Talk:Magneto

Initial post

What /sucks/ is the clutter about contact points? I've never seen contacts on a magneto although I hear motorcycles have them and I suppose they are common enough. Typically it's even more fault tolerant due to the absence of moving parts aside from the flywheel bearing (which isn't really part of the magneto). The coil placement defines the firing window and is sometimes adjustable on the fixed gap & I've seen fixed timing with an adjustable gap. The former is ideal, but I came here looking for the effects of the gap adjustment... The article seems to imply points are necessary and I feel like points are more of a refinement. The most basic magneto drives the coil directly as the magnets sweep past. I suppose the flywheel is technically a moving part but it doesn't wear due to any association with the nearby coil.

Then you've never taken a magneto apart. All magnetos on engines have a contact breaker (points). It is possible these days that some bright spark (!) has devised a way to operate them electronically, but without a constant source of power, it is difficult to se how. 86.184.24.140 (talk) 12:50, 17 June 2011 (UTC)

Dispute about Restructuring

I totally sucks that this has been changed into a disambig page. The term "magneto" is recognised by 99% of people to mean the electrical generator thingy - that's where the term originates. The other names are secondary. Therefore the correct thing to do is to make this the article page, with mention and wikis to the other two meanings in a separate section. Otherwise all the existing links need to be updated, which is just silly. I intend to put this back how it was, in keeping with the guidelines. GRAHAMUK 06:04, 15 Nov 2003 (UTC)

I don't see much to agree with in your arguments, particularly your gratuitous and insulting observation that "I [sic] totally sucks". I'd bet that 99% of people neither know nor care about the "electrical generator thingy" (you don't seem to care, given your terminology). The other names are secondary - to whom? "Electrical generator thingies" carry more weight than popular culture characters because... why? And as for "all the existing links": I count 7 total pages, one of which is a redirect and two of which are users. Updating those links seems neither difficult nor silly. Also, the guidelines you refer to in such reverent tones note that references to other pages for a term should be listed at the top of a page, not the bottom, so at the very least I'll do that. -mhr 06:35, 16 Nov 2003 (UTC)

No need to be so touchy. Maybe I shouldn't have been either... but fact remains that "magneto" primarily means the generator. The other meanings, however "popular" they may be - which is highly subjective (personally they mean nothing to me) - are secondary, simply because of the precedence of time and usage. Magnetos have existed since Faraday's time, presumably the other usages are derivative, or else were arrived at independently by somebody who didn't think to check what it meant. To me - and probably anyone with an engineering bent, - naming a superhero after an engine component seems a bit, well, silly - what's next, rubber gasket man? (Hmmm... gives me an idea....) Anyway, this is not the point. I have no wish to argue about this, not upset anyone for whom "Magneto" is their favourite band/superhero/soft drink/panty liner brand or whatever, but the way the article is laid out now is correct, as far as I can see. You were right about putting the disambig at the top, but wrong about moving the primary meaning in the first place. I think we can agree at that! (I hope anyway). Incidentally if moving the associated links didn't seem difficult nor silly, why didn't you do it? GRAHAMUK 11:04, 16 Nov 2003 (UTC)

Sorry for being touchy, but I was taken aback by your comment, given the usually even tone of disagreement I usually see on WP.

Alas, I don't agree that magneto is primarily the engine component. Even discounting the fact that I'm a comic book fan, I've heard the term used to refer to the villain dozens of times in the past 5 years (from commercials for and reviews of the X-Men films alone), whereas in the last 20 years I've heard it used to refer to the engine component... well, maybe in a physics class at some point, but I can't remember a single concrete example. It's just not a term in common use, and I think there's good reason to think it's being eclipsed - in general usage - by the pop culture character. I would certainly argue that people on WP who are looking up Magneto are as likely to be looking for the character as the engine component.

Many technical and engineering terms fall out of favor over time (e.g., carburator), becoming of interest primarily to specialists. While I would not argue that any pop culture figure who adopts a name from science immediately (or ever) grows to equal the weight of the original term, I think the marginal nature of the magneto component combined with the prominence of the character makes this an exception. -mhr 06:58, 18 Nov 2003 (UTC)

Yes, terms fall out of favour over time. Did you mean carburettor? AFAIK, carburator isn't even a word - which might have been your point! I disagree about magneto though. I suppose it just depends what you're interested in - since you're interested in comic books then you a probably more likely to "notice" the usage of Magneto as a comic book hero's name than someone who isn't, and vice versa - maybe you don't notice the use of magneto in its engineering sense. It all depends on who you ask in other words. As for whether it is in common use, I believe it is, it it still very much used in small and aero engines, and hasn't been replaced by something with another name. I just bought a brand new petrol-driven grass trimmer for example, and that has a magneto. What has to be considered is whether the relevant articles of either type are easily found by those looking for them. In its present form I think it accomplishes that pretty well. Those who only have ever heard of the comic book character will discover something interesting they didn't know into the bargain ;-) My apologies for the outburst you objected to - obviously it wasn't aimed at you or anyone in particular, it was just a final irritation at the end of a very long day.... GRAHAMUK 11:40, 18 Nov 2003 (UTC)

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It occurs to me that my role in cleaning up the history might be construed as the only opinion being expressed here by a third party, and as an opinion that the device sense should be the main article to the exclusion of "equal disamb" i.e. that the second move would have been a good one if "move this page" had been used instead. In fact, my strongest opinion in that area is that expressing a preference would impair my ability to communicate about the technical and "process" issue, followed closely by my opinion that you each knows more about what the subject of Magneto should be than i do. --Jerzy 16:32, 2004 Jan 10 (UTC)

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Just read this with interest - have been having some early flying lessons and wondered what on earth a magneto is, and found what I was looking for. It seems that it's great to list words that aren't in common usage - if I already knew what it was it's highly unlikely that I would have visited. I'm also aware of Magneto as an X-Men baddie, but would never consider looking him up in Wikipedia! Jon-stewart 11:27, 7 September 2006 (UTC)

Reconstruction of Mangled History

When an editor renames an article by cutting and pasting its text to a page that has the new title (but "Move this page" should have been used), it is possible for a developer to correct the history entries of the page. The reconstruction of the history for the period from 2003 Nov 14 thru 2003 Nov 16 was instead performed by means of ordinary edits, after a sysop kindly

1. moved Magneto to Talk:Magneto/temp (along with its history),
2. deleted Magneto (as required by next step),
3. moved Magneto (engine component) to Magneto (along with its history), and
4. reverted the text to a convenient point.

(The need for a sysop was for the deletion, which only they can perform.)

The point of those maneuvers was to rejoin the history of the edits made under the title "Magneto" before the creation of "Magneto (engine component)" (and the ones made under the title "Magneto (engine component)" back with the text of "Magneto" and the history of future edits that will be added there. (The history of edits of text that are documented only as history entries on a redirect is essentially lost.)

They ugly way the history was recorded in this case is by using the summary field of reversion edits and dummy edits to store information, most significantly the summaries of early edits whose results are recapitulated as new revisions. Thus the differences in the text can be seen by clicking "cur" or "dif" links in the recapitulation entries, instead of the confusing and misleading ones involving the original Nov 15 entries. (Note that some of these recapitulation entries reflect previous content of Magneto, but others that of Magneto (engine component).)

Jerzy was the one who made up that approach, and as to what's not clear abt its meaning, ask me specific questions at this convenient spot and i will use them to tell me what more i need to say here to explain them. TIA for your patience. --Jerzy 10:40, 2004 Jan 10 (UTC)

How it got that way

Damage was done in the process of the competing edits motivated by the positions taken in the preceding section -- done, specifically, by the cut-and-paste move that was made to partially reverse the earlier true move. (The latter was executed with proper technique as described at Wikipedia:How to rename (move) a page, but gave no apparent attention to the advice given there for taking account the impact on this community.)

In any case, i have obtained the help of a sysop and am now in the process of creating have created a record, within the history of Magneto, of what the history of the article on the device should have looked like. (The result will make more sense than its description, worry not.) --Jerzy 08:28, 2004 Jan 10 (UTC)

Well, somewhat more sense, even if it sucks, but better than taking up a developer's time to do a pretty job of making the information available.

Contrary to my recollection, i see that clicking on "Move this page" doesn't point a user to Wikipedia:How to rename (move) a page, so i regert my willingness to let some harshness possibly creep into my earlier references to it. Please don't let that keep you from studying it. --Jerzy 10:40, 2004 Jan 10 (UTC)

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Disambiguation header

I restored the single-line disambiguation header to the page. I think this reads better, and it's more in keeping with the form at Cream, which is explicitly referenced in Wikipedia:Disambiguation. This seems to be the standard, and I think it's desirable to keep the header as vertically short as possible. If we end up adding yet another meaning, then we should probably created Magneto (disambiguation) - but for only two secondary meanings I don't think we're there yet. -mhr 23:27, 12 Jan 2004 (UTC)

Aircraft spark

'and two sparks burn more efficiently than one', why is that anyway? Surely when the avgas is ignited its going to burn the same with one spark than two? What about aircraft shower of sparks system anyway? I mean you might be right, just seems like the kind of thing to prove with a citation.

I can't give you a citation but I'm a pilot and I assure you that this is true. Part of the preflight check in an airplane with a reciprocating engine is to turn off the magnetos one at a time, which causes a drop in RPM. Maybe "efficiently" isn't the right word to use but having two sparks does make a difference. -- Captaindan 18:06, 7 July 2006 (UTC)

Although not an expert I think the two spark efficiency comes from igniting the fuel simultaneously in two places. The flame front takes a significant time to spread from the point of ignition and so igniting the fuel/air mixture in two places causes it to burn marginally quicker and thus deliver power at a more optimum time during the stroke of the piston.

I'm also a pilot and flight instructor and wanted to mention that the 'shower of sparks' is only used on certain mags while the engine is being cranked. It uses a vibrator to create a near constant spark on one of the cylinder's spark plugs to make starting easier. As soon as the engine starts, the mag reverts to normal operation.

I have somewhere heard that before, that one magneto had a sort of spring loaded trip so that it would always flick past its spark point with adequate speed even at low revs. It appears to be related to the thinking behind "Some luxury cars before that time were dual-plugged as well, but had only one set of plugs fired by magneto. The other set was wired to a coil, dynamo, and battery circuit because the magneto would generate high voltage at high engine speed, but not at low engine speed, whereas the other ignition system would perform well at low engine speed but not as well as a magneto at high speed." Can anyone back this up so it can go in the article? PMLawrence (talk) 12:14, 8 November 2008 (UTC)

Lawrence, the system you're referring to is called an "impulse coupling", and is only used during starting. Once the engine hits a minimum RPM (usually around 150), the impulse coupling is disabled by a flyweight system. And in the other department, about using a magneto ignition on one side and battery ignition on the other, this has been used on a few aircraft engines, most notably some versions of the Jacobs R-755 radial engine. It's used because magnetos are considered more reliable, but they have fixed timing, while battery ignition has the ability to vary the timing. Since magneto timing is fixed, it must be adjusted to a compromise setting which is neither the best for starting nor for full power. On the other hand, the battery ignition timing can be retarded in order to start the engine below the magneto's coming-in speed, or advanced to achieve greater fuel efficiency at cruise RPM. The idea has seen a resurgence in modern homebuilt aircraft, with the old style analog battery ignition being replaced by a modern, sophisticated electronic unit not unlike those used in automobiles. Australian Jon Johanson used such a setup (among other modifications) in order to achieve the fuel efficiency necessary to fly his RV-4 across the vast expanses of the Pacific Ocean. Shreditor (talk) 06:58, 9 November 2008 (UTC)

Magneto ignition can be advanced and retarded in exactly the same way as battery coil ignition can. 86.180.171.123 (talk) 14:56, 30 March 2010 (UTC)

Magnetos

Is it true that magnetos are also called permanent magnetic generators (PMG's)?

ANSWER: The human being can call the same object of the reality in different ways. Of course a magneto is a Permanent Magnets Electric Generator (not magnetic), or PMEG, but this is so complicated, something like to say a common cat is a Felix Catis... do you know anybody that calls sugar, for its chemical name, sacarosa? ... please... don´t complicate technology and science, they are enough complicated by themselves..

Needs a starter

I'm moving this sentence to the talk page:

Most importantly, the magneto does not have the ability to start the rotation of the engine or of itself, so that an alternative starting method will be required for a machine using a magneto. Some such methods are the starter motor, kickstart, starting crank or pull cord, starting charge, or the like.

This statement is somewhat misleading in that it implies that only engines with magnetoes require separate starters. All reciprocating internal combustion engines need an external starting method, regardless of ignition type. Nibios 21:10, 11 July 2007 (UTC)

Magnetos are not just for ignition

I'm going to re-write the opening sentence. Magnetos today may be used mostly for ignition but I don't think that's the definition of a magneto. I think what makes it a magneto is 1) permanent magnets and 2) no commutator, so AC output. If you have a good reference please feel free to refine my definition. Rees11 (talk) 15:55, 16 March 2009 (UTC)

That definition does not quite distinguish modern alternators which charge the battery and AC generatators (magnetos) that powered spark coils. Also to be included should be the hand-cranked AC generators (magnetos) used in late 1800s telephones to signal the switchboard operator that the user of the magneto wanted to make a phone call. Greensburger (talk) 19:33, 6 August 2009 (UTC)

Technically: a magneto is a specific type of permanent magnet generator that uses an interupting device of some sort (traditionally a contact breaker) in conjunction with a secondary coil to produce a pulsating high voltage output (typically thousands of volts). As ever in engineering, the term gets borrowed to describe other types of generator. The telephone 'magneto' described above and in the article does not work this way, but is in reality just a permanent magnet alternator that produces a few hundred volts only. The term has similarly been usurped to describe other types of permanent magnet generator. 86.180.171.123 (talk) 15:05, 30 March 2010 (UTC)

I'm confused. "Primary"/"Secondary"? "Points" ? Ignition magnetoes don't have a primary - there's no battery, and no points. It's been a while since I took apart a lawn mower engine, but I don't recall anything other than a coil and an insulated wire to the spark plug. I think the article is in error, or at least describes one of several cases (some of which have no points or primary/secondary coils). --Wtshymanski (talk) 15:24, 30 March 2010 (UTC)

Magnetos don't usually have a transformer, but see Eisemann magneto system, 1911 or Magneto ignition with low-tension magnetic spark plugs, 1909. Andy Dingley (talk) 21:17, 31 March 2010 (UTC)

Magnetos are permanent magnet AC generators, no more, no less. No commutators, but the windings can be either on the stator or rotor, so they don't always have slip rings. I've recently split the Commons categories into

• Media related to Magnetos at Wikimedia Commons
  • Media related to Magnetos (ignition) at Wikimedia Commons
  • Media related to Magnetos (telephone) at Wikimedia Commons
  • Media related to Magnetos (generators) at Wikimedia Commons

I would suggest re-structuring this article similarly - probably by moving this to ignition magneto and then starting with a disambiguation page under magneto. As to the assertion that they have either transformers, or always have points, then I think that's an excessive inferrence from some specific ignition magneto example somewhere. Andy Dingley (talk) 15:32, 30 March 2010 (UTC)

I wasn't playing close attention the last time I took apart a lawnmower engine, all those years ago - from what I've been reading, a permanent-magnet generator is a magneto, but magnetos used for ignition have both an internal primary and secondary winding and also points and a condensor. Usually all this stuff is under the flywheel on a small engine so it's hard to see (and I haven't been around many aircraft engines).

I don't think the article needs to be split up as much as all that; the unity of permanent-magnet field is the common defining element, and we can briefly discuss the particulars of ignition and telephone uses. How would magneto (generator) differ from magneto (telephone) ? We would start off with a general description, discuss the telephone bell ringer, then discuss small engines and aircraft ignition (with some history in automobile use and current use in racing vehicles), and finish off with the lights the headlamp on a snowmobile. --Wtshymanski (talk) 14:19, 1 April 2010 (UTC)

Bicycle dynamo

I don't have a source so I'm not putting this in, but the wheel mounted generator used power the headlight on a bicycle is a magneto, although it is incorrectly called a dynamo in common usage. Rees11 (talk) 16:14, 11 April 2010 (UTC)