How to make the simplest electric motor

You have one drywall screw, one 1.5 V alkaline cell, six inches of plain copper wire, one small neodymium disk magnet, and no other tools or supplies. You have 30 seconds to make an electric motor running in excess of ten thousand RPM. Can you do it? Surprisingly enough, you can.

Let’s take a step back. The most common type of electric motor is the brushed dc electric motor. This is the kind that you’ll find inside essentially everything that moves (or shakes) and runs on batteries. This type of motor attracts an electromagnet towards a permanent magnet. When the two are close enough,the polarity of the current through the electromagnet is reversed, so that it now repels the permanent magnet, and thus keeps turning. It’s quite easy to build a working model; Christian built this example for his third-grade science project.

A simpler yet motor (sometimes sold as the sold as the “world’s simplest motor“) just switches off the current for half of the cycle, letting the angular momentum of the spinning motor armature carry it through. In Make Magazine Volume 1, the Howtoons comic shows how to make an electric motor that works that way.

None of these is really the simplest motor. The real champion is the homopolar motor.

Ready to build one? Let’s get started:

The ingredients (L-R): One ferromagnetic screw, one battery cell, a few inches of copper wire, and a neodymium disk magnet.I used a drywall screw both because it has a flat head and because it’s easy to tell when it’s turning. You can use a nail instead. The battery needn’t be any particular type; an alkaline C-cell works fine and is easy to hold. Just about any copper wire will work fine for this application. I used some wire with partially stripped (and partially striped) red insulation that is easy to see in the photos. Bare copper will work just as well.

The magnet came from an LED throwie with a dead battery. The best magnets for this job are neodymium disc magnets with a conductive plating. You can get them from plastic toys or buy them from a number of magnet discount and surplus shops.

Homopolar - 2.jpg

Set the screw on the magnet, bend the wire.

Homopolar - 3.jpg

Attach the magnet to one end of the battery. The weak, single-point contact that you are making serves as an low-friction bearing. I like to attach it to the button end, but the other end will work as well. (If you do so, the motor will spin the opposite direction. You can also reverse the direction by flipping the magnet up side down.)

(Note to physics geeks: The heavier your magnet plus screw system is, the lower the friction will be, right up to the point that magnet isn’t strong enough to hold them any more. This is because the friction force is proportional to the normal force. In other words, a bigger magnet is usually better.)

Homopolar - 4.jpg

Press and hold the top end of the wire to the top end of the battery, making an electrical connection from the top battery end to the wire.

Homopolar - 5.jpg

Here we go: Lightly touch the free end of the wire to the sideof the magnet. The magnet and screw start to spin immediately. We can get ours up to 10,000 RPM in about fifteen seconds.Watch out: The screw and magnet can easily fly out of control, and you do not want that screw ending up in your eye. Also note that some of the components, like the wire, can get very warm while you’re doing this. Wear safety glasses and use common sense!

Short movie (25 s): spinning up the motor (embedded below, or click through to YouTube)

Wondering what to try next? You may also like this project, which is about building a similar sort of motor that spins water instead of a magnet.


How does this work?

When you touch the wire to the side of the magnet, you complete an electric circuit. Current flows out of the battery, down the screw, sideways through the magnet to the wire, and through the wire to the other end of the battery. The magnetic field from the magnet is oriented through its flat faces, so it is parallel to the magnet’s axis of symmetry. Electric current flows through the magnet (on average) in the direction from the center of the magnet to the edge, so it flows in the radial direction, perpendicular to the magnet’s axis of symmetry. If you took physics at some point, it’s possible that you’ll remember the effect that a magnetic field has on moving electric charges: they experience a force that is perpendicular to both their direction of movement and the magnetic field. Since the field is along the symmetry axis of the magnet and the charges are moving radially outward from that axis, the force is in the tangential direction, and so the magnet begins to spin. Neat! For a slightly more thorough explanation, have a look at the end of this article, which is about a magnetohydrodynamic homopolar motor.

It’s called a homopolar motor because you never need to reverse the polarity of any motor component during operation, unlike the other types of motors that we’ve described. I first learned about this type of motor in an article by David Kagan, in the magazine The Physics Teacher, February 2005. It turns out that it’s been around longer than that: it was invented in 1821 by Michael Faraday. Somewhat surprisingly, this is more than just a curiosity: motors of this design are currently being developed for quiet, high-power applications.

Homopolar - 6.jpg

Final note: How do we measure the rotational speed of the motor?

You can get an optical tachometer for $20 or less, intended for use with model airplanes. I have model LXPT31 from Tower Hobbies, which is expecting to see an airplane propellor with two blades. I added two wide black stripes to the magnet with a Sharpie, which allow the tachometer to read the rotational speed of the motor. Pointing the tachometer at the magnet and spinning up the motor, we were able to clock a speed above 10,000 RPM after spinning up for about fifteen seconds. Spiffy.

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118 thoughts on “How to make the simplest electric motor

  1. Not cool: this author is NOT the inventor of this motor. If they got it from their physics teacher, they should say so. (But perhaps they just didn’t realize that if they hide the source of the idea, that’s almost the same as pretending to be the original inventor.) In reality, physics teachers have been playing with this version of Homopolar Motor for some time. The following website says it came from some physics teachers in Japan, called "The Stray Cats." http://scitation.aip.org/journals/doc/PHTEAH-ft/vol_42/iss_9/553_1.html
    There’s also a different version on SciToys website: http://sci-toys.com/scitoys/scitoys/electro/homopolar/homopolar.html

    • I don’t think there’s any claim of invention here (please point it out if I missed it…). This is a really well known high school/college physics experiment. This article is just a how-to-build and how-it-works for anyone who missed out on it in school…

    • The author states in the section, "How does this work," this type of moter was invented by Michael Faraday in 1821.

    • The source that you cite is essentially the same one that (as I said) I first
      heard about this motor from. Both articles are from the "Little Gems"
      column of the magazine "The Physics teacher." I certainly did not, and do
      not claim to have invented this motor.

      -Windell.


      Windell H. Oskay
      drwho(at)evilmadscientist.com
      http://www.evilmadscientist.com/

    • I most definitely did not get the impression that Windell claimed to have created this motor. Unfortunately, I never took physics in either University or HS. Evilmadscientist.com makes me wish I had. Thanks for showing us the motor, Windell!

    • It might help if you read the entire article. Have a look at the second to last paragraph where the author explains where he first heard about the motor.

    • what an idiot! – pretending to be intelligent and then attacking someone when you are too lazy to read the ENTIRE article is pathetic.. The Author NEVER claims to have invented this. He states in several DIFFERENT ways that he is NOT the originator of this… eg it was invented by Michael Faraday in 1821, From the "Physics Teacher" Magazine, and he notes that MANY people TODAY are developing this IDEA!!! – Please go back to school and learn to read before attacking people who are helping, instructing and generally making the world a more interesting place.
      Thanks Windell H. Oskay (the Author) for posting this "little Gem"

  2. Adding a plate of metal in a disc shape after screw and before the magnet would make it more stable. The plate would work as a gyro.

  3. Read what the vendor of your device has to say:

    This Tachometer uses a sensitive photocell to measure the number of times the propeller blade crosses between the sensor and the light from the sun. If the readings become erratic, change the direction the model is facing by 90 degrees and take another reading. Do not use indoors, reading will not be accurate.

    Your ass got factchecked. Do I win a prize?

    • Yes, the directions on the tachometer do say that. The first way to check
      that it’s accurate is (as it also says in the instructions) to point it at a
      fluorescent light. Ours reads 3600 (RPM), as it should. The sensor on the
      tachometer is an exposed photocell; it looks like a standard CdS type. All
      that it can sense is the frequency of light/dark changes, which can be from
      the shadow of a propellor, or in this case, from the reflection off of light/
      dark stripes on the magnet. Just to satisfy you (r ass), we just went outside
      and measured the motor speed again, twice, 90 degrees apart. Everything
      seems to be working properly. =)


      Windell H. Oskay
      drwho(at)evilmadscientist.com
      http://www.evilmadscientist.com/

  4. I love it! I just wish this site had been around when I was at school (or the internet for that matter :-) I would have gotten into sooo much more mischief than I did.

    Keep the great geek/tech ideas coming.
    –FarmGeek
    farmgeek.co.nz

  5. By definition, a motor imparts motion to SOMETHING.

    This thing is just a whirligig. Would you call a pinwheel a motor? A gyroscope?

    Also, you forgot to mention that you need gravity for this thing to work. It obviously wouldn’t be useful in zero-G. The moment you touch it with the wire, it would spin off the battery. The gravity pulling downward keeps it spinning.

    How many joules of angular momentum is this thing generating?

    • I disagree. This is indeed a motor: it converts electrical power into
      rotary motion that is imparted to a central shaft. There needn’t be
      something external that is powered by it. If you take the electric motor
      out of a toy car and run it by itself, it doesn’t cease to be a motor either.

      Gyroscopes, pinwheels, and whirligigs are not motors because they do
      not “generate” the motion; they are spun up by existing motive forces. In
      contrast, the homopolar motor really does convert electric potential
      energy to kinetic energy.

      You do not need gravity to run a homopolar motor. Angular
      momentum, not gravity, keeps it spinning. This should work the same
      way in zero-G; the only difference is that it will be more difficult to place
      the screw pointed away from the battery when you’re first starting it.
      This should be quite possible with a steady hand. After that, it will be
      gyroscopically stabilized. If anyone reading this happens to be on the
      space station, please try this out and send me some pictures.

      Joules are units of energy, not angular momentum. I leave to the reader
      the calculation of both the kinetic energy and the angular momentum.
      The magnet is a solid disk 3.2 mm thick by 12.7 mm in diameter, and has a
      density of 7.4 g/cc. It is spinning at 167 Hz. You may neglect the mass
      and moment of inertia of the screw.


      Windell H. Oskay
      drwho(at)evilmadscientist.com
      http://www.evilmadscientist.com/

      • Nice how-to. You sure are drawing a lot of attention on this project Windell.

        …Guy designs world’s most accurate clock, but then gets 60,000 hits on a homopolar motor! Sheesh, what century are we in…
        :)

    • if you didn’t have gravity you could just substitute a magnet under the hanging magnet at a distance to simulate gravity. so you don’t need gravity.
      And a motor is a motor even when its not hooked up to something. So if you wanted to use this hanging Magnet *MOTOR* for something you could attach a fan blade(propeller) to the spinning shaft (or on any spinning part) and it would move wind like any fan *MOTOR*. You do agree an fan and an airplane both use motors? But you point was well taken and made me think to verify this. Of course you probably realized after you said "it was only a wurlygig" that you should have thought about it before you said it. Or were you just interested it communication through debating? I wasn’t sure if you were being negative, ignorant, or just a friendly instigator. end

    • Actually he does have a point. Gravity keeps it hanging downwards more or less in line with your battery. In zero-g the attraction between the magnet and the steel components of the battery would cause the motor to fall apart. But then again gyroscopic effects would tend to keep it in line. Might be interesting to watch it precess to destruction.

    • There are a great many online stores that sell neodymium magnets. I keep
      a list of them; take a look. The one shown in the
      pictures is very much like part number D82 from [link:kjmagnets], $0.60
      each.

      Alternately, you can extract them from cheap plastic toys.


      Windell H. Oskay
      drwho(at)evilmadscientist.com
      http://www.evilmadscientist.com/

  6. That is so cool.. I’ve never seen it before and had to try it… it does work.. cool… and after i had power applyed for about 20 seconds it took well over 5 minutes to spin down.

    One question…

    Can you tell me why my cat is so enthralled by it?? I mean she’ll jump into my lap to investigate it, & she’s not a lap cat…. Doesn’t even like to be petted. Is it making some kind of noise?

    -PurpleJesus
    -not affiliated with any soul ripping agencys

    • That’s funny!

      Our cats haven’t shown any particular attraction to the motor, although
      JellyBean has often shown distinct interest in eating copper wires. (The one
      that was left lying on the kitchen table after we took pictures was no
      exception.)

      The motor is usually pretty close to silent, and I don’t expect there to be
      significant ultrasonic components, but cats do sometimes react strangely
      to quiet noises. Perhaps it’s related to that mysterious attraction to
      crinkly pieces of plastic. Other than that, could your kitty be interested
      in the little dangly magnet?


      Windell H. Oskay
      drwho(at)evilmadscientist.com
      http://www.evilmadscientist.com/

      • I thought that too… So I started it up where she couldn’t see it.. and volla… same thing…
        So I did it again, this time next to my ear… it does make a noise… kinda like some strange metalic alien critter burrowing or munching on some strange metalic substance…
        .. the noise is the wire brushing against the magnet does it…

        Also… I noticed if the wire is bent, or hooked … kinda like ….) at the motor it doesn’t go as fast as it does if the wire is straight ….- & held directly perpendicular…

        btw- She does love crinkly plastic bags too.. Sometimes enough to play fetch with wadded up grocery bags.. psycho cat.

        -purplejesus
        -not affiliated with any soul ripping agencys

  7. This is long, and has to do with the term ‘simple.’ A simple
    motor may be simple because, like this one, it has only four parts including the battery and the wire. A simple motor might also be simple if it is simple to understand, which this one is definitely not.

    I assume that since most ceramic magnet materials are poor electrical conductors, the current goes out of the battery, down the screw, through the nickel plating of the magnet, and then down to wherever the wire is touching the edge of the magnet. The magnetic field is normal to the top flat surface of the magnet, and the current is radial across it, so we get the crossing of an electric and a magnetic field and thus enough push to spin the magnet.

    This ain’t so simple. The classic homopolar motor with the copper disk and the horseshoe magnet is simple in appearance, and when explained it sort of makes some sense to the uninitiated, so it isn’t a great teaching tool, either, notwithstanding that you can’t use mercury for the lower contact these days.

    The simple motor I designed uses an electromagnet, a switch, and a steel bar pivoted on good bearings halfway along its length. The electromagnet is placed near the bar and attracts whichever side of the bar happens to be nearby, and the switch is switched on and off at the appropriate time by the action of the rotating bar. Not particularly clever, but you can see it work and feel it work when you push the bar around by hand and feel the electromagnet grab it.

    There are still people who think it’s pretty much magical, I’m afraid, but we do our best.

    M Kinsler

    • So-called “Neodymium” magnets are actually sintered Neodymium-iron-
      boron powder. It’s metal, not ceramic. If you remove the plating from
      one, you’ll find that it’s still an excellent conductor. (It will, however,
      shed dust, so it’s much better to leave the plating on.) Regardless of the
      exact path that the current takes, all we need to know
      is that the current direction has a radial component. As you say,
      that direction crossed with the magnetic field results in the torque. I
      truly think that this is as conceptually simple as a motor can get, even on
      the sole basis of understanding the forces. If you break this up into
      parts and replace the simple magnet with a horseshoe surrounding the
      disk, that does not make anything simpler.

      While reducing the component count further is possible (and might
      even be interesting), it’s already small enough that many folks
      can make it from stuff that’s lying around at home, which is exactly how
      simple it needs to be.

      If I read your description correctly, your motor sounds like it might best
      be described as a continuous-rotation brushless solenoid motor: sounds
      like fun!


      Windell H. Oskay
      drwho(at)evilmadscientist.com
      http://www.evilmadscientist.com/

  8. Excelent toy. I duplicated it and it`s nice to look at. Just so few details ant it runs at such high RPM`s :)
    Every grown man (so I am) can play with such a toy for hours :) Coz it`s fun. And there we have possibility to invite ours kids into science world using some interesting demo. Such a toy should be a must in any physics choolbook.

    Now, let`s start it in reversed mode e.i. – generator. As far as I heard rumours – such a type of motor reversed to generator should not produce back EMF while generating electricity.
    High amperes and low voltage of course. Homopolar Faraday`s generator ??

      • Sure :)

        Screwvinder toy draws about 0.67 A at 1.5 V, thus ~ 1 W power; just to fight against loses in mechanical, magnetical, air friction etc.. Thus, reversed mode would generate some small amounts of voltage at higher amperes, I guess.

        I`ve made some horizontal, more powerfull ~3 W model :).
        It`s fast and simple to build too.

        1/3 inch neodymium magnet has attached two screwvinders at both sides. Screwvinders` endings are placed between two 1.5 batteries at "+" sign (there should be some small holes), and two "-" signs were connected together as power wire. Runs quite fast and now it is possible to feel even some power :) while touching toy. ASCII drawing of more powerfull model :) Draws ~2.1 A at run.

        bat.1 magnet bat. 2
        -[]———{}———-[]-
        I…..+……I……..+…I
        I________I_______I

  9. For every action there is an equal and opposite reaction. There is a torque on the magnet, but where is the equal and opposite counter-torque?

    • The battery is the recipient of the counter-torque, transmitted through the low friction bearing, but the battery is (a) much more massive than the magnet and screw, and (b) held in place by the outside force of friction applied by your hand. As a result, the counter-torque is not easily perceived.

    • The reasons that we usually say to use a NdFeB magnet are (1) that it’s strong, and (2) that it usually has a conductive coating. Obviously, any other strong magnet with a conductive surface will work as well. Certainly when this sort of thing was invented– 1.5 centuries ago– the rare earth magnets hadn’t been invented yet.


      Windell H. Oskay
      drwho(at)evilmadscientist.com
      http://www.evilmadscientist.com/

      • hi
        i dont have a neodymium disk magnet nor is it available to me in any store nearby. All i have is two oval shaped magnets which are strong but the homoploar motor does not work with them. Please help!!!

        • You can still build a homopolar motor with some other types of magnets. It is necessary to figure out the orientation of the magnetic field and point it upwards, towards the screw, and it is also necessary to have a conductive outer surface. I don’t know what kind of magnet you *do* have, but some are conductive, some aren’t. (Does it look metallic?) If it is not conductive– like a ceramic magnet– you can possibly get away with wrapping it in aluminum foil.


          Windell H. Oskay
          drwho(at)evilmadscientist.com
          http://www.evilmadscientist.com/

  10. GAAAAHHHH!!!!!! I would have more luck moving the damn thing with my mind than this, now before anybody says anything, YES it’s probably my materials. Soooo, does anybody have any tips to give me!!!??

    • Most important: Your magnet needs to have a conductive coating– one that’s plastic, rubber, paint, or varnish covered will not work. Ceramic magnets usually will not work (not conductive) and alnico magnets may not work because they are not strong enough. Second, your screw needs to be conductive– not painted or plastic or anything. Third, you need the wire stripped on both ends. Top wire gets held to the (-) terminal of the battery, and *lightly* touch the other stripped end to the outer radius of the magnet. Good luck!


      Windell H. Oskay
      drwho(at)evilmadscientist.com
      http://www.evilmadscientist.com/

    • Try sanding any coating off the tip and head. I had the same problem but that fixed it. :)

    • I appear to be having some problems with this. Whenever i try to make it run it doesnt so im guessing it is a problem with my materials, i just dont know which one it is, I use a screw just like the one in the experiment, i then attach a 15mm x 2mm N38 Nickel Plated Disc Magnet, which I purchased from http://www.gaussboys.com, I then put the magnet on the screw-head, the buessness end of the screw on the positive side of a Ni-Hm D-sized battery and use electrical tape to tape an insulated copper house wire (1 side only) on to the negative side and touch it against the magnet, nothing happens, i have tried everything i know, including recharging it, testing the voltage (it was OK), using more magnets & putting 3 of the Ni-Hm’s in series, what did I do wrong?

    • First of all, is your battery any good? and are you using a neodymium (nickel pleted) disk magnet?

  11. my class has a better idea you use an motor,wire,swich plate and a battery this is easier!!!!!!!

  12. Works great…but makes the wire hot if you leave it there too long :-)

  13. Great! This is one of the best science experiments on the internet! It does spark like crazy though, wich is so cool! (I am using copper speaker wire. It may spark more using copper speaker wire.) If you use speaker wire, keep all of the components away from the skin and any clothing. It does spin really fast, and even faster when I hooked it up to 2 AA batteries!

  14. got no neodymium magnets so i piled up 7 pieces of tiny disc magnets from worn-out cellphone cases, you know, those with flaps that stick because of a pair of \magnets inside. they are non-conducting so i wrapped the pile with aluminum foil.. attached to the head of a small1-inch nail or a big 2-inch cocrete nail it turns just like a high-speed motor.
    attached to the negative end of the battery, it is powerfull enough to hang the positive of the battery on the tip of the concrete nail and turn very fast with a wobbling spin.

  15. This made me think about the reports of World War 2 Foo Fighters and early man-made flying saucers.
    If you regulated the speed, and If you could generate enough torque, a large circular blade assembly would push a tremendous amount of air – sort of helicopter style but with a much different and lower volume of sound.
    Additionally, the high spin rate could be harnessed for a stabilizing gyroscope effect, eliminating the need for wing and tail control surfaces.
    Quartz watch batteries are much smaller and lighter. I may try and add some very lightweight plastic structural rings and a propeller and at least see if I can make it move on its’ own.

  16. If you change the polarty you change the direction of the movement, don’t you?

  17. Hey,

    i was wondering, what parameters would determine the angular velocity of the screw?? Atm, i have considered voltage (since i am using a power pack) and magnetic properties (which will go with height/diameter of magnet and the magnetic strength). Would u agree with these?? and what else is there?

  18. this is not what i had in mind. i would like to build one that will power a go kart, not a nail. good idea though

  19. Hi,

    I want to say thank you for taking the time to write this article. I was able to learn from you and reproduce this simple motor. Thank you.

    Best regards,

    Tom

  20. Have a problem with this project. Maybe I am using the wrong type of battery. Can’t get the motor to spin because just as I move the wire close to the magnet the magnet grabs the wire. Is this the reason for the neodymium magnet?

  21. Hi Windell and thanks for the info. This is listed on wikimedia commons as creative commons. Does this just apply to the picture or is the video of it also creative commons. Thanks.

  22. I assume you’ve also seen the homopolar Roller then –

    http://www.grand-illusions.com/articles/homopolar_roller/

    battery, bent wire and TWO magnets (get the poles right when you stick them on the battery).

    Here is a homopolar motor that actually DOES something.
    I wonder if you could make a little car that holds the battey, and has little wheels with magnets glued on them and then little copper brushes, with a switch…. Now I have to find an old hot-wheels to cannibalize…

      • Thanks for mentioning this part. That means it has a divide by 2 calc built in. I was wondering the 10k number and was going to ask if it was 5k and this prevented me from reading ALL the comments (boy are there a lot) ;)

        10k is not a high number at all for this practically frictionless motor with ~no load

  23. Are you an idiot? Check the bottom of the article. He clearly states that he got it from a science book.

    • naw not moron, just a bit of a handicap with reading, thats it. like many, dont read the important parts. NP though its all good, we all human and make mistakes, now will he admit it or just make more of a jackass out of himself?

  24. F=M x A or A = F/M Accell = Torque/Moment

    The magnet/screw combo experiences a force (torque) and therefore accellerates. There is no limit on angular velocity… Friction determines the terminal velocity. I think air is the primary limiting factor, then there’s the friction of the wire ‘brush’. Oooo A "mono brush". Also, the low friction "mono bearing".

    Steve (DCI)

  25. NOPE! Not through the point bearing.
    Better rethink this. more carefully. The "re-action" must "act" on the ‘other end’ of the magnetic force. The magnetic force pushes, or pulls between two ‘things’. Figure out what the other end of the _magnetic force_ is attached to…
    It ain’t through the bearing(s) just like in all other motors. Bearings DON’T transmit torque, that’s the whole idea of bearings, so where is it?…

    73, Steve, (DCI)

    The brush friction it pretty noticable. Requires a light touch.
    This is a very slick little motor/generator. Next I’ll be spinning up one connected to a milliameter…

    I like dropping these buggers down copper pipes…

    Have U seen the floading globe in the Discovery.com catalog?

    • New account now…so I’ll add to my last on Where’s the Beef…

      If you haven’t figured it out, the following shows a hint as to where the "reaction" part is:

      http://www.youtube.com/watch?v=VhaYLnjkf1E&NR=1
      http://www.youtube.com/watch?v=iG0pzGcy4xU&NR=1

      This puppy needs some serious thinking for more ways to do this… I have a really low friction ball bearing that I’ve played with for years. It’s time to make an adapter for it so I can hook up some of my super magnets and have some fun. That should dispell all the "It’s not a motor" talk.

      Some ideas:
      Multiple brushes placed, say 90 degrees around the magnet to cut the required brush current by 1/4th … or increase the torque 4 times HE HE HE

      I tried to make a single, simple wire dancing "Buzzer" but couldn’t get it to play..gotta try harder.

      I wanna’ see how many sizes of copper pipe I can get nested to get the loop resistance VERY low and the magnet drop VERY SLOWLY. A quick check with an available 1/2" alumimum and a 3/4 " copper netted about a 50% slower fall….no, that’s a 50% increase in fall time (1.5x time)
      73, Steve
      Keep this stuff up, Wendell!

  26. Shades of Mr. Wizard. I love it.

    I scanned the posts and am surprised no one mentined the Hall Effect. Seems to be the same thing to me… Crowd the current sideways – spin a screw…hmmm … same thing, no?

    73, Steve, (DCI)

    Nice work, Wendell

    Hard to tell your Kapcha (sp) Qs fromn Os… Good thing you allow so many re-tries.

    • The Halls Effect generates a current when passed through a magnetic field. In the automotive world, they are abbreviated to (HAG) or Halls Affect Generator. They are generally used to generate an electrical pulse to fire the spark plug as a magnet passes inside the distributor.
      In a homopolar motor the magnetic field of the magnet attracts to the point of current exiting the magnets outer ring thus creating rotation. Many Homopolar motor samples are on YouTube.
      Search for “Homopolar Motor”.

      • Hall Effect, Current affected by magnetic field, yes I do see the similarities.
        How about The Corbino effect, Radial current affected by magnetic field?

  27. DOES THE FLAT HEAD FERRMAGNETIC SCREW MATTER, I HAVE A MAGNETIC SCREW, AND I TRY IT AND IT DOESNT WORK!! I HAVE THE EXACT SAME THINGS HE USES EXCEPT THE SCREW AND THE COPPER WIRE.

  28. well to bad for u just get used to it and have patience and luck will come

    camaros r awesome

  29. hi
    how do we attach this motor to something else like to the back of a pen refill to make it rotate for a project
    plz reply soon

    • Use ur brain buddy ……… probably u could find or make something sort of a frame or smthing to hold the magnet still ….. u can use bushes for a connection to a rotating link ……. and probably put the entire apparatus in an appropriate container such that enough part of the screw is out …….. and u can use a screw much appropriate …….. or rather some connections to connect it to a pen refill ……… I think this could be done with suitable switching arrangement ………. only thing u got to do is jst try ……

  30. I still couldnt get it to work, i use an AA battery, stripped speaker wire, black drywall screw (yes the current runs through it and it works with the magnet) and a magnet that i got out of a perpetual motion machine, does anyone know whats wrong.
    -Dylan

  31. Alright another problem, and yes I’m completely new to this. The problem is that the screw will not spin (duh) but the funny thing is, when I touch the head of the screw to the battery there are sparks (tiny ones) but thats all. The battery is brand new, the wire is copper, the magnet is working like a charm and the screw is definatly ferromagnetic. Not sure what is wrong though.

    Any help would be appreciated, thanks.

      • Is the polarity from the magnet supposed to power the spinning of the screw, or is the battery powering it. I smashed a couple broken iPod headphones and took out the magnet from those. Maybe the magnetism isnt enough? They are pretty small magnets

        • Magnets can’t provide power; obviously the power comes from the battery. The magnet from a speaker or headphones won’t work unless you’re very careful or clever; the pole configuration is not as simple as with a disc magnet, and so it probably won’t work by just touching the edges.


          Windell H. Oskay
          drwho(at)evilmadscientist.com
          http://www.evilmadscientist.com/

    • Okay so we know that this design of a simple electric requires a complete circuit of electricity. So what you’re doing is attaching the wire first to the screw. That means that the screw is charged with the opposite charge than the side of the battery you are trying to put it to. Just before they touch the circuit is already complete. You will see this in the form of sparks just before they are together. Don’t try to see the electricity connection between them. The screw is charged so you might be…….not so good. This is the best answer I can give you.

  32. Does it really matter as long as they r helping pple and not using it 4 der own personal gain like sellin it….. go somewhere and leave well enough alone!

  33. Will button batteries work in place of such big pencil batteries.I mean cant we use hi energy and long lasting button batteries for this motor?

  34. Please read the whole article before snapping out at people by acusing them
    thanx

    —HPcom
    aka wolvesrock99
    akaka facetheconsequences12345

  35. First question: How do I make a homopolar generator? I’m sorry if this was asked before, I’m tired & will be the first to admit not researching it myself is very lazy.

    Second question: Would I be able to hook up a homopolar generator to my home as an alternative form of electricity?

    Third question: Would it be safe as long as it was someplace secure?

    Fourth question: Would it better for the environment?

    Fifth question: If second-fourth answers are yes, can you please post a link to a how-to for that on the bottom of this one so I can do it?

    Thank you. :)

    • Hey….

      If you think your self lazy… then your not cuz is you are you woudnt search in this site

  36. Am I the only one who sees that the guy who made the comment posted on August 10 2006 @ 4:06 AM PDT & got a reply on August 7 2006 @ 5:46 PM PDT? O_O If not, please ask Windell to teach us time travel. If so, my computer has a glitch and may need another repair. Sorry. ^~^’

  37. There’s a problem with the screw and magnet connecting to the battery.
    They just fall off. They don’t stick to it.
    What do I do?

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