Inductance with an air gap

Discussion in 'General Electronics Chat' started by kender, May 8, 2007.

  1. kender

    Thread Starter Senior Member

    Jan 17, 2007

    I need to make a small-signal inductor with an air gap. The gap will vary from 0 to 1mm. The core material will be stainless steel. What could be the potential pitfalls?

  2. Johann

    AAC Fanatic!

    Nov 27, 2006
    Stainless steel is, to my knowledge, not a good choice for core material. Why do you want to use stainless steel?
  3. kender

    Thread Starter Senior Member

    Jan 17, 2007
    I’m expecting shorted-turn losses. The inductor is planned to be built on the surface of a thin (few mm) plate of Alloy 49 stainless steel. It’s not the worst stainless alloy from the magnetic standpoint.

    I’d be happy to use a ferrite pot core instead of stainless, but that would present at least 2 mechanical challenges:
    - The pot core should be low profile. Well, I could take a taller core and grind it down.
    - The top of the pot core should be coplanar to the surface of the stainless plate. Of course, the pot core could be ground together with the stainless plate. But I don’t have access to good grinding equipment to do this.

    At the moment I’d rather deal with magnetic challenges posed by the stainless steel rather than with these mechanical challenges.