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Magnetic Linear Accelerator Questions

  1. Jun 6, 2010 #1
    Firstly, Im sorry if I sound like a moron I only finished 1 year at university before leaving so I don't have the firmest grasp on some of this. I do have a massive facination with nuclear physics and quantum mechanics, string theory etc.


    Im looking at building a linear accelerator (not those little one shot toys you see online) and am looking at a series of switched electro magnets to accelerate ferritic (yes magnetic) stainless steel balls. Still looking at what can be fired but the ss balls are eaiser to come by.

    Concern 1,
    I want to reroute the back EMF through a rectifier and back into the capacitors to reduce next cycle charge time but dont know if there are diodes large enough to handle the power output and also the size of the magnetic field may induce back EMF on the wrong side of the recifier causing a "missfire" by draing the capacitors rather than charging. is there a way to prevent EMF being induced in certain sections of the wiring?

    Concer 2,
    Firing (turning on and off) the magnets, the effect it would have on the next magnet in the sequence. Would it start inducing currents in the the next magnet causing a missfire, or could they be switched fast enough to avoid the EMF affecting the projectile.

    Any help would be appreciated.

    Last edited: Jun 6, 2010
  2. jcsd
  3. Jun 6, 2010 #2
    Next cycle charge time?
    If I'm not mistaken, separate capacitors(already charged) should be used for each stage.
  4. Jun 6, 2010 #3
    Hi pallidin,

    Thanks for your reply. Let me clarify. I will be using a capacitor for each stage, but I want to be able to continouisly (yes i know its spelled wrong) fire the entire mechanism. If I can capture the back EMF and feed it into the capacitors it will reduce complete cycle charge time. So it can fire, by the time it gets to the last stage the first stage will be fully charged again.
    Maybe a cascade feed system to the capacitors, but theres some technical issues around that one.
    And yes I realise there will be heat issues i'm working on it.

  5. Jun 6, 2010 #4
    Ok, I see. Instead of a "'single shot" you want a "repeater"
    Well, I'm sure it can be done within design limits, but I am not versed enough to know precisely how. Sorry I can not be of more help.

    Chris, my only other thoughts are to please keep safety first and foremost in mind.
    Homebuilt accelerators can be fun and instructive, but also dangerous.
    Especially a repeating kind.
    For example, let's say you get this thing working, but your 10th ball gets "stuck" at the end and your 11th ball slams into it. Anyway, ALWAYS look at what can go wrong and provide safety measures.

    Nonetheless, happy experimenting!
  6. Jun 7, 2010 #5
    Thanks Pallidin

    I plan on using a laser system to fire each magnet and in thoery it should be possible to electronically "jam" the mechanism should a ball get stuck preventing the one behind it impacting, which could lead into an interesing experiment into kinetic energy.

    Another idea I had was to pre-magnetise the "ammo" and have the magnets reverse as it passes providing increased acceleration. Obviously safety is a top priority and Ill be using a non metallic barrel so there shouldn't be any issues with the barrel magnetising and sticking the balls.
  7. Jun 10, 2010 #6
    Re: Force and Magnetics Equations


    Could anyone give me the equations for finding out:

    Magnetic field strength
    acceleration of a metallic object due to a magnetic field
    the force felt by said object
    and any others you think would be useful

    Id like to do some math before buying anything because I have a couple of ideas on the boil
    Last edited: Jun 10, 2010
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