[TenTec] Re: EMI (was Argonaut 505 - The Answer)

[David McClafferty]

I did not mean the shorted turns that are purposely
applied to transformers, but accidental shorted turns
formed by clam-shell styled cabinets and cases. Any
conductor that forms a loop and is in the transformer
field can act as a shorted turn. I have seen this
effect cause hum in audio equipment,distorted traces
on scopes and twisted rasters on TV screens.

Dave, VE1ADH

 --- Bill Fuqua <wlfuqu00 at uky.edu> wrote: > I tried to
sent the following with attachment to
> clear up the confusion 
> between the end bells or clam shells ( ferrous metal
> magnetic shields and 
> shorted turns. But due to size it bounced. I had
> pictures of a transformer 
> with shorted turns.  If you want to see the pictures
> email me and I'll send 
> you the attachments.
> 
> Mu metal is expensive and unnecessary. It is great
> for a light weight
> shield but soft steel (hot roll sheet) an 1/8 inch
> thick will do very well.
> What you need is to use the steel.  Clam shell
> shields are not
> shorted turns but iron (soft steel)  shields,
> shorted turns are thick pieces of
> copper strap that are wrapped around the core and
> windings and soldered
> together. These are the same width as the windings
> of the transformer
> and must be formed to be tight against the core and
> windings. A gap
> usually allows leakage.
> 	Attached are photos of shorted turn. Low resistance
> is absolutely 
> necessary. The copper strap is overlapped and then
> soldered to get lowest 
> resistance in the connection as possible
> 
> 
> 73
> Bill wa4lav
> 
> _______________________________________________
> TenTec mailing list
> TenTec at contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec 

______________________________________________________________________ 
Post your free ad now! http://personals.yahoo.ca