Talk:Alternating current

Just wondering if anyone else finds it confusing that the multiplication sign is an 'X', the symbol for cross product. I realize that this or a dot are often used, but with the inclusion of the sine function in the equation already it may be misleading. --Bmalicoat 23:47, 26 October 2005 (UTC)[reply]

The problem, of course, is that the "x" is the Wiki-generated symbol from the "times" markup (shown below). As long as that's the case, I think it should stand as currently written. You could, of course, start lobbying the Wiki software guys for a change (that would affect every usage of "times").

:<math>v(t)=A \times\sin(\omega t),</math>

Atlant 12:07, 27 October 2005 (UTC)[reply]

Ahh, I didn't realize that, thanks.

Bmalicoat 03:12, 28 October 2005 (UTC)[reply]

The wording "His design was a primitive precursor of the modern transformer, called an induction coil" is not very NPOV.

I'd like to see some pictures of AC in action words can't describe it well enough. --Cyberman 02:30, 10 Feb 2005 (UTC)

I think this page is nice. Congratulations to those who've been working on it. I nominated it for featured articles. A picture would be nice, though. Power cables, transformers or something. Washington Irving | Talk 23:21, 25 Mar 2004 (UTC)

I could write a part about transforming DC->AC through a solenoid- condensator circuit and a triode. Anyone think this is useful and/or fitting here?
- Xorx77 17:09, 28 Mar 2004 (UTC)

That would be good, but perhaps it would be more appropriate in the HVDC article under "Rectifying and Inverting". You could add a link from this article to that one. -- Heron 17:16, 28 Mar 2004 (UTC)

I changed the usual Teslaphile stuff to give due credit to some of the other critical workers in the field. Look guys, I know you venerate the guy, but the reality is that his contribution to the field, although undoubtedly important, was just one aspect of many advances in electrical engineering at the time. In particular, describing him as the father or inventor of AC makes a good book blurb but is totally unsupportable. Among the critical parts of the infrastructure he didn't invent were: transformers, the AC distribution system, AC generators, or meters. His major practical contribution was AC motors - and the first one he ever built that actually worked, was under contract to Westinghouse. Securiger 13:18, 21 Jun 2004 (UTC)

I updated the sections on power and 3 phase systems, which are hopefully a bit clearer now. Also the section on earths and neutrals which had become a little muddled. The earth is not the same as a neutral. A neutral is used to form a complete circuit in a healthy system, an earth is used to provide a specified path for current during a fault.

Did the guy who wrote this ever actually stick the probes of an oscilloscope into the wall outlet?

The article currently has a lot of stuff that is covered in other articles; three phase, grounding, etc. I think the discussion here could be compacted since details are only a mouse-click away. I also cleared up some leading spaces in the talk page - not everyone is signing contributions - use the button for signatures in the editor or else manually put --~~~~ at the end of your comments. --Wtshymanski 17:26, 1 Jun 2005 (UTC)

"(In this section overline will be used to indicate phasor or complex quantities and letters with no annotation will be considered the magnitude of those quantities.)"

Is this a standard notation? - Omegatron 23:16, August 14, 2005 (UTC)

It wasn't standard when I was studying or practising electrical engineering (although that may just indicate how old I am!). A one-side-head horizontal arrow over a symbol was sometimes used to indicate a vector quantity, but most texts used boldface symbols for that. I always used a simple overline in the statistics sense - a mean or average (rms of course). Magnitude was denoted with matrix notation e.g. |z|. Plain symbols were used only for DC. Of course we used e for electromotive force and i for current, which drove the mathematicians nuts because they had totally different meanings for them. To top it off, because i was already in use, we used j for what mathematicians call i. I'm certain we can never find a notation that satisfies everyone, so we have to clearly specify the one that we use, then keep it consistent across related articles. Boldface and || have the advantage that they can be expressed directly within WP - no CSS or PNG required. JohnSankey 17:54, 5 October 2005 (UTC)[reply]

I consider the concepts of electrical current/voltage, resistance/reactance and power to be sufficiently different that they should not be merged, otherwise the combined article will become too long and very difficult to organize clearly. I note that there is inadequate discussion in these articles of non-sinusoidal waveforms, particularly of the substantial 3rd and 5th harmonics generated by the non-linearity of standard power transformers - that would make a combined article even longer. Then there are the square and 2-step waveforms of DC-AC power converters. I recommend keeping these three separate but consistent, with appropriate cross links. As a retired electrical engineer, I could try to start this process, but would do so only when agreement is reached on separation. JohnSankey 15:31, 5 October 2005 (UTC)[reply]

So much for an offer :-( JohnSankey 22:59, 5 October 2005 (UTC)[reply]

Can we remove some of the merge templates then?--John 23:45, 16 October 2005 (UTC)[reply]

Just to note that "mains power" is a British term. I have never heard it used in North America. JohnSankey 22:59, 5 October 2005 (UTC)[reply]

It's used at least occasionally in North America. Especially as compared to (say) "battery power".

Atlant 01:03, 10 October 2005 (UTC)[reply]

Why do these articles simply redirect to this article, when this article makes no mention of them?

I am sorry if I sound negative, but this article/entry (Alternating current) is un-organized, and even though it's extraordinarely short for such an important and vast subject, it feels too long to read.

The consequences of the bad architecture of the entry, is that even contributors have trouble striking the right balance when trying to add relevant information. For example, Nikola Tesla is under-represented, even though he has almost single-handidly produced virtually all the elements of the puzzle necessary for the AC power system (I won't spend time documenting this point, if anyone thinks it's open to dispute, I'm willing). I don't blame it on anyone's agenda, but simply, on the fact that the article is discouraging of contribution. I have tried, anonymously, to correct few of the more evident errors, and am preparing to beef up the body on Steinmetz and Tesla. Still, every time I think of this wikipedia entry, I feel pain in my stomach, so I keep putting off the big work for another day. Old-fool 17:56, 21 October 2005 (UTC)[reply]

One way to handle this dilemma is to create an entirely new version of the article. You can initially create it in something like "Alternating Current/new_version", tweak it until it's as you want it, and then open it up for review and collaborative editing. When the article is "fully baked" we can replace the existing article with the new article.

There is definitely a life-cycle to many Wiki articles:

1. They're initially created terse
2. Over time, they "accrete" aditional information, often in a somewhat-jumbled way
3. At some point, somebody takes the initiative and resturctures the whole thing to make all the accreted info flow as a coherent narrative.

That somebody sounds like you! Time for you to be bold!

Atlant 12:17, 27 October 2005 (UTC)[reply]

I don't know what you mean by power lost = I^2 * R. This is supposed to be the equation for power transmitted, and since V=I*R, power = V*I also. Therefore, I don't see why the power equation explains why current affects power lost and not voltage. Can someone clarify this please?

It depends on which R you are referring to. Power lost is I^2 * R(of the conductor). Power delivered is I^2 * R(of the load). pstudier 03:55, 3 November 2005 (UTC)[reply]

I do see a problem with formulas however. P=I^2R and P=IV of course, but coupled with introduction of "This implies that in the same wire, if the current is doubled, the power loss will be four times greater", to some readers this might suggest that if the voltage is doubled, the power loss will NOT be four times greater, which is certainly not the case because P=V^2/R too. Something should be done about this, but I am not sure what. Nikola 09:33, 4 November 2005 (UTC)[reply]

You have to be careful, when you are using P=V^2/R, to specify what V you are referring to. Your statement above suggests that you are talking about the voltage drop across the wire. Doubling this would indeed cause a quadrupling of the power loss. However, the V usually referred to in this context is the transmission voltage. Doubling this causes a quartering, not a quadrupling, of the power loss. I'm reluctant to explain this in the article because it would just add confusion where there is presently simplicity. However, I'm open to ideas. --Heron 17:09, 5 November 2005 (UTC)[reply]

I would suggest that you read Wikipedia articles on alternating current and direct current. Nikola 22:54, 28 November 2005 (UTC)[reply]

This is a shockingly sparse and badly organised article considering the importance of AC power in the world.

Volt-amp redirects to this article, but I don't see any mention of it here. In particular, I'd like to know how volt-amps are related to watts. (I thought were the same, but then why is a UPS I'm looking at rated at "500VA" but "300W"?) - dcljr (talk) 04:50, 16 January 2006 (UTC)[reply]

i've just changed the redirect to point to AC power. enjoy ;) Plugwash 04:51, 16 January 2006 (UTC)[reply]

Quote:""It is generally accepted that Nikola Tesla chose 60 hertz as the lowest frequency that would not cause street lighting to flicker visibly. The origin of the 50 hertz frequency used in other parts of the world is open to debate but seems likely to be a rounding off of 60 Hz to the 1-2-5-10 structure, called a set of preferred numbers, popular with metric standards.""

What other parts of the world? I assume other than the U.S.A. If you take a look at the frequencies used you will notice that 50 hertz is the most commonly used frequecy , with a few (but major) exceptions (mainly North America). It's a minor issue of how you put it , since I don't think all users of wikipedia regard this from the point of view of an american as we can't be all americans :))