Dale,
I've got quite a few CFL's here also and have not found them to be a RFI
producer yet. I had one out in the garage which did interfere with a wireless
intercom that used the power line for the communication line. Whenever that
CFL was on the intercom was not useable. I have two CFL's in my shack luxo
lamps right above the rigs and they are RFI quiet. They are turned on for
hours at a time so they save quite a lot in electricity.
Your idea of marking the CFL's is a good one. I will start doing that too.
73
Dale, k9vuj
On 21, Jan 2011, at 13:55, Dale Svetanoff wrote:
> Fellow RFI/EMC folks,
>
> I thought I'd provide some update information on two oft-discussed topics on
> this reflector: CFLs and LEDs. Here goes.
>
> First, I just purchased a set of 5 CFLs to relamp the light bar in my master
> bedroom bath. I had 5 conventional 60 watt "globe" lamps in there that have
> worked well for the purpose, but not only do they suck up 300 watts of
> energy, they deliver just as much heat. Over the past 3 or 4 years, I have
> replaced many standard bulbs with CFLs of varying lumen ratings and been
> mostly happy with both performance and CFL life. I have had zero RFI issues.
> My chief reason for installing CFLs is to reduce heat load on the A/C system
> in warm weather, with reduced power consumption running a close second.
>
> I mention these 5 lamps because of what they are and what the manufacturer
> says about them. Please take note: The bulbs are marketed by Feit Electric
> of Pico Rivera, CA. They are called "Ecobulb Plus" and are listed as 60 watt
> equivalents, drawing 15 watts, delivering 800 lumens, with an estimated life
> of 8000 hours. (These specs are for each bulb.) The home use warranty is
> for 2 years, and the cost was $4.88/each. A prominent note on the side of
> the box discusses "Proper CFL Usage". I quote: "Globe-shaped covered twist
> CFLs are best suited for fixtures that are left on for 15 or more minutes at
> a time." The rest of the statement deals with airflow, no use of dimmers,
> and so forth. I typically run those bathroom lights for about 30 minutes at
> a time at least twice per day. A small print notice on the bottom of the box
> says that "this product complies with Part 18 of FCC rules but may cause
> interference with radios, televisions, wireless telephones and remote contr
ol
> s." Note that Part 18 addresses ISM devices, which does include intentional
> emitters. I presume that the reference to remote controls is to RF-type
> remotes, as opposed to the more common IR ones.
>
> This is the first time, in my CFL-buying experience, that I have seen a
> manufacturer actually state the recommended operating conditions on the bulb
> packaging. I've checked my other in-stock bulbs, and no, none of them make
> that statement. I have saved my sales receipt and the proof of purchase for
> each bulb, just in case they don't last 2 years in my application. I might
> add that my normal routine with new CFLs is to use a fine-tip marker and
> place the date of first use on each bulb (near the base, so that if it dies
> early, I'll know. (I have a CFL flood lamp that was installed on 1-31-09 and
> died on 8/20/10. The 3 others I installed at the same time are still
> running.) As for RFI, I don't expect any, but then again, I'm not usually
> running those lights while operating.
>
> A final CFL note: I ran a test this morning that I should have run long ago,
> but just never found the round-tuit. I have a Teac AM-FM tuner in the family
> room as part of my eclectic stereo system. (It's a blend of ancient and
> modern components, with the heart being a Dynaco PAS-2 pre-amp fresh from the
> 60's.) The AM part of the tuner uses a factory-supplied wire loop antenna
> (no ferrite core) that is mounted on a hinge so that the user can pivot the
> loop (in a vertical plane) to adjust for best reception. Now that my power
> line issues are gone (for the moment, anyway), I can enjoy "armchair"
> listening to the major Chicago AM stations that are located about 150 miles
> or so to the east. I first tuned in WBBM-AM on 780 kHz and noted usual band
> noise, but no significant arcs or buzzes. I then switched on the 2 separate
> groups of CFLs (in ceiling fixtures) which light the shared area that
> includes both the family room and the kitchen (divided by a breakfast
> counter). No c
ha
> nge to what I heard. Then I switched on the wall plate dimmer that controls
> the set of 4 incandescent bulbs (3 @ 40 watts and 1 @ 60 watts) hanging
> beneath the family room ceiling fan. Aaahh - that familiar old buzz-saw
> sound! I might add that the dimmer, which was installed by the builder's
> electrician, is rated as having an RFI filter! Bottom line: the CFLs are
> "clean" enough for AM BC band use.
>
> Quick note on LED lights: I recently received an interesting booklet from
> Digi-Key under their "techzone" magazine name. The publication appears to be
> partly sponsored by Cree Technology, a major maker of LEDs and related
> systems. There are several articles within dealing with the major topics
> related to LED lighting technology, including power supplies, thermal issues,
> and achieving color balance. I am not quite certain how I got this copy sent
> to me, I strongly suggest that anyone interested try contacting Digi-Key to
> see if you can get one for yourself.
>
>> From the RFI perspective, one of the more interesting articles was
>> contributed by National Semiconductor and is entitled "Driving LEDs: To Cap
>> or Not to Cap". Huh? Well, what the title refers to is to use (or not use)
>> capacitors on the output side of the switching power supply that is integral
>> to LED lamp array operation. Not surprisingly, LEDs work best with constant
>> CURRENT power sources, and the article talks about the design of buck-type
>> converters that deliver constant current performance AND which offer dimming
>> control! Here is the catch: you can not dim the LEDs using the wall plate
>> dimmers as discussed above in the CFL discussion. The dimming control
>> signal must go directly to the pulse width modulator ("PWM") ship in the
>> power supply. If output caps are not used, the limiting factor in the buck
>> converter design becomes the series inductor, and that allows more precise
>> control of brightness than if there are filter caps after that inductor.
>> So, where are th
es
> e LED dimmers used? In products, such as displays, not in general lighting.
> The article also mentions that typical operating frequencies for these buck
> converters are in the range of 50 kHz to 2 MHz.
>
> Hope these comments help. Disclaimer: I have no financial interest in any
> product or supplier mentioned.
>
> 73, Dale
> WA9ENA
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|