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Please help simulating a solenoid.

Discussion in 'General Electronics Discussion' started by Circuitz, Dec 7, 2013.

  1. Circuitz

    Circuitz

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    Dec 7, 2013
    Hello!

    I am trying to simulate a bi-directional rotary solenoid. I am using an 18 Henry inductor and a resistor to simulate the circuits static resistance and inductance but am having a problem simulating the work or current usage that a solenoid does. A capacitor will charge and drain the inductor but what do I do with the voltage potential to prevent it from going back to the inductor? If I discharge it through an LED I can dump it in heat and light with little extra resistance- but will it survive for very long?

    Thanks for any suggestions!
     
    Last edited: Dec 7, 2013
  2. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
    I'm sorry, your explanation isn't all to clear to me. Can you supply a circuit diagram, please? (go advanced, use the attachemnt function).
     
  3. Circuitz

    Circuitz

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    Dec 7, 2013
    Ok- here is the circuit and solenoid load I am trying to simulate.

    The solenoid is bi-directional in that at a specified point the polarity of the pulse width modulation will switch and the direction of the solenoid will as well. I believe it is half of of an H-bridge driving it.

    Thanks!
     

    Attached Files:

    Last edited: Dec 11, 2013
  4. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
    I still don't get the problem. Where is the capacitor you're talking about? What work do you want to simulate?
     
  5. Circuitz

    Circuitz

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    Dec 7, 2013
    I am trying to use an inductor and a few resistors to simulate the work of that solenoid shown in the circuit diagram (3 amps) as it moves a load with its electromagnetic energy. If I hook my multimeter across the leads of that rotary solenoid when it is not energized it is about 2.5 ohms. I am using resistors in series to approximate that value. The inductance of the solenoid is 18 Henry and I have purchased an inductor of the same value, also in series. The problem in my simulation is the work that the solenoid is performing or current it is using. The inductor and resistors simulate the coil in the solenoid but not the electromagnetic work that causes more current to be drawn into the solenoids coil.

    That is why I was proposing a capacitor to drain the coil and then some LEDs to bleed off that energy so it can keep draining the coil without adding that much more resistance? When the circuit above is energized the multimeter drops to zero.

    I apologize if I am missing something obvious in my explanation.

    Thanks!
     
    Last edited: Dec 13, 2013
  6. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
    You can "drain energy" from the coil by adding a second coil connected to a load resistor (possibly variable in time to simulate changing loads) and coupling the two inductors like a transformer.
    Also, to speed up simulation, do not use discrete resistors for the ohmic resistance of the coil, use the series resistance parameter built into the inductor model instead.
    A sample result looks like this:
    [​IMG]
    The siulation file for this is here:
    View attachment solenois.zip
     

    Attached Files:

  7. Circuitz

    Circuitz

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    0
    Dec 7, 2013
    Thanks a lot!!!!
     
  8. Circuitz

    Circuitz

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    Dec 7, 2013
    Looking back at this, I was impressed but never understood it. In this diagram is the circle the original solenoid or the second coil you refer to? I see the two 18 Henry inductors and a resistor but not sure what that formula is for and how to make a resistor variable in time in real life? What Program am I supposed to use with that simulation file?
     
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