Inductance with an air gap

Thread Starter

kender

Joined Jan 17, 2007
264
Colleagues,

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?

Cheers,
Nick
 

Johann

Joined Nov 27, 2006
190
Colleagues,

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?

Cheers,
Nick
Stainless steel is, to my knowledge, not a good choice for core material. Why do you want to use stainless steel?
 

Thread Starter

kender

Joined Jan 17, 2007
264
Stainless steel is, to my knowledge, not a good choice for core material. Why do you want to use stainless steel?
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.
 
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