Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

I have a questian

  1. Mar 7, 2004 #1
    i am making a magnetically levitated train for my 8th grade science fair project and i need some help!!

    questian #1. how can i make the whole track one big electromagnet??
    (the track is a 3/4 inch square steel pipe) if i wrap the whole thing in copper wire and put a current through it will that make it an electromagnet??

    questian #2.once i get the track to work is there anything that i need to do to the train base itself to get it to repel off of the track??

    questian #3. after i get the train and the track to work how do i get the train to propell its self down the track, and stop, and reverse, and so on...?? (without needing to manually do it all myself)[b(]
     
  2. jcsd
  3. Mar 7, 2004 #2
    i need help fast my fair is in 17 days
     
  4. Mar 7, 2004 #3
    come on someone please
     
  5. Mar 7, 2004 #4

    chroot

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I suggest you spend some time at the library learning how the trains work. What you propose to do is a lot more difficult than wrapping wire around pipe.

    - Warren
     
  6. Mar 7, 2004 #5

    Integral

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    What you are describing is actually a pretty complex thing. No you cannot, nor do you want wire wrapped on your main track, your car will need a pretty close ride to maintain control and stability, windings of wire would get in the way. What you are making is called a LINEAR MOTOR do some research on that term. I am not sure what you will find. Generally they require complex control systems to make them move. You need to be able to turn on and off the magnets (either in the track or on the car) in a carefully timed manner to get motion. This requires a relatively complex control system.

    For the size you are talking about you should be able to use permanent magnets, perhaps rather then attempt to actually drive the car you could simply let it slide.
     
  7. Mar 8, 2004 #6
    i already tryed to use perminent magnets :frown:
    i looked up linear moter online and i got nothin but deffinitions of what it is nothing aboult how to make one
    does anyone have a plan on how to make one???

    what should i do to the trak if i cant just wrap wire around it ??
    all the research i did led me to think that wraping wire around the track would work!?!
     
  8. Mar 8, 2004 #7

    enigma

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Maglev trains are one of the more difficult engineering problems currently being worked on today.

    You won't be able to get one working for an 8th grade project, much less one that's due in 17 days.

    I'd pick another topic.
     
  9. Mar 8, 2004 #8

    Cliff_J

    User Avatar
    Science Advisor

    Agreed with above, this is a far more involved project than you might have previously thought.

    You could simplify your experiment to something far more achievable even if still somewhat daunting. The levitation part is the most difficult area, so you could (and should) forget it for now.

    Ok, now take a toy train, put a permanent magent on the first car. Make some electromagnets by winding some small wire around some small bolts you get at a hardware store. Mount those on piece of wood or something, then the track on top of that maybe on a sheet of 1/4" acrylic found at a home center.

    Now turn the coils on/off in sequence to make the train move. To do that you could wire up a circuit with a 555 chip and 4017 chip and some 2N2222 transistors from Radio Shack to sequence the magnets. Or find an old switch with multiple positions that you could use to manually turn the coils on/off, about 100x easier than the circuit.

    You could easily fill a notebook with the research and results from just that simple experiment with magnetic propulsion to move a toy train car back and forth a couple feet.

    If you think I've given you the entire answer, nothing personal but my apologies, you should pick a different project as this could still be a very ambitious thing to accomplish in 17days with no background.

    My 7th grade science fair project was a logic circuit borrowed from an old book about moving a farmer and his corn, goose, and dog across the river in a boat. Spent too much time making the thing pretty and not enough time on soldering....and with a bad relay, it didn't work until the weekend before the fair.

    Cliff
     
  10. Mar 8, 2004 #9

    LURCH

    User Avatar
    Science Advisor

    It is actually possible to make a maglev with permanent magnets. It won't be propelled by the magnets, but only levitated, so you won't get the controlls to start, stop, reverse, etc., but you'll still get a good "gee-wiz" factor from people seeing the train float up off the trck on magnets. Plus some bonus points when the magnets work without a power source. You can make it an inductrack . This requires a magnet arrangement known as a Hallbock Array. I'm not sure how difficult that would be to construct, but I think it's a lot easier than other maglev designs.
     
  11. Mar 8, 2004 #10
    what would hapen if i wraped the whole thing in small wire and use permanant magnets on the train
    then i used a toggle switch and a dimmer switch

    will the train move with current against the current or will it just sit there??
    ......then will the train slow down if i "dim" the current going throug the wire . then i slowly shut of the current entirely and flip the toggle to change the direction of the current and slowly turn the dimmer on again.... will the change of current cause the train to change direction??????[?] [?]
     
  12. Mar 8, 2004 #11
    or do u think i should still change my project[?]



    if there is ANY way of geting this done i want to try for it.. i want to be challenge and feel proud of myself after im done... and i will work SO hard on this project (that is if there is any possible way to accomplish this) so if there is somethin that would help me out in this let me know I WOULD BE SOOOOOOO GREATFUL TO YOU!!!!
     
  13. Mar 8, 2004 #12
    Try here

    Can't see it working in 17 days unless you buy one in kit form.
     
  14. Mar 8, 2004 #13

    Cliff_J

    User Avatar
    Science Advisor

    go to guy - I understand the enthusiasm for accomplishing a difficult task, it has its own rewards. But note the link that Lurch posted has a lot of very valuable information on it. It is a site dedicated to creating a simple and easy mag-lev train. But how many years did this idea gestate before a working model was created?

    You would be far better served with a project that was finished and demonstrated the scientific method (hypothesis and all that) with good documentation than a project that's barely started and hasn't moved past the idea phase.

    Regarding your questions, a wire wrapped around the rod used as the track might suck the train right against the rod (or push it off) if you could get enough current to flow and had enough turns of wire. The same could be done with the permanent magnet and a nail. Very difficult. Think of balancing a bowling ball on top of your head while standing on ice and juggling three balls.

    Using the dimmer would only adjust with how much force the train would be stuck to the rod (or how far it would push off). You might construct a couple walls to locate the magnet on top of the rod. But it will want to move, and then fall quickly. Then four walls, and you could levitate it (or suck it down) but that's zero movement forward/backward. So at a minimum, you'd need two walls and many coils and complex circuits to pull off levitation and movement, tough task.

    What is your hypothesis?
     
  15. Mar 8, 2004 #14
    nnnnnooooooo thats no what i meen its not a flat base. its a biger peice of pipe that fits AROUND the track ot on top of it (that way it will have stabillity) it looks like this
    /\
    \/ (track)


    /\
    / \
    \ /
    \/ (train) then the permanent magnets would be mounted on the inside of the train and the coil would be on the outside of the track and the train is fited over the track and the track is turned on

    then i get to my hypothisis. the track will push out on the track in all directions thus keeping the train very stable



    :wink: :wink: :wink: :wink: :wink:
     
  16. Mar 8, 2004 #15
    about that link...... how would i go about puting it togaither and how do i arange the magnets??? i need that info put into laymens terms
     
  17. Mar 8, 2004 #16

    Cliff_J

    User Avatar
    Science Advisor

    Lets back up a step. If you have a magnet, you have a north & south pole. Opposites attract and likes repel.

    You can't just have two magnets, one a permanent magnet and one electromagnet surrounding it. You need a bunch of the electromagnets, and the ones on top need more power to offset the force excerted on the permanent magnet by gravity. The rest of the magnets would help hold the one in place in the center, but needs a nice feedback loop to do so otherwise the permanent magnet is going to just smash into one of the magnets.

    Circular magnets do exist, but the N/S poles are inline with the circle (if you look through them one pole is near you and the other is away from you). You need to use the poles (attract/repel) to pull of what you want to do.

    There's a diagram on the second or third page of that link shows how to set them up. The only hard part I see is winding the coils for the track, its not very specific but their test model has like 1000 coils or something.

    Again, I'd suggest changing your project. Magnetic propulsion would be challenging enough, as would many other projects.

    Cliff
     
  18. Mar 9, 2004 #17
    i am useing the polls but its not working...
    to make the hallbock array do i need to buy a bunch of square mabnets and put them in the order shown on the diagram?? how do i make the hallbock array
    and could i use circular magnets to acheave it or do i need square or rectangle ones ??
     
  19. Mar 9, 2004 #18
    i know u all want me to give up on this one and move to another one but i will need to do this project in order to beat out the other kids in my class (they have good projects)
     
  20. Mar 9, 2004 #19

    Cliff_J

    User Avatar
    Science Advisor

    The Hallbock array is used to increase the magnetic field on the bottom, for a small light application like yours wouldn't necessarily need it.

    Next trick, and its the neat one, is winding and orienting the coils. You need to speed the magnetic train along the coils to get it to levitate. Now we have the hat trick.

    They said like 10 kph in the article - if your track is 2ft long your train needs to cross it in less than .25 of a second in order to levitate. You could make it circular and angled, or have the train bounce back and forth like a ping-pong ball, which would be fun because it would be a neck stretcher to keep up with it flying back and forth that fast. If your track was 9ft long, the train needs to cover that in a second, hope you see the challenge there in getting the train to that speed. For a small toy train at that speed, you could create small wings to provide enough lift and make your train 'levitate'.

    If you had two months and lots of space to setup your display (in other words lots of track to get the 6MPH or whatever for levitation) and lots of funds to build a big track, this might be a different story. But now you're on two weeks time. Sorry dude.

    Cliff

    P.S. What are these good projects you're up against?
     
  21. Mar 10, 2004 #20
    the go to guy:


    If you're really serious about making this train for a science project, why not do something easier this year, and have the train be an early start on a project for next year?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: I have a questian
  1. I have an idea (Replies: 13)

  2. I have a crazy theory (Replies: 8)

  3. I have a quiz -_- (Replies: 2)

Loading...