Asking for help on an electromagnet project...

Discussion in 'The Projects Forum' started by germanninja, Nov 26, 2009.

  1. germanninja

    Thread Starter New Member

    Nov 26, 2009
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    I am trying to construct an electromagnet in a grid-type formation...1. What should I use to connect the "breaks" in the iron core? Should I keep it ferrous or can I use copper wire? and 2. I plan to use a disposable camera with the capacitor replaced by the leads to the electromagnet for the power source, how can I keep the wire from burning out since I am using the smallest gauge enameled wire possible to ensure maximum potential.
    I am still new to electronics and I am still learning so please no harassment.
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    Hello germanninja, and welcome to AAC.
    OK, could you please elaborate on that? Make a sketch and post it? .png type images are preferred; they are small in size and load very quickly with no special software.

    It is unclear what you mean.
    Are you going to attempt to build this from many individual pieces?
    Could you post an image of some of the breaks or pieces that you are talking about?

    Well, a disposable camera's electronics basically uses a small flyback-type power supply to charge up the flash capacitor to around 300v over a number of seconds. It really wouldn't be suitable to power an electromagnet.

    I'm not an expert in electromagnetic design by any stretch of the imagination. Electromagnets and solenoids are fairly similar, but rather specialized.

    It would help a great deal to know more about what your intended application is.
    Harassment of members is not tolerated. This board has an extraordinary group of staff members and moderators that would squelch such activities very quickly.
     
  3. Duane P Wetick

    Active Member

    Apr 23, 2009
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    I am unclear of what you mean by breaks in the iron core? Are you talking about core laminations? Electromagnets are subject to time constants in charging and discharging, so instantaneous operation is impossible. Lead wire burnouts are the result of an over-current condition, but what? Please provide some details of your coil design.

    Regards, DPW
     
  4. germanninja

    Thread Starter New Member

    Nov 26, 2009
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    0
    I originally had several pieces of ferrous metal as the core and I was trying to connect them...however I have decided to use coat hanger wire since it is the length I need.
    I am attempting to make 2 electromagnets say in a 12 x 12 by 1in thick grid to be placed side by side to create a strong magnetic field between them.
    I am going to take the straightened coat hanger and wrap it in enameled wire, then bend it in a ununununun snake-type formation with the spacing close together and hopefully that will get the effect I'm going for.
    As for using a disposable camera...I like how it amps up 1.5v into 300v...that's why I chose to use that to power the electromagnet...more power that goes trough the coils means stronger magnet right?
    I also see the problem with the power being increased to 300v over a few seconds and it won't have a continuous voltage to work with...so I want to put it on a 3 second delay so it will charge and discharge once every 3 seconds...kind of like a slow strobe light.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    I'm no electromagnet engineer, but I'll suggest that a coat hanger wire would not make a very good magnetic core material.

    The magnetic poles will be at the two ends of the coat hanger wire, one end will be N and the other S. In the middle, you will not notice much (if any) magnetic attraction/repulsion.

    The disposable camera trades high current at low voltage for high voltage at low current. I'm afraid that you won't see much output from it - except smoke. :eek:
    Sorry, but I just don't think you'll get the effect that you're hoping for.
     
  6. Duane P Wetick

    Active Member

    Apr 23, 2009
    408
    19
    The strength of your magnet will be determined by amperes x # of turns of wire. The time constant of your circuit will be L/R. Five time constants will be required to charge your magnet to 98% of its final value; and those same 5TC will be needed to discharge it to 98% of the final figure of 0. The basic principle of an inductor is that it resists a change in current flow. Hope this helps you.

    Regards, DPW
     
  7. germanninja

    Thread Starter New Member

    Nov 26, 2009
    3
    0
    Ok then...it was just a theory I had...What about taking the same setup but instead of an electromagnet, could I generate an EMP between the grids by adding a capacitor bank?
     
  8. SgtWookie

    Expert

    Jul 17, 2007
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    It is more likely that you would generate smoke. :eek:

    It would be potentially hazardous to attempt charging a bank of capacitors up to 300v. That represents a fair amount of energy, and you could be seriously injured or killed if you made a mistake.

    We try to discourage our "newbies" from experimenting with high voltages due to the hazards involved.

    It is much better to stick with low voltage projects, as they do not present a lethal shock hazard. You can still get burned by touching overheated components or a soldering iron, but such injuries are relatively trivial.
     
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