Homopolar generator

by cala
Tags: generator, homopolar
P: 5,641
 Quote by wolfblum Acyclic Electromagnetic interactions are those that are time invariant (as in any true homopolar machine.) This, as opposed to the Cyclical (time varying) EM interactions found in all other electromagnetic machinery (AC or DC.)
I think I get the concept. What branch of study does this term come from?
 Please do not amalgamate anything, mercury is nasty stuff!
 Faraday used to lick his experimental apparatus to have his tongue "sense" electric potential, that's what probably caused his mental and health problems in later life and his death.
I think you could well be right. I read him speaking about "the flash", which apparently was a flash of light in the field of vision when he got a particularly strong shock from touching his leads to his tongue. He simple considered it a measure of of current and seemed to have no conception it might be dangerous.
 FYI, I have a complete original set of Faraday's diaries and can tell you that he did co-rotate a disk with a cylindrical magnet and observed the generation of EMF (although he was never certain himself about the rotation of the field itself.)
I'm quite envious. When you say "original" you mean first edition? I'd be happy to have any edition of them. Haven't discovered where I might get them. I just happened to find these published experimental findings of his last week, and I am amazed, page after page, by how thorough and meticulous he was, leaving no potential question unanswered, exploring every possible angle of every phenomenon.

I think it would be great, if you had the time, if you could quote the text of that particular experiment, if it isn't too long. So far, I haven't found anything about it in the book I have.
 Further stuff, the term unipolar should not be used, it means "having one pole" and that is not possible.
I see what you mean.

Are you interested in the homopolar dynamo for theoretical reasons or for engineering?

-Zooby

P.S. To quote you hit the "quote" button at the bottom of the post you want to quote from and respond to. To quote a section you write QUOTE in brackets in front of the first word of the quote, and /QUOTE in brackets after the last word of the quote.
You write your own reponses just like in a normal post with nothing in brackets.

You can delete anything in the person's post you don't need to respond to.

At the bottom there is a place to select "Preview Post". This will show you what your finished post will look like without actually submitting it. If it looks OK, and you have made all your quotation brackets properly, you can hit submit. If you need to correct you just scroll down to the box where the text is waiting to be corrected.
P: 5,641
 Quote by wolfblum As far as "Faraday's Diary" is concerned, there is of course only one original set by him (bequeathed to, and in the possession of the Royal Institution in London. BTW, I have been there and snooped extensively, lots of forgotten and misconstrued stuff on exhibit, ask me sometime!)
Wow! That must have been fun!
 There was one transcription and printing thereof (i.e., there was only one edition), and it was over a period of 1932 to 1936 by G. Bell and Sons of London
It's amazing to me there haven't been more editions.
 Zooby, depending on what country/state you are in, you might be able access the set at a University library. If you want, let me know your rough location and I can run it through the International library database.
San Diego, Ca.
 Sorry, I shouldn't be so gleefull.
Don't be hard on yourself. In your shoes, I would be insufferable.
 So I propose to perhaps post one important experiment per week (this should keep the final total number of posts to about 60 or so.) I will not do this unless there appears to be some positive endorsement and agreement by the forum group as a whole.
Hmmm. My assessment is that the people interested would more likely form a small, enthusiastic group. Faraday is under- appreciated around here in my opinion and there is also a lack of interest in reading anyone's original papers for some reason.

Since you're willing to make the effort to copy them, though, it would be a shame not to get them onto the web somewhere. There is alot of interest at large in homopolar dynamos and Faraday.

What is the copyrite situation with these diaries? Any chance they're in the public domain?
 As to the specific experiment I referred to and that you refer to Zooby, that one is very enlightening and I will post it over the next few days, OK?
That would be great. I'm looking forward to it. I had decided it must not be true before you came along.
 Lastly, Zooby, I'm interested in acyclic/homopolar machinery from both a theoretical and practical viewpoint, hence my research over the past ten years or so - Wolf
My own interest is practical. I'm fascinated by how simple they are. I have a penchant for reducing things to the lowest possible level of complexity, labor, and expense, and maintenence. It's a kind of laziness, I guess.
P: 5
 Quote by zoobyshoe Wow! That must have been fun!
It was amazing to see some of Faraday's original experimental apparatus and his laboratory (in the basement of the Royal Institution, almost a dungeon I might add!)

 It's amazing to me there haven't been more editions.
There was only the one printing, also I don't think anyone has even attempted a Project Guttenberg on the diaries, because the most important and amazing part of them are the many, many margin drawings and illustrations Faraday made throughout. There have been text only attempts for small partial periods of the diary, but that's about it. I'll come back to this later 'cause of your post Zooby.

 San Diego, Ca.
Aha, San Diego State U. has a copy. You should be able to at least view.

 Hmmm. My assessment is that the people interested would more likely form a small, enthusiastic group. Faraday is under- appreciated around here in my opinion and there is also a lack of interest in reading anyone's original papers for some reason.
Point taken, I'll hold back until we see what we should do (except for the specific set of experiments from 1831 that I promised.)

 Since you're willing to make the effort to copy them, though, it would be a shame not to get them onto the web somewhere. There is alot of interest at large in homopolar dynamos and Faraday. & What is the copyrite situation with these diaries? Any chance they're in the public domain?
If there is such an interest, I might be willing to start a most interesting project. The copyright situation isn't an issue, and as I said above, only little bits have made it into the public domain. Let me warn everyone though, as simple as acyclic/homopolar machinery may seem, this subject leads to the involvement of the likes of Ampere, Barlow, Foucalt, Siemens, Kirchoff, Tesla, Lorentz, Einstein (yes!, his Special Theory of Relativity), Westinghouse, WWII German stuff, Feynman (Quantum Electrodynamics) and others, General Electric, the US Navy, the U. of Texas at Austin, Parker Kinetic Design, Dresser Engineers and Constructors, rail guns, plasma fusion reactors, directed energy beam weapons and pipe welding, and also the US Army (&NASA). Quite a handfull of players, don't you think?

Please give me feedback as to what we should do - Wolfblum
 P: 5 Zooby, here is the experiment by Michael Faraday on December 26, 1831. (Faraday's Diary, Vol. 1, pp 402, G. Bell and Sons, London, 1932) 255. A copper disc was cemented on the top of a cylinder magnet, paper intervening, the top being the marked pole; the magnet supported so as to rotate by means of string, and the wires of the galvanometer connected with the edge and the axis of the copper plate. When the magnet and disc together rotated 'unscrew' (CCW) the marked end of the needle went west. When the magnet and disc rotated 'screw' (CW) the marked end of the needle went east. 256. This direction is the same as that which would have resulted if the copper had moved and the magnet been still. Hence moving the magnet causes no difference provided the copper moves. A rotating and a stationary magnet cause the same effect. 257. The disc was then loosed from the magnet and held still whilst the magnet itself was revolved; but now no effect upon the galvanometer. Hence it appears that, of the metal circuit in which the current is to be formed, different parts must move with different angular velocities. If with the same, no current is produced, i.e. when both parts are external to the magnet. I took pictures of the relevant passages and the margin drawing, but have no idea as to how to post those? - wolfblum
P: 5,641
 Quote by wolfblum I took pictures of the relevant passages and the margin drawing, but have no idea as to how to post those? - wolfblum
The easiest and fastest way is to put them on a webpage somewhere and then just give us a link to the page.

It is also possible to "attach" images that will show up in a post. The problem there is that Greg Bernhardt, PF owner and administrator, wants to personally inspect all attachments before he will approve them. He wants to avoid taking up alot of bandwidth with junk pictures, which is reasonable, but it takes him forever to get around to approving stuff. If you post the images as "attachments" therefore, it could take three or four days before anyone could see them.

I would definitely love to see what the pages look like. I'm particularly interested to see what he means by the magnet being supported "so as to rotate by means of a string."

It is quite exiting to see this whole thing described in his own words, and it clears up about two mysteries in my mind, which I'll explain after I dig up a couple quotes.

Thanks, wolfblum!

-Zooby
 P: 5,641 OK, here goes. I was reading a bio of Einstein and the author says that in the pre-relativity days there was a contradiction about the relative motion between conductor and magnet which this author attributes to Faraday's law of induction: "This had for years been one of the accepted facts of life and to raise awkward questions about it was to spit in a sacred place. yet, Einstein pointed out, the current induced between a magnet and a conductor depends according to observation only on the relative motion of the conducting wire and the magnet whereas the customary view', in other words, the accepted theory of currents, draws a sharp distinction between the two cases in which either the one or the other of these bodies is in motion.' Faraday had discovered the induction law in 1834 but, as Born put it, everybody had known all along that the effect depended only on relative motion, but nobody had taken offense at the theory not accounting for these circumstances.'" Einstein, The Life and Times Ronald W. Clark, p.116 In fact, this issue was very important to Einstein because the first paragraph of On the Electrodynamics of Movng Bodies, where Special Relativity made its first appearance, addresses this very thing: "It is known that Maxwells electrodynamics--as usually understood at the present time--when applied to moving bodies, leads to asymmetries which do not appear to be inherent in the phenomena." He is saying, in other words, that Maxwell (following Faraday's lead) misunderstood something. "Take for example, the reciprocal electrodynamic action of a magnet and a conductor. The observable phenomenon here depends only on the relative motion of the conductor and the magnet, whereas the customary view draws a sharp distinction between the two cases in which either the one or the other of these bodies is in motion." At this point I start not being able to follow Einstein: "For if the magnet is in motion and the conductor at rest, there arises in the neighborhood of the magnet an electric field with a certain definite energy, producing a current at the places where parts of the conductor are situated." First, I don't understand if he is saying this is the incorrect "customary" view, or if it's supposed to be the correct one. I haven't come across the notion that a magnet in motion produces an electric field in it's neighborhood. All I'm aware of is that a magnetic field in physical, kinematic motion can induce current in a conductor. "But if the magnet is stationary and the conductor in motion, no electric field arises in the neighborhood of the magnet. In the conductor, however, we find an electromotive force, to which in itself there is no corresponding energy..." Huh? "...but which gives rise--assuming equality of relative motion in the two cases discussed--to electric currents of the same path and intensity as those produced by the electric forces in the former case." Again, I can't sort out if he is presenting stuff as the erroneous "customary" view, or if he is presenting what "everybody knows" is actually happening. Anyway, 16 pages later Einstein, having made many points, concludes this first section by saying: "Furthermore it is clear that the asymmetry mentioned in the introduction as arising when we consider the currents produced by the relative motion of a magnet and a conductor, now disappears. Moreover, questions as to the seat' of electrodynamic electromotive forces (unipolar machines) now have no point." So, it is clear that he is aware of and seems to be discussing the Faraday disc dynamo. I don't know, however, to what extent Faraday's induction laws were meant to explain "homopolar" configurations, and if the strange case that you quoted is taken into account. Did Maxwell know about it, and did figuring it into his equations cause the "asymmetry" that was bugging Einstein? Or, am I barking up the wrong tree, and the asymmetry in Maxwell has nothing to do with this experiment? -Zooby On the Electrodynamics of Moving Bodies Address:http://www.fourmilab.ch/etexts/einst...81082217897574
P: 5,641
 Quote by wolfblum It was amazing to see some of Faraday's original experimental apparatus and his laboratory (in the basement of the Royal Institution, almost a dungeon I might add!)
Yes, I can imagine this was incredible.
 Aha, San Diego State U. has a copy. You should be able to at least view.
This is good to know. I wonder if they let people make photocopies of any of it? I'll have to call and see what their policies are.
 If there is such an interest, I might be willing to start a most interesting project.
If you google various permutations of "Faraday Dynamo" Homopolar Dynamo" and all that, you come up with ton's of sites, indicating that there is alot of interest at large in this particular aspect of Faraday's experiments. Quite alot of people are crazies looking for overunity, but there are plenty of level headed researchers.
 The copyright situation isn't an issue, and as I said above, only little bits have made it into the public domain.
By "Public Domain" I'm refering to the situation where the copyrite of a written work has lost all claims to be legally owned by any person or organization. Works that are in the public domain can be reprinted by anyone without anyone's permission. This happens to all books after a certain amount of time has elapsed. In some cases, though, people can take special measures to hold on to a copyrite beyond the normal time period. Some of Mark Twain's books are in the public domain, for instance, but some of his writing is not (last I heard); it is still owned by the decendents of one of his daughters, or the Mark Twain Society, or whatever.

It could be, therefore, that the Royal Philosophical Society, or the publishers of your edition, or Faraday's descendents have managed to retain the copyrite to Faraday's diaries in some way, shape, or fashion.

The thing I had in mind was to create a website on which to put the experiments that have to do with the disc dynamo, just because it would be nice to have it on the web where people could have access to it.

The other idea that occured to me would be to collect them all into a small book, publish them yourself, and get them distributed by Lindsay Books. This is a fascinating little company that specializes in reprints of old technology books. I have ordered several dozen of their fascinating and sometimes quirky books over the years.

Lindsay distributes quite a few self-published books for people, odd ball subjects like "How To Make Tiny Drills", "How to Make Your Own Charcoal in the Backyard", "How to Melt Iron and Steel in a Backyard Cuppola" "How to Make an Entire Machine Shop from Scratch", that sort of thing. The collected disk dynamo experiments of Michael Faraday would be right up his alley.

Lindsay Publications Books Available

 Quite a handfull of players, don't you think?
Don't get complicated on me, wolfblum. A disc, some magnets, and some wire. That's all we need.
 P: 26 Yes The Faraday Original notes are very interesting - please dont leave me out And it is nice to find someone else on the forum who has done some real and objective experiments with the homopolar theme Binki
 P: 1 Dear All I am new to this forum and it looks now everyone is quiet, Have you made homopolar generator or not? If not I have two questions a) instead of making a brush on outer surface of copperconductor if we solder insulated wire on outer surface of Copper disk and connect other end to the rotating shaft as it is done in most of car dynamos then due to less surface velocity heat will not cause any demage b) After getting so huge current , if we switch this current (using appropriate transformers) to rotatining motor then will not it be a self rotating device(generator)?
 P: 57 I found this web site "http://www.animations.physics.unsw.edu.au/jw/homopolar.htm" most educational about homopolar generators. Check it out, it has demostration videos. I believe that there is a discovery waiting to be made that Faraday missed. I also believe that Binki is the closest one to that discovery.
P: 4,663
 Quote by Relay I found this web site "http://www.animations.physics.unsw.edu.au/jw/homopolar.htm" most educational about homopolar generators. Check it out, it has demostration videos. I believe that there is a discovery waiting to be made that Faraday missed. I also believe that Binki is the closest one to that discovery.

http://en.wikipedia.org/wiki/Homopolar_generator

Bob S
 P: 57 Michael Faraday, (22 September 1791 – 25 August 1867) had a truelly impressive intellect but he did not solve all the misteries of the homopolar generator. He couldn't explain why the generator would create electric current when both the copper disk and magnet rotated together. Please see "http://en.wikipedia.org/wiki/Faraday_paradox". I have never seen this demonstrated in real life. It took Hendrik Antoon Lorentz (18 July 1853 – 4 February 1928) a Dutch physicist to solve the Faraday Paradox. Although he didn't do until 1892, 25 years after Faraday's death. Additionally Maxwell stated this "Lorentz force" in a paper he published in 1861. All the above information is taken from the wikipedia.org site. I still wonder if a homopolar generator has back torque once current is sent to a load. If so, what slows the disk down? If not, how does it obey the first law of thermodynemics?
 P: 57 I now believe that a homopolar generator does have back torque. The laws of thermodynamics don't fail.
P: 2
i'd like to add some comment in here... trully there are lots of people who are indulge in the search of free energy concepts, i cannot deny that even i myself cannot help but think about it. and surely i have gone through a lot of theories and experiments but one thing i found is that for the mean time or i should say in our present time free energy concepts is still a dream come true... no one and not one can proved that we can get larger output than input in anything we like to happen.

it means to say that those who claims that they have invented a device or machines that generates free energy is absolutely not true, other's are claiming that they won't tell their secretes of how they have made it works! but alas, if they were true then why won't they made such device and use it for themselves?

And one thing they woul claim is that it needs a lot of money to build it... then tries to attract and convince someone to invest money to fund the project. Well i'm sure that no one is fool enough to invest such kind of unsure project.

What i am trying to convey here is that our world is ruled by the laws of nature and no one can break that law. there is no such thing as free energy, the only thing we can do is find a way to minimize the cost and produce the most effecient output which is very close to the amount of input of any projects that we want to happen.

but i did not say that we should stop searching the concepts of free energy because in that way there are many improvements that will come out of the way.

 Quote by cala Well, i'm sorry, i talked under your point of view, and i had not license to do that. Ok, so you think the system can't do more output than input COP. Yesterday I was thinking how to explain the working of the homopolar generator on an easy way. A lot of things came to my mind (i could not sleep yesterday), and one thing that came to my mind was the Maxwell Daemon example. Here, i put just an ad-hoc explanation of the Maxwell Daemon from a web page: "Maxwell was a famous scientist who discovered electromagnetic waves. But only theoretically; he could not prove it. It was proven by Heinrich Hertz 20 years later. But Maxwell put forward a theory saying that in the world there must be something called electromagnetic waves. There is a famous second law of thermodynamics which states that in each system, energy must be constant. But Maxwell said, imagine two spaces: between the two spaces you have a door with a little slit. One space filled with gas is very hot, and the other is very cold. According to the law of thermodynamics, when such a door is opened, both spaces will be of equal temperature. But Maxwell could mathematically prove that the hot space would become hotter, and the cold space would become colder. So this was a riddle, a paradox: Maxwell's daemon.(...) But then along came Zurek, a scientist, who wrote an article in 1984, "Maxwell's daemon, Szilard's engine and Quantum measurement." He solved the paradox in such a way that it could even obey the second law of thermodynamics. He said, this daemon is doing work - Somebody is doing work. Even when he just counts molecules, this also uses energy, this also uses information. So when something is becoming hotter, and something is becoming colder, we can exactly measure this difference of energy, and we can say this is an amount of information, that is energy which the daemon uses for himself. So we could explain it even within the second law of thermodics. He calls this daemon 'Quantum daemon.'" Peter Weibel, "Ways of Contextualisation," Place, Position, Presentation, Public,(ed. Ine Gevers), De Balie, Amsterdam, 1991-1992, pp.232-3. Ok. Russ, now imagine the conducting disc of the homopolar generator as a "charge gas". positive and negative particles are there, but they are mixed and externally, the disc is neutral, but internally, the particles are there for the daemon. We always see this daemon as something intelligent that not only have to count the particles, in order to get potential, it should recognyze them, and order the particles depending on their charge, changing also their location. But on the homopolar generator, our "maxwell Daemon" is just an autistic one: We help the daemon, and create a zone on the disc (by the B field and velocity of the disc) were the daemon have not to move any single one of the particles passing under the B field. Our daemon only have to count the positive and negative particles to create the EMF!. I mean, the "charge gas" is neutrally distributed on the whole disc, but as we make the disc rotate, there is a specific radius on the disc (under the B field) where the existence of this particles is taken into account. Imagine that this special radius is a kind of toll or frontier where we have our Maxwell Daemon. As the disc moves, the neutral "charge gas" of the disc goes passing through the toll. Then you have the daemon saying: 659 positive charges, 678 negative charges - 0.080 V (for example) 698 positive charges, 687 negative charges - 0.081 V .... 645 positive charges, 643 negative charges - 0.079 V He must do nothing else to get potential! he have not to move the charges. If we take the Zurek explanation, the work or information than the Daemon must have on these conditions is less than if the Daemon had also to move the charges depending on their charge type. I have other examples, and you can't imagine how clear now I see some other ideas that use a similar principle on other physic concepts. For example, i tried to do an homopolar generator rotating water analogy, and then it reminded me the experiments of Viktor Schauberger, a man that is known on the free energy world by claim that vortex of rotating water can also extract more output than input.
 P: 2 the only one thing that a homopolar generator has advantage over the other types of dc generator is that it produces a large current and low voltage output which is very suitable for electrolysis, now talking about electrolysis which should be the concern of everybody is the electrolysis of water to produce hydrogen gas which is believed to be the fuel of the future in terms of advantages over the hydrocarbon fuels, and we all know the many advantages of hydrogen fuel so i won't mention that anymore in here. now to make things clearly, what we want here is to build a high current and low voltage dc generators suitable for electrolysing water in such a way that the hydrogen produce would be inexpensive than any by-products of hydrocarbon fuels. We all know thatthe greater the amount of electron we can produce in a dc generator the greater the volume of hydrogen we can produce, the problem is that such type of generator has not been built as far as today... and i'd like to mention here that the homopolar generator is the only one that offers a promising outcome but there are too many flaws on this type of generator, one is that the collection of electron in the rotating disc is not that simple it needs a brush as a point of contact inorder for the electron to flow in a circuit, now imagine that in order to produce 58 barrels of hydrogen gas @STP per second we need at least 96 million 500 thousand electron per second to pass through the circuit, so how will this come possible if we only rely on a homopolar generator? homopolar generator can electrolyse water but it cannot produce large vulume of hydrogen gas that is enough to supply even just one small city. In conclussion there must be another way... and i won't claim that i have a way to do it untill i can demonstrate it in an actual experiments, because theories are nothing it won't work in an actual experiments.

 Related Discussions Electrical Engineering 4 General Discussion 12 Introductory Physics Homework 2 Electrical Engineering 9 Classical Physics 9