[Amps] Re: 12V 120A Switching Power supply?

[Steve Katz]

> Hi Jeff.
> I had the same experience buying a CE certified supply.
> 
> ::Note: There is no such thing as a "CE certified" supply, or any other
> product.  CE is an acknowledgement program by which manufacturers "self
> certify" that they abide by rules written by CENELEC for products sold in
> the European Union, and there are many rules that may or may not apply,
> depending upon the nature of the product sold.  For Information Technology
> Equipment, CE elements which apply include the Low Voltage Directive for
> product safety, as well as several elements pertaining to radiated &
> conducted emissions, and radiated & conducted immunity.  In terms of
> performance, "CE Mark" means very little.  And, truth be told, it means
> even less since there is no governing agency or official body auditing the
> products that are so marked.
> 
> 
> Compliance emissions testing must have been done without any wire
> attached to the output leads! As soon a a wire was applied , it sang
> like a bird.
> How did thet expect you to draw power without wire?
> 
> 
> ::For one thing, radiated and conducted emissions test performance is only
> over a range of frequencies that may or may not impact your actual use and
> application.  Normally, for power supplies the range is 300 kHz to 1 GHz,
> and the tests are performed on a 10 meter range or equivalent calibrated
> anechoic chamber, and the standards are quite loose.  Further, it is
> totally possible to "certify" equipment which requires outboard, accessory
> filtering in order to meet the standards, as long as that accessory
> filtering is specified in the engineering specification for the equipment
> being sold.  For example, a manufacturer may fail to meet radiated
> emissions standards per EN 55 022, but if he can meet the standard by
> applying a $10,000 filter network in the output leads of the power supply,
> and stipulates that in the test report and the operating manual or
> engineering specification, that would be acceptable.
> -WB2WIK/6
> 
> ---
> Ron