Talk:Transformer/Archive 9

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Lede

What is "... or winding circuits" adding to the definition? Spinning Spark18:46, 16 January 2013 (UTC)

Autotransformer says one winding. See also Types which refers to circuits.Cblambert (talk) 19:16, 16 January 2013 (UTC)

Maybe '. . . two or more of its windings or circuits of the same winding.' would be better.Cblambert (talk) 20:10, 16 January 2013 (UTC)

It's a little confusing. Definitely fringe. Can't an autotransformer have a primary winding and a secondary winding even though some winding turns are shared? They are still linked inductively, and act as the rest of the breeds, otherwise current transformation could not occur. 174.118.142.187 (talk) 21:24, 16 January 2013 (UTC)

I tend to agree but one winding is definitely not two or more windings. I am comfortable with '. . . its winding circuits. Grounding zigzag transformers also don't have 'two or more windings', which is why you can ground them. Polygon transformers, used on input toVFDs, don't have 'two or more windings'. . .Cblambert (talk) 00:26, 17 January 2013 (UTC)

That phrase is a good compromise, for lack of a beter one that covers the continguencies. Zig-zag windings on grounding banks were never called transformers in my world. They have no secondary and do not transform voltages (in the usually defined way) Zig-zag windings on transformers are just another shape of wye winding configuration. I am not very familiar with VFD technology. 174.118.142.187 (talk) 02:54, 17 January 2013 (UTC)

Zigzag transformer exists in wikipedia world and real world. And yes zigzag bank is often used but the two terms, transformer and bank, are not mutually exclusive. Phase-shifting zigzag transformers have two windings, which are definitely transformers. And, zigzag are often evidently derived from two-winding transformers judging from Lawless citation, but I have see them customized for fit-for-purpose grounding application. The point is that caution is in order in lede woring regardless of grounding zigzag definitive description. Polygon transformer details are not very common on the web but windings are exactly that, polygon in physical configuration.Cblambert (talk) 03:24, 17 January 2013 (UTC)

Knowlton, p. 550 says 'A grounding transformer is a transformer primarily for the purpose of providing a neutral point for grounding purposes.' Ergo, hence, grounding transformer seems ligit. And zigzag transformer being a special type of grounding transformer also seems ligit.Cblambert (talk) 03:34, 17 January 2013 (UTC)

Yeah, a zig-zag grounding transformer falls about the same spot as an autotransformer. Not all grounding transformers are zig-zag windings and not all zig-zag transformer windings have anything to do with grounding. I have worked with both types of grouding banks. I built one out of three 5 MVA trans. once for a 40MVA delta transformer system conversion. :) (I guess "bank" is a just short form of "transformer bank"). You would be an interesting guy to reminisce with. 174.118.142.187(talk) 04:43, 17 January 2013 (UTC)

Lawless citation uses zigzag term throughout but I'm used to and more comfortable with zig-zag. Also, Lawless talks of zigzag grounding banks . . . Cblambert (talk) 05:11, 17 January 2013 (UTC)

Here is, compliments of Block, VDE/IEV-based approach to LEDE:

'A transformer is a static device with two or more coils which transforms a system of alternating voltage and alternating current through electromagnetic induction, usually with different values but the same frequency, for the purpose of transmitting electrical energy.'

Cblambert (talk) 19:09, 28 January 2013 (UTC)

Zig-zag?

I understand that "zig-zag" is a winding configuration and not a major transformer type as discussed in this article. "Zig-zag is a nickname used by EE people as a shortform description. Should the term "grounding transformer" be used more appropriately? We don't refer to transformers as "delta" or "wye" for their types. Many power transformers have zig-zag wndings but are not referred to as zig-zag, delta or wye to describe them as their major descriptor. It only describes one winding. Also, there are other winding configurations used for grounding trasformers. Anybody have sources for the official usage of this name?174.118.142.187 (talk) 17:12, 17 January 2013 (UTC)

I could not disagree with you more. Transformer article is part of Electrical engineering WikiProject. Zig-zag term is a very well known term, on a par with delta, wye, and autotransformer, which is used for both phase-shifting and grounding purpose. Is Wikipedia an encyclopedia or not? Where does Wikipedia draw the line on truth?Cblambert (talk) 22:24, 17 January 2013 (UTC)

Re official usage, have a look as Lawless reference, which provides all the various EIC winding configuration combination.Cblambert (talk) 22:29, 17 January 2013 (UTC)

Strawman arguments. "Zig-zag" being a term or its importance is not disputed. Please read what I wrote. Would you describe all the transformer types under the zig-zag heading all over again? e.g. "Zigzag/wye tr.", "zig-zag/delta tr.", "zig-zag/zig/zag tr.", "zig-zag grounding tr." I believe people, here using "zig-zag transformer" are referring to a "zig-zag grounding transformer". Should we mention the "star/delta grounding transformer" also? We haven't been entering transformer types as "star transformer", "delta transformer" or "open delta transformer". Types have been listed by their distinct functions. 174.118.142.187(talk) 22:48, 17 January 2013 (UTC)

The current issue is the importance of zigzag in no far as showing zigzag Types category in Transformer. According to Lawless and EIC delta is delta, wye is wye, autotransformer is autotransformer and zigzag is zigzag. Further, details should go in Zigzag transformer article. IEEE Xplore gives about 50 titles of zigzag transformer search, another 50 titles for zig-zag transformer search.Cblambert (talk) 23:05, 17 January 2013 (UTC)

See [1], which defines 4 general winding configuration letter designations: D or d for delta, Y or y for wye or star, Z or z for interconnected star or zigzag, and N or n for neutral brought out to terminal (ie, not a winding phase), where uppercase is primary and lowercase is secondary. Note change making distinction for General winding configuration type according to IEC vector group or 'other'.Cblambert (talk) 02:05, 18 January 2013 (UTC)

You have only provided strawman arguments, refusal to understand and discuss the actual issue, article links to articles that do not exist, references that are behind paywalls, obscure Lawless reference, and a Google book that both agree with my initial post and (the book never once mentions "zigzag transformer"). I have to reject your input to this discussion. Now I see you have gone and editted more of the same confused thinking into the Transformer type section while we are discussing it? We need to wait for other fresh input and eyes. 174.118.142.187 (talk) 02:22, 18 January 2013 (UTC)

We will see. All this seems to be too much for some to absorb. Please provide specific arquements to points. No sweeping generalizations. Please.Cblambert (talk) 03:09, 18 January 2013 (UTC)

And what is your contention with paywall? Verifiability do not require openly accessible for free through WWW.Cantaloupe2 (talk) 09:42, 18 January 2013 (UTC)

See WP:PAYWALL. There is nothing in our rules about free. Cantaloupe2 (talk) 12:02, 21 January 2013 (UTC)

Here is way another source puts it: "Winding connection designations

First Symbol: for High Voltage: Always capital letters.

D=Delta, S=Star, Z=Interconnected star, N=Neutral

Second Symbol: for Low voltage: Always Small letters.

d=Delta, s=Star, z=Interconnected star, n=Neutral.

Third Symbol: Phase displacement expressed as the clock hour number (1,6,11)

See link at http://electrical-engineering-portal.com/understanding-vector-group-transformer-1 Where interconnected star & zigzag used interchangeably. All of this as been known for over half a century.Cblambert (talk) 03:38, 18 January 2013 (UTC)

Still another [2], p. 105. Zigzag pretty clear. Very good source, by Shoaib Khan.Cblambert (talk) 04:03, 18 January 2013 (UTC)

I rest my case with this source: http://www.transformerworld.co.uk/vector.htm.Cblambert (talk) 04:31, 18 January 2013 (UTC)

In South Africa, it is called zig-zaghere

This is a German book in English. Page 89-92 is a wealth of information on zig-zag. And it calls it that.here Cantaloupe2 (talk) 09:38, 18 January 2013 (UTC)

I looked over Cblambert's references. It seems that that zigzag is used to describe a type of winding (such as Wie or Delta) and it is also used to describe a type of transformer. It seems the most common usage is in grounding, but it has other uses. I think that the only thing that needs to be done is to explicitly write either zigzag winding or zigzag transformer.Constant314 (talk) 13:54, 18 January 2013 (UTC)

Beeman reference says on p. 349: 'Grounding transformers may be either of the zigzag or Y-delta type.' and provide excellent treatment of both types.Cblambert (talk) 00:24, 19 January 2013 (UTC)

On more careful reading, that should have/now read, I gather from the three previous comments about paywall, free, www and so on that this is no longer an issue.'Cblambert (talk) 18:24, 22 January 2013 (UTC)

Error in Transformer universal EMF equation?

In Transformer universal EMF equation and in

E_{\text{rms}}={\frac {2\pi fNaB_{\text{peak}}}{\sqrt {2}}}\!\approx 4.44fNaB

$B_{\text{peak}}$ becomes $B$ .

What's wrong (2*pi/sqrt(2)≈4.44...)?

212.152.15.118 (talk) 16:44, 23 January 2013 (UTC)

I agree. There are several issues:

Re 1st equation line

$a$ is not defined; it should be defined in SI system as square meter unit
$B_{\text{peak}}$ should be used instead of using $B_{\text{peak}}$ and $B$
as 4.44 is accurate to 2 decimal places $=$ should be used instead of $\approx$
N is not defined as to which winding relates to which emf

ie, emf of respective winding should read

E_{\text{rms}}={\frac {2\pi fNaB_{\text{peak}}}{\sqrt {2}}}\!=4.44fNaB_{\text{peak}}

Re 2nd equation line

This is also an issue here as Knowlton reference (p. 38, equation 2-36, Sec.2-32) suggests that 2nd equation line should, for any half cycle interval of time

t_{2}-t_{1}

, read:

E_{\text{avg}}=2NaB_{\text{peak}}/(t_{2}-t_{1})\!

and not

E_{\text{avg}}=4fNaB_{\text{peak}}\!

.

Cblambert (talk) 20:52, 23 January 2013 (UTC)

Better lead 2nd paragraph

Following is proposed for the transformer's lead's 2nd paragraph:

From:

"Transformers range in size from a thumbnail-sized coupling transformer hidden inside a stage microphone to huge units weighing hundreds of tons used in power plant substations or to interconnect portions of the power grid. All operate on the same basic principles, although the range of designs is wide. While new technologies have eliminated the need for transformers in some electronic circuits, transformers are still found in many electronic devices. Transformers are essential for high-voltage electric power transmission, which makes long-distance transmission economically practical."

To:

"Transformers range in size from a thumbnail-sized coupling transformer hidden in microphones to units weighing hundreds of tons used in electrical substations at power generation locations and to interconnect the power grid. Transformers are used in wide-ranging designs for electrical and electronic devices of all types and are essential for transmission, distribution, and utilization of electricity."

Cblambert (talk) 20:50, 31 January 2013 (UTC)

Cooling

Most of the discussion of cooling should be moved to the Distribution transformer page.Constant314 (talk) 16:19, 2 February 2013 (UTC)

I tend to not agree. In my view, good treatment of cooling in Transformer is important to anchor the article to the two main types of transformer insulating systems: dry-type and liquid-immersed. Not having cooling in Transformer would overly delute the article. My 2 cents.Cblambert (talk) 22:51, 2 February 2013 (UTC)

Most of the transformers in existence don't have a cooling system, other than the ambient, and they don't have any type of liquid in them. You can still mention the temperature effect on insulation, but most of what you write is specific to power distribution transformers.Constant314 (talk) 06:03, 4 February 2013 (UTC)

We're in this together. Cooling section was all there before my arriving on the scene. The value of liquid transformers is very high. It would take an awfull lot of dry type transformers to equal to the value of a 1,000 MVA liquid transformer, likely multiplied by two or more in terms of generation-transmission-distribution stepup, stepdown, etc. But let's not quibble. I don't have strong feelings. If all are agreed, so be it. If so, consideration should be given toDistribution transformer being renamed, say, 'Transformers (Liquid-immersed)' or 'Power and distribution transformers and reactors'Cblambert (talk) 07:40, 4 February 2013 (UTC)

The article is way too long and reducing the size of the Cooling section, similar to the way I reduced the size of Types would be a good sart to reduce some bulk. Constant314 is correct in that cooling only applies to distribution transformers and should be mostly moved or merged in there. Microphone transformers, and most other types, do not have cooling fins or oil pumps. 174.118.142.187 (talk) 03:37, 8 February 2013 (UTC)

What does 'way too long' mean? While having no strong feeling either way, rhe logic of microphone transformers have nothing to do with fins may be beside the point. Cooling is a transformer property that applies to all types of transformers. In electrical matters, cooling is always a life and death isssue. The issue here is where you draw the line - a matter of degree. There is no black and white here. , , ,

Also what is wrong with the following stats: 'Transformer has been viewed 549549 times in the last 90 days. This article ranked 1882 in traffic on en.wikipedi a.org.'

And Distribution transformer 'has been viewed 13771 times in the last 90 days.'

And Transformer types 'has been viewed 51157 times in the last 90 days.'

Quadrature booster 'has been viewed 3678 times in the last 90 days.'

Delta-wye transformer 'has been viewed 18408 times in the last 90 days.'

Autotransformer 'has been viewed 42054 times in the last 90 days.'

Scott-T transformer 'has been viewed 7643 times in the last 90 days.'

Zigzag transformer 'has been viewed 8162 times in the last 90 days.'

Capacitor voltage transformer 'has been viewed 10424 times in the last 90 days.'

Isolation transformer 'has been viewed 28487 times in the last 90 days.'

Padmount transformer 'has been viewed 4413 times in the last 90 days.'

Neon-sign transformer 'has been viewed 4439 times in the last 90 days.'

Current transformer 'has been viewed 76533 times in the last 90 days.'!!!!!

Maybe it is Distribution transformer that needs to come to Transformer.Cblambert (talk) 08:10, 8 February 2013 (UTC)

Staying on topic: Since we agreed in a previous thread[3] that we should start a new article title to group all this cooling and power transformer related information away from this overcrowded article; the title needs to be kept simple (not compound) in order to be easily found by readers. I cannot initiate new article titles so it would require effort on your part to start this process and keep this article from specialising too much on one type of transformer. Perhaps the title Transformer liquid cooling systems or something to suggest a more specific area other than another transformer type? It would be found with the autocompletion feature of WP after typing Transformer.

Distribution transformer includes mostly air cooled types. Larger substation transformers with gas detection systems and advanced driven oil cooling systems would not fit. There is a whole field of gauges and oil protection systems waiting for an article like that and it would overload this article. 174.118.142.187 (talk) 14:47, 8 February 2013 (UTC)

There are millions and millions of oil-immersed distribution transformer like that in article's lead showing pole-mounted photo. You mean 'lighting' or dry-type transformers, not distribution transformer. See definition for distribution transformer in Types section. I say leave cooling as a general property of transformer. Half a million hits is good enough for a general property of transformer called cooling. Cblambert (talk) 16:45, 8 February 2013 (UTC)

Finishing off on stats:

'Flyback transformer has been viewed 24005 times in the last 90 days.'

'Buck–boost transformer has been viewed 7986 times in the last 90 days.'

'Trigger transformer has been viewed 1029 times in the last 90 days.'

Here is some thoughts about what to do of all these stats:

Make Padmount transformer & isolation transformer part of distribution transformer, dividing latter article into more or less: general, pole-mounted, padmounted etc.
Converter Current transformer, Capacitor voltage transformer & Rogowski coil into a new 'Instrument transformer' article expanded with new 'potential transformer' sub-section.
Combine Quadrature booster, Delta-wye transformer, Autotransformer, Scott-T transformer, and Zigzag transformer into an article for group various vector group and other phase configurations.
Clean up Transformer types, this task being harder than it might seem at first blush.
Combine Trigger transformer & Neon-sign transformer with Transformer types.

Also, went through 'View reader feedback', in which no trend was discerned other than impression that those who comment are all over the map, with however some excellent feedback comments.Cblambert (talk) 21:01, 8 February 2013 (UTC)

@Constant314 Re rule for halving of life expectancy for every 8 C increase, it should be clear that while the rule applies, in context, strictly-speaking, to the paper insulation of such paper-oil insulation system transformers, it remains that, everything being equal, insulation life expectancy is the best predictor of life expectancy for all electrical equipment including transformers of all types, motors of all types, etc. Concerning oil-paper insulation system transformers, the focus is necessarily on paper insulation because that is where irreversible damage occurs. Regarding failure that is not directly due to insulation, it is generally not possible to predict failures due to transportation damage, short-circuits, tap-changer mechanisms, etc.. Also, as paper insulation ages, transformers become more vulnerable to failures due to other causes such as due to transportation, short-circuits, and so on. All to say that the 8 C rule is generic to all transformers and should therefore be so reflected in this article.Cblambert (talk) 18:38, 11 February 2013 (UTC)

The reference is clearly talking about the lifetime of the insulation and not the lifetime of the transformer. If you want to say that the lifetime of a transformer doubles with every 8 degree decrease of temperature then you need a reference that says that. The Arrhenius equation equation only applies to chemical reactions and the reference is careful to use it that way.Constant314 (talk) 07:31, 12 February 2013 (UTC)

Re Arrhenius equation, it should be clear that paper insulation IS considered a chemical reaction, there indeed being quite a bit of literatue about it. See for example the paper "Chemical degradation of cellulosic insulation paper for power transformers" at http://dx.doi.org/10.1109/ICPADM.1994.414127, the abstract of which says 'An Arrhenius analysis of these rate parameters yielded an activation energy for chain scission of 79.5 kJ mol-1. These data have been used to prepare lifetime prediction curves for transformer insulation at the typical operational temperatures of power transformers.' Arrhenius equation is admitedly somewhat crude, but it does serve as thumb of rule useful for encyclopedia inclusion.Cblambert (talk) 04:15, 22 February 2013 (UTC)

None of this is related or progressing the question you posed and discussion of it. "Most of the discussion of cooling should be moved to the Distribution transformer page." 174.118.142.187 (talk) 15:09, 12 February 2013 (UTC)

@Constant314 I am not disagreeing with your. In fact I agree 100% with you. All I'm saying is that the insulation life expanctancy rule is generic to all electric machine insulation, not just paper insulation and that insulation's thermal degradation is pretty well the best predictor of overall electrical machine life expectancy. But I agree with you. I have re-wording the life expectancy rule accordingly. Please comment to suit.Cblambert (talk) 18:57, 12 February 2013 (UTC)

Wall wart picture

I have removed the AC adapter picture (and I seem to remember that this was reverted by someone else some time ago) because it is not actually a transformer. It might contain a transformer, but if it is at all recent it probably doesn't. Most AC adapters nowadays are switched mode. I can provide a picture of a wall wart type adapter that is just a transformer if anyone wants it - that is, AC to AC adapter, but that is probably too obscure and confusing and not adding a lot to the article. Spinning Spark 18:45, 16 January 2013 (UTC)

I added it in an attempt to show contrast from a larger pole-top unit to a miniature unit. I agree that it may not be completely a transformer and contain other parts and not show the windings, laminations or even sheilding but it was the best I could findat the time. A small RF trans. photo would be really great. A few 100 MVA (not a bunch of switchyard coolers and bus work) unit would be good too to show some middle and extreme cases. 174.118.142.187 (talk) 18:54, 16 January 2013 (UTC)

A small RF trans. photo is just not the place for this article.Cblambert (talk) 19:26, 16 January 2013 (UTC)

Yup. My bad. Wrong article. A really small core unit would have been better. SInce this article is gravitating towards power transformers, only perhaps it should be renamed? I believe this was raised before. The trouble is Transformer types needs to adopt this article name as Transformers as a disambiguation article linking to the various types. Other clean-ups would be in order, here, and there, but the appropriate article titles would define that. 174.118.142.187 (talk) 21:20, 16 January 2013 (UTC)

"It might contain a transformer, but if it is at all recent it probably doesn't. Most AC adapters nowadays are switched mode."

Switched mode wall warts still contain a transformer to provide isolation and voltage conversion. It's just that rather than running at line frequency the transformer operates at a much higher frequency. This allows a much smaller transformer to be used and generally works out more efficient for small power supplies. Plugwash (talk) 03:47, 16 March 2013 (UTC)

Dot Convention

This looks like just "I want to get the last word in even if I have to make it unintelligible by adding more flowers".

Want to discuss before somebody gets their ass kicked in a drive-by? 174.118.142.187 (talk) 03:08, 11 April 2013 (UTC)

I am satisfied for now with the wording as is.Cblambert (talk) 16:28, 11 April 2013 (UTC)

You don't mind if I call you 187 for short? I have a problem with 2nd sentence's ending, '. . . and polarities of voltages are the same instantaneous polarity at each marked winding terminal.'

What is intent of:

. . . polarities . . .' are '. . . same instantaneous polarity . . .'?! Is this not circular nonsense?
'instantaneous polarity'?! Are transformer voltages and currents not always instantaneous? Do you mean changing waveform? What?

As nothing about this ending makes sense, it cannot remain long without explanation from you or others.Cblambert (talk) 18:44, 11 April 2013 (UTC)

It could be a lot simpler all around. You might as well say " a chiral embedment in an orientable 3-space manifold". What's wrong with saying "When current goes in at the dot end of a primary winding, current comes out at the dot end of secondary windings." ? --Wtshymanski (talk) 20:14, 11 April 2013 (UTC)

I note addition of citation to Csanyi reference, which gives clue as to origin of word 'instantaneous', quoting from Csanyi post:

"Transformers are sometimes marked at their terminals with polarity marks. Often, polarity marks are shown as white paint dots (for plus) or plus-minus marks on the transformer and symbols on the nameplate. These marks show the connections where the input and output voltages (and currents) have the same instantaneous polarity."

Csanyi is a unreliable source as Csanyi is a draftsman with no known engineering credentials, his reference to the 'instantaneous polarity' term not surprisingly being as technically sloppy as currently used in =Dot convention=. Not only should Csanyi reference be removed from this citation but Wikipedia should block references to the complete Electrical Engineering Portal.Cblambert (talk) 20:41, 11 April 2013 (UTC)

Here is how some unknown author from Shanghai Jiao Tong University define dot convention:

'When the reference direction for a current enters the dotted terminal of a coil, the reference polarity of the voltage that it induces in the other coil is positive at its dotted terminal.'

Here is how Professor King define dot convention on slide 3 of Lecture 13 of his Fall 2003 EECS40 course:

'If a current “enters” the dotted terminal of a coil, the reference polarity of the voltage induced in the other coil is positive at its dotted terminal. If a current “leaves” the dotted terminal of a coil, the reference polarity of the voltage induced in the other coil is negative at its dotted terminal.'

Though Wtshymanski tends to be right in thinking this all this effort seems terribly complicated, it is also obvious that pinning the dot convention to a stable, intelligent strings of words is evidently very illusive.

Proposed new wording, assuming existing ref. [43] is removed, follows:

"Often used in transformer circuits, nameplates or terminal markings to define the relative polarity of transformer windings with polarity dots such as shown in Ideal transformer circuit diagram, the dot convention is understood to mean that positively-increasing current I_P entering (or leaving) the primary winding's dot induces positive (or negative) polarity voltage E_S at the secondary winding's dot."Cblambert (talk) 01:47, 12 April 2013 (UTC)

Whether the current is entering or leaving or rising or falling, it produces the same polarity at all the dots, including the one that it may be entering or leaving.Constant314 (talk) 03:59, 12 April 2013 (UTC)

Quoting from current Brenner reference, where subscripts 1 & 2 refer respectively to primary & secondary winding, L refers to winding inductance,

M{\frac {di_{1}}{dt}}

refers to the emf induced by mutual inductance:

"With no current in L₂, the voltage of its [ie, secondary's] dotted point with respect to its undotted point is equal to

M{\frac {di_{1}}{dt}}

, where i₁ is the current whose reference arrow goes from the dotted point to the undotted point in L₁."

Which is the exactly equivalent to what is stated by above references by Professor King and Shanghai anonymous source.

To Constant314: since

M{\frac {di_{1}}{dt}}

is a derivative, one has to specify whether waveform is increasing or decreasing to determine whether voltage at the dot is positive or negative. For example, the classic test for determining polarity is a positive step function. A steady state DC current signal will not determine polarity. And so on.Cblambert (talk) 06:17, 12 April 2013 (UTC)

I didn't write carefully enough. What I mean is the polarity of the signals at all the dots is the same, whether that be positive or negative.Constant314 (talk) 23:36, 12 April 2013 (UTC)

Perhaps we should discuss atomic electron charge theory using RPN math notation, in Latin so that all will understand what is really happening here. It's convenient way of frequently avoiding resolution discussion. 174.118.142.187 (talk) 03:16, 13 April 2013 (UTC)