Talk:Fleming's left-hand rule for motors

Fleming's Left Hand rule is used for determining the field direction where conductors carrying a current in a particular direction is concerned. The current is not being induced in the coil but is provided by an external source.

Error in first sentence of article

How can any reader be expected to put any faith in an article that has the title of "Fleming's left-hand rule for motors" and then follows up with an initial first sentence that reads "Fleming's right-hand rule for electric motors ..." - I am unable to contribute to which is the correct rule in order to fix the error as I had hoped to learn this information for myself from the article.Norlesh (talk) 08:38, 18 April 2020 (UTC)

Fleming's Right Hand rule may be used to determine the direction of an induced current in a conductor if it is moved in a magnetic field.

Errors with Current and Electron Flow

I think there is still some confusion in the paragraph that states "if the electrons flow away from you..." because the current and the electrons flow in different directions, and that, as stated below, this Left Hand Rule uses the postive-to-negative flow convention. It then goes on to say the electrons want to move 'to the left', which I don't follow. The answer is correct, but by using the electron flow and not the current, you can't use the left hand rule! Right? Lordjim13 (talk) 10:05, 27 April 2010 (UTC)

ERROR ON LEFT-HAND RULE PAGE??

I would like to show a potential error in the page (or me..lol WOO LEMONS :p) -

No error. Current flows from +ive to -ive. Electrons, flow from -ive to positive.

Fleming's left hand rule

Electric current actually flows from Neg. to Pos, not the opposite, as anyone who works with electronics will tell you. This is a common mistake for laymen, yet you are writing about some really technical stuff, so am I missing something?

The offending sentence says:"The Second finger represents the direction of the Current (in the classical direction, from positive to negative)."
does "in the Classical Direction" mean something I am not seeing??

-Jf 18:52, 17 October 2007 (UTC)

Depends--are we speaking of electron current flow or "hole" current? Either one has been referenced in industrial and academic applications. Depends upon the preferred point of reference and there is certainly a difference of opinion as to which is most appropriate given the nature of the application. <AR user>

As I understand it, the Left Hand Rule simply uses the current flow in the direction it was assumed to go in - Positive to Negative (hence the "classical", although this has since been changed in the article). I don't know the history of this, but I'd assume that it is kept that way purely because it isn't possible for many people to bend their second fingers back in the CORRECT direction (negative to positive). Of course, that would need a source :-) hurdygurdyman1234 (talk) 21:00, 12 March 2009 (UTC)

While it's true that electronics flow from negative to positive, the convention for electronics schematics is to draw the "current" as going from positive to negative -- i.e., following the flow of the electron holes. Toybuilder (talk) 03:30, 14 September 2009 (UTC)

Conventional current flows from positive to negative. Charge carriers can either flow negative to positive (most common, as most charge carriers are electrons, which are -vly charged) or positive to negative (e.g. electron holes can move and act like they are transferring +ve charge)or even both (as happens in semimetals: when an electron jumps the band gap, it can move and the hole it left can move) Conventional current is just a sign convention. On another note, I personally don't like the expression 'The lines of force'. The author must mean field lines: a force only results from a charged particle in an electric field and not from a field alone: this gives the impression that force exists without a particle there to experience it. I am British, however, so this may be fine in the US? Also, can anyone provide an explaination that links this in with the cross product? I'm afraid I wouldn't be confident about doing it myself. Archie (talk) 18:10, 11 March 2011 (UTC)

On the Fleming's right hand rule discussion page, I promise to have a go at rationalising these two pages, some time next week... unless someone else beats me to it over the weekend. TheAMmollusc (talk) 11:02, 25 March 2011 (UTC)

OK, I've made a start. I'll spread the work out over several lunch-times. If anyone wishes to view the current state of the draft article, or even to help edit it, I am currently developing it at my User:TheAMmollusc/Incubation page. TheAMmollusc (talk) 10:53, 28 March 2011 (UTC) Just to confirm that the development of the page continues, and it is starting to shape up (hopefully for a transfer to the live page on Friday). TheAMmollusc (talk) 06:52, 30 March 2011 (UTC)

There, I've done it. It's not perfect, so I look forward to any polishing that others are able to do. In particular, it needs a diagram to illustrate the last paragraph of the "Physical basis of why the rules apply" section, showing the cross-section of a wire in a horizontal magnetic field, with all the lines of force bunched round underneath it. (My skills aren't up to this, I'm afraid). I did think of moving the article to "Fleming's left hand rule and Fleming's right hand rule", but have left it as "Fleming's left hand rule for motors" for the present. What do others think? TheAMmollusc (talk) 12:32, 1 April 2011 (UTC)

References

Why were these pages merged?

@TheAMmollusc:

The result of merging the left-hand and right-hand rules has caused some problems, not least of which is the article title no longer makes any sense. This is especially confusing for readers who have followed a right-hand rule link. These rules come across as quite confused when merged together. We already have a page comparing mnemonics at FBI mnemonics. It would be better to leave Fleming's two rules as separate pages and discuss comparisons at some overview page, either the FBI page or a new page. SpinningSpark 11:19, 19 January 2014 (UTC)

If you think the page tells a confused story now (which I don't doubt might be the case) you should have seen it before 01-Apr-2011. It really was all over the shop, with people saying how confused they were (on this talk page) about why conventional current flows the opposite way to electrons, why the left-hand rule has to be chosen for some electrical devices, and the right-hand one for others, and more significantly why the left-hand rule has to be chosen for some mnemonics, and the right-hand one for others. What I did was to try and knock some order into all this, and to answer some of those FAQs in the page, before the reader even started to ponder them. The confusing use of other mnemonics turned out to be restricted to the FBI mnemonic, and I wanted to quarantine this off on that other page (which is the one to which I think you are referring), and which is why I included the sentence, "Of course, if the mnemonic is taught (and remembered) with a different arrangement of the parameters to the fingers, it could end up as a mnemonic that also reverses the roles of the two hands (instead of the standard left hand for motors, right hand for generators). These variants are catalogued more fully on the FBI mnemonics page."

You say that you would prefer to have separate pages for the left- and right-hand rules. So would I. However, I cannot see how to do it without massive duplication of material (not least because of my aim of clearing up the confusion in the reader's mind as to why there has to be two rules, with a decision as to which one to use, and on what basis to make that decision). Good luck to you, if you wish to give it a go. I have just looked at the state that the right-hand rule page was in on 18-Feb-2011 (the previous edit to mine), and it was not only a largely uninformative stub of an article, but what little material it had (a single bullet list) was just an edited copy-paste from the left-hand rule page. As I say, good luck if you can see how to do better :-) TheAMmollusc (talk) 07:45, 20 January 2014 (UTC)

The conventional current confusion is something that comes up on numerous articles and has nothing to do with confusion between the left and right-hand rules. I am going to restore Fleming's right hand rule page, it is just not acceptable that following a link to the right-hand rule goes to the left-hand rule page. I might tackle some of the other issues later. Comparison and selection of Fleming's rules should be on the Fleming's rules page. None of these articles should be confused with descriptions of other rules (although they can be linked). That should be on some overall rules page, perhaps a renamed FBI mnemonics page. Have you any suggestion for a title for that page? SpinningSpark 11:11, 20 January 2014 (UTC)

Yes, the conventional current explanation was, indeed, removed soon after it had been introduced (for the reasons that you mention). I think that your first suggestion sounds very good: that of moving the current material to the "Fleming's Rules" page (presently, it is simply a redirect to this page). Then, this page can be turned into the mirror image of your newly restored "Fleming's right-hand rule" page, and both of them can link to the "Fleming's rule" page. Then, the "Fleming's left-hand rule for motors" and "Fleming's right-hand rule for generators" could be made to redirect to their respective pages. What do you think? TheAMmollusc (talk) 16:43, 20 January 2014 (UTC)

I think I'm slowly talking myself into a bunch of work that I didn't want. I like "Fleming's left-hand rule for motors" as a title even though it is not the most concise. It makes clear from the very beginning its scope and applicability. I would propose renaming the right hand rule to conform to that pattern (I was going to do it today but the bots that fix double redirects can't cope with too many moves at once). The real problem name is what to call the FBI page. This has a really bad name; it includes the corkscrew rule which is not only not an FBI mnemonic, but is not a mnemonic at all. SpinningSpark 16:56, 20 January 2014 (UTC)

Yes, I didn't know what to do with that page either, and decided that it wasn't part of the problem that I was attempting to resolve (the explanations on the pages connected with Fleming). I think it is a good place for all the FBI, IBF, FIB (whatever) to be collected together, and made available for scrutiny/comparison by the reader. I agree, the corkscrew rule is a red herring in that article, and could be removed (since it is now also in the Fleming rules page(s). TheAMmollusc (talk) 07:38, 21 January 2014 (UTC)

It shouldn't be on the Fleming's rule page. It is a different rule. That's why we need an overview page, and that's why the FBI page is part of the problem. SpinningSpark 12:21, 21 January 2014 (UTC)

True. However, if the reader asks, "Why do Fleming's rules work?" then the answer definitely involves invoking the corkscrew rule. That is why I included that rule on this page (more convenient than having to click on a link to another page, and then come back again). However, I will happily bow to your proposed solution (whose virtues I acknowledge). TheAMmollusc (talk) 15:42, 21 January 2014 (UTC)

That's completely wrong. The corkscrew rule is just another rule addressing the same phenomenon. It does not get you any closer to the fundamental cause of electrodynamics. The directions are a result of the arbtrary choice of signs of field quantities and reference frame. SpinningSpark 19:23, 21 January 2014 (UTC)

I'm not sure why you say that (the corkscrew rule is a mnemonic for Orsted's discovery of the way magnetic fields flow round a current-carrying wire; this, when set in the context of Faraday's model of how conflicting magnetic fields interact, explains where Fleming's rules fit into the picture). However, I agree with you that the corkscrew rule is another subject. Thinking about it last night, I was wrong in my previous message... the reason that I chose to include the corkscrew rule on this page wasn't the otherwise inconvenience of having to click over to that page and then come back again... it was that the corkscrew rule carries this alternative model of someone's right hand with the thumb representing current, and the fingers representing magnetic field. At the time, my mission was to clear up the tangle of mnemonics on the old version of the pages, with Th.F.C, FBI, FIB, mnemonics mixed together, along with whether it should be left or right hand, and electron flow of conventional current. At least by putting the corkscrew rule, with its alternative right-hand rule, on this page, the reader could be sure (perhaps) that the switch from left to right hand was intentional. I agree with your thesis, though... the corkscrew rule should be no more than referred to, not explained, on this page. TheAMmollusc (talk) 07:42, 22 January 2014 (UTC)