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B Ring magnet sliding on iron core solenoid actuator

  1. May 7, 2016 #1
    Hi everyone, I have lots of (potentially dumb) questions about this "project" I'm working on. It's a voice coil actuator, but with things a bit reversed. Here's how a regular voice-coil actuator is constructed:

    The rod that is inside the coil is a magnet and the outer cylinder continues the magnetic path, sort of like an axial horse-shoe magnet. The coil and magnet push or pull each other, based on polarity..

    I already ordered a magnet, but in the meantime I found some cheap ring-magnets, still axially polarized, and I'm wondering how well this would work:

    I actually already did this experiment with two coils - one loose to slide and one fixed and they did repel or attract each other nicely along the iron bar. With the ring magnet, I suppose the ring and the iron rod inside the ring magnetic fields will move in opposite directions, i.e the iron bar will be "closing" the magnetic field of the ring magnet.

    So, then the coil produces a magnetic field and it's either in the same, or in the opposing direction of the field in the rod inside the magnet, moving it left or right..

    What I was first wondering is about saturation...If the magnetic field of the magnet saturates the iron rod in it, the magnetic field created by the coil won't be able to "pass" through that point. Is that correct? Or am I wrong?

    Can one of the magnetic fields "overpower" the other, so that no linear motion will be efficiently produced? Also, what if I close the magnetic path of the iron rod, would this require less power to produce the same force?

    Also I found a thread here:https://www.physicsforums.com/threa...ally-magnetized-permanent-ring-magnet.867355/

    that said if the ring magnet is long, the magnetic field near the center will be almost zero. I suppose with an iron rod inside, this is not the case?

    Will the force of the movement be linearly proportional to the length of the magnet?

    Guess I should just test it, but thought I'd ask before ordering the magnets.
  2. jcsd
  3. May 12, 2016 #2
    Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
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