Talk:Transformer/Archive 14

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New Transformer template

I would like to create a new Transformer template that might include:

• content in current transformer's Classifications and Types sections
• content similar or like Electric motor template (see below) including especially row about SI electromagnetism units
• possibly even to summarize transformer's pesky article's equations
• and so on.

As embarrassing as this may be, for I know the answer is certain to be trivial, my immediate problem is not being able to create this template. So any comments about the idea and suggestions about creating this new transformer template will be greatly appreciated.Cblambert (talk) 05:39, 19 June 2014 (UTC)

Thanks. I managed to create the template. So I invite reaction to the idea per se.Cblambert (talk) 23:25, 19 June 2014 (UTC)

As embarrassing as this may be, I don't even know what you would do with such a template.Constant314 (talk) 23:32, 19 June 2014 (UTC)

Embarassing part is behind us. The template is as described earlier in this thread and as now shown here at bottom. It would go at the bottom of Transformer. Next to Power delivery template. Only issue is that current Classification parameter and Types section content includes references and notes, which I excluded from the template. Template could be invoked in any other transformer articles (eg, Distribution transformer). I have kept motor template to give sense of other categories that might be included (eg, Historical 'People'). Cblambert (talk) 01:14, 20 June 2014 (UTC)

I have stripped down template to SI EM Units group for starting to use in Transformer. Ideal Transformer Equations should obviously not be included in template as they are now in dedicated Ideal Transformer box.Cblambert (talk) 01:21, 21 June 2014 (UTC)

Maybe I missed it, but I don't see the electric scalar potential or the magnetic vector potential.Constant314 (talk) 06:12, 21 June 2014 (UTC)

I changed one entry today. Anything in principle can be changed in WP. Feel free to change yourself to suit.Cblambert (talk) 06:51, 21 June 2014 (UTC)

GA Review

This review is transcluded from Talk:Transformer/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: QrTTf7fH (talk · contribs) 16:25, 24 July 2014 (UTC)

Hello, I'm planning to review this article soon (In the next 72 h). Regards and thanks to the editors for their dedication and work. --QrTTf7fH (talk) 16:25, 24 July 2014 (UTC)

GA review – see WP:WIAGA for criteria

---

Hi. This review is based on the latest version of the Article in the moment that it was written (Including small modifications of my own described in this review).

1. Is it reasonably well written?

   A. Prose is "clear and concise", without copyvios, or spelling and grammar errors:

   I found a DuckDuckGo hit of a part of the article text in [1]. This page contains the text “cm3” as such, rather than properly formated, a sign of careless copy-pasting and so it seems to me like the aforesaid web page is plagiarizing Wikipedia rather than the other way around. I searched other 3 pieces of the article with no results showing a sign of plagiarism.

   B. MoS compliance for lead, layout, words to watch, fiction, and lists:

2. Is it factually accurate and verifiable?

   A. Has an appropriate reference section:

   B. Citation to reliable sources where necessary:

   See comments below.

   C. No original research:

3. Is it broad in its coverage?

   A. Major aspects:

   B. Focused:

4. Is it neutral?

   Fair representation without bias:

   Transformers don't seem to be a controversial topic, and I have seen no conflicting information to the way it's presented in the article.

5. Is it stable?

   No edit wars, etc:

6. Does it contain images to illustrate the topic?

   A. Images are tagged with their copyright status, and valid fair use rationales are provided for non-free content:

   B. Images are provided if possible and are relevant to the topic, and have suitable captions:

7. Overall:

   Pass or Fail:

   Thanks for all the authors of this article and congratulations.

I could access a few of the sources used in the article. Here's the fragments with inline citations that I attempted to verify and the results:

“Ideal transformer” section:

“According to Faraday's law of induction, since the same magnetic flux passes through both the primary and secondary windings in an ideal transformer”: Failed. The pages used for the citation describe board aspects of transformers and a section about the physics of transformers begins there as well but there was no mention of this claim.

“a voltage is induced in each winding, according to eq. (1) in the secondary winding case, according to eq. (2) in the primary winding case.”: Passed. Both the source and the Wikipedia article on electromagnetic induction support the equations with a leading “−” due to Lenz's law (And explicitly mention Lenz's law); As I understand it, the sign here has a physical significance. Given a coil with a current through it in a fixed direction, it's a matter of sign convention whether to describe the resulting magnetic field in one direction or the other, but whatever the choice is, the voltage generated by changing this magnetic field (Either by a change in current or an externally applied magnetic field, as in a transformer secondary winding) is opposite in sign to the rate of change of the magnetic field. I inserting the sign to make the equations verifiable.

“The primary emf is sometimes termed counter emf.”: Passed. The web reference calls it “back-emf” and so does Heathcote's J & P Transformer Book but the corresponding Wikipedia article has sources for the name used here. Note that the reference for this fragment is a self‐published source and may not be suitable for providing verifiability, though it seems very useful. Consider changing it to an external link.

“The transformer winding voltage ratio is thus shown to be directly proportion to the winding turns ratio according to eq. (3).”: Passed. Given the verifiability of eq. (1) and (2), this could be considered routine calculations needing no additional sources according to my understanding of Wikipedia policy. I couldn't access the sources for this claims, however, but Heathcote's book support this as well.

“Polarity” section: Passed. Verified in Kothari and Nagrath; and Withaker.

Other possible issues with references:

Page numbers in references to Say's Alternating Current Machines are missing in 4 citations, but I don't have access to this source.

Miscellaneous:

“Percent impedance” was mentioned, but there was no mention of what it is. I added a footnote regarding its meaning as used in the article and a corresponding reference.

I substituted the normal spaces used in expressing a quantity as a numerical term and a unit with non breaking spaces.

Explaning emf and counter emf in terms of circuit diagram

Transformer article reflects much editing and discussion in attempt to simplify ideal transformer, which evidently ultimately requires a delicate balance for encyclopedia entry treatment. These simplification efforts included change in the two ideal transformer circuit diagrams made starting last February 11 shown below. It might be good to revert to some circuit diagram version that explicitly supports explanation of emf, counter emf and associated inductances (including especially mutual inductance) and which is seamlessly consistent with both Transformer article's equivalent circuit section and Leakage inductance article.Cblambert (talk) 16:46, 5 August 2014 (UTC)

Previous circuit diagram

Current circuit diagram

In my opinion, the proposed illustration is not appropriate for the idea transformer section. It is an expert's diagram and far too complicated for the ideal transformer section, Constant314 (talk) 20:50, 6 August 2014 (UTC)

I'm not accustom to hearing the voltage across an inductor referred to as counter EMF. I am familiar with counter EMF as a voltage produced by the motion of a motor.Constant314 (talk) 22:24, 5 August 2014 (UTC)

See popular YouTube video on explosion effect of back emf on inductor that is suddenly open-circuited.Cblambert (talk) 03:33, 6 August 2014 (UTC)

I'm sure the you-tube video is entertaining and I am acquainted with what happens when you try to suddenly stop the current in an inductor. I just haven't seen it called counter emf. You are, I believe, an expert on the subject and counter emf may be a common term for you and those who practice in the same field. For the rest of us including most practicing electrical engineers, it is just voltage.Constant314 (talk) 20:45, 6 August 2014 (UTC)

I am not suggesting necessarily reverting to the previous diagram. It is easy to say it is just voltage but transformer voltages actually are derived by the following image. This is the challenge for Transformer editors - to explain but not oversimplify technical truths. At the very minimum, diagram should include mutual inductance M. Cblambert (talk) 07:46, 7 August 2014 (UTC)

Transformer emf and counter emf

Minor grammar change

In the first section, I've changed "A wide range of transformer designs are used..." to "A wide range of transformer designs is encountered..." Akld guy (talk) 02:12, 17 August 2014 (UTC)

Animated figure in the "Effect of frequency" section

I find this animation to be confusing. The only way it makes sense to me is if the green signal is the primary voltage from a low impedance source, like the power line. But also, it is moving too fast for me to follow.Constant314 (talk) 17:57, 21 September 2014 (UTC)

Effect of Frequency

The section on the effect of frequency is inadequate. Yesterday I removed the word "time" before the word "derivative"; previously it read "the time derivative of flux with respect to time". Now I don't really think the part succeeds in explaining the effect of frequency at all, mainly due to;

1. unnecessarily long sentences cause ambiguity (quite common in \\//ikipedia), and more importantly,
2. missing explanation of details involved in altering the frequency of the power transmitted through a transformer.

The first paragraph with the suggested modifications/expansions is:

By Faraday's Law of induction shown in eq. (1) and (2), transformer emf voltages vary according to the derivative of flux with respect to time.[32] The ideal transformer's core behaves linearly with time for any non-zero frequency.[6][33] However, flux in a real transformer's core behaves non-linearly in relation to magnetization current beyond a linear range due to magnetic saturation of the core, which eventually leads to transformer overheating → 'How' is missing, and maybe even the statement is wrong. Magnetizing current, i.e. the current that flows within the primary winding, excites a magnetic field around the turns, and thus within the magnetic core surrounded by the turns as well, according to Biot-Savart law. According to the magnetic hysteresis curve of the material used as the core, the magnetic field applied by the primary winding causes a certain amount of remanence in the core. Hysteresis curve is a loop; it represents the (nonlinear) relationship between the applied magnetic field and the retained magnetization; and the area within the loop represents the energy dissipation due to reversal of the applied magnetic field, which is the case with alternating current that constantly magnetizes the transformer core in opposite directions. The reason of energy dissipation upon field reversal is (increased, or non-randomized) molecular/atomic collisions due to realignment motion of magnetic domains. Saturation happens when the applied magnetic field is maintaned even though the domains are completely aligned. However, the reason of heating up (energy dissipation within the core) is not still-existing magnetic field, the heat dissipation is caused by alternating magnetic field. How can a magnetic field that alternates less frequently (e.g. 50Hz AC) causes more heat dissipation within the core than a magnetic field that alternates more frequently (e.g. 400Hz AC). One explanation of increased heating upon decreasing frequency is decreased reactance of the windings, and the consequent increase in current. But what about the heating up of the magnetic core upon decreasing the frequency? If it is known that it is not just the windings but also the magnetic core that heats up (more) upon decreasing frequency, and if the sole reason of the (increased) heat dissipation is decrease in reactance of the magnetic core, which is typically made of insulated laminates specifically in order to decrease reactance, then increase in heat dissipation within the core has got nothing to do with magnetic saturation phenomenon.

85.110.4.121 (talk) 01:27, 21 September 2014 (UTC)

The page is not saying that when transformers are appropriately designed for the frequencies involved, the lower frequency one will experience greater internal heat losses than the higher frequency one. What it's saying is that lowering the frequency applied to a given transformer while keeping the applied voltage and load constant results in greater internal heating. Effectively, the transformer becomes less efficient. The remedy is to redesign for a core size appropriate to the frequency. Akld guy (talk) 04:32, 21 September 2014 (UTC)

This "the page is not saying.....it is saying...." template of yours, it not only reveals your opinion on the person to whom you are responding, but it is also statistically doomed to failure (much sooner even if failure is inevitable) in an atmosphere like \\//ikipedia, hopefully still withstanding, regardless of your intentions, and thus needs to be changed. This place is a product of free-ly offered personal energy, therefore it is advisable to concentrate on what the page should say, rather than assuming people don't understand what it is saying, especially when it seems to be highly probable that you did not even read carefully what I wrote in red up there.

I agree with both of you. I agree with Akid that the first paragraph probably refers a constant voltage situation and lowering the frequency below the deign frequency, such as operating a 60 Hz power transformer on a 50 Hz power system. But I also agree with 85.110.4.121 that the first paragraph needs work. The first paragraph should make sense on its own. If it actually is talking about the constant source voltage then it should say so.Constant314 (talk) 17:50, 21 September 2014 (UTC)

And, ConstantPie, I don't think you can really agree with both. Just like I don't expect a fifty year old fellow who wasted his life on magnetohyrodynamics to get to surface from a lab a hundred stories below and say "Do you know why it heats, and what else you can do with it? Let me show you..". That'd be unreal.

P0S:After about five years of anonymous contributions of mine (while everybody did and still do seem to be so eager to emphasize "I did that... and that... and that", I see that catastrophic responses still keep coming around here. A quick one liner; Constant314, and another guy, hmm spin-something-.. old and experienced, and much more importantly, wise people need to do a better job at guiding younger flame throwers.

P1S:This organization asks for donation saying "it is something different", and I sincerely believe it IS something different... well, at least meant to be, by higher life forms I presume, although contamination (some prefer propagation) of the same machinery working "outside" has been quite successful to penetrate: Pretty much all kinds of information, -mis/-dis/-hiss/-kiss, clashing, wildly.

P3S: They were right; being self-righteous has quite a feeling per se. Now I hope this wasn't the only way to understand, although it was the one I chose.

After all the crap I have just wrote, let me be a better person. As complex as it may sound or even be, in a simplictic model, the main constituents of a transformer can be listed as:

1. primary_winding(conductor, insulation, number_of_turns)
2. core(air|soft_iron|laminated_steel|...)
3. secondary_winding(conductor, insulation, number_of_turns)

Main parameters of the dynamic system can be listed as:

1. primary_winding(primary_voltage, magnetizing_current, magnetic_flux_density, reactance(inductive_skin, capacitive_proximity))
2. core(material, structure, reluctance(heat_dissipation), coercivity(external_magnetic_flux_density), remanence(retained_magnetic_flux_density))
3. secondary_winding(secondary_voltage, output_current, reactance(inductive_skin, capacitive_proximity))

NOTE: counter_magnetic_flux_density can be attributed to every conductor within the system, but its effect is inherently captured by every oscillating parameter.

Parameters that have frequency as one of their attributes can be listed as:

1. primary_winding(primary_voltage, magnetizing_current, magnetic_flux_density)
2. secondary_winding(secondary_voltage, output_current)

Parameters that depend on frequency can be listed as:

1. primary_winding(reactance)
2. core(reluctance, coercivity, remanence)
3. secondary_winding(reactance)

You want to explain the "effect of frequency"? You got a 5x5 matrix each cell of which needs to be filled, my friend. If you can already see that in the article as it is, I am perfectly comfortable with it. 78.162.12.132 (talk) 20:39, 21 September 2014 (UTC)

Turns ratio - IEEE definition

Refer to Jess Aaron Stuart's 6th of March last edit, Added Note regarding IEEE definition of Turns Ratio. IEEE definition is opposite of the definition, which was undone on the same day. Having had time to belatedly review this issue more carefully, it seem that Jess's edit may have been undone in error. For IEEE%20295-1969. par. 2.1.1 does indeed say Turns Ratio should preferably be 'defned in terms of the primary turns as the number of turns of a given secondary divided by the number of primary turns' and so on. This issue should be resolved asap in light of, for example, article Knowlton reference to the contrary and of Brenner et al information supporting the IEEE definition.Cblambert (talk) 18:29, 5 August 2014 (UTC)

I suppose you have to account for the case of a transformer with multiple secondaries.Constant314 (talk) 01:21, 23 September 2014 (UTC)

I have today added 'However, some sources use the inverse definition.' along with associated citation to Turns ratio definition note in Ideal transformer section.Cblambert (talk) 20:07, 25 September 2014 (UTC)

Core saturation

Hello Jeffreagan, thanks for contributing to Wikipedia. I noticed that you added this claim to the article:

The earliest distribution transformers began failing prematurely, after about a year in service. Core saturation was appearing with time. Addition of silicon to the iron core material was found to prevent this.

I removed it because it's contradicting with my knowledge about transformers. In steady state with a sine voltage the magnetic flux gets reset to zero 2 times per period. Even if there is a bias in the magnetic flux because some of it was leftover when the transformer was powered down (happens all the time), that causes only an inrush current (because the transformer core reaches saturation—but it isn't continuously saturated—) and that phenomenon quickly dies out. Magnetic flux don't increases continuously as the transformer operates but just oscillates around zero (for sine voltage). I can see why transformers which saturate can be said to fail (harmonic current is generated and in extreme cases the voltage is badly distorted), but that should happen the first time it gets connected to its operation voltage. There's no reason of why saturation should be a cause of failure after about a year in service, since as I explained here (summarizing the article), magnetic flux don't accumulates as wear or dust does. Of course, saturation can cause overheating, which in turn damages the transformer and the effects may take time to settle, but that's not what the added text says, or at least as I underestand it. Yet if I'm wrong don't hesitate to add reliable sources backing up that claim or rewording it in a way that avoids an erroneous interpretation. Please note that in Wikipedia it's the editor who adds information who has the burden of proof if his addition is challenged. Regards and again thanks for contributing. Mario Castelán Castro (talk) 23:18, 19 October 2014 (UTC).

What about piezoelectric transformers?

The article doesn't seem to be so good, as long as it completely neglects the existence of the now ubiquitous piezoelectric transformers. — Preceding unsigned comment added by 88.19.228.43 (talk) 22:19, 29 October 2014 (UTC)

Since they work by an entirely different principal and have a completely different history, they should probably have their own page such as Transformers (piezoelectric). Constant314 (talk) 00:02, 30 October 2014 (UTC)

Agreed. Although they've been around for a decade or so they're still far from "ubiquitous". They're numerically common, but AFAIK in only one application: AC inverters for CCFL backlights. An article on piezoelectric transformer would definitely be a good thing. Andy Dingley (talk) 00:07, 30 October 2014 (UTC)

Ideal transformer

It shoud be noted that an ideal transformer is not only lossless but is is unable to save electrical energy like a coil. So there is no mutual inductance in it. --Wefo (talk) 14:30, 31 October 2014 (UTC)

Since ideal transformers don’t exist, it is not particularly important to debate this. But, just for fun: 1. Transformers don’t store energy in their mutual inductance, they store it in the self-inductance (a.k.a. magnetizing inductance). 2. Ideal transformers cannot store energy because their self-inductance is nominally infinite. You cannot store energy in an open circuit. An infinite inductance is indistinguishable from an open circuit so you cannot store energy in an infinite inductance. Actually, storing it is not the problem. The problem is getting the energy to go into an infinite inductance.Constant314 (talk) 22:18, 31 October 2014 (UTC)

Given a transformer without load. Then it behaves like a coil with [2]. You are nearly right with "Ideal transformers cannot store energy because their self-inductance is nominally infinite." but there is no inductance at all. There are simply equations, formulas, nothing else. Therefore a really precice definition in important. -- Wefo (talk) 21:47, 1 November 2014 (UTC)

I agree with you that it is meaningless to attribute internal structure to an idea transformer, but people do. But you can make it precise by starting with a linear transformer of the correct turns ratio and then taking the limit as the leakage inductance goes to zero and the self-inductance becomes unboundedly large. An ideal transformer doesn’t exist, but it is a useful artifice.Constant314 (talk) 00:46, 2 November 2014 (UTC)

This usefull artifice is shown in [3]. But it is to define properly. There is no self-inductance at all, and so it isn't usefull to make it "unboundedly large". -- Wefo (talk) 21:03, 2 November 2014 (UTC)

Just curious, what do you think no inductance means?Constant314 (talk) 00:08, 3 November 2014 (UTC)

You are right, it is really very curious, but the inductances in the picture are only "reminding" a transformer. Let us think, of a transformer 1:1. Then the rest of the picture shows the elements of replacement, but the ideal transformer is only dividing the circuits electrically. without the dividing the woud be almost nothing in it, only one link on the upper side and one at the lower: [4]. -- Wefo (talk) 01:02, 3 November 2014 (UTC)

The entire point of introducing the ideal transformer is to discuss what effects the transformer has on the external circuit without having to consider what is happening on the inside. Really all it requires are the two-port equations. But some people like to keep their inductances even if the are zero in the case of leakage inductance and infinite in the case of the magnetizing inductance. You could certainly say that there are no detectable inductive effects. Constant314 (talk) 21:50, 4 November 2014 (UTC)

Core losses

Greetings all,

Just a casual user here looking through the transformer article and noticed that there seems to be one or more formulas missing in the section about hysteresis loss. I don't have the knowledge to fix it, but perhaps someone else could have a look at it.

I've quoted the "problem" paragraph below....

Thanks!

Steve

Hysteresis losses

Each time the magnetic field is reversed, a small amount of energy is lost due to hysteresis within the core. According to Steinmetz's formula, the heat energy due to hysteresis is given by

, and,

hysteresis loss is thus given by

where, f is the frequency, η is the hysteresis coefficient and βmax is the maximum flux density, the empirical exponent of which varies from about 1.4 to 1 .8 but is often given as 1.6 for iron.[40][41][42]

— Preceding unsigned comment added by 69.39.242.99 (talk) 18:49, 2 January 2015 (UTC)

Steve: thanks for taking the time to write about the problem. Maybe the article was vandalized while you looked at it or the images failed to load in your browser; the formulas show to me and they're fine (I use Iceweasel under a fully free software GNU/Linux system). I have put your comment in a section of its own and deleted the leading whitespaces in your comment because they cause a spurious formatting. Mario Castelán Castro (talk) 03:05, 13 February 2015 (UTC).

Also

Re. the ungrammatical use of "also", I put the wrong link in my edit comment it should be Talk:Electromagnetic induction#Also. Sorry about that. — Cheers, Steelpillow (Talk) 10:08, 16 March 2015 (UTC)

Second paragraph

The second paragraph was crafted with a great deal of discussion and compromise. I am reverting back so we can talk about any changes. The main issue here is that, even though it has been told that way, the flux in the core does not cause the emf at the secondary. If it did, then the flux would be acting at a distance. The magnetic vector potential at the secondary wire produces an E field at the secondary wire which accounts for the EMF produced in the secondary wire. The paragraph, as it is now, uses the term magnetic field instead of magnetic flux because magnetic field includes the vector potential. It uses the word impinges to imply that it is a component of the magnetic field (the vector potential) at the secondary wire that is causing the EMF.

Also, the field does not have to be changing sinusoidally. Constant314 (talk) 13:15, 5 September 2015 (UTC)

Hello Constant314. Your reference to "crafted with a great deal of discussion and compromise" may help explain why the language in this section seems so tortuous and convoluted- an explanation crafted by committee that no one is entirely satisfied with! Would you be so kind as to direct me to these discussions as at the moment I cannot appreciate many of the reasons you give for reverting my edit. Thanking you in advance for your forebearance. Spyglasses 14:03, 5 September 2015 (UTC)

Spyglasses, sorry, I did not see your request for directions to the discussion. It has been archived. I have no idea as to how to find it. If you have a copy of the Feynman lectures, I can direct you to Feynman's discussion of vector potential versus magnetic flux. Constant314 (talk) 14:13, 6 September 2015 (UTC)

I am not opposed to making it better. Since this paragraph is in the introduction, there is a desire to keep it simple by not mentioning the vector potential and yet keep it from being incorrect. The vector potential and the flux in the core are both caused by the primary current and both are proportional to primary current and hence the rate of change of the vector potential is proportional to the rate of change of the flux in the core, so it is correct that the EMF is proportional to the rate of change of flux in the core, it is just isn't caused by it. Constant314 (talk) 14:22, 5 September 2015 (UTC)

+/- signs on ideal transformer image

On the diagram in Ideal transformer there are positive and negative sides marked despite the device is powered by an AC source. Does it make any sense? I’ve copied the symbols from the source “as is”, but I believe this should be fixed. --Wikimpan (talk) 09:25, 14 June 2016 (UTC)

The signs give you the reference polarity of voltage; strictly speaking, they are required, although if you know circuit theory, the default choice of signs may be the obvious. But the choice of signs is as arbitrary as choosing the reference direction for current. You could switch the signs on the secondary side and then the ratio of Vp to Vs would be negative; that would be awkward, but it would be valid. If you want to analyze a complicated schematic and you care about the phase between the voltage across a component relative to some other voltage, you need the polarity signs. Often, we leave them off, because all we care about is the magnitude of the voltage. If we we connected a simple AC voltmeter across the component, it would read the same regardless of which way we connected the probes across the component. But if we used an oscilloscope with differential probes, the signs tell you where to hook positive probe and the negative probe. If you swapped the probes, then there would be a 180 degree phase change in the displayed voltage.Constant314 (talk) 14:31, 14 June 2016 (UTC)

Insufficient explanation of current transformation principles?

Why are the voltage and winding turns ratios inversely proportional to the corresponding current ratio; in other words, why does a step-up transformer produce high voltage but low current instead of high voltage and high current, or at least current that is equal to the input current? I think this is important information that should be included in the article. Or is it already included, and I have overlooked it? ZFT (talk) 23:42, 22 June 2016 (UTC)

In the ideal transformer section it notes that the ideal transformer is lossless, therefore power out = power in. If output volts go down then output current must go up. That’s a conclusion and not an explanation, but maybe if you look at the equations it will enough. Unfortunately, the reliable sources tend to write a bunch of equations and conclude that current transforms inversely with the turns ratio. Again it is a conclusion and not an explanation.

I have an explanation, that I consider to be just another way of telling the same story, but I don't have reliable sources for this version of the story. I’ll outline it here, hoping that maybe someone else can find a reliable source or determine that the explanation is supportable by the sources already in the article. The gist is this: take a transformer with turns N_P and N_S and a load on the secondary and try to force a current I_P into the primary. If the quantity N_P × I_P – N_S × I_S ≠ 0, then you are forcing flux into the nominally infinite (or very large) self-inductance. It responds with an infinite (or very large) voltage seen on both the primary and the secondary. But there is a load on the secondary that would draw an infinite (or very large) current, so you can’t really get an infinite voltage. In fact, the secondary voltage that you can get is just enough to to cause the secondary load to draw just enough current to satisfy N_P × I_P – N_S × I_S = 0. The transformer, in effect, generates the voltage required to get the secondary current that will satisfy N_P × I_P – N_S × I_S = 0. A transformer with an infinite self-inductance is, so to speak, intolerant of N_P × I_P – N_S × I_S ≠ 0. You can make a Lenz's law argument that any deviation from N_P × I_P – N_S × I_S = 0 would create huge reaction that would oppose the deviation.Constant314 (talk) 01:40, 23 June 2016 (UTC)

Semi-protected edit request on 7 August 2016

151.243.255.176 (talk) 06:03, 7 August 2016 (UTC) http://3rd.transfo.ir/en/ international transformer conference and exhibition

Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format.Constant314 (talk) 15:14, 7 August 2016 (UTC)