Somebody recommended a line filter Schaffner FN2010-20-07 for a noisy
appliance. Thank you.
We moved to a new QTH with relatively new appliances. Fortunately the,
HVAC, dryer and washing machine are RF quiet despite variable speed DC
motors.
The high end Kitchenaid dishwasher was another story. (High price = high
RFI ?) It generated noise 30 db above ambient. Looking at the
schematic, it's clear why. Lots of triacs and motors with speed
controllers. No line filtering except for one ferrite bead (one turn)
wound around the hot side of the AC line.
We first tried ferrites on most leads. This helped about 10 db. Not
enough.
Then we went to the Schaffner filter with the ferrites. It dropped the
noise to 1-2 db above ambient and occasional spikes a few dB higher.
Nice. Now to go back and try and recover some of the ferrites.
I don't know what the incremental cost of such a filter/filter design
would be. For a $1K+ diswasher, it should have been included.
73 DE Brian/K3KO
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