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Toroidal Transformer Screening

Started by Syd Rumpo July 17, 2015
On 7/20/2015 1:20 AM, Tim Watts wrote:
> On 20/07/15 03:15, John S wrote: >> On 7/19/2015 9:14 PM, John S wrote: >>> On 7/19/2015 8:13 PM, Robert Baer wrote: >>>> Syd Rumpo wrote: > > >>>> OK, i will bite: what is Edward Current? and where do i get a >>>> description? >>>> The quacker DuckDuckGo fails. >>>> >>> >>> He is using the formal name rather than the nickname (Eddie). >> >> Oops! Should be Eddy. >> > > I thought it was rather clever!
Me, too. I wish I had thought of it. In fact, I did and from now own it's mine.
John S wrote:
> On 7/19/2015 8:13 PM, Robert Baer wrote: >> Syd Rumpo wrote: >>> Hi >>> >>> Another magnetics question! >>> >>> I have a SMPS which uses a toroidal ferrite transformer. It switches at >>> ~100kHz, works very well, it's not my design and I can't change it. >>> >>> However, it introduces noise at about 50kHz onto/into my electronics >>> which causes a problem. After much experimentation, I found that putting >>> an earthed screen around the transformer kills the problem quite >>> dramatically. The screen must be earthed, and doesn't need to be >>> magnetic. >>> >>> This is something I can do. I don't have much room but I guess that >>> wrapping copper tape around its exposed enamelled wire will cause >>> problems for Edward Current. Is there a rule of thumb for what sort of >>> gap to leave between the windings and a screen? How quickly does the >>> field drop off? >>> >>> (And yes, I know not to make a shorted turn.) >>> >>> Cheers >> OK, i will bite: what is Edward Current? and where do i get a >> description? >> The quacker DuckDuckGo fails. >> > > He is using the formal name rather than the nickname (Eddie).
Thanks. Kissing cousin of Mister Justin Case..