Help with making an electromagnet pulse

Discussion in 'The Projects Forum' started by InTylerable, Aug 14, 2014.

  1. InTylerable

    Thread Starter New Member

    Aug 14, 2014
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    Please help! I am working on an invention and I need to make electromagnets pulse. I made the electromagnets and attempted using a 12v strobe light circuit board to create the pulses of electricity I need. I fried two circuit boards doing this, they worked for a short amount of time. My theory is there is not enough resistance or anything to "absorb" the electricity and too much is returning to the circuit board.
    Thoughts anyone?
     
    Last edited: Aug 14, 2014
  2. MrChips

    Moderator

    Oct 2, 2009
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    Did you include a back-emf absorbing diode in your output driver?
    An electromagnet is largely inductive. Every time you turn off the current to the electromagnet there will be a large back-emf which will blow your electronics.

    Posting a circuit schematic is appropriate here.
     
  3. InTylerable

    Thread Starter New Member

    Aug 14, 2014
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    0
    No I did not, I was using a prefabricated output driver. A 12v auto strobe light kit meant to run LED's. I am considering purchasing a 9 volt strobe light kit http://www.goldmine-elec-products.com/prodinfo.asp?number=C5175. Where would the back emf absorbing diode need to be placed? Unfortunately I do not want to post the schematics as I would like to patent my idea. If you have any suggestions I would greatly appreciate it. Is there a certain diode I would need for a 9 volt system?
     
  4. MrChips

    Moderator

    Oct 2, 2009
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    Put a diode such as 1N4007 across the electromagnet such that it is reversed biased, i.e. the cathode goes to the more positive side of the supply line.
     
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  5. BobTPH

    Active Member

    Jun 5, 2013
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    Most likely your LED strobe cannot deliver nearly the current your electromagnet wants. You need to deal with that as well as the back EMF protection.

    Bob
     
  6. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    There's really not any way we can help you without a schematic. If you want to invent something and patent it, then go right ahead. But that means you can't get any outside help especially if you plan on being that secretive about it. If you want all the credit, then YOU must do all the work. You can't ask other people to help you.
     
  7. InTylerable

    Thread Starter New Member

    Aug 14, 2014
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    No, Mr. Chips had the answer I needed but thanks anyway...
     
  8. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    Did adding a freewheel diode fix the problem?
     
  9. Lineout

    Member

    Nov 20, 2013
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    0

    Is this the 'snubber circuit' ?
    When using one for a dc motor can't you also throw in a capacitor, if so could you talk about why the capacitor is helpful ?

    I've not yet found a definitive tutorial on the snubber circuit, have you found a source that shows appropriate values of capacitors for different size motors or a formula to arrive at a correct size.
    I think the last info I got was 'just about any size will do' , which seems correct, but it would be nice to have a better way to choose.
     
  10. alfacliff

    Well-Known Member

    Dec 13, 2013
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    the capacitor is to reduce electrical noise generated by the brushes. the resistor and capacitor "snubber" is mostly for ac motors, where a diode would not work.
     
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