Powering an Inductor with 120v AC

Discussion in 'The Projects Forum' started by jerbear8000, Aug 20, 2014.

  1. jerbear8000

    Thread Starter New Member

    Aug 20, 2014
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    I'm building a circuit that is going to use a wall outlet as source (120v AC). I need to cut the power down to run an inductor (electromagnet) intermittently at 50v max off of a capacitor, and also a chip at 3v and 12mA continuously. I can't figure out how to cut down the voltage, and I'm struggling with starting this project as a whole. I'm not exactly sure where to look for guidance as this is my first project using an AC source, so I was hoping for a little help on what parts I should be researching. Any assistance would be great!
     
  2. crutschow

    Expert

    Mar 14, 2008
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    The first thing to do is use an isolation transformer as it is way too dangerous to experiment with voltage directly from the mains.

    What do you mean "off of a capacitor"? :confused: Do you mean in series with the cap?

    What is the current through the inductor?

    The chips can be powered from a low voltage DC power supply such as a wall-wort.
     
  3. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    As I interpret your question, what you are needing is called a step down transformer. You may have to use a couple of them to get the voltages you need. Or have one made(expensive). They/it would have 120VAC on the primary and 50V and 3V on the secondaries. This will also give the isolation that Crutschow was talking about.
     
  4. jerbear8000

    Thread Starter New Member

    Aug 20, 2014
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    Yes the inductor will be in series with the cap, and the current through the inductor will be around .5 amps max.

    Is there a chance I could build the transformer myself?
     
  5. Papabravo

    Expert

    Feb 24, 2006
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    Yes, you can buy a torroidal core and wind the transformer with enameled magnet wire. If you are skilled in metal fabrication, you can use sheet steel to fabricate transformer core laminations and wind the same enameled magnet wire around the steel laminations.
     
  6. jerbear8000

    Thread Starter New Member

    Aug 20, 2014
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    Sounds like something that I could do. How would I go about integrating this into a circuit board like 2 or 3 inches long?
     
  7. Papabravo

    Expert

    Feb 24, 2006
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    You can lay the torroid flat on the board for the best mechanical attachment. The wires will go through the board in any arrangement you care to make. If it was me I would arrange for the primary pair to be on one side and the secondary pair to be on the other side.

    Alternately you stand the torroid up and do the same thing with the four wires. Arrange it so they support the torroid.
     
  8. alfacliff

    Well-Known Member

    Dec 13, 2013
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    what will the inductor be used for? you mention an electromagnet, if used for lifting, it will have to be fed with dc. why is there a cap in series with the inductor?
     
  9. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    And isn't the correct term for an electromagnet "solenoid" instead of "inductor"? Even though the electromagnet has inductance. Or at least thats what the books on electromagnets say.
     
  10. alfacliff

    Well-Known Member

    Dec 13, 2013
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    there are many kinds of inductors, I would just like to find out whtch his is, and why the cap in series.
     
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