Hi Dave
Like the mess that is "open frame power supplies"
These power supplies were allowed to be sold with no filtering because the OEM
manufacturers and equipment builders would install filtering when they use
these power supplies. Who installs filtering? The answer is nobody!
Today they are sold in consumer big box hardware stores and 1 dollar shops
with no filtering for use by consumers to power their garden lights, pumps,
tools and everything else on the planet.
I have never seen a open frame power supply that was installed with the
required filtering. I doubt that the law s will be changed to forced the
manufacturers to install these filters as part of the open frame design rather
than making it optional or having no recommended filter designs available that
will meet the spirit of the EMC laws.
I am dealing with one neighbour at the moment who ran new garden lighting with
one of these cheap Chinese open frame power supplies that wipes out a chunk of
spectrum from 7 through to 30mhz with a string peak at around 20 and 21mhz. The
lawmakers should have seen this happening.
73
Craig
VK3OD
""
"" Fast forward a year or so. Same publication. Now EE Times was covering
the RFI caused by their newest baby, switch mode power conversion units.
It was major. Then another 6 or so months, all kinds of articles on how to
tame the RFI from SWPSs.
Something similar needs to occur with the present mess associated with wall
warts and, in general, even more switch mode power conversion units.
Dave - WØLEV
Retired EMC/RFI Engineer
EMC Design & Test, LLC "
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