk) 20:00, 4 September 2009 (UTC)

Needed: article on soft magnetic materials

In editing the lead, I wanted to link to the article on soft magnetic materials. There isn't one! Magnetic material redirects to an article on hard magnetic mateirals (called magnet); soft magnetic material redirects to an article on coercivity.Ccrrccrr (talk) 01:39, 25 July 2009 (UTC)

Invention of Transformer formula

Ottó Bláthy turned his interest more and more towards electro-technology and thoroughly studied Faraday's experiments and Maxwell's theoretical work. He soon recognised a method of practically applying Ohm's magnetic law, the connection between the magnetic field and the excitation creating it. Bláthy was the first who was able to calculate magnetic circuits using magnetising curves and, in this way, economically design electric direct current machines.

http://www.omikk.bme.hu/archivum/angol/htm/blathy_o.htm --Zolika76 (talk) 18:38, 9 September 2009 (UTC)

The above comment is entirely plagiarized from the source material. It also has little if any relevance to the "Invention of Transformer formula". Moreover, it is almost certainly posted by banned user Celebration1981. Rico402 (talk) 21:31, 9 September 2009 (UTC)

I think it was meant to be presented as a quotation, but he got the mechanics of presenting a quotation wrong. But I agree that it is not relevant, and I restored the citation tag for that information in the article. --Ccrrccrr (talk) 22:49, 9 September 2009 (UTC)

Not likely he merely got the mechanics wrong. Zolika76 is a sockpuppet of Celebration1981, and plagiarism is his customary method of adding content. (I just rephrased a bit of his plagiarism re the Ganz Company's work.) He's been blocked as of 22:47, 9 September 2009 (UTC). (And I had nothing to do with it. ;) Cheers, Rico402 (talk) 00:37, 10 September 2009 (UTC)

I suggest this whole section be deleted, as it is just more blather from banned user Celebration1981 using sockpuppet Zolika76. Rico402 (talk) 20:15, 17 September 2009 (UTC)

PS: The transformer formula is not an "invention"; Bláthy et al discovered and formalized the relationship between turns ratio and emf. A discovery or realization does not constitute "invention". (Did Einstein "invent" E = mc² ?) Rico402 (talk) 20:30, 17 September 2009 (UTC)

Title of Faraday section

There seems to be an edit war going on over the title of the section about Faraday. Please discuss here rather than engaging in an edit war. Ccrrccrr (talk) 22:53, 9 September 2009 (UTC)

Well, one warrior has been banned for now, so at least you might get a civil discussion. I have no strong feelings on the matter, but it seems to me that "Discovery" is too vague a title. "Discovery of induction phenomenon" isn't bad, but perhaps "Discovery of electrical induction" would be more appropriate; or just "Electrical induction" (or "Electrical self-induction", sans the italics).

Btw, I'm of the opinion that at some point this subsection should be expanded a bit. In particular, I would like to see Joseph Henry mentioned, as he discovered electrical induction independently and at about the same time as Faraday, and of course, the SI unit of inductance (the "henry") is named after him. (Although apparently Faraday formalized the equations.) Cheers, Rico402 (talk) 04:46, 13 September 2009 (UTC)

Research away, but Henry didn't do much for transformers as such and his contributions should be amplified elsewhere. Hungarian nationalism aside, it's plain that whatever Faraday called his device, it's a transformer - it even has the much-praised closed magnetic core. I don't know if Faraday ever published any description of a theory as to how his device worked or if he ever worked with AC on it. --Wtshymanski (talk) 14:27, 13 September 2009 (UTC)

I don't disagree that "whatever Faraday called his device, it's a transformer". (Nor that he essentially invented the electric motor as well.) In fact, I would like the article to expand a bit on Faraday's contributions to the development of the transformer. (That's something I was hinting at when I wrote that the "subsection should be expanded a bit.")

Re Henry: I was just referring to a mention of his co-discovery of electromagnetic induction. For example: "In 1831, Michael Faraday and Joseph Henry, working independently, discovered the phenomenon of electromagnetic induction, [the whatever of the whatever]. Faraday would go on to [blah, blah, and blah], now known as 'Faraday's law of induction', or simply 'Faraday's law'." (I believe this is covered in one of the refs already cited.)

At present it reads, "Michael Faraday discovered the principle of induction, Faraday's induction law, in 1831 and did the first experiments with induction between coils of wire", suggesting that Faraday alone discovered the principle of electromagnetic induction, which simply isn't true. Nor is it true that "the principle of induction" is "Faraday's law of induction". The law of induction describes and mathematically formalizes the induction phenomenon; it is not the phenomenon itself. So that bit needs some clarification. Cheers, Rico402 (talk) 20:26, 14 September 2009 (UTC)

Naming

Can it be mentioned in the definition that electricity transformer or electrical transformer are also valid terms ? http://encyclopedia.farlex.com/Electrical+transformer Transformer alone can also mean "one who transforms" (eg shapeshifter, ...) ; see http://dictionary.reference.com/browse/transformer —Preceding unsigned comment added by 81.243.187.171 (talk) 15:15, 12 September 2009 (UTC)

That would be redundant; the header already states "This article is about the electrical device". What you're suggesting is differentiating the term from a non-specific "dictionary definition". Moreover, it's quite common, perhaps more often than not, that names given to electrical/electronic devices (or properties) have a much broader application outside this technological sphere; e.g., a "resistor" is anything (or anybody) that "resists", yet in electronics it refers to a component capable of performing a specific function within a circuit. Such nominal specificity is exceedingly common, which is why we have "disambiguation" pages. Cheers, Rico402 (talk) 04:00, 13 September 2009 (UTC)

Definition change

A transformer is a device that that converts high-voltage electrical energy to low-voltage electrical energy or vice versa. A transformer that converts high-voltage to low-voltage energy is called a step-down transformer. A transformer that converts low-voltage to high-voltage is called a step-up transformer. —Preceding unsigned comment added by 81.245.90.148 (talk) 09:22, 9 October 2009 (UTC)

Yes, but a DC to DC converter changes the voltage too. --Jc3s5h (talk) 14:45, 9 October 2009 (UTC)

True, and the "dictionary definition" suggested by 81.245.90.148 is not only limiting, but inaccurate; cheers to Wtshymanski for restoring the previous version. However, it may not be a bad idea to insert a few lines that describe the most common (is it?) use of a transformer akin to Ccrrccrr's recent edit; i.e.:

"Although a transformer may serve a variety of functions, perhaps the most common is to manipulate the EMF of an electrical current. A transformer that converts low voltage to high voltage is called a step-up transformer; a transformer that converts high voltage to low voltage is called a step-down transformer."(Insert appropriate ref.)

Cheers, Rico402 (talk) 02:56, 10 October 2009 (UTC)

Why?

Why in all languages it is 'transformator' and only in English 'transformer'?--MathFacts (talk) 08:19, 15 December 2009 (UTC)

Don't really know, but it's probably because a lot of Latin-derived words get shortened in English. Modern English "transform" is derived from Middle English "transformen", from Latin "transformare". (The American Heritage Dictionary, Second College Edition, 1985) It's also common in English to make a noun from a verb by simply adding "er"; maybe in other languages it's done by adding "ator". English is a relatively new and economical language, "borrowing" from many sources, and often simplifying the spelling and pronunciation. Cheers, Rico402 (talk) 08:46, 18 December 2009 (UTC)

Incorrect image

The first image under the section "Practical Considerations" (located at http://en.wikipedia.org/wiki/File:Transformer_flux.gif) is incorrect. For the shown winding sense, the output (secondary) current would be opposite of what is shown. The first image under "Basic Principles" (located at http://upload.wikimedia.org/wikipedia/commons/thumb/6/64/Transformer3d_col3.svg/350px-Transformer3d_col3.svg.png) is correct, and can/should be used as a reference to fix the image.

For the incorrect image, if the winding sense (and nothing else) is changed, then everything would be correct including voltage, current, and flux orientations (note that the primary leakage flux and mutual flux are in the same direction, but the secondary leakage flux and mutual flux are opposite... This is correct).

I would be happy to provide a correct image if needed.

Cheers, Electrophysics_matt Electrophysics matt (talk) 06:18, 31 December 2009 (UTC)

secondary winding, secondary coil, secondary circuit

Was cleaning this DAB page for "Secondary" and came here to see which secondary it was referring to. Very unclear. Are secondary winding, secondary coil, and secondary circuit all the same thing? If so the terminology needs to be cleaned up. Fountains of Bryn Mawr (talk) 23:24, 4 February 2010 (UTC)

With respect to transformers, "secondary" should only apply to a "secondary winding". (A transformer may have multiple secondaries.) The term is synonymous with "secondary coil", but I believe "winding" is preferred (at least by me ;). The circuit connected to a transformer's secondary is often called a "secondary circuit", and therein lies the confusion.

The disambiguation page has been edited to (hopefully) clear up the confusion. Cheers, Rico402 (talk) 08:26, 10 February 2010 (UTC)

Ty for the clearification. I rewrote the DAB entry to match MOS. There is still the small problem of terminology, this article uses the term secondary coil 11 times and secondary winding 18 times with no explanation as to if this is the same thing. Fountains of Bryn Mawr (talk) 14:58, 17 February 2010 (UTC)

Ground loops

In physics experiments 1:1 transformers are often used to eliminate ground loops. I guess it's a similar usage in audio applications. Is it worth mentioning this usage and/or discussing/linking? Grj23 (talk) 05:58, 10 February 2010 (UTC)

These are isolation and/or impedance matching transformers. Audio signal coupling is mentioned in the intro and there is a brief mention of "isolation" under "Classification", but I suppose the topic could be expanded upon and links added. Audio transformers include 1:1 isolation transformers as well as impedance matching transformers, i.e. a direct box (or DI, for "direct input" or "direct injection") for matching a high impedance output (guitar or keyboard) to the low impedance input of a mixing console. Cheers, Rico402 (talk) 09:07, 10 February 2010 (UTC)

I use 1:1 transformers all the time in my live sound career. They eliminate ground loops, certainly, and they balance unbalanced circuits such as laptop headphone outputs, or RCA jack outputs, for the purpose of having a very long cable run carry the audio signal to an audio mixer input. I'll keep tabs on any expansion to see if the subject is well treated. Binksternet (talk) 09:31, 10 February 2010 (UTC)

This article also needs to have ground loop isolation listed: Transformer_types#Audio_transformers.

Furthermore, the transformer's limited frequency response has been used to help prevent radio frequency interference from causing trouble in an audio mixer. The AM radio band starts around 500 kHz, and 1:1 audio frequency transformers drop sharply in response above some target high frequency design goal such as 20 kHz or whatever, meaning you don't get the local AM station playing in your audio circuit if there is a transformer in line. Audio transformers are limited in their high and low frequency response by several factors, primarily size: high frequency becomes more difficult to obtain with larger transformers, and low frequency becomes more difficult with small transformers.

• http://www.jensen-transformers.com/iso_aud.html
• http://www.jensen-transformers.com/apps_wp.html
• http://www.lundahl.se/papers.html
• http://www.lundahl.se/probsolv.html
• http://www.whirlwindusa.com/spcint.html
• http://allenavionics.com/AVI_Trans/AGL.htm

HTH. Binksternet (talk) 10:06, 10 February 2010 (UTC)

Split-Phase transformer

Please, when a pole mounted transformer is powered by a single phase primary (typically 7,2 KVAC) and its output is a secondary winding of 240 VAC which is center tapped to produce two 120 VAC sources, it is called split-phase. The secondary center tap is grounded to earth. Please read the Wikipedia http://en.wikipedia.org/wiki/Split_phase article. We should use split-phase when we talk about these transformers and not call them single phase transformers.

Often three single-phase transformer's are powered by three phase electric, typically at 7.2 KVAC. These transformer's secondaries are connected together to power a facility with three phase power.

Sponsion (talk) 13:48, 12 July 2010 (UTC)