> Hi Topbanders,
>
> Are there any particular brands or specific models of dimmer
> switches(!!) that don't pollute our low frequency bands with RFI?
>
> 73,
> Charlie, N0TT
>
Yes, there are. The problem is that there are so many styles and models of
dimmers---rotary knobs with switches at the CCW end or with push-in
switches, sliders with or without switches, and toggles. There are single
and double pole dimmers, 600W and 1000W (and more) dimmers, dimmers for
low-voltage lighting, designer dimmers, and so on. I think you get the
picture.
Generally, the "good" units include small ferrite beads and maybe
capacitors, and often the product description will mention the RFI
protection in some way. Unfortunately, such switches often have a (small)
added cost increment--so most people, unaware of what RFI is and why they
should be concerned, buy price and get the cheapest units from Ace Hardware.
Several years ago, I made up a test jig with a bunch of different dimmers
and a 100W bulb, and put a portable AM radio next to the kludge. To achieve
a meaningful comparison, all were single-pole, rotary knob, 600W
incandescent units---the most common denominator. I think I had a
representative sampling---by no means was it comprehensive.
The difference between these dimmers in terms of RFI was quite
significant---stunning, really. My hands-down favorite for a plain vanilla
rotary 600W single-pole incandescent application was and is the Lutron
"Traditional" D-600 series. Lutron claims "superior radio frequency
interference (RFI) filtering" and I agree.
I have since placed a half-dozen of these in neighbors' homes. To find the
offending RFI generator, I walk the neighborhood with a portable AM radio
tuned to the top of the BC band. The buzzer will often just leap out at me
as I walk past a house. Most folks, when I explain my mission, allow me to
replace their units, but there is a possible liability factor involved in
not being a licensed electrician.
W.W. Grainger sells the D-600's for $5.14 in singles. Their stock number is
4LX92 (white) or 4X603 (ivory). The 3-way versions are the D-603 series:
Grainger numbers are 4LX93 (white) and 4X852 (ivory) @ $7.84.
There are also Lutron toggle (AY-600 single-pole and AY-603 3-way) and
slider (GL-600 single-pole and GL-603 3-way) units in that series. These
cost a LOT more ($12.12 for the GL-600 to $54.90 for a 1000W 3-way toggle
unit), so I don't even consider them for freebie replacements. Ditto the
"Designer" Series, which run from $16.26 to $91.45! As if these were not
enough, there are High Power dimmers (to 2000W) which generally sell to
commercial and public space applications and which can cost hundreds of
dollars eaach.
The relevant pages in the huge and wonderful Grainger catalog are 879-882. A
whole tree died for each one of these.
The standard disclaimers apply---I have no personal interest in Grainger or
Lutron. But Grainger is a toystore for adult males, fer sherr.
Aren't you glad you asked? :-)
Garry, NI6T
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