how to design an inductor

Discussion in 'General Electronics Chat' started by Sakwiti, Sep 15, 2010.

  1. Sakwiti

    Thread Starter New Member

    Sep 7, 2010
    I want to get 10 amp. load at 170v from 230v domestic supply to feed a heating element that I have fabricated. Going to a step down transformer is a tiresome job. difficult to find a big core, much enameled wires. Instead I decided to use a big iron core inductor in series with the element to reduce the excess 92v. What I have to do is fabricate an inductor of which impedance is about 9.2Ω. This circuit contains a SSR to control the load to the element and the SSR receives on/off signals from a digital temperature controller.

    Will this system work? If it work, Will the phase shift at the inductor affect the performance of SSR? What is cross sectional area of the iron core suitable for this inductor. Should I use a big enameled wire to wind the inductor enough to deliver 10 amps?

    Can I use a triac based power controller to reduce the voltage? Will this power controller affect SSR ?
  2. Papabravo


    Feb 24, 2006
    Doesn't matter. This kind of circuit cannot be made safe and so it will probably be quickly banned by the moderators. The importance of using a transformer cannot be overstated. If not for yourself then for the unaware who may come into contact with the device now or in the future.
  3. marshallf3

    Well-Known Member

    Jul 26, 2010
    Yea, don't go messing about with the line voltage end. A large capacity light dimmer by itself might be your best shot.
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    It would seem that the load is not properly designed. At any rate, homemade ballasts are not likely without an iron core.

    A big dimmer may be your best way to control power.
  5. marshallf3

    Well-Known Member

    Jul 26, 2010
    Really is no choice. Trying to eat up that amount of power with a choke is kind of crazy, it would have to be a monster to hold up to the load and what's it going to do? Put out heat anyway.
  6. Wendy


    Mar 24, 2008
    Thing about a choke, they don't dissipate power. They use reactance to resist current flow, which does not generate heat like a resistor. This is why they are used as ballasts for fluorescent lights.
  7. Ghar

    Active Member

    Mar 8, 2010
    I don't know what you'd gain, the inductor would still need a gigantic iron core to be able to support the large voltage and current without saturating.
  8. SgtWookie


    Jul 17, 2007
    Not just iron; it would need to have high silicon content, and to have many layers to minimize eddy currents.

    Core material for transformers is rather specialized stuff. You can't just walk into your local hardware store and buy it. If you tried to use something like a portion of an old cast-iron automotive engine block, you would wind up with horrific losses due to eddy currents.
  9. marshallf3

    Well-Known Member

    Jul 26, 2010
    Perfect inductor yes, normal one with eddy current losses no.

    I'm still for the light dimmer and would probably prefer one that was rated to control inductive loads whether or not the heating element was as they tend to be toughter in design. He's also going to need one rated to work with 240V devices.