Re: Rf problem


David Cutter
 

Hi Chris 

What type of core do you recommend?  How many turns?

David

G3UNA

On 01 May 2019 at 16:37 Chris Moulding <chrism@...> wrote:

Hi David,

I had exactly the same problem you have.

We have a Samsung fridge freezer that radiated a lot of RF noise. The problem is that to increase energy efficiency it uses a switch mode inverter power supply to power the fridge and freezer refrigeration units and the internal fans. In our case the inverter is mounted in a metal box on the top of the fridge freezer so that the mains cable hangs down from it making a pretty good antenna for radiating RF noise.

In our case I fitted one of our Mains Filter units to the mains cable. This stopped the RF noise getting into the rest of the house wiring. I had to add an extra three clip-on ferrite cores to the mains cable directly where it runs into the box on the top of the fridge freezer to clear the rest of the noise radiating from the mains cable. Testing with the three ferrite cores on their own the RF noise levels were still too high and it needed the combination of Mains Filter and ferrite cores together to bring the noise down to a workable level.

The fridge freezer is situated about 3m from the end of my Terminated Inverter U antenna so it was a severe test for the Mains Filter and extra ferrite!

Regards,

Chris

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