Shielding material. Aluminum?

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ChrioN

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Joined
Aug 31, 2005
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I'm going to bend me a sheet of metal for the toroids in my G9, for shielding purposes.

I thought I had a nice piece of copper, but that showed out to be too small. Aluminum on the other hand, I got a pretty much endless supply of that. Is this a decent shielding material in lack for better ones?
 
If you are talking about magnetic shielding, then neither copper nor aluminum are worth anything. The shielding material must be ferromagnetic, which could easily be determined with a permanent magnet.

If you need a shield for a toroidal transformer and want something simple, but pretty effective, a tin (steel) food can of a somewhat larger diameter than the toroid can be cut down to about 1/4" greater than the height of the toroid and then cut open, so it can be fitted tight around the toroid's circumference. I tape the sharp edges with thick packing tape to make them less likely to cut me or especially any wires that exit the windings. The ends should be insulated from each other where they overlap and the whole thing held on with tape. Make sure that you don't inadvertantly creat a shorted turn by somehow touching the mounting washer with this shield. This is an effective low-tech way to reduce magnetic flux leakage.
 
[quote author="CJ"]Then use that copper to line the tuna can.[/quote]

The copper needs to be grounded at the starground. It serves for shielding not magnetic but the electric field.

Watch out that you don´t construct a magnetic short around your tranny with the can. This could easily destroy it.
 
Thanks alot for the help.

I believe one could cover the inside of a can with electronic tape to isolate it from a transformer short.
 
[quote author="ChrioN"]Thanks alot for the help.

I believe one could cover the inside of a can with electronic tape to isolate it from a transformer short.[/quote]

That would not prevent a magnetic short, only an electric short. Besides, a functional transformer is always electrically isolated anyway. Otherwise it would be kind of dangerous to use.

/Anders
 
Opps...thats right. How do I avoid a magnetic short then? Just be sure the can doesn't tough the transformers/mounting hardware?
 
Anything ferrous metal, other than the copper wire inside the xfmr, this metal, if it makes a complete path thru the torroid center hole and back to itself, is a shorted turn.

I do not know if the copper needs to be grounded.
On the V series cans, it just kind of floats in there.

I have some stuff on shielding I should dig up.

The more layers, the better.
Use three metals, and two coppers, and you might have a pretty good shield, even if not exotic anealed conductive atom alloys.
 

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