Re: Inductive Coupling through a Steel Enclosure

John Popelish wrote:
Ms.Malamu Habavir wrote:
So basically, two coils with signals 180° out of phase. One coil generating a negative pulse when the other is generating a positive pulse?

That is the idea, though you can accomplish the same thing by bending the flux from the inside end of the coil, and sending that back through the hole beside, or around the original flux. A common way to do this is to add a high permeability core to the coil, that has both a center post, and a surrounding shell. When the post is the north pole, the shell is the south pole, and vice versa. A matching core on the receiving side captures the flux from these two poles and wraps it around and through the second coil.

Google [pot core].

The distance you can transmit energy with a pair of poles depends on the spacing between them. The larger the gap between the opposite poles, the further out the field fringes. This means that the pot core may not give the best performance. See this page for some pictures of different core shapes that are commonly available.

http://en.wikipedia.org/wiki/Magnetic_core

If you could find a U or C core whose poles just fit in the hole, you would have a pair of magnetic poles further apart than you would get with a pot core that would produce slightly further reaching fringes. If you could actually place the core in the hole, so that the air gap between halves was very much smaller, then the pot core would be better, because of its symmetry and ease of winding.

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  • Re: Inductive Coupling through a Steel Enclosure
    ... a negative pulse when the other is generating a positive pulse? ... That is the idea, though you can accomplish the same thing by bending the flux from the inside end of the coil, and sending that back through the hole beside, or around the original flux. ... A common way to do this is to add a high permeability core to the coil, that has both a center post, and a surrounding shell. ... When the post is the north pole, the shell is the south pole, and vice versa. ...
    (sci.electronics.design)