Talk:Magneto (power generation)

Early magnetos were probably very inefficient

That is, in a sense. The air gaps, for some particular ranges of rotor positions, were comparatively huge. Different geometry, such as found in modern alternators, would have made them much smaller. (Regarding large physical sizes for given conversion power, electrostatic motors, based on electric (electrostatic) fields instead of magnetic fields, have been built, but for a given power output, are quite large.)

The huge air gaps in early motors, however, had much more serious consequences; such motors were horribly inefficient. These motors (until the Gramme ring, afaik) were based on a magnet's attribute of attracting ferromagnetic objects — Progressively reducing the air gap.

Only when air gaps were greatly reduced did motors have practical efficiencies. Modern electrodynamic loudspeakers (all midrange and woofers) are based on a more-sophisticated geometry, which depends upon mutually-orthogonal current flow, lines of magnetic force, and resulting force created by the conductor. This is in contrast to the earlier principle of attraction (which was used in early loudspeakers).

There are a few illustrations of early inefficient motors in Ganot's Physics, translated into English; it was extremely popular in the late 1800s, apparently; different editions are likely to include different designs, because they were evolving rather quickly. Google has digitized at least two editions of Ganot, even preserving highlight color in illustrations (one color of ink only).

I was quite surprised to see this article's definition of a magneto; I had regarded all generators with AC output to be alternators.

Best regards, Nikevich (talk) 05:39, 17 September 2011 (UTC)

What does "efficiency" mean? Do we mean work done vs. power out, or do we mean a power rating for the size, weight and cost of the machine? Early magneto generators were mostly limited by the second, not directly the first. The weak magnets meant a very expensive machine to achieve useful power, which was their main drawback. As the machine also became physically large, this imposes mechanical inefficiencies too (friction, inertia, windage etc.). As to the magnetic efficiency of their pole circuits, for a sophisticated magneto from Nollet or de Meritens, this was probably better than their contemporary bipolar machines.

Motors work by the Lorentz force between two fields, not simple attraction from one field. Only the very earliest motors, such as the mouse mill motor, used simple attraction. These necessarily had large pole gaps_(sic) because they relied on some distance over which to do the work of attracting the rotor, not just flux across a gap and generating a perpendicular force. Andy Dingley (talk) 10:05, 17 September 2011 (UTC)

Merge

It has been suggested that this page or section be merged with magneto. Both articles seem to have the same referent and scope. Chrisrus (talk) 14:57, 6 June 2012 (UTC)

• oppose Yet again, magneto and magneto (generator) describe the same physical principle, but have different scope in terms of their engineering. Broadly, magnetos weren't used as generators - the more complicated dynamos and alternators were needed to do that efficiently. In some rare and narrow cases (lighthouses are hardly commonplace), the simplicity of the magneto did win out. This is the well-defined scope that magneto (generator) covers.

I would agree that this is perhaps not clear from the two paragraphs of the lead, and it's necessary to read into the body of the article to find the distinction. That would seem to be reason to expand the lead, not to merge. Andy Dingley (talk) 15:21, 6 June 2012 (UTC)

Ok, but as a reader please accept my feedback that something be done because it's very strange for the reader. Of course we are allowed to have two articles about the same referent so long as they have clearly different scopes. These don't have clearly different scopes. The fact that I am not the first implied by you saying "yet again" only supports the position that this situation needs correction because other readers must have found the situation confusing. Chrisrus (talk) 17:39, 6 June 2012 (UTC)

Ok, I've been reading these two articles a little. This reader understands that a magneto is a hand-cranked magneto (generator). The other way to say that would be that a magneto (generator) is a differently-powered (not hand-cranked) magneto. Both are generators that produce electricity by spinning a coiled wire inside a magnet. The difference is what is doing the cranking, is that correct? Have I understood or misunderstood? Chrisrus (talk) 13:31, 29 June 2012 (UTC)

A "magneto" is a physical principle. There are many, many sorts. Some are hand-cranked, some driven by engines, but their distinguishing feature is the permanent magnet field (and nothing else). Only three types were mass-produced (telephone, ignition, bicycle) and they were not, in general, used for large-scale power generation. Large scale power was done by dynamos, later by alternators.

There are of course exceptions. In some obscure cases (arc lamps and lighthouses), large power magnetos were indeed used. As this is the exceptional case, it's worthy of separate note.

There are several articles within scope here: magneto is obvious, but the sub-types of ignition magneto, telephone magneto and bicycle dynamo all deserve decent coverage in their articles too. I'm thus puzzled as to why the one article here that is anywhere near a decent treatment of its topic is the one under attack for merge or deletion? How about the effort going into that instead being put towards fixing ignition magneto? Andy Dingley (talk) 15:46, 29 June 2012 (UTC)

Nothing and no one is under attack. I'm just a reader that noticed we have two articles which as written apear to be generators called magnetos, that's all: they bpth say they are about generators, not physical principles. One is called simply "magneto" and the other is called "magneto (generator)" All I know about the subject is what is written in these articles.

Let's leave those other magnetos out of it, as those others you mention are clearly about particular kinds of magnetos and are not confusing to this reader. "Magneto" as written refers to a type of generator which works on a certain principle, not a principle that is used to make a certain type of generator. It's not the same.

Please, in as few words as possible, what is the difference between the scope of the article Magneto and the scope of the article Magneto (generator)? For example, you could say "one is a subset of the other" or "a ven diagram of their scopes would overlap imperfectly" or "one is a particular sort of the other". As written, both are clearly subsets of the article generator. Chrisrus (talk) 00:25, 30 June 2012 (UTC)

What is the difference between a Magneto and a magneto (generator)? Chrisrus (talk) 19:13, 12 September 2012 (UTC)

Hello Chrisrus. I agree with you that all magnetos are generators so there is no justification for having two articles. I think Andy Dingley is claiming that the term "generator" only applies to high power generators but I would disagree with this definition. Anyway, he does not own the articles so there is no reason why we should not have another try at merging them. Biscuittin (talk) 14:20, 20 March 2015 (UTC)

• Again, the strongest possible oppose to a merge with either of the really high level articles at generator or magneto. How does that sort of "Merge everything into one huge article" possibly improve structure or readability? We wouldn't merge brushless motor and universal motor into electric motor, just because they're both motors? Andy Dingley (talk) 14:33, 20 March 2015 (UTC)

You still have not answered the question: "What is the difference between a Magneto and a magneto (generator)?" All magnetos are generators. Biscuittin (talk) 16:20, 20 March 2015 (UTC)

I have added a merge tag on the grounds that all magnetos are generators. Indeed, the first line of the Magneto article reads "A magneto is an electrical generator..." Biscuittin (talk) 23:14, 20 March 2015 (UTC)

I am quite happy to keep Ignition magneto and Telephone magneto as separate articles because they describe particular types of magneto. Biscuittin (talk) 23:19, 20 March 2015 (UTC)

Andy Dingley has still not answered the question "What is the difference between a Magneto and a magneto (generator)" so he is not making a good case. However, I will try to answer the question for him. I think he is trying to distinguish between low-power magnetos (e.g. Ignition magneto) and high-power magnetos, e.g. for arc lighting. If so, I think the problem could be solved by renaming magneto (generator), perhaps as High power magneto. My objection to the existing arrangement is that it creates confusion because all magnetos are generators. Biscuittin (talk) 11:33, 21 March 2015 (UTC)

I can't tell for sure because I'm just a reader of these articles who is still pretty confused by there being two of them and why they should be separate. But it looks to me like some kind of WP:POVFORK here or something similar, where Wikipedians couldn't get along and so agreed that instead of working together they decided to have two articles about the same thing. But you all know more about this than I do, but if I don't know what's going on with these two articles it's not my fault, it's the fault of the articles, because I've read them both and it's their job to teach people like me what the difference is between these referents, which based on reading these articles seem like the same thing. Chrisrus (talk) 02:00, 22 March 2015 (UTC)

You may be right about WP:POVFORK but I think we can resolve the problem by treating Magneto as a Broad concept article. There are already two sub-articles about specific types of magneto - Ignition magneto and Telephone magneto. I propose that Magneto (generator) be treated as a third sub-article and re-named High power magneto. Does this make sense to you? Biscuittin (talk) 19:46, 22 March 2015 (UTC)

The lead currently includes, "Despite this, they have never been widely applied for the purposes of bulk electricity generation, for the same purposes or to the same extent as either dynamos or alternators. Only in a few specialised cases, as described here, have they been used for power generation."

What part of that is unclear to you?

Magnetos are a broad topic. This article is on a narrow topic. It is appropriate to separate them like that. This article manages to give reasonable coverage of that significant, but narrow, topic without being sidetracked into covering too many other aspects of magnetos (although the wind turbine overlap is starting to look dubious). We are not best served by throwing everything into one huge unstructured article - something that WP already has far too much of. Andy Dingley (talk) 13:29, 23 March 2015 (UTC)

Both Chrisrus and I have repeatedly asked you the question "What is the difference between a magneto and a magneto (generator). Until you answer this question, you have no credibility. Biscuittin (talk) 17:00, 23 March 2015 (UTC)

Permanent magnet synchronous generator

It seems to me is that permanent magnet synchronous generator is just another name for magneto (generator). Maybe we should just change that page to redirect to this page. Z22 (talk) 02:41, 17 October 2013 (UTC)

oppose Maybe we should have even one reference on permanent magnet synchronous generator before we start seeing it as suitable notable content to dump into other, referenced, articles? Otherwise why not invent another unsourced article, perhaps "whirly roundy generator" that is an obvious and trivial combination of terms, but with no sourcing to support that their combination makes a notable whole as a concept and article topic, then we could merge that in too. Andy Dingley (talk) 09:47, 17 October 2013 (UTC)

See my clarification below. No contents dumped from there to here. Just simply wipe out the whole thing and change it to redirect to this page. With your new reference on wind turbine, it appears that permanent magnet synchronous generator is another term for magneto (generator). Another reason for the redirect. Z22 (talk) 12:00, 17 October 2013 (UTC)

Clarification: I actually proposed to wipe out the whole contents on permanent magnet synchronous generator page and change that page to redirect to this page. Are the merge from and to the right tags for this situation? The contents there are unsourced and it has a discussion about generic alternator stuff which already exist in various pages. So there is no point on having that as a separate page or having any of its contents to transfer anywhere. Z22 (talk) 12:00, 17 October 2013 (UTC)

I would possibly support making it a redirect to here, my concern is that when we don't have any sourced explanation of what a PMSG is, then it's inappropriate to merge such unsourced content. So far we have content that is a trivial duplication of the magneto principle, some vague unsourced woffle, and a big chunk of important content that isn't even written yet.

It does seem that PMSG is a novel development for use in wind turbines, and its function is not merely to be a permanent magnet generator, but to solve what is a real problem with wind turbines – matching shaft speed to line frequency. As wind turbines are a growing area, this is a significant technical problem and it appears that this solution to it is both important and novel, then I think there's a better article under that title alone – subject of course to writing and sourcing it. Electrically I'm more of a historian than a current_(sic) engineer, and I just don't know what these new frequency-matching PMSG inverter drives are about as yet. Andy Dingley (talk) 12:29, 17 October 2013 (UTC)

Andrew Dingley, what is the difference between a Magneto and a magneto (generator)? Chrisrus (talk) 19:13, 12 September 2012 (UTC)

Both are "generators" as a physical principle, however magnetos were not the generator type adopted for bulk power generation (dynamos and alternators were used instead). However, in a few narrow uses, magnetos were used for this type of larger power generation. That's what this article covers. Compared to most of the articles under the broad topic of "generators", the article does it rather better too. It is sourced and accurate: some of the others are dire. Andy Dingley (talk) 14:12, 23 March 2015 (UTC)