toroid transformer Q

[Magnus Danielson]

From: Hallgeir Helland <hhelland at mailandnews.com>
Subject: toroid transformer Q
Date: Wed, 16 Aug 2000 17:47:08 +0200

> Hi all,
> 
> A thought suddenly struck me: I have mounted a 15 VA toroid transformer inside
> an aluminum enclosure by means of a screw through the hole. But this screw is
> in contact with the enclosure at both ends, actually. So isn't this then 
> actually a winding, which is shorted?? 
> Is this bad? It has worked fine so far. The aluminum enclosure is just a little
> bigger than the toroid itself. It doesn't get hot, nor does it make funny noises.
> 
> Thoughts?

Well, first off you have built a rather poorly coupled secondary winding.
Then, this makes me recall the copper shorting loops (basically a piece of
copper ring put around the core somewhere. The shorting loop will cause loss
which increases with the square of the frequency, thus, it can be a good way
to keep high energy stuff out.

If you don't feel excess heat I would not worry too much.

Cheers,
Magnus