Talk:Dynamo

Testing Testing..

Hmm, this talk page is blank. That looks weird. Is this a bug? Or just a result of the other editor's experimenting? Seems odd to have a talk page with no talk. DMahalko (talk) 02:27, 7 May 2008 (UTC)

This is an engineering article, not Sarah Palin you know. We just do the facts here, not wiki-drama. SpinningSpark 10:10, 10 May 2009 (UTC)

You do realize of course that your comment has extremely high irony and is itself content-free. but now that some real talk is occurring below, this whole section can go. DMahalko (talk) 20:12, 11 May 2009 (UTC)

Jedlik

The refs for Jedlik do not prove the extraordinary claims made. The claims should be held to what is reliable referenced in scholarly sources which document in what year he published and publicly demonstrated any devices he invented. A claim is not a proof.Edison (talk) 23:59, 10 May 2009 (UTC)

Agreed they do not prove, but they are valid refs by the standards of Wikipedia. As I had gone to the trouble of searching to try to verify the claim, I put them in. If you think the statement still needs tagging, put it back, I don't mind. Or the wording could be changed to "it is claimed . . ." rather than stating as fact. SpinningSpark 06:14, 11 May 2009 (UTC)

The Made in Hungary book has this in its bibligraphy;

• GK Cwierawa, "Ányos Jedlik-wengierski pioner elektrotechniki", Kwartalnik Historiki Nauk i Techniki, No 2, 1971

which I guess is were the author got it from, and hopefully cites the original publication, but I cannot locate it online. SpinningSpark 06:39, 11 May 2009 (UTC)

Original meaning of Dynamo

The opening sentence states that the word dynamo originally referred to an electric generator but more recently defines a DC commutated generator. Can this be verified? In some of the oldest literature I have on electrical systems the word dynamo always describes a DC commutated generator. Thomas Edison called his commutated DC generators a dynamo and they were in use as early as 1878. —Preceding unsigned comment added by Thaddeusw (talk • contribs) 07:25, 17 July 2009 (UTC)

Prior to the War of Currents in the 1890s, the only type of generators existing were DC commutated machines, and the words dynamo and generator were used synonymously for them. When AC power proved practical, AC generators were produced; they used slip rings instead of comutators. Gradually the word dynamo was reserved for the older DC machines, and AC generators were called either "AC generators" or "alternators" and the word generator became a generic term for both. --Chetvorno^TALK 19:16, 17 July 2009 (UTC)

Arc lights used high voltage alternating current before Edison introduced his DC central station in 1882. So AC generators existed were in commercial use for arc lighting by the 1870s. Pixii's generator in 1831 produced alternating current by rotating a magnet near a fixed coil. Most early generators were alternators, before the commutator was invented in the 1830's. Edison (talk) 20:03, 17 July 2009 (UTC)

I understand that dynamo could have been used to describe any type of electrical generator. But the wording: "but more recently defines a DC commutated generator" is unnecessary since the definition is over 100 years old. Over 100 years is not exactly recent. Thaddeusw (talk) 06:20, 22 July 2009 (UTC)

Early Work

Werner von Siemens is commonly credited with the discovery of the dynamo-electric principal (using electromagnets instead of perminant magnets). There are also claims that Danish inventor Soren Hjorth had this idea first [1]. There are probably many other inventors as well, so this article can still use some research. DonPMitchell (talk) 03:38, 28 August 2009 (UTC)

Siemens is certainly not "commonly credited" with this. Although he did claim it himself, there's little to support it and his claim is generally disbelieved. Andy Dingley (talk) 08:37, 28 August 2009 (UTC)

File:Jedlik's dynamo.jpg Nominated for speedy Deletion

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Basic pinciple diagram

This article needs a diagram illustrating the basic principle, of the type found in school physics textbooks, of the two magnetic poles outside a spinning loop of wire. Does anyone have a suitable diagram in the public domain that could be used ? It would also be useful on the "Electric Generator" page. Darkman101 (talk) 12:39, 18 August 2012 (UTC)

Welding

Regarding this edit, it amy well be true that dynamoes were used in welding, but linking to the welding article as a "see also" is entirely unhelpful to our readers when that article does not discuss the matter. SpinningSpark 21:16, 15 April 2013 (UTC)

So fix it. Expand it. Andy Dingley (talk) 21:37, 15 April 2013 (UTC)

What? That's no answer. Other than perhaps an admission that you shouldn't have reverted me so I'm removing it again. Your the one who is claiming to know about this, why don't you write something? SpinningSpark 22:48, 15 April 2013 (UTC)

So you're ignorant of welding applications for dynamos and you're too lazy to do any research on them but "If I don't know it then it isn't true" is now a reason to remove links? Do the work, or at least don't break things and waste the time of other editors. Andy Dingley (talk) 00:19, 16 April 2013 (UTC)

Please don't put words into my mouth, I am not claiming it is untrue, or even {{dubious}} or {{cn}}. Nor is it a question of laziness; it is simply unhelpful to point a reader to another article which has no relevant information. It can only be deduced why the link is there if one already knows the missing information. I haven't broken anything or wasted anyone's time. On the contrary, I have saved reader's time by not uselessly looking up an unhelpful link. It's not as if I deleted a swathe of uncited text without checking for sources or something. SpinningSpark 10:16, 16 April 2013 (UTC)

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Output of dynamo = ripple current

We make the point that dynamos were used to replace batteries, so there is an implication that they produce DC 'like a battery'. Actually their output is alternating current with a DC offset, analogous to rectified AC current. For use in other than purely resistive circuits, it'll have to be cleaned up. In DC power transmission, power line harmonics are a significant problem. I think I'd like to see some exposition of this. Sbalfour (talk) 00:29, 11 November 2017 (UTC)

So, were they ever cleaned up? Not as I can see. Andy Dingley (talk) 00:45, 11 November 2017 (UTC)

Remember that this was the early days of electricity. Ripple probably was either ignored or just accepted as good enough. The oscilloscope didn't exist, and the ondograph added up hundreds waveform samples to produce its averaged graph. There weren't a huge number of applications at first. Power line harmonics were likely just absorbed as excess / waste heat in the coils. -- DMahalko (talk) 10:00, 31 March 2018 (UTC)

Yes, for example one of the first applications was as a power source for electroplating. Ripple would have been unimportant here. As for power line harmonics, DC power was seldom transmitted further than about a mile, because the voltage could not be changed, it had to be transmitted at the low voltage used by consumers, which required large copper conductors to handle the higher current. That's why Edison's DC power grids lost out to Westinghouse's AC. Dynamo power plants were located near the industries that used them. --Chetvorno^TALK 11:55, 31 March 2018 (UTC)

The early power company generators, such as Edison's Pearl Street station in New York, had multiple poles to reduce flicker, so the power was not going from zero to max voltage like rectified single phase AC. Early central stations in the US supplied DC with a three conductor system providing 110 and 220. It was used initially for incandescent lighting, replacing gas lights, and soon thereafter for operating motors, to replace local powerhouses with steam engines. In the 20th century some of these downtown DC grids were replaced by low voltage AC networks, The downtown DC grids were often connected to a large bank of storage batteries, which would have reduced the ripple. If the ripple was of a high enough frequency to be above the critical flicker frequency, then it was not a problem for lighting customers. Some first generation DC motors stayed in service for a hundred years, with the original DC replaced by rectifiers, and kept fans, pumps and elevators going. Edison (talk) 12:18, 31 March 2018 (UTC)

Yes. Actually reduction of ripple was one of the major goals throughout the 70 year development of the dynamo. Perhaps more should be said about it in the article. The reduction of the magnetic circuit air gaps in the Siemens and Graeme designs made the MMF waveform and thus the current in each winding less spiky and more sinusoidal, so it overlapped more with the waves in the adjacent windings. And the increase in the number of poles superposed more of these waves in the output waveform. In some of the images of the industrial dynamos from the 1880s I count 60-80 poles (30-40 pole pairs). These would have very minimal ripple, maybe a few percent. --Chetvorno^TALK 12:53, 31 March 2018 (UTC)

Dispute of who came up with the name

Someone added a cite referring to "Experimental Researches in Electricity", Volume 1, by Michael Faraday as the source of the word. Well, here it is. And nowhere do I find the word "dynamo" in it. So, what now?

The Project Gutenberg eBook

Experimental Researches in Electricity, Volume 1, by Michael Faraday

http://www.gutenberg.org/files/14986/14986-h/14986-h.htm

• I have been in the habit of referring to Demonferrand's Manuel d'Electricité Dynamique
• 1648. As long as the terms current and electro-dynamic are used to express
• Curves, magnetic, their relation to dynamic induction.
• 39. Demonferrand's Manuel d'Electricité dynamique, p. 121.
• 224. Recueil d'Observations Electro-Dynamiques, p. 285.

-- DMahalko (talk) 09:54, 31 March 2018 (UTC)

Instead search historical docs for first use of "dynamo-electric" machine. 71.212.105.50 (talk) 21:46, 28 November 2021 (UTC)

Pacinotti

In the italian page about Pacinotti, they claim that he is the inventor of the Dynamo. can anybody contribute to clarify the issue? Farhoud Tebiani (talk) 21:04, 24 September 2022 (UTC)