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Thread: changing the poles of an electromagnet

  1. #1 changing the poles of an electromagnet 
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    I am new to the forum, and I have been doing some research into electromagnets. Does anyone know of a way to rapidly change or alternate the poles of an electromagnet? The frequency of alternation I am looking for is somewhere between 20-60hz. Any thoughts/ideas are welcome.


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  3. #2  
    Forum Ph.D. Leszek Luchowski's Avatar
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    Using AC power?


    Leszek. Pronounced [LEH-sheck]. The wondering Slav.
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  4. #3  
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    Quote Originally Posted by Leszek Luchowski
    Using AC power?
    That will work.
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  5. #4  
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    Quote Originally Posted by Leszek Luchowski
    Using AC power?
    Either AC or DC. I would prefer AC, but DC would probably be easier.
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  6. #5  
    Your Mama! GiantEvil's Avatar
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    Considering that AC power is potentially dangerous, you should certainly use DC. The lowest voltage possible.
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  7. #6  
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    Quote Originally Posted by GiantEvil
    Considering that AC power is potentially dangerous, you should certainly use DC. The lowest voltage possible.
    It is going to be rather to alternate polarity with DC.

    AC can be handled safely. It is rather common. That is what is available at the outlet that powers your computer, or charger in the case of a laptop.
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  8. #7  
    Your Mama! GiantEvil's Avatar
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    Well yea, you can handle AC power safely Doc, but...
    Either AC or DC. I would prefer AC, but DC would probably be easier.
    I thought maybe this person shouldn't try to.
    Does anyone know of a way to rapidly change or alternate the poles of an electromagnet? The frequency of alternation I am looking for is somewhere between 20-60hz. Any thoughts/ideas are welcome.
    Considering AC cycles at 60Hz it's perfect in this case. But attempting to use DC would be a more intense(less crispy) learning experience.
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  9. #8  
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    Quote Originally Posted by GiantEvil
    Considering AC cycles at 60Hz it's perfect in this case. But attempting to use DC would be a more intense(less crispy) learning experience.
    If you swap the leads on a DC source to change polarity, what you get is AC. If you don't you don't change the polarity of the magnet.
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  10. #9  
    Your Mama! GiantEvil's Avatar
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    I was considering house currant=110v, battery current=1.2v to 12v. I wasn't considering AC to be inherently dangerous.
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  11. #10  
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    Quote Originally Posted by GiantEvil
    Well yea, you can handle AC power safely Doc, but...
    Either AC or DC. I would prefer AC, but DC would probably be easier.
    I thought maybe this person shouldn't try to.
    Does anyone know of a way to rapidly change or alternate the poles of an electromagnet? The frequency of alternation I am looking for is somewhere between 20-60hz. Any thoughts/ideas are welcome.
    Considering AC cycles at 60Hz it's perfect in this case. But attempting to use DC would be a more intense(less crispy) learning experience.
    From what I have read I would be more inclined to go with DC.

    What I am mostly trying to achieve would be rapid rotations between polarities. The only way I can see to change the poles of an electromagnet would be to reverse the current. That being said my idea would be to set up wiring for both polarities: + to A and - to B, and + to B and - to A. Connect these to a switch that enables only (+A and -B) or (-A and +B) at any one time. The switch will then toggle between opposite polarities by connecting one circuit and disconnecting the other circuit.

    Now the tough part. Does anyone know of a switch that can switch up to 60 toggles per second? Or does anyone know how to set this up so that it would work?
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  12. #11  
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    Quote Originally Posted by twinspick22
    From what I have read I would be more inclined to go with DC.

    What I am mostly trying to achieve would be rapid rotations between polarities. The only way I can see to change the poles of an electromagnet would be to reverse the current. That being said my idea would be to set up wiring for both polarities: + to A and - to B, and + to B and - to A. Connect these to a switch that enables only (+A and -B) or (-A and +B) at any one time. The switch will then toggle between opposite polarities by connecting one circuit and disconnecting the other circuit.

    Now the tough part. Does anyone know of a switch that can switch up to 60 toggles per second? Or does anyone know how to set this up so that it would work?
    What you are describing is basically 60 Hz AC, what comes out of an ordinary wall socket. The only difference is that switching an ordinary DC source will give you a square wave rather than a sinusoid, but with an inductive load like the coil of the magnet that will make little difference.
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  13. #12  
    Forum Ph.D. Leszek Luchowski's Avatar
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    Quote Originally Posted by GiantEvil
    I was considering house currant=110v, battery current=1.2v to 12v. I wasn't considering AC to be inherently dangerous.
    Household power mains run at 230V AC where I am, and it's enough voltage to kill you if you do something really stupid or deliberately suicidal. And by the way, we have 50Hz.

    But when I said AC power, I did not necessarily mean using directly wall-outlet voltage. Why not use a safety transformer to lower the voltage AND provide galvanic insulation from the mains, while keeping the 50Hz or 60Hz charm of AC to alternate your poles.
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  14. #13  
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    Quote Originally Posted by Leszek Luchowski
    Quote Originally Posted by GiantEvil
    I was considering house currant=110v, battery current=1.2v to 12v. I wasn't considering AC to be inherently dangerous.
    Household power mains run at 230V AC where I am, and it's enough voltage to kill you if you do something really stupid or deliberately suicidal. And by the way, we have 50Hz.

    But when I said AC power, I did not necessarily mean using directly wall-outlet voltage. Why not use a safety transformer to lower the voltage AND provide galvanic insulation from the mains, while keeping the 50Hz or 60Hz charm of AC to alternate your poles.
    All great stuff. However, I am less concerned with the safety of it than I am the functionality.
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