[RFI] Autopsy on a Lutron dimmer

Dale svetanoff at earthlink.net
Mon Dec 2 10:32:05 EST 2013


Thanks for the comments.  Getting some inside info like that is excellent (except for stock trading, of course!) and tends to lend some credence to the performance that users have observed.  BTW: Yes, components and techniques used to reduce erratic operation or to improve protection from line surges and transients will, in most cases, reduce emissions, too.

I should also mention that I have a partial error in my original posting: I said that the .01 mfd cap is likely in  series with the inductor.  I think it is electrically in series with the inductor, but NOT in series with the load.  The inductor is surely in series with the load because it is wound with what appears to be #20 or #18 AWG magnet wire.  Without pulling the unit totally apart, I believe that one end of the cap is between the load and inductor (or line and inductor - it depends upon which lead the user connects to whichever wire in the wall box) and the other end goes to the other user connection.

I guess that's what I get for filing late night autopsy reports.

73, Dale

-----Original Message-----
>From: Charlie Gallo <Charlie at TheGallos.com>
>Sent: Dec 2, 2013 6:20 AM
>To: Dale <svetanoff at earthlink.net>
>Cc: rfi at contesting.com
>Subject: Re: [RFI] Autopsy on a Lutron dimmer
>On 12/2/2013 Dale wrote:
>> RFI Fans and Victims,
>> Some weeks back, Jim Brown, K9YC, asked for input on what brand of
>> dimmers seemed to create the least amount of RFI.  The consensus,
>> supported (in part) by me, was that Lutrons seemed to be pretty
>> quiet.  All of my in-service dimmers are Lutron brand.
>I have a good friend who used to (a couple of years back) work for Lutron writing software, but over in engineering.  There is/was a known problem with the plastic on the Diva lamps of a certain era, so you might have been able to get a replacement.
>That said, he says they are VERY VERY EMI/FRI aware, in BOTH directions (emissions and susceptibility).  Says they have a bunch of RFI carts that are used to both test new designs, AND submit new designs and production samples to RFI!  Says they have gone around the country recording RFI and then submitting their dimmers to recreations, to make sure they hold up.  What he said is they have found that making them not fail to anything they can throw at them tends to also make them very rfi quiet
>73 de KG2V - Charles Gallo
>Quality Custom Machine-shop work for the radio amateur (sm)

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