Talk:Transformer/Archive 11

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Core form and shell form transformers: where are the secondaries?

The figure shows four examples. The single phase core type (upper left) has an obvious primary and secondary. I presume that in the other three cases that each winding represents a primary and a secondary. Is that true? Constant314 (talk) 16:23, 20 April 2013 (UTC)

Yes. I would say that upper left is representative, not literal, such that both winding could in practice be wound on one side only or more typically as half winding on each of the two legs. That is my general recollection. Hameyer reference shows, on p. 39, core form with full winding describing it as 'high magnetic leakage -> useless!' and core form with half each winding on each leg describing it as 'low magnetic leakage'. Hameyer shows w₁ (presumably usually HV) winding closest to the core, which is probably typically preferred, for economical reasons.Cblambert (talk) 20:21, 20 April 2013 (UTC)

Where are the transformers hidden in microphones?

Not to put to fine a point on it but the lead's thumb-sized transformers are hidden so well that I'm having a hard time find them either in or inside microphones. What I discern from such as http://www.holmco.de/mik.html,is that microphones are generally either dynamic type voice coil based or electret consender-based. As a minor deception, the thumb-sized microphone transformer is a good one judging from the number of internet sites copying the expression. In any case, the lead should use a more robust example to illustrate the small end of the transformer size range. Instead of 'thumbnail-sized units hidden inside microphones', how about 'ultra miniature fraction-of-a-watt PCB transformers'? See for example http://www.block-trafo.de/en_IN/products/electro_transformers/product/1703963/ http://www.picoelectronics.com/plugin/pe40_41.htm http://www.picoelectronics.com/plugin/Pe30wb.htmCblambert (talk) 17:38, 15 March 2013 (UTC)

Much smaller miniaturized transformers are used in power supplies for some handheld devices like cellphones and electronic meters, somebody should be able to ref this. Reify-tech (talk) 20:36, 15 March 2013 (UTC)

"Generally" isn't "always" - piezelectric microphones need transformers, as do other types according to various dull "handbook for sound engineers"-type books found on Google Books. I like the pithy "ultra miniature fraction-of-a-watt PCB transformers" because its so Wikipedia-like in its precision and obscurity. "Ultra" miniature, no less. Now all we need to do is work in Tesla's contribution in the lead and we'll have all the criteria for a "Misfeatured Article: Some of Wikipedia's Worst Work." --Wtshymanski (talk) 20:50, 15 March 2013 (UTC)

About 1023 revisions ago, that sentence said "stage" microphones, which would have helped narrow it down a bit...but that bit of wordiness had to go, even though we have infinite tolerance for "It is important to note that" and "From this it can be seen that" and "This can be accomplished by" elsewhere in the 'pedia. --Wtshymanski (talk) 20:55, 15 March 2013 (UTC)

Googling on " microphone transformer picture" gives scads of 'em; including one fellow who shows you how to soup up your ribbon microphone by changing the transformer (with step by step pictures), and a manufactuer's site that warns you not to check resistance with an ordinary multimeter because it will magnetize the core! Cool...these are *really* bitsy tranformers if a DMM can saturate them!--Wtshymanski (talk) 21:27, 15 March 2013 (UTC)

An 'ordinary multimeter' and a DMM are not the same thing, as I am certain that you are well aware. I B Wright (talk) 18:46, 17 March 2013 (UTC)

It is hard to say if you, Wtshymanski, are for or against. Precision is not the object in the lead. Plausibility and currency is. I would settle for something like 'fraction-of-a-watt cellphone power supply transformers'. I have a thing about transformers 'hidden' inside microphones.Cblambert (talk) 21:48, 15 March 2013 (UTC)

Umm, i'd think the transformers in a cellphone power supply would be a big bigger than "fractions of a watt". Plugwash (talk) 03:35, 16 March 2013 (UTC)

I believe the transformers being referred to are the ones that are actually in the cellphone itself, rather than in its charger. I B Wright (talk) 18:49, 17 March 2013 (UTC)

Well ok, back to original 'fraction-of-a-watt PCB' then Reify-tech says cellphone power supplies are much smaller than fraction-of-a-watt.Cblambert (talk) 04:00, 16 March 2013 (UTC)

Don't forget to link "PCB". And "watt". And "fraction". And (probably) "of". And to use the right kind of dash/hyphen. And non-break spaces. --Wtshymanski (talk) 17:44, 16 March 2013 (UTC)

Some professional . . .Cblambert (talk) 22:37, 16 March 2013 (UTC)

Where? I B Wright (talk) 18:46, 17 March 2013 (UTC)

"We're all bozos on this bus." --Wtshymanski (talk) 2:34, 17 March 2013 (UTC)

I'm sorry I brought it up. No hard feelings but for my part this discuss is closed.Cblambert (talk) 23:28, 17 March 2013 (UTC)

Do not let Wtshymanski get to you. That is where he gets seems to get his kicks. He is seldom happier than when engaged in a good edit war and extending what should be a short discussion into lengthy argument. For more information see here (and from what I have seen recently elsewhere, I would say that this RfC is highly likely to be extended and enhanced). I B Wright (talk) 16:44, 19 March 2013 (UTC)

Perhaps try to add constructive edits to the article or discussion instead of canvassing. 174.118.142.187 (talk) 16:39, 20 March 2013 (UTC)

For someone who seems to spend his waking hours compiling 'evidence' against editors who oppose you, that is the pot calling the kettle black. In order to be canvassing, I would have to invite the editor to contribute to the RfC. If you read my post again, you might discover that at no point did I do that. I B Wright (talk) 18:10, 23 March 2013 (UTC)

Only one bozo here as you so admirably proved with you stupid post above. I B Wright (talk) 16:44, 19 March 2013 (UTC)

The page you linked to is reminiscent of the Slam books books compiled by middle school mean girls. Such an "evidence page" compiled in preparation for some supposed future RFC which might never be filed seems inappropriate, when it has been sitting there for five months as a private forum for a few editors to post criticisms of another editor. You can collect your "evidence" offline and out of view until you are ready for your next RFC. No one should keep a supposed draft RFC open indefinitely as a forum for one sided criticism of an editor. Edison (talk) 16:45, 23 April 2013 (UTC)

Close gaps to get to 'Equivalent circuit' with Heyland factor?

There are now unexplained gaps in getting from 'Real transformer deviations from ideal' section and 'Equivalent circuit' section, which motivates the question 'Add new section about Heyland factor?', the question in turn being asked as a question instead of fait accompli because of the relatively high encyclopedically complexity. Referring for example to Hameyer reference, the Heyland factor σ is, by neglecting winding resistances, defined as the ratio of transformer's σ short circuit and no-load inductances as follows:

$\sigma =1-{\frac {M^{2}}{L_{1}L_{2}}}={\frac {L_{k}}{L_{o}}}={\frac {i_{o}}{i_{k}}}$

where,

- M is mutual inductance, i is current & L is winding self-inductance

- subscripts 'o', 'k', '1' & '2' are no-load, short-circuit, primary & secondary, respectively.

Where a is equal to winding turn ratio, the 'Equivalent circuit' can then be defined to the way it is now as follows:

$L_{P}=L_{1}-a{M}$, primary leakage inductance -> $X_{P}$, primary leakage reactance

$L_{M}=a^{2}{M}$, magnetizing inductance -> $X_{M}$, magnetizing reactance.

$L_{S}=L_{2}-a{M}$, secondary leakage inductance -> $X_{S}$, secondary leakage reactance

The 'Equivalent circuit' can lastly be expressed with all secondary terms referred to the primary as follows:

$L_{S}^{'}=a^{2}L_{2}-a{M}$, secondary leakage inductance -> :$X_{S}^{'}$, secondary leakage reactance

$R_{S}^{'}=a^{2}R_{S}$, secondary resistance referred to primary side

$V_{S}^{'}=aV_{S}$, secondary voltage referred to primary side

$I_{S}^{'}=I_{S}/a$, secondary voltage referred to primary side.

This is worth pondering because of the importance of this derivation for all electrical machines, not just transformer. The derivation all ties in to Thévenin's theorem, Norton's theorem, short circuit test, open circuit test, blocked rotor test, circle diagram, Steinmetz equivalent circuit, etc.. The Heyland factor allows relatively simple visualization of electric machine principles.

Comments?Cblambert (talk) 21:06, 21 April 2013 (UTC)

This is not an engineering text, a place to confuse readers, or a place to show off to the crowd with, it is an encyclopedia. You can add all this gooble-dee-gook techno-babble formulae but I can assure you it will be erased and simplified before too long. Most readers could not care less about formulae, they want prose explanations. You know the professor you couldn't wait to get away from? I don't place any value about hit counts similar to the masses slowing down to see the dead body at the side of the road? That doesn't make it good. Let's hear about how long readers stayed. 174.118.142.187 (talk) 22:30, 21 April 2013 (UTC)

This response is clearly not made in good faith. Sour grapes on steroid, so to speak. The response is not worthy of Wikipedia pillars. So I will ignore it. I have made some corrections to my initial comments.

You have made it clear that you do not want anybody else's input, here. You have reverted most changes other editors have advised to the article, gone against discussion consensus several times and continue to inject stealth edits to items previously discussed not to inject. I was attempting to give you some advise about your time spent on styles that are not typically wanted on WP for articles. You respond with complete ABF garbage response to what you don't like to hear. Continuing on the same uncollaborative pathway may not end well, typically, and may be a waste of your efforts. 174.118.142.187 (talk) 01:35, 22 April 2013 (UTC)

If you don't believe I have Wikipedia's best interests at heart that is your problem. I don't appreciate vindictiveness and don't react well to treatens. I am one of many, many contributors. A bucket in the Wikipedia ocean. I believe that my contributors have signitantly improved a select number of articles in terms of context, accuracy, format, and so. I consider myself to be a profession and insist on reflecting this professionlism in articles. I don't get paid for these Wikipeadia contributions. The challenge for you is to keep it at the professional level and avoid heaping abuse and subjectivity in the to and fro of article editing. The onus is on you to debate as an equal. Could it be that the Luddite fallacy has anything to do with the viscerral reaction to such an innocent question: Close gaps to get to 'Equivalent circuit' with Heyland factor? Any reasonable, rational contructive comment is valid - including especially 'I don't agree for such and such reason(s). . .', silence is also logical acceptable possibility, though not preferred . . .Cblambert (talk) 04:01, 22 April 2013 (UTC)

This is becoming your classic response, as in past attempts at collaboration. I have no idea what you are going on about or why the emotional response. You seem to have some trouble with the English language, at times. Stay focused on content and not people. You asked for input and I gave you an opinion. You didn't like my opinion, and suddenly you have trouble with basic English constructs, and civility as a device for your argument? If I don't agree it doesn't mean I am being uncivil. I don't see anywhere that I have insulted you. Perhaps we need some outside assistance and opinions to clear up some confusion, here. You have used this technique in other content discussions causing editors to just give up on discussion with you, and then revert your edits later. Not the correct method but with your article ownership attitude, editors do not want to get into confrontations with you. 174.118.142.187 (talk) 13:39, 22 April 2013 (UTC)

I think the Heyland factor is too specialized for this article.Constant314 (talk) 02:11, 24 April 2013 (UTC)

It is admitedly complicated to make something out of this. Yet there seems to be something encyclopedically compelling about the fact that pretty well all there is important to say about a transformer's circuit variables can be derived from two simple, elementary tests! Something that is a lot more important than say (in no less than Applications!):

"The principle of open-circuit (unloaded) transformer is widely used for characterization of soft magnetic materials, for example in the internationally standardised Epstein frame method."

I will leave it at that for now.Cblambert (talk) 17:16, 24 April 2013 (UTC)

Maybe you could start a section called Transformer Engineering. Those that don't want to look at all the math can skip over it. Those that are interested can dive in.Constant314 (talk) 04:15, 26 April 2013 (UTC)

Given that transformer is an extremely popular, successful Electrical Engineering Project article, there is in my view no need for a section called Transformer Engineering catering somewhat artificial to a readership clientele graded acoording to relative formula sensitivity. For example, in order to address 'Close gaps to get to 'Equivalent circuit' with Heyland factor? question, all one has to do is build on and edit correctly such associated articles as Inductance (lots of formulas there) and Leakage inductance and integrate these associated article with transformer article.

The 90 day statistics are showing a steady decline.Constant314 (talk) 16:34, 4 May 2013 (UTC)

Why are 90-day stats in steady decline? Only major change has been putting History section at the bottom. I suggest reverting to History as was before.Cblambert (talk) 19:18, 4 May 2013 (UTC)

Also, it is not unusual for stats to fluctuate, but I suggest putting History section back to the top.Cblambert (talk) 23:41, 4 May 2013 (UTC)

The decline began well before the history section was moved.Constant314 (talk) 14:25, 5 May 2013 (UTC)

Why do you think 90-day stats in steady decline? What do you sugges be done about it? Do you agree to putting History back the way it was?Cblambert (talk) 15:14, 5 May 2013 (UTC)

No, I do not think that the history section should be moved back to the beginning. I have no idea why the stats indicate a decline. I simply point out that if one uses the stats to infer the quality of the article, then one must conclude that over the last 90 days the quality has degraded. I don't believe that the quality has degraded. I do believe that the stats cannot be used to argue that any particular recent change was an improvement.Constant314 (talk) 15:52, 5 May 2013 (UTC)

Sounds good enough to me.Cblambert (talk) 20:00, 5 May 2013 (UTC)

One more time. Hit counts do not indicate how long a reader stayed, how much they read, how interested they are in the subject presentation method, or how well written an article is written. Perhaps the article is ridiculed as a joke, somewhere else on the Internet. To use this fantasy to advantage to further a point is ridiculous, and your response last time this was brought to light clearly demonstrates your awareness that it is just plain BS. Please refrain from using these strawman unrelated statistics in further content discussions. 174.118.142.187 (talk) 12:11, 1 May 2013 (UTC)

I do agree that the Leakage inductance article would be a much better place for the Heyland factor discussion.Constant314 (talk) 14:47, 5 May 2013 (UTC)

Leakage inductance

Discussion of this section moved to 'Proposed article revamp' section of Leakage inductance Talk pages.Cblambert (talk) 15:38, 5 May 2013 (UTC)

References

I've noticed that reference, '67 Kulkarni, pp. 2-3' does not give the title of the book. I believe it is one of these - http://www.princeton.edu/~kulkarni/publications.html — Preceding unsigned comment added by 199.255.204.2 (talk) 16:17, 12 July 2013 (UTC)

Wow

Was there a conscious effort to make this article as arcane as possible? "Consider the ideal, lossless, perfectly-coupled transformer shown in the circuit diagram at right having primary and secondary windings with NP and NS turns, respectively. The ideal transformer induces secondary voltage ES =VS as a proportion of the primary voltage VP = EP and respective winding turns as given by the equation . . . ." Consider the fact that most people reading this article do not have a PhD in electrical engineering and just want a plain English explanation of what a goddamn transformer does. — Preceding unsigned comment added by 12.33.141.36 (talk) 17:19, 21 August 2013 (UTC)

It is best to avoid sweeping generalizations and to make specific positive suggestions. There is no value whatsoever in making above comments.Cblambert (talk) 05:09, 26 August 2013 (UTC)

Electrical Wiring Sidebar

Out of the blue Electrical Wiring Sidebar may, just may, warrant inclusion way down there as a, well, sidebar, in Transoformer article but certainly not in my view anywhere near the top. Push comes to shove, don't include on basis Electrical Wiring Sidebar is too tangential.Cblambert (talk) 05:13, 26 August 2013 (UTC)

Resistance of primary windings

I can not find a direct answer in here to a simple thing I was wondering about. I understand generally most of the explanation in this article, but I'm not clear on two things:

1) Why does a transformer not trip a circuit breaker when you plug it in an outlet? I am just going to make a guess here that it's either because a)The primary winding is so long and thin that it just inherently has high resistance (or impedance), and/or b) the creating of magnetic flux in the core actually causes that resistance (or impedance) unless a secondary load is attached. Is any of that correct, and can it be added in simpler terms to the article?

Usually it doesn't trip the breaker becasue its inductance is high enough to limit the current. But check the "Laminated steel cores" section about remanence.Constant314 (talk) 23:42, 6 September 2013 (UTC)

2) why does a transformer not draw much primary current when no secondary load is attached? This I partially understand. I think that also might have to do with "b" above based on some of the equations and explanation of Z_L in the article, but I'm not sure.

It does draw primary current, but the unloaded primary looks like an inductor so the current drawn through the primary lags the primary voltgae by 90 degrees and no (or very little) power is consumed.Constant314 (talk) 23:42, 6 September 2013 (UTC)

Basically what I'm saying is that it seems as if this article suggests I can take a 100ft spool of say 14 gauge wire, wrap it around an iron donut, plug one end into each side of a receptacle, and nothing will happen. I'm pretty sure that will trip a circuit breaker though (best case anyway). Now If I used 1000ft of that wire, would it still trip a breaker? 10,000ft? How big of an iron donut would I need? car wheel sized? swimming pool sized? Anyway, I was hoping for a clearer explanation of where R_P comes from in the "equivalent circuit." Perhaps it should be noted in the "windings" section for how the number of windings and wire gauge affects that?Autumn Wind (talk) 19:15, 5 September 2013 (UTC)

Also, I'm not sure why that last edit was considered vandalism. I was, and still am serious. I hope I don't seem offensive. My "donut" and "swimming pool" analogies may appear unintelligent and colorful, but that is the point. Anyway, simply put I'd like to see an explanation in the article of how R_P is calculated.Autumn Wind (talk) 19:24, 6 September 2013 (UTC)

I apologize for reverting your edit. I saw big donut and swimming pool over reacted.Constant314 (talk) 23:05, 6 September 2013 (UTC)

Rp is nothing more than the resistance of the wire used to wind the primary. Depending on the frequency, skin effect and proximity effect can make the AC resistance higher than the DC resistance.Constant314 (talk) 23:42, 6 September 2013 (UTC)

Transformer_flux.gif

In the picture Transformer_flux.gif the direction of the current in the secondary coil is wrong. It violates the right hand rule. 2.84.248.191 (talk) 13:38, 17 January 2014 (UTC)purple

True, but there are two fluxes. The main flux, and the leakage flux. It is the leakageflux that is important here, and this one is in accordance with the secondary current. Moreover these are just definitions. When you start to calculate, the quantities that are chosen in the 'wrong' direction will simply come out negative. - Snaily (talk) 15:33, 17 January 2014 (UTC)

The problem is, it is not clear that the arrow is supposed to show the direction of current caused by the leakage flux only. And considering the fact that the total current has the opposite direction than what is depicted, the picture can be confusing for a non-expert like me when there is no clarification. Keep in mind that both the strong main flux and the weak leakage flux are show in the picture. 94.69.20.184 (talk) 12:35, 20 January 2014 (UTC)purple

I had a look at the gif. It looks OK to me. The secondary leakage flux opposes the main flux in accordance with Lenz law. The secondary current has the correct polarity to produce the secondary leakage flux as depicted in accordance with the right hand rule.Constant314 (talk) 03:19, 21 January 2014 (UTC)

This became clear after Snaily's response. But as I said, a person that uses wikipedia to march in a new territory and learn something previously unknown to him/her may not understand that the current polarity depicted in the secondary winding is in accordance with the leakage flux, not the main flux, because there is no clarification. The depicted direction is that of a hypothetical secondary winding where only leakage flux is applied and the sum of currents (caused by main flux and leakage flux) has the opposite direction.94.69.5.17 (talk) 12:10, 27 January 2014 (UTC)purple

The drawing only shows the leakage flux caused by the secondary current. There would be core flux caused by the secondary current also. I’m not sure that you could get all that on one diagram.Constant314 (talk) 01:36, 28 January 2014 (UTC)

Recent edits to the ideal transformer section

This section was added, as a product of a consensus building process, to answer the complaint that the article was too technical. It was decided to place a section as near to the beginning as possible that would focus entirely on the single most significant behavior of the transformer which is its transformation ratio. The focus of the section is the effect of the transformer on the external circuit. It ratios voltage and current and impedance. Discussions of internal mmf’s and fluxes etc. is counter-productive. The ideal transformer is a mathematical idea that has no internal variables. Constant314 (talk) 01:35, 6 February 2014 (UTC)

Well no one has commented or made any moved to simplify the ideal transformer section so I will be doing that to return it to its consensus condition. If anyone disagrees, please comment here and let’s reach a new consensus.Constant314 (talk) 18:13, 8 February 2014 (UTC)