I experienced exactly that oscillatory behavior when multiple LED fixtures were
connected to ANY model of dimmer. The problem was induced by adding commercial
EMI filters to each fixture. There was no time to investigate the exact nature
of the interaction. My guess is that the switching frequencies of each fixture
were beating against one another, which appeared as low-frequency cyclical
changes in line voltage. The dimmer apparently responds to that. But it’s only
a guess… A Lutron dimmer was one of three brands tested and all behaved the
same. Ultimately, we removed the EMI filters and replaced them with CM chokes.
Everything worked properly but the RFI suppression In that case was not nearly
as effective as with the EMI filters.
Here’s a detailed report on a particular Lutron dimmer:
https://na6o.com/main/RFI_files/Lutron_Diva_Dimmer_Switch.pdf
I found it’s RFI generation to be unacceptable on the low bands. No way to know
if other/later versions are similar without testing.
Gary NA6O
> On Mar 11, 2022, at 7:30 AM, rfi-request@contesting.com wrote:
>
> From: Dan K2YWE <dan.k2ywe@gmail.com>
> To: Rfi List <RFI@contesting.com>
> Subject: [RFI] Dimmer Behavior
>
>
> I just replaced a chandelier that had 5 LED candelabra base 4-element LED
> lamps in it (the ones shaped like flames). It worked fine for years with
> our ancient Leviton dimmer (up-down buttons and little leds) using a mix of
> GE and Feit LED lamps.
> The replacement chandelier has only 4 sockets. I put in the same LED lamps
> and the dimmer just continuously cycles the lights from bright to dim. If I
> remove one of the four lamps it behaves normally. The brand of the three
> doesn't seem to matter.
> If I put in a Feit in the 4th slot it stays unlighted but the other three
> work fine. If I put a GE in the 4th slot I get the cycling behaviour. An
> incandescent 4th lamp makes everything work normally.
> Clearly the old dimmer can't handle the 4 LED loadline.
> I need a recommendation for a modern LED friendly dimmer that is known to
> be EMI-Free, I operate 160m-6m.
> 73, Dan
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|