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How to reproduce a battery with a power supply

  1. Jul 27, 2009 #1
    I am expermenting with a sperical metallic neodymium magnet ball that spins like a DC motor when I hook up a + or - charge up to the north or south pole of the ball and then hook up the other charge to the equator of the ball. I have only used alkaline batteries and it works with a AA 1.5 volt battery, a 9 volt battery, and a 6 volt camping lantern battery. It shoots sparks if I try to hook up a 12 volt lead acid battery so I can't use that. I also tried 3 volt, 6 volt, and 12 volt cell phone chargers with amp ratings varying from 300 to 1,500 mA but these will not spin the ball because of the low current. As the balls spins faster it eats up the battery quickly and the battery gets hot. I want to spin the ball but am tired of wasting my money on dead batteries so I need a wall socket adapter that I can plug into my 120 volt AC house current and invert it down to a low voltage, but a high amperage and therefore high current. I was told by someone that I might be able to use a car battery charger or I could buy an electroplating power supply so that I can have low volts but high current. Basically the ball requires a high current flow. Also, whatever power supply system I buy, I also need that to be limited to 6.5 amps, because I will be hooking up that power supply to a separate pulse width modulator that can only handle 6.5 amps maximum. I would then hook up the pulse width modulator to the ball to spin it. Then I would be able to spin the ball as fast or as slow as I want with the turn of a knob and also won't be wasting my money on buying batteries. I have a few questions. How does the ball spin from such a small battery and is the voltage going down or the amperage going up as it speeds up? The ball will spin like 10,000 rpm's if the current continues to flow through it so that is why I am using a pulse width modulator to slow it down. Would I have to gradually increase the current from whatever power supply I buy or could I hook it directly to the ball like I do with the battery? Any help would be very much appreciated. Does anyone have any suggestions on what kind of power supply I should buy to get the exact same effect as preferably a 6 volt camping lantern battery? Thanks
  2. jcsd
  3. Jul 27, 2009 #2


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    Staff: Mentor

    Welcome to the PF>

    Could you post a link to something that shows the ball magnet, and how you are hooking it up? You need some form of current limiting in the hookup -- you shouldn't just be shorting the outputs of batteries (as you have seen with the sparks and hot batteries).

    Sounds like you should look for a 12Vdc lab power supply that can output something like 5A. Maybe do a search on e-Bay to see what you can find. They will generally have a current limit adjustment knob, so you can experiment with setting that.
  4. Jul 27, 2009 #3


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    Staff: Mentor

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